A FORENSIC INVESTIGATION OF PAVEMENT PERFORMANCE ON INTERSTATE 86 IN OLEAN, NEW YORK. A thesis presented to. the faculty of

Transcription

1 A FORENSIC INVESTIGATION OF PAVEMENT PERFORMANCE ON INTERSTATE 86 IN OLEAN, NEW YORK A thesis presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Master of Science Charles S. Swart August 2006

2 This thesis entitled A FORENSIC INVESTIGATION OF PAVEMENT PERFORMANCE ON INTERSTATE 86 IN OLEAN, NEW YORK by CHARLES S. SWART has been approved for the School of Civil Engineering and the Russ College of Engineering and Technology by Shad M. Sargand Russ Professor of Civil Engineering Dennis Irwin Dean, Russ College of Engineering and Technology

3 Abstract SWART, CHARLES S., M.S., August 2006, Civil Engineering A FORENSIC INVESTIGATION OF PAVEMENT PERFORMANCE ON INTERSTATE 86 IN OLEAN, NEW YORK (151 pp.) Director of Thesis: Shad M. Sargand Four test sections of the jointed reinforced concrete pavement (JRCP) on Interstate 86 in Olean, NY will be rehabilitated using various methods. To compare the results of these techniques with the pavement s initial condition a detailed forensic investigation was performed. Non-destructive tests were conducted with distress surveys, the Falling Weight Deflectometer, and Georgia faultmeter, along with destructive testing by using the dynamic cone penetrometer and removing concrete cores. Data gathered were used to inspect the quality of the base materials and the concrete slabs and joints. Opened in 1972, I-86 has had no rehabilitation outside of minor asphalt patching and crack sealing. Because of this the JRCP exhibits an array of distresses, of which faulted transverse cracks and corner breaks were the most prominent. The pavement condition index (PCI) was determined for each test section using ASTM D , while the functionality of the pavement was modeled using ACPA Pavement Analysis Software and the FHWA Rigid Pavement Design Program. The results of these analyses verified the need for rehabilitation of this pavement and allowed for predictions to be made for the next phase of testing. Approved: Shad M. Sargand Professor of Civil Engineering

4 Acknowledgements I would like to thank Shad Sargand, Ph.D., P.E. for supplying me with the opportunity to attend graduate school at Ohio University. The assistance given by him and the ORITE and NYDOT employees, especially Mr. Michael Krumlauf and Julian Bendaña, Ph.D., P.E., made this research possible. I sincerely thank Mr. Issam Khoury for his leadership throughout the duration of graduate school. If I gleaned even onequarter of his fervor and knowledge my personal expectations will be exceeded. Lastly, I am deeply indebted to my parents, Charlie and Sandy, and my girlfriend Ashleigh. Without their continuing support I would never have been able to endure the rigors of the program and the adjustments made in my life.

5 Metric Conversion Factors When You Know Multiply by To Find Length inches (in) 25.4 millimeters (mm) feet (ft) meters (m) Mass pounds (lb) kilograms (kg) Pressure pounds/inch 2 (psi) Pascal (Pa) Density pounds/inch 3 (pci) kilograms/meter 3 (kg/m 3 ) Speed miles/hour (mph) kilometers/hour (km/hr)

6 6 Table of Contents Page Abstract....3 Acknowledgements..4 Metric Conversion Factors...5 List of Tables...8 List of Figures..9 Chapter 1: Introduction General Statement Literature Review Objective Thesis Outline..21 Chapter 2: Project Background General Information Pavement Background Information Geotechnical Background Information Traffic Background Information Project Summary..27 Chapter 3: Testing and Results Non-Destructive Testing Distress Survey Testing Procedure Descriptions of Distress Types Results of Distress Surveys Falling Weight Deflectometer Testing Procedure Results of Falling Weight Deflectometer Testing Georgia Digital Faultmeter Testing Procedure Results of Georgia Digital Faultmeter Testing Destructive Testing Dynamic Cone Penetrometer Testing Procedure Results of Dynamic Cone Penetrometer Testing Concrete Core Removal Testing Procedure Results of Concrete Core Removal Testing...66 Chapter 4: Pavement Analysis Pavement Condition Index Procedure.68

7 4.2 Pavement Condition Index Results Pavement Analysis Software Procedure Pavement Analysis Software Results Rigid Pavement Design Program Procedure Rigid Pavement Design Program Results 83 Chapter 5: Conclusions and Recommendations Conclusions Recommendations 88 References Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H Appendix I NYDOT Subsurface Log Data...92 Distress Maps.94 Normalized D f0 Plots 106 Revised Normalized D f0 Plots..109 Average Spreadability Plots.111 Georgia Digital Faultmeter Plots.116 Dynamic Cone Penetrometer Blows Versus Depth Plots 120 Dynamic Cone Penetrometer Penetration Index Versus Depth Plots..128 Dynamic Cone Penetrometer Modulus of Resilience Versus Depth Plots.136 Appendix J Appendix K Pavement Condition Index Distress Summary Spreadsheets..142 Rigid Pavement Design Program Input Screens..145

8 8 List of Tables Page Table 2.1 Test Section Details Table 3.1 Sensor Spacing for I-86 FWD Testing..38 Table 3.2 Average Load Transfer Efficiencies. 49 Table 3.3 Average Joint Support Ratios...50 Table 3.4 Locations of DCP Testing..60 Table 4.1 Distresses and Deduct Values, Section Table 4.2 Corrected Deduct Values for All q, Section Table 4.3 PCI Results Summary 73 Table 4.4 Results of Pavement Analysis Software 77 Table 4.5 Estimated General Input Values 79 Table 4.6 Estimated Traffic Input Values..81 Table 4.7 Estimated Faulting Check Input Values 82 Table 4.8 Comparison of Rigid Pavement Design Program Service Life Analyses

9 9 List of Figures Page Figure 2.1 New York I-86 Eastbound Test Sections Figure 2.2 Rubblized (a) and Cracked and Seated (b) Concrete 24 Figure 2.3 Subsurface Exploration Log, Station Figure 2.4 AADT Growth for I Figure 3.1 Distress Map for Section 3, 300 to Figure 3.2 High Severity Corner Break, Section 1 30 Figure 3.3 High Severity Transverse Crack, Section Figure 3.4 Low Severity Longitudinal Crack, Section Figure 3.5 Low Severity Flexible Patch/Patch Deterioration, Section Figure 3.6 High Severity Longitudinal Joint Spalling, Section Figure 3.7 Area of Scaling and Multiple Popouts, Section 2.34 Figure 3.8 Severities of Transverse Cracking in Test Sections.35 Figure 3.9 Severities of Corner Breaks in Test Sections...36 Figure 3.10 NYDOT KUAB Falling Weight Deflectometer.37 Figure 3.11 KUAB FWD Sensors During Data Collection Figure 3.12 Diagram of Sensor Arrangements for FWD Testing..38 Figure 3.13 Normalized Section 1 FWD D f0 Deflections, Figure 3.14 Revised Normalized Section 1 FWD D f0 Deflections, Figure 3.15 Normalized Section 4 FWD D f0 Deflections, Figure 3.16 Normalized Section 2 FWD D f0 Deflections,

10 10 Figure 3.17 Average Spreadability for Both Testing Dates, Section Figure 3.18 Average Spreadability for Each Section. 46 Figure 3.19 Average Pavement Temperature During FWD Testing Periods 46 Figure 3.20 FWD Sensor Placement at Joint Approach 47 Figure 3.21 FWD Sensor Placement at Joint Leave..47 Figure 3.22 Load Transfer Positioning with ODOT Dynatest FWD.48 Figure 3.23 ORITE s Georgia Digital Faultmeter.51 Figure 3.24 Extent of Transverse Crack Faulting, Section 1.53 Figure 3.25 Extent of Transverse Crack Faulting, Section 3.53 Figure 3.26 Transverse Crack Faulting Profile, Section 1.54 Figure 3.27 Transverse Crack Faulting Profile, Section 3.54 Figure 3.28 Extent of Transverse Crack Faulting, Section 4.55 Figure 3.29 Transverse Crack Faulting Profile, Section 4.55 Figure 3.30 Faulting of Transverse Joints, Section 1.56 Figure 3.31 Faulting of Transverse Joints, Section 3.57 Figure 3.32 Lane-to-Shoulder Dropoff, Section 1.58 Figure 3.33 Lane-to-Shoulder Dropoff, Section 2.58 Figure 3.34 ORITE s Vertek Automated Dynamic Cone Penetrometer...60 Figure 3.35 Blows vs. Depth, Station Figure 3.36 PI vs. Depth, Station Figure 3.37 Modulus of Resilience, Station Figure 3.38 Resilient Modulus for Station , Section 3..64

11 11 Figure 3.39 Resilient Modulus for Station , Section Figure 3.40 Resilient Modulus for Station , Section Figure 3.41 Variation of Concrete Core Thicknesses 67 Figure 4.1 Pavement Condition Index and Rating Scale...69 Figure 4.2 Corrected Deduct Values Chart, Section 1 Example 72 Figure 4.3 Pavement Condition Indices and Ratings of Test Sections..74 Figure 4.4 Pavement Analysis Software User Interface 76 Figure 4.5 Pavement Analysis Software Output for Heavy Impact Loading 77 Figure 4.6 Daily High and Low Temperatures for 2005 at Bradford, NY Regional Airport 83 Figure 4.7 Calculated Pavement Thickness vs. Design Traffic, 34 Year Analysis...84

12 12 Chapter 1 Introduction 1.1 General Statement Originally approved by Congress in 1944 the construction of a massive interstate highway system in the United States began in Envisioned to provide improved travel, interstate commerce, and the rapid movement of military equipment, the Dwight D. Eisenhower System of Interstate and Defense Highways was to consist of a total length of 42,500 miles and be finished by The network was not completed on time, but has since exceeded the original proposed length. (Cox and Love, 1996) After its 40 th anniversary in 1996 the overall performance of the entire highway system was assessed. Half of the interstate pavements had reached their design lives by 1985 while 90 percent of the system was twenty years or older by Since the 1950s the growth in the interstate highway system not even closely paralleled that of the population increase of nearly 100 million people. This leaves the nation with a continuously deteriorating and overextended roadway network, of which approximately 60 percent of these interstate pavements are rated from fair to poor in condition. (Cox and Love, 1996) This infrastructure of aging pavements does offer some worth, even if they are not functioning at their original design standards. A more desirable form of pavement rehabilitation, as opposed to complete reconstruction, is often the overlay procedure. In this rehabilitation process the existing pavement is covered with a new pavement layer. A variety of overlay methods exist with specific types performing better for different

13 13 pavement conditions. Research is still being conducted to determine the response of specific overlays under these differing pavement conditions. In order to compare the performance of the overlayed pavement to the existing pavement a forensic study is required. This provides the study with information on the pavement and subsurface conditions while suggesting the reasons for the pavement s distresses. 1.2 Literature Review The surface condition of a pavement is an important factor in determining how a driver perceives and reacts to the road, along with determining the safety level of the roadway. A 2004 paper entitled Road Surface Distress and Driving Performance presented the hypothesis that a decrease in pavement condition causes a decrease in driver comfortability. (Cafiso and Di Graziano, 2004) Their research began by visually conducting distress surveys, a single aspect of a full forensic study, to classify the pavements conditions at the testing locations. The ratings given to the pavements were then used to relate the levels of distress to the driving performance imposed on users. In general, they claim, that when the pavement is in bad condition a driver tends to reduce their speed due to an increase in the perception of risk. (Cafiso and Di Graziano, 2004) Their research consisted of measuring the Pavement Condition Index (PCI) of each section. This process considers the distress distribution within a pavement section and assigns it a rating of 0 to 100, where 100 is the best condition attainable. Motorists were then surveyed using laser instrumentation to gain the mean speed and the 85 th percentile speed. This procedure was conducted both before and after maintenance work in order to compare the results gathered. (Cafiso and Di Graziano, 2004)

14 14 They concluded that a lower PCI does cause the driver to reduce their speed under certain conditions. On sections where the PCI was less than 50, indicating more evident surface distress, it was found that the drivers tended to lower their traveling speed. This included a maximum reduction, compared to the speed under good conditions, of up to 7% of the 85 th percentile speed and 11% of the mean speed. (Cafiso and Di Graziano, 2004) These results were localized in the passenger car category as they were not reproduced when heavy vehicles were studied. They deduced further that pavement distresses such as patching, longitudinal cracking, and transverse cracking, among others, caused for a medium level of driver conditioning. (Cafiso and Di Graziano, 2004) The correlation between pavement condition and driver response resulting from this study makes the need for a well maintained roadway surface apparent. It also shows the importance of conducting some form of distress surveys or forensic studies in order to continually monitor the quality of the pavement. A distressed pavement may warrant the option of using an overlay for rehabilitation. One such rehabilitation procedure performed on Portland cement concrete (PCC) is cracking and seating, described in Performance and Structural Evaluation of Cracked and Seated Concrete. (Ahlrich, 1989) In the cracking and seating process the existing concrete slab is broken into pieces that measure between 18 in and 36 in using a large impact force generated by various types of hammer devices. These pieces of concrete are then seated into the subgrade material using a heavy pneumatic roller. (Ahlrich, 1989) Cracking and seating is employed primarily to prevent the potential for existing cracks to reflect into the overlay material. The propagation of these cracks causes the

15 15 early deterioration of the overlayed pavement. Destroying the integrity of the pavement reduces the movement in the rigid layer thus reducing the effects of thermal stress at the joints. The broken pavement must still maintain aggregate particle interlock such that its strength is reduced but it still functions as a load carrying medium. (Ahlrich, 1989) It was determined that segments which were cracked to a size less than 12 in may cause spalling and loss of structural strength. During the cracking and seating process areas of weakness quickly became evident. Punch throughs in the PCC and rocking of the PCC slabs indicated the pavement was in need of repair. In these cases the pavement was removed and replaced by full depth asphalt or base course. (Ahlrich, 1989) Analysis of these test sites using the Falling Weight Deflectometer (FWD) showed a reduction in the elastic modulus of the subgrade and the cracked and seated concrete. This indicated a higher stress being applied to the top of the subgrade because of the reduced strength of the concrete. With each asphalt overlay, meanwhile, the modulus values for both the concrete and the subgrade increased consistently. (Ahlrich, 1989) The research and data presented in Field Performance of Crack and Seat Projects draws more conclusions on the cracking and seating process. (Carpenter et. al., 1989) In this study data from existing crack and seat projects located in various areas of the United States was compiled. These projects all dealt solely with asphalt overlays of cracked and seated jointed plain concrete pavement (JPCP) and cracked and seated jointed reinforced concrete pavement (JRCP). Their subgrade results correspond with those presented by Ahlrich as they concluded better subgrade support permits larger cracked pieces to be produced in the cracking operation. Better performing overlays tended to be in areas with milder

16 16 climates, such as California and Florida, and were not necessarily the thickest. (Carpenter et. al., 1989) It was also found that in areas with larger annual rainfall less low severity cracks developed while more medium and high severity cracks were prevalent. This was probably due to the moisture causing a lower support in the subgrade that facilitated the breakdown of existing cracks. (Carpenter et. al., 1989) This study noted that the overlays of JRCP tended to develop more high and medium severity cracking while the JPCP overlays exhibited much more low severity cracking. It was hypothesized that this was due to the smaller joint spacings not permitting deterioration in the reflective crack. (Carpenter et. al., 1989) This may not be entirely valid since the data shows the average age, traffic loads, and percent trucks of the JRCP being greater than that of the JPCP. It was further suggested that during cracking of reinforced concrete the steel must be ruptured. If this is not attained then the broken slab will still operate as a single unit and transmit reflection cracks. (Carpenter et. al., 1989) It should be noted that this research was done without a full forensic investigation prior to the overlay procedures. The text suggests that there are five basic data types required to develop life prediction models and for analysis. These are field condition data, in situ conditions, rehabilitation design factors, historical traffic values, and environmental data. (Carpenter et. al., 1989) Many of these parameters can be determined by way of a thorough forensic investigation. The lack of forensic data in this study precluded the correlation between the previous pavement conditions and those after rehabilitation. It is suggested further that without deflection testing, part of a complete forensic study, there is no way to truly evaluate the cracking operation beyond

17 17 recognizing the size of the cracked pieces. (Carpenter et. al., 1989) Judging by these recommendations the need for the forensic investigation process when conducting overlay research is mandated. Another often used rehabilitation method for concrete pavements is called rubblization. The benefits and drawbacks of the rubblization process are described in Rubblizing of Concrete Pavements: A Discussion of its Use. (ACPA, 1998) Rubblization is also mainly employed to reduce the effects of reflective cracking on the overlay. This procedure differs slightly from crack and seat in that rubblization essentially pulverizes the existing concrete pavement. The concrete fragments range from sand size to 8 inches in width, effectively reducing the pavement layer to a base course. (ACPA, 1998) A specific case study within this American Concrete Pavement Association s (ACPA) report showed an asphalt overlay of rubblized JRCP. Two asphalt thicknesses were used, 4 in and 8 in, and both were determined to be controlling reflective cracking early on. They both eventually began incurring other distresses such as longitudinal and fatigue cracking, though the 8 in overlay performed better than the 4 in. (ACPA, 1998) Background data within the report for this project was lacking and other factors may have contributed to these problems, so it was impossible for the reader to draw any other conclusions. This report also discussed the infrequently used procedure of rubblizing with a concrete overlay. It claims that because of the integrity of the concrete overlay it operates as a better long term solution as compared to an asphalt overlay. (ACPA, 1998) Suggestions regarding the design procedure for this option were also provided. It is

18 18 recommended that the overlay be designed as a new concrete pavement on an improved granular base with a higher modulus of subgrade reaction, k. The modulus value of the slab is determined, this is converted to a corresponding k-value, and the overlay is designed using the improved k-value. A complication of design is that a wide range of backcalculated modulus values exist and may vary as much as 40% within a project. (ACPA, 1998) Though this entrains variability into the design procedure, if done properly it has been proven to be effective. A forecast for new technology in pavement condition analysis is available in the National Cooperate Highway Research Program s (NCHRP) Automated Pavement Distress Collection Techniques. (NCHRP, 2004) A set of guidelines for pavement distresses were established by the Long Term Pavement Performance (LTPP) program s distress identification manual in Visual distress surveys are still frequently conducted manually, but the technology to implement automated data collection is becoming more applicable. Analog imaging procedures such as using 35 mm film for pictures or video recording can be used, but are not easily converted to a digital format. Because of this digital imaging is quickly becoming the preferred method to record distress data. Data collected digitally is advantageous since it is able to be reduced through automated methods. Distresses can be identified by recognizing a variation in grayscale in the digital file. (NCHRP, 2004) Roughness, or ride quality, of a pavement is typically used to indicate the functional capacity of a pavement surface. An international roughness index (IRI) is now able to be determined by vehicles equipped with accelerometers and some form of laser, acoustic, or infrared sensor. The accelerometer establishes a horizontal reference plane

19 19 while the sensor measures surface deviations in the pavement based upon this horizontal plane. (NCHRP, 2004) The measurement of joint faulting in concrete pavements can now be automated as well using the same technology as for roughness determination. In this procedure a 300 mm sensor width covers each side of a joint, both the end of the approach slab and the beginning of the leave slab. (NCHRP, 2004) Since joint faulting is simply measured as the difference in elevation between these two points a sensor reading is taken at a single point before and after the joint. Though a threshold of faulting of 5 mm using this procedure is less than that attainable by manual methods, the ease and data collection abilities of the automated procedure make it preferable. (NCHRP, 2004) A benefit of having a fully automated system would be the development of a vast and easily accessible database containing pavement condition data. Road networks could be continually monitored without the time consumption inherent in manual data collection. This would greatly enhance the effectiveness of maintenance on the roadways. In most operations a certain pavement condition rating is typically set to determine when rehabilitation is necessary. If this information was able to be gathered by a single pass from a vehicle then the rehabilitation process could be implemented almost immediately. This is contrary to the manual system which infrequently, if ever, conducts surveys to gain this knowledge. Rehabilitation procedures are then often enacted too late which may cause for a design that is less than adequate. Rehabilitation, as opposed to the complete reconstruction, of an aging pavement is typically an appealing alternative. Studies show this is a cost effective (ACPA, 1998; Carpenter et. al., 1989) and less labor intensive method of returning the pavement

20 20 structure to a level of higher serviceability. Because of the multitude of possible circumstances research is still being conducted to determine the best overlay procedures for specific pavement and subgrade conditions. An integral part of maintaining the effectiveness of this information is through the use of forensic investigations. The data collected in these studies proves to be invaluable when assessing the performance of a specific overlay type compared to the pavement s original conditions. 1.3 Objective This thesis intends to display the relevance of the data collection and analysis in regards to the condition of the pavement. Through this work the causes of such pavement distresses are predicted and their effect on the pavement s condition is discussed. The necessity of an in depth forensic study such as this is validated by the generated results. The outcome of this thesis will provide for the eventual correlation between the information presented in this thesis and the data collected after the next steps in this research process are taken. 1.4 Thesis Outline This thesis, consisting of five chapters, is constructed so that the research methods employed are fully described. Their significance is confirmed through the use of specific procedures which enabled the drawing of certain conclusions. The thesis is outlined as follows:

21 21 Chapter 1 introduces the topics covered by this thesis. Chapter 2 provides background information on the project site as well as details regarding the existing pavement, soil, and traffic conditions. Chapter 3 describes the methods used in the forensic investigation to collect, analyze, and interpret data. The results of each specific test procedure are also discussed. Chapter 4 describes how the pavement s condition was analyzed using several programs and procedures. Chapter 5 provides a conclusion to this study as well as recommendations for continuing research.

22 22 Chapter 2 Project Background 2.1 General Information I-86 is a four lane divided interstate which traverses the southern tier of the state of New York in an east/west direction. The areas of testing, Figure 2.1, lie just east of Figure 2.1 New York I-86 Eastbound Test Sections. the city of Olean in Cattaraugus County, NY kilometers of the existing jointed reinforced concrete pavement (JRCP) roadway will be overlayed in both directions with 225 mm of asphalt pavement. Four test sections in the eastbound travel lane, however, will not share this same rehabilitation procedure. The existing concrete in these sections

23 23 will be subjected to different fracturing and overlay procedures. The locations, treatment methods, and overlay types of the test sections are shown in Table 2.1. These sections will then be instrumented and monitored using strain gauges, linearly variable displacement transducers (LVDTs), time domain reflectometry (TDR) moisture sensors, and thermocouples. Table 2.1 Test Section Details. Section Beginning Treatment Station Method Overlay Type No Treatment 75 mm AC, 225 mm PCC Rubblizing 75 mm AC, 225 mm PCC Crack and Seat 75 mm AC, 225 mm PCC Rubblizing with AC Overlay 300 mm AC Section 1 will receive no treatment and will be used as the control section to which the results of the others are compared. The existing pavement in Section 2 will be rubblized while the concrete of Section 3 will be cracked and seated; both are shown in Figure 2.2. These three sections will be overlayed with a 75 mm thick layer of asphalt concrete then followed with 225 mm of jointed plain concrete pavement (JPCP). Section 4 differs slightly from Section 2 in that it will be rubblized then completely overlayed with 300 mm of asphalt concrete.

24 24 Figure 2.2 Rubblized (a) and Cracked and Seated (b) Concrete. 2.2 Pavement Background Information The existing pavement structure consists of 229 mm (9 in) of JRCP with 18.3 m (60 ft) joint spacing and was completed in October of It is 7.3 m (24 ft) wide with 3.65 m (12 ft) wide lanes and has mesh reinforcement, transverse joint supports, and longitudinal joint ties. The only records available regarding the apparatus used for transverse joint support stated that it was an Acme two component malleable iron device. A search for any supplementary information on these pieces produced nothing more than the notion that the NYDOT seemed to be the only department to have implemented them. Shoulders for this interstate were 1.2 m and 3.6 m (4 ft and 11.8 ft) wide and were constructed with 76.2 mm (3 in) of bituminous stabilized course with 25.4 mm (1 in) of asphalt concrete top course placed over stabilized gravel. Aside from some asphalt patching and the sealing of large transverse cracks very little maintenance occurred over the duration of this roadway s service life. The field observations supplied by the NYDOT for this 34 year old interstate assert that the initial drive through of the project indicates a deteriorated pavement with poor rideability due to multiple transverse and longitudinal slab cracking and faulting. Various other distresses

25 25 are present in the wheel paths, longitudinal joints, and the transverse joints/cracks. Though the classification of these distresses is not quite accurate, as will be shown by the distress surveys in Chapter 3, the inferior quality of the pavement is adequately conveyed. 2.3 Geotechnical Background Information The NYDOT field observations further stated that there are noticeable settlements within the project limits. This would tend to indicate the presence of isolated subsurface deficiencies. Two locations of pavement settlement with suspected foundation problems were identified at Stations and Subsurface explorations were conducted by the NYDOT at these locations on September 5 and 6, This study found some organic and unsuitable soils below the highway embankment at both exploration locations. It was concluded that these soils probably consolidated under the weight of the highway embankment leading to the described settlements. The subsurface exploration logs also showed a m (21.6 in) thick layer described as Brown Sandy GRAVEL, Silty which was present in both sections just beneath the pavement structure. For the purpose of analysis, since initial plans for this roadway no longer exist, this will be assumed to be the entire non-permeable aggregate base layer. The geotechnical report also seems to imply drainage may have been a problem at these two locations, suggesting that during reconstruction the depth of the edgedrain trench should extend down to the bottom of the existing subbase course. Figure 2.3 displays the subsurface log from Station while the results for Station can be located in Appendix A.

26 26 Figure 2.3 Subsurface Exploration Log, Station Further geotechnical information was gathered by the dynamic cone penetrometer (DCP) and Falling Weight Deflectometer (FWD) analyses. Testing using these instruments and the interpretation of the generated data will be discussed in the following chapter. 2.4 Traffic Background Information It is suggested in the NYDOT brief that the one-way average annual daily traffic (AADT) volumes along this segment range from 8,800 to 11,200 vehicles per day. This AADT is comprised of between 14% and 25% trucks. The NYDOT website also provided some traffic counts upon which these estimates are based. Figure 2.4 shows the

27 27 AADT growth which spans from 1994 to This information will also be needed when modeling the pavement using the FHWA s Rigid Pavement Design Program in Section I-86 Traffic Growth AADT (veh/day) Year Figure 2.4 AADT Growth for I Project Summary The performance of these different overlay procedures will eventually need to be compared to one another. The forthcoming project required a condition survey in order to adequately accomplish this. A complete forensic investigation described in this thesis was necessitated to establish base conditions for all test sections. The study encompassed pavement condition and subgrade properties which existed prior to the scheduled rehabilitation of the four sections. This was conducted through non-destructive testing using the Falling Weight Deflectometer, the Georgia digital faultmeter, and distress surveys, as well as destructive testing using the dynamic cone penetrometer and concrete core removal.

28 28 Chapter 3 Testing and Results 3.1 Non-Destructive Testing Non-destructive testing (NDT) was performed to gain information about the existing pavement structure. This type of testing inflicts no permanent distress on the pavement. The NDT procedures carried out on I-86 included use of distress surveys, the Falling Weight Deflectometer, and the Georgia digital faultmeter. Their corresponding processes and results will be discussed in the following sections Distress Survey Testing Procedure On September 21 and 22, 2004 distress surveys were conducted over the first m (500 ft) of each of the four I-86 test sections. These were done in accordance with the Distress Identification Manual for the Long-Term Pavement Performance Program (LTPP), FHWA-RD (FHWA, 2003) Each recognized distress type was categorized using the LTPP distress symbols and recorded in the appropriate distress map as seen in Figure 3.1. The entire set of distress maps for the project is contained in Appendix B.

29 29 Figure 3.1 Distress Map for Section 3, 300 to 400. Within the four sections surveyed there was evidence of the following distresses: transverse and longitudinal cracking, corner breaks, transverse and longitudinal joint spalling, transverse joint faulting, popouts, patch/patch deterioration, and lane-toshoulder dropoff. All distresses are described completely in Section According to the LTPP procedure, low, moderate, or high severity levels were assigned for transverse and longitudinal cracks, corner breaks, transverse and longitudinal joint spalling, and areas of patch/patch deterioration. Popouts were simply counted, while scaling was quantified by the size of the affected area. Lane-to-shoulder dropoff and transverse joint faulting were measured but not recorded on the distress maps. (FHWA, 2003) These values will be discussed in further detail when describing testing using the Georgia Digital Faultmeter in Section

30 Descriptions of Distress Types Corner breaks occur when a portion of the slab is separated by a crack intersecting both the transverse and longitudinal joints at approximately a 45-degree angle. A low severity corner break is not spalled for more than 10 percent of the crack length, has no measurable faulting, and has no broken or missing material. Moderate severity corner breaks are not broken into more than one piece and have either low severity spalling over more than 10 percent of their total length or < 13 mm of faulting of the crack or joint. A high severity corner break is characterized by having either moderate to high severity spalling for more than 10 percent of its total length, crack or joint faulting 13 mm, or the corner piece is broken into two or more pieces or contains patching material. (FHWA, 2003) Figure 3.2 High Severity Corner Break, Section 1. Transverse cracks are described as those which arise mainly perpendicular to the centerline of the pavement. Low severity transverse cracks have a width < 3 mm, no

31 31 spalling or measurable faulting, or are well sealed with an indeterminate width. A transverse crack having a width 3 mm and < 6 mm, spalling < 75 mm, or faulting < 6 mm is considered to be moderately severe. High severity transverse cracks, Figure 3.3, are 6 mm in width, have spalling 75 mm, or faulting 6 mm. (FHWA, 2003) Cracks are considered longitudinal when they run predominantly parallel to the centerline of the pavement, as seen in Figure 3.4. The severity levels of longitudinal cracks are similar to that of transverse cracks, with the low severity category being exactly the same for the two. A moderately severe longitudinal crack has a width 3 mm and < 13 mm, spalling < 75 mm, or faulting < 13 mm. High severity longitudinal cracks have a width 13 mm, spalling 75 mm, or faulting 13 mm. (FHWA, 2003) Figure 3.3 High Severity Transverse Crack, Section 4.

32 32 Figure 3.4 Low Severity Longitudinal Crack, Section 4. Patch/patch deterioration is possible when an area greater than 0.1 m 2 has been removed and replaced, or if material has been added to the pavement after the completion of construction. Low severity deterioration, Figure 3.5, is when the patch has any low severity distress, no measurable faulting or settlement, and pumping is not evident. Moderate severity deterioration exists when the patch has moderate distress, faulting or settlement < 6 mm, and pumping is not evident. Patch/patch deterioration is considered high severity if the patch has a high severity distress of any type, or faulting or settlement 6 mm, and pumping may be evident. (FHWA, 2003)

33 33 Figure 3.5 Low Severity Flexible Patch/Patch Deterioration, Section 1. Figure 3.6 High Severity Longitudinal Joint Spalling, Section 4. Spalling of both transverse and longitudinal joints consists of cracking or breaking of the slab edges within 0.3 meters of the joint s face. The severity levels for these two types of joint deficiencies are identical. Low severity joint spalling is < 75 mm in width (measured to the joint face), has no loss of material, and no patching. A joint spall between 75 mm and 150 mm wide with loss of material is classified as moderate.

34 34 High severity joint spalling, illustrated in Figure 3.6, exceeds 150 mm in width with loss of material, is broken into two or more pieces, or contains patch material. (FHWA, 2003) The surface defects of scaling and popouts, both seen in Figure 3.7, were documented as mandated by the LTPP protocol. Scaling is defined as deterioration of the upper surface of the concrete slab, and is typically between 3 mm and 13 mm. The number of occurrences and square meters of area affected by this defect are recorded. Popouts are where pieces of pavement, usually having a diameter from 25 mm to 100 mm and a depth of 13 mm to 50 mm, have broken loose from the surface. (FHWA, 2003) Figure 3.7 Area of Scaling and Multiple Popouts, Section Results of Distress Surveys Since the entire area being tested must be meticulously visually dissected, distress surveys are quite effective for developing a tangible sense of a pavement s condition. Simply driving over the sections made it initially apparent that many distresses were evident along with considerable faulting. The results of the distress surveys served to

35 35 further corroborate this easily deduced hypothesis. Furthermore, as the second phase of this project is rehabilitation oriented, AASHTO states these accurate condition surveys which assess a pavement s physical distress are vital to a successful rehabilitation effort (AASHTO, 1986). Three types of distress- transverse cracking, corner breaks, and patch/patch deterioration- were recorded in all four test sections. Of these three distresses high severity transverse cracking was the most prominent. Sections 1 and 3 had the most high severity transverse cracks, with 33, while Section 3 had the most total transverse cracks, at 47. Section 4 contained less transverse cracking, of all severity levels, than the other three. These quantities are plotted in their entirety for each section in Figure Severities of Transverse Cracking Number of Transverse Cracks High Moderate Low Section Number Figure 3.8 Severities of Transverse Cracking in Test Sections.

36 36 Flexible patch/patch deterioration was present in all sections, although in all but one high severity instance in Section 4 these distresses were of low severity. Section 1 had the fewest total corner breaks, but all of the high severity level. Sections 2 and 3 had the most corner breaks, with 6, while Section 3 was most affected by high severity corner breaks, with 5. A summary of corner breaks for all sections is shown in Figure 3.9. Severities of Corner Breaks 7 6 Number of Corner Breaks High Moderate Low Section Number Figure 3.9 Severities of Corner Breaks in Test Sections. The distresses of transverse cracking and corner breaking were discussed in more detail than patch/patch deterioration because of their importance in the Pavement Condition Index (PCI) rating. The density of these two types of distress made them the most influential factors when determining the PCI for all four sections and will be explained in greater depth in Section 4.1. It should also be noted that both transverse cracks and corner breaks are classified as primarily traffic load caused. (AASHTO,

37 ) This tends to indicate the service life of the pavement was exceeded rather than the pavement being improperly designed Falling Weight Deflectometer Testing Procedure Testing was performed using the New York Department of Transportation s KUAB Falling Weight Deflectometer (FWD). This setup consists of the testing trailer towed behind a van containing the control system, see Figure Data is collected by dropping a set of two weights from different heights onto a rubber cushioned load cell with a radius of 150 mm (5.91 in) resting on the pavement surface. The ensuing impulse force, ranging from 2698 to lb (Huang, 2004), generates vertical deflections throughout the pavement which are recorded, to the thousandth of an inch, by nine linearly variable displacement transducer (LVDT) sensors. These LVDTs make contact with the surface of the pavement and are positioned along the length of the FWD trailer. Figure 3.11 displays the rack of LVDT sensors making contact with the pavement during data collection. Figure 3.10 NYDOT KUAB Falling Weight Deflectometer.

38 38 Figure 3.11 KUAB FWD Sensors During Data Collection. Testing using the FWD was conducted on September 21 and 22, 2004 as well as on November 30, The spacing of the sensors differed slightly during these two testing periods and is illustrated in Figure 3.12 and Table 3.1. During both test intervals the FWD was used to inspect the right wheelpath of the traveling (right) lane while continuously collecting air and pavement temperature data. Figure 3.12 Diagram of Sensor Arrangements for FWD Testing. Table 3.1 Sensor Spacing for I-86 FWD Testing. Test Period FWD Sensor Distance from D f0 (in) D f0 D f1 D f2 D f3 D f4 D f5 D f6 D f7 D f8 September (behind D f0 ) November (behind D f0 )

39 Results of Falling Weight Deflectometer Testing The amount of data collected by the NYDOT FWD device from the two test periods was vast, but also somewhat inconsistent. On September 21, 2004 deflection basin testing for Sections 1 through 3 was conducted, but the impact loads eventually strayed from those intended. At the beginning of the testing these three loads were approximately 9,000, 12,000, and 16,000 lbs, with some higher loads occurring between 327 m and 448 m. From 652 m onward, however, the first impact load dropped below 15,000 lbs only once and was consistently between 17,000 and 21,000 lbs. The second and third impact loads applied were never below 22,000 lbs and 24,000 lbs, respectively. In a number of situations the force of the second impact load actually exceeded that of the third. The deflections of the sensor located within the load cell (D f0 ) were plotted versus the horizontal distance. This deflection parameter is the most obvious measure of compressive stiffness of the pavement system. Deflection of the D f0 sensor will decrease with increasing pavement stiffness. (Sargand et. al., 2002) Because of the differences in impact loads at different drop locations deflection data must be normalized in order provide an accurate comparison. This is accomplished by dividing the vertical deflection, in mils, by the impact force, in kips, to obtain a normalized vertical deflection with the units of mils/kip. The two previously mentioned anomalous areas, highlighted regions of Figure 3.13, can be compared to the rest of the more compact data from Section 1. It seems counterintuitive, though, that the deflections from the higher, and less separated, impact loads in these portions generated smaller deflections compared to the others. This suggests some form of mechanical failure during the testing when the load cell was gathering bad impact load data.

40 Normalized Load Sensor Deflection (D f0 ) Section Normalized Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure 3.13 Normalized Section 1 FWD D f0 Deflections, Since the deflection data in the problematic areas seemed reasonable it was assumed for analysis that the mechanical troubles were confined to the reading of the load cell itself. In an attempt to make this data somewhat reasonable the deflections were normalized based on the impact loads from the observed good drops, those outside the boxed areas in Figure An average was calculated for the three loads from this data giving, respectively, impacts of 9619 lbs, lbs, and lbs. These values were used for the normalization of the entire data set collected on The revised load cell deflection data for Section 1 is plotted in Figure The change is evident in the flattening of the data, but is especially apparent when comparing the boxed areas in Figures 3.13 and Once again the revised data is not taken to be exact but rather an estimate used to form a general idea of how the pavement is performing.

41 Revised Normalized Load Sensor Deflection (D f0 ) Section Normalized Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure 3.14 Revised Normalized Section 1 FWD D f0 Deflections, Heavier loading, and similar separation between normalized deflections, continued throughout the duration of testing of Sections 2 and 3 on September 21, Section 4 was tested singularly on September 22, 2004 and began with proper loadings. Testing was not completed due to time constraints, but the data showed evidence of consistent load cell readings being a recurring problem. The three impact loads recorded for the final four drops were approximately 16,000, 21,000, and 24,000 lbs. A trailing off of data in Figure 3.15 shows the possibility of this repetition. Unfortunately, the higher than normal drop loads experienced throughout most of the four test sections caused the American Concrete Pavement Association s (ACPA) Pavement Analysis Software to report extraneous results for the back calculation of the concrete s elastic modulus. This problem, and its remedy, will be discussed in more detail in Sections 4.3 and 4.4.

42 Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure 3.15 Normalized Section 4 FWD D f0 Deflections, The problematic load cell was replaced before the second round of tests and a new controller board was also installed. The FWD testing conducted on November 30, 2004 produced much more consistent impact loadings and, consequently, the deflection data collected was more realistic. Sections 1 and 2 were tested thoroughly but, because of time limitations, the rest could not be entirely completed. Only 246 m of Section 3 were able to be tested while no segment of Section 4 was tested. The normalized D f0 deflections from for Section 2 are plotted in Figure Appendix C contains the complete set of normalized FWD D f0 plots for both test dates, while Appendix D consists of the revised FWD D f0 plots for

43 Normalized Load Sensor Deflection (D f0 ) Section Normalized Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure 3.16 Normalized Section 2 FWD D f0 Deflections, The Falling Weight Deflectometer data was used to calculate the spreadability percentage of each section, which is beneficial when assessing slab support. Spreadability, defined as the average deflection as a percentage of the maximum deflection, is a parameter that describes the slab action of the pavement and its ability to distribute loads (Edwards et. al., 1989). This parameter is calculated using Equation 3.1, where a higher spreadability suggests better quality load distribution. A high D f0 value, however, does tend to yield a lower spreadability. (ODOT, 1999) SPR (%) ( D, D D ) f 0 f 2 f = (3.1) 8 D f 0

44 44 Where: SPR(%) = Spreadability (%) D D D = Normalized deflection at each sensor (mils/kip) f 0, f 2 f 8 At all drop locations the spreadability was calculated for each of the three impact loadings and then averaged. Plotting this value versus the distance displays the fluctuation of spreadability even between drops separated only by a few meters. This is likely attributed to the large amount of transverse crack occurrences in all sections. Figure 3.17 shows the spreadability of Section 2 for both testing dates. During the FWD testing notes were taken when the device was set over severe distresses. In this case the extremely low value of 47.86% was a result of the heavily patched area at 322 m. Average Spreadability plots for all investigated sections from both test periods are available in Appendix E.

45 45 Average Spreadability Section Spreadability (%) "heavily patched area" Distance (m) Figure 3.17 Average Spreadability for Both Testing Dates, Section 2. Averaging the spreadability values over each section showed a consistently increasing trend through the sections, shown in Figure 3.18, during both testing periods. Section 4 had the highest single average value of 68.44%, though data was only collected over half of the section in September, 2004 and could not be analyzed in November, Section 3 had the highest average value of the November testing, at 64.06%, but again this is probably due to the fact that Section 4 went untested in November. The spreadability values generated during November were markedly less than those in September, but still exhibited the same increase. The discrepancy between average spreadability for the two test periods can be attributed to the difference in pavement temperature. The rise in spreadability through the sections, furthermore, is most likely caused by the pavement relaxing as the temperature increased during the testing procedure, which is visible in Figure 3.19.

46 46 Sectional Average Spreadability Average Spreadability (%) Section Number Figure 3.18 Average Spreadability for Each Section. Average Pavement Temperature During FWD Testing ( F) 80 Average Pavement Temperature ( F) Section Number Figure 3.19 Average Pavement Temperature During FWD Testing Periods.

47 47 The Falling Weight Deflectometer was also used to inspect the condition of the pavement s joints via load transfer testing. During a load transfer at a joint the FWD load cell is first placed just before the joint on the approach slab with the sensors from D f2 onward resting upon the leave slab, Figure After conducting the drops on the approach side of the joint the load cell is moved to the leave slab with only sensor D f1 remaining on the approach slab, Figure These two different load transfer setup positions are depicted with the Ohio Department of Transportation s Dynatest Falling Weight Deflectometer in Figure Figure 3.20 FWD Sensor Placement at Joint Approach. Figure 3.21 FWD Sensor Placement at Joint Leave.

48 48 Figure 3.22 Load Transfer Positioning with ODOT Dynatest FWD. Data gathered from these load transfers was used to calculate the load transfer efficiency (LTE) for the joint approach, using Equation 3.2, and for the joint leave, using Equation 3.3. Just as with spreadability, the LTE was calculated for all three drops then averaged. D f LT (%) = 2 JA 100 (3.2) D f 0 Where: D f LT (%) = 1 JL 100 (3.3) D f 0 LT JA (%) = LT JL (%) = Load transfer efficiency of joint approach Load transfer efficiency of joint leave D f 0 D f 2 = Normalized deflection of sensors (mils/kip)

49 49 The LTE fell fairly steadily between 30% and 60% for Sections 3 and 4. The most variation within the nine joints was displayed in Section 2 which also contained the highest realistic LTE of 97.75%. Section 1 contained two LTE values that were greater than this, % and %, but these can likely be dismissed as erroneous as they exceeded the maximum possible LTE value of 100%. All load transfer efficiencies at both the joint approach and joint leave for each section are shown in Table 3.2 Table 3.2 Average Load Transfer Efficiencies. SECTION 1 (%) SECTION 2 (%) SECTION 3 (%) SECTION 4 (%) Joint Number Joint Joint Joint Joint Joint Joint Joint Joint Approach Leave Approach Leave Approach Leave Approach Leave Joint support ratios (JSR) were averaged for the three drops at each joint using the FWD data and Equation 3.4: Where: D f 0 leave JSR = (3.4) D approach f 0 JSR = Joint Support Ratio D f 0 leave = Deflection of sensor Df0 at edge of leave slab (mils/kip) D f 0 approach = Deflection of sensor Df0 at edge of approach slab (mils/kip)

50 50 A joint support ratio falling between 0.5 and 1.5 is considered acceptable. (ODOT, 1999) Throughout all test sections the JSR values were between these criteria, except for Joint 5 of Section 3, seen in bold in Table 3.3. This high value, a JSR of 1.68, was due to the small D f0 on the approach and much larger D f0 on the leave slab also resulting in the second lowest joint leave LTE in all the test sections, at 30.28%. This extreme difference in deflection was caused by the loss of support beneath the edge of the leave slab. Table 3.3 Average Joint Support Ratios. Joint Number Section 1 Section 2 Section 3 Section Georgia Digital Faultmeter Testing Procedure The Georgia Faultmeter was originally designed and developed by the Georgia Department of Transportation Office of Materials and Research personnel. (FHWA, 2003) This device uses a single LVDT to measure transverse joint faulting, transverse crack faulting, and lane-to-shoulder dropoff in conjunction with distress surveys. The ORITE constructed faultmeter, shown in Figure 3.23, differs slightly from the GDOT design. The Georgia design measured to the nearest millimeter while the ORITE faultmeter displays the reading in units of 1/32 which are then converted to millimeters by the user.

51 51 Figure 3.23 ORITE s Georgia Digital Faultmeter. Faulting of transverse joints and cracks is categorized as the difference in elevation between the pavement surfaces on either side of a transverse joint or crack. (FHWA, 2003) When the approach slab is higher than the departure slab faulting is considered positive. If the approach slab was lower than the departure a negative sign was applied to the reading. Measurements were taken at each transverse joint or crack at 0.3 m from the right longitudinal joint and the value was entered into the data collection sheet. Lane-to-shoulder dropoff is defined as the elevation difference between the pavement and shoulder surfaces. (FHWA, 2003) Using the faultmeter, dropoff of the right bituminous shoulder was measured beginning at 0 m and at m intervals throughout the test section along the lane-shoulder interface. The m long section used for LTPP forensic surveys is covered by eleven readings of lane-to-shoulder dropoff.

52 Results of Georgia Digital Faultmeter Testing Faultmeter data is useful in longitudinally profiling the sections surveyed. The data gathered for transverse crack faulting can be used to further visualize distress surveys, while joint faulting information can be compared to the FWD load transfer data. Transverse crack and joint faulting along with lane-to-shoulder dropoff are also necessary parameters when determining a pavement s PCI rating. As discussed previously in test Sections 1 and 3 contained the most high severity transverse cracks of any section, with 33. The transverse crack faulting data shows that the magnitudes of faulting for these two sections are very comparable. Section 1 had 22 cracks exhibiting no faulting while Section 3 had 23. Section 1 had two instances of negative faulting, at 0.79 mm, compared to one instance in Section 3. The total occurrences of faulting between 0 and 20 mm, 17, were the same for both sections. Section 3 also contained one high severity transverse crack that had mm of faulting. This was the only crack with faulting greater than 20 mm in any of the four test sections. Figures 3.24 and 3.25 show the similarities between Sections 1 and 3 by displaying the faulting severities in 5 mm intervals. Figures 3.26 and 3.27 display the somewhat similar transverse crack faulting profiles plotted along the length of these two sections. These plots for Section 4, Figures 3.28 and 3.29, further illustrate the discrepancy in the amount of transverse cracks when compared to the other sections. The remaining graphs of these results for Section 2 are available in Appendix F.

53 53 Extent of Transverse Crack Faulting Section Number of Cracks Number of Cracks to <0 No Faulting >0 to 5 5 to to to to to to 35 Categories of Fault Severity (mm) Figure 3.24 Extent of Transverse Crack Faulting, Section 1. Extent of Transverse Crack Faulting Section Number of Cracks Number of Cracks to <0 No Faulting >0 to 5 5 to to to to to to 35 Categories of Fault Severity (mm) Figure 3.25 Extent of Transverse Crack Faulting, Section 3.

54 54 Section 1 Transverse Crack Faulting Profile Transverse Crack Faulting (mm) Distance (m) Figure 3.26 Transverse Crack Faulting Profile, Section 1. Section 3 Transverse Crack Faulting Profile Transverse Crack Faulting (mm) Distance (m) Figure 3.27 Transverse Crack Faulting Profile, Section 3.

55 55 Extent of Transverse Crack Faulting Section Number of Cracks Number of Cracks to <0 No Faulting >0 to 5 5 to to to to to to 35 Categories of Fault Severity (mm) Figure 3.28 Extent of Transverse Crack Faulting, Section 4. Section 4 Transverse Crack Faulting Profile Transverse Crack Faulting (mm) Distance (m) Figure 3.29 Transverse Crack Faulting Profile, Section 4.

56 56 Section 3 had the worst, and most abundant, transverse joint faulting among the four test sections. Of the eight transverse joints in each test section four joints in Section 3 exhibited some degree of faulting- three had 0.79 mm of faulting and another had 4.76 mm. The only other section to contain a joint faulted more than 0.79 mm was Section 1 with one occurrence of 1.59 mm. Section 2 had two faulted transverse joints, both 0.79 mm, while only one joint in Section 4 had faulting, also of 0.79 mm. Plots of the two sections with the most transverse joint faulting, Sections 1 and 3, are shown in Figures 3.30 and 3.31, while the data for Sections 2 and 4 are found in Appendix F. When comparing the larger joint faulting values of Section 3 to the load transfer efficiencies for these joints there seems to be no correlation. Section 1 Transverse Joint Faulting Transverse Joint Faulting (mm) Joint Number Figure 3.30 Faulting of Transverse Joints, Section 1.

57 57 Section 3 Transverse Joint Faulting Transverse Joint Faulting (mm) Joint Number Figure 3.31 Faulting of Transverse Joints, Section 3. Some amount of lane-to-shoulder dropoff was measured at every test point in all sections. Section 1 exhibited the worst overall lane-to-shoulder dropoff; this section contained no dropoff less than 19 mm and also had the highest single dropoff value of mm. Section 2 consistently had the smallest lane-to-shoulder dropoffs and contained the lowest single dropoff value, 5.56 mm, of all test sections. The dropoffs in Section 3 were the most consistent of the test sections; of the eleven test positions nine values fell between mm and mm. Plots of the lane-to-shoulder dropoff versus the point distance of testing for Sections 1 and 2 are shown in Figures 3.32 and 3.33, respectively, and the remaining plots are located in Appendix F.

58 58 Lane-to-Shoulder Dropoff Section 1 Point Distance (m) Lane-to-Shoulder Dropoff (mm) Figure 3.32 Lane-to-Shoulder Dropoff, Section 1. Lane-to-Shoulder Dropoff Section 2 Point Distance (m) Lane-to-Shoulder Dropoff (mm) Figure 3.33 Lane-to-Shoulder Dropoff, Section 2.

59 Destructive Testing Destructive testing, where conducted, permanently affects the condition of the pavement. Destructive testing was performed on I-86 with the dynamic cone penetrometer (DCP). The drilling necessary for the DCP probe insertion through the pavement also enabled the recovery of concrete cores at all of these locations. These testing procedures along with their results will be explained in the following sections Dynamic Cone Penetrometer Testing Procedure On September 21 and 22, 2004 the subgrade of the four test sections was examined using ORITE s Vertek automated dynamic cone penetrometer, as shown in Figure This trailer mounted machine consists of a 1270 mm drive rod with a 60º conical tip 20 mm in length. By continually releasing an 8.0 kg (17.6 lb) mass from a drop height of 574 mm the rod is driven into the soil to collect subsurface data. The DCP data acquisition system records the number of blows and penetration depth for each blow. Using this information, necessary values such as the California Bearing Ratio and Modulus of Resilience can be computed. The procedure for these calculations, and their importance, will be described in the following DCP test results section.

60 60 Figure 3.34 ORITE s Vertek Automated Dynamic Cone Penetrometer. The NYDOT core drilling equipment was used to remove 4 diameter concrete cores in order to expose the soil beneath the pavement layer for DCP testing. A total of fourteen DCP tests were conducted along the right wheelpath throughout the four test sections. The locations for these tests varied within each section as shown in Table 3.4. Table 3.4 Locations of DCP Testing. Section 1 Section 2 DCP Test Number Distance from Beginning of Section (ft) Station Number

61 61 Section 3 Section 4 Table 3.4 Continued Results of Dynamic Cone Penetrometer Testing ORITE s dynamic cone penetrometer continually collects blowcount and depth of penetration data. The penetration index (PI) is defined as the difference in depth between each blow and the one preceding it. Example blows and PI per depth plots for Station , located in Section 2, are shown in Figures 3.35 and These plots show the non-uniformity of subgrade soils, which was common throughout all sections. 0 Blows vs. Depth Station Depth (mm) blow Number of Blows Figure 3.35 Blows vs. Depth, Station

62 62 0 PI vs. Depth Station Depth (mm) PI PI (mm/blow) Figure 3.36 PI vs. Depth, Station The collected data can also be used to derive the resilient modulus (M r ) of the subgrade soil by calculating the California Bearing Ratio (CBR). Equation 3.5 shows the relationship between CBR and PI while Equation 3.6 relates the CBR to the M r. 292 CBR = (3.5) 1.12 PI M r = 1. 2 CBR (3.6) Where: CBR = California Bearing Ratio PI = Penetration Index (mm/blow), and M r = Modulus of Resilience (ksi)

63 63 The correlation between CBR and PI given by Equation 3.5 was derived by the United States Army Corps of Engineers for various soil types (Webster et. al., 1992), while Equation 3.6 is a relationship commonly used by the Ohio Department of Transportation (ODOT, 1999). This equation gives a more conservative estimate of the soil s resilient modulus based on the AASHTO equation that uses a multiplier of 1.5 instead of 1.2 (AASHTO, 1986). The M r plot for Station , generated using Equations 3.5 and 3.6, is shown in Figure All plots of blow, PI, and M r versus depth for each testing location can be viewed in Appendices G, H, and I, respectively. Due to the presence of rocks in the subgrade some of the plots in this Appendix display portions of extraneous data. When the M r plot suddenly extends far along the x-axis it is likely that a rock has been found and viable data is not collected until the probe is beyond the obstruction. 0 Modulus of Resilience Station Depth (mm) Mr M r (ksi) Figure 3.37 Modulus of Resilience, Station

64 64 The subgrade stiffness in Section 3 was very low for the most part, except for the M r calculated at Station , as seen in Figure 3.38, which showed the presence of some stiffer segments. Figure 3.39 shows the least favorable M r plot for Section 3, at Station , which displays the weak layer lying just beneath the pavement structure at this location. M r plots for the remaining sections also displayed this variability with Sections 1 and 4 containing the largest segments of high, yet reasonable, stiffness. The M r plot for Station , located in Section 4, is shown in Figure NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure 3.38 Resilient Modulus for Station , Section 3.

65 65 NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure 3.39 Resilient Modulus for Station , Section 3. 0 NY I-86 East Bound Station Mr 400 Depth (mm) Mr (ksi) Figure 3.40 Resilient Modulus for Station , Section 4.

66 Concrete Core Removal Testing Procedure 4 diameter concrete cores were extracted from each hole drilled by the NYDOT for the purposes of conducting DCP testing. These fourteen cores were measured to the nearest using digital calipers to determine the pavement s thickness at the coring locations Results of Concrete Core Removal Testing The design thickness for the existing concrete pavement was 9 inches and the extracted cores deviated considerably from this value. Thicknesses across all four sections ranged from inches to inches, however an average thickness of inches was found throughout the sections. Core thicknesses for each section are plotted in Figure 3.41 with the target thickness of 9 inches shown as a line for comparison. It is interesting to note cores from Section 1 were significantly less than the design thickness, while all those from Section 4 exceeded it. Aside from a single core in Section 3 that measuring exactly 9 inches all others were thicker than the design value. The plot also illustrates the seeming trend of increasing thickness as the paving operation progressed.

67 67 4" Diameter Concrete Core Sizes I-86 Olean, NY Thickness (in) Section 1 Section 2 Section 3 Section Core Hole Number Figure 3.41 Variation of Concrete Core Thicknesses.

68 68 Chapter 4 Pavement Analysis 4.1 Pavement Condition Index Procedure The distress surveys conducted on September 21 and 22, 2004 provided the necessary data to calculate the pavement condition index (PCI) and condition rating of the test sections. The ASTM Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys (ASTM, 2004) was used to assess the PCI for each of the four sections. The PCI is a numerical indicator ranging from 0 to 100, where 0 denotes the worst rating possible and 100 the highest, which measures a pavement s condition based on observable distresses. From the PCI value determined a pavement condition rating from failed to excellent is given to the section as illustrated in Figure 4.1. (ASTM, 2004) The procedure states that if the PCC slabs have a joint spacing larger than 8 m (26.2 ft), as is the case with the 18.3 m (60 ft) spacing on I-86, then these slabs must be further divided into imaginary slabs which are less than or equal to 8 m (26.2 ft). Where two imaginary slabs meet imaginary joints occur. For the purpose of the PCI survey these imaginary joints are considered to be in perfect condition. (ASTM, 2004) The 18.3 m slabs were each divided into three segments, which resulted in a test section consisting of 25 imaginary slabs 6.1 m (20 ft) in length.

69 69 Figure 4.1 Pavement Condition Index and Rating Scale. (ASTM, 2004) The distress severity classifications defined by the ASTM standard for PCI differed slightly from those described previously for the LTPP distress survey procedure. Some distresses then needed to be reclassified to their proper category for PCI consideration. Data gathered using the faultmeter, which was collected but not reported during the distress surveys, was also used to determine the pavement s PCI. Each slab affected by a discrete combination of distress type and severity level was noted and the total number of slabs containing this specific distress and severity were

70 70 then added up for the entire section. This value was divided by the total number of slabs in the section, 25, and multiplied by 100 to generate the percent density of each distress type and severity combination. A deduct value (DV) was then obtained from deduct value curves specific for each distress type and severity level. (ASTM, 2004) Joint seal damage is assessed over an entire section but, because this data was not collected, the damage was assumed to be moderate for all test sections. Faulting at joints could affect the PCI, but faulting of transverse cracks was only considered when determining the severity level of that distress. (ASTM, 2004) Faultmeter lane-toshoulder dropoff data was also required to determine the PCI of a section. The results of the deduct value procedure to this point for Section 1 are shown in Table 4.1. Distress Description Table 4.1 Distresses and Deduct Values, Section 1. LTPP Distress Type ASTM Distress Type Severity # Slabs Affected Density (%) Deduct Value Corner Break 1 22 H Transverse Cracking 4 28 L Transverse Cracking 4 28 M Transverse Cracking 4 28 H Popout Patch/Patch Deterioration (Small) L Patch/Patch Deterioration (Large) L Joint Seal Damage - 26 M Lane/Shoulder Dropoff - 27 L From the deduct values the maximum corrected deduct value (CDV) was then determined. Deduct values were first listed in descending order then the allowable number of deducts, m, is used to find the CDV was calculated using Equation 4.1.

71 71 9 m = 1 + ( 100 HDV ) (4.1) 98 Where: m = Allowable number of deducts, including fractions; must be 10 HDV = Highest individual deduct value The number of deduct values was then reduced to the largest m deduct values, which includes the fractional part of this number as well. Summing these deducts, including the fractional portion corresponding to the last term, yields the total deduct value (TDV). The set of deduct values is reduced to encompass m where the number of deduct values greater than 2.0, q, was needed to determine the CDV. Where the TDV and q intersect a CDV value is read off of the y-axis. A maximum CDV is found iteratively by reducing the smallest deduct value in the set to 2.0 and subtracting 1 from q until q = 1. The maximum CDV gets subtracted from 100 to finally give the PCI for the section of pavement. A PCI calculation example for Section 1 using this procedure is presented next, based on the survey results contained in Table 4.1. First, m is found using the highest deduct value, HDV, of 58: 9 m = 1+ ( ) = 4.86 (4.2) 98

72 72 Next, the five highest deduct values, corresponding to m = 4.86, are listed in descending order as: 58, 27, 12, 10, 4. These five deduct values yield q = 5. The total deduct value (TDV) is then calculated with Equation 4.3 including the fractional portion of the 5 th term: ( ) + ( 0.86* 4) = TDV = (4.3) Using a TDV = and a q = 5 a corrected deduct value (CDV) of 60 is determined by relating q, TDV, and CDV using Figure 4.2: Figure 4.2 Corrected Deduct Values Chart, Section 1 Example. (ASTM, 2004) Table 4.2 shows the entire process of reducing the lowest deduct value to 2.0 for each subsequent q. The maximum CDV from this set, 64, is then subtracted from 100 to give a PCI of 36 for the section. Distress summaries based on the ASTM procedure and deduct value tables for Sections 2 through 4 are contained in Appendix J.

73 73 Table 4.2 Corrected Deduct Values for All q, Section 1. # DEDUCT VALUES m TDV q CDV Pavement Condition Index Results The process outlined previously was repeated to determine the PCI for each of the four test sections. These PCI results were associated to the rating system such that all sections were included within the Poor category. Table 4.3 summarizes the results of this procedure, while Figure 4.3 depicts these PCI values placed on the rating scale. Table 4.3 PCI Results Summary. Section PCI Rating 1 36 Poor 2 36 Poor 3 26 Poor 4 38 Poor The PCI for Sections 1, 2, and 4 were very similar, however Section 3 had a much lower index, 26, than the other three. Prior to the PCI calculation, distress survey data indicated that Section 3 may have the worst PCI. This section had the most transverse cracks, including the most of this distress classified as high severity, as well as the most slabs containing high severity corner breaks. The sizeable gap between this and the other sections, however, was unexpected. The reason for this can be traced to the prevalence of transverse cracking, at all severity levels, and high severity corner breaks within the

74 74 section. This led to the largest TDV of any section (140.39) for q = 5 which corresponded to a much higher maximum CDV, thus resulting in the considerably lower PCI. Figure 4.3 Pavement Condition Indices and Ratings of Test Sections. High severity transverse cracks generated the highest deduct value in all four sections while high severity corner breaks were always the second highest. The PCI results for Sections 2 and 4 correspond to those anticipated by the distress surveys and faultmeter testing. Section 4 had the highest PCI, nearly bordering on a Fair condition

75 75 rating, along with the fewest transverse cracks of all severities. The only two deduct values for this section that exceeded single digits were due to high severity transverse cracks and high severity corner breaks. Judging by the data presented in Chapter 3 and the PCI of Section 4 it was reasonable to assume that the condition index of Section 2 would probably be similar to, but lower than, that of Section 4, which was later confirmed. Though Sections 1 and 3 were compared in the previous chapter based on their transverse cracking distributions, Sections 1 and 2 had exactly the same PCI. The PCI of Section 1 was much higher compared to that of Section 3 mainly because it had fewer low and moderate severity transverse cracks, high severity corner breaks, and no transverse or longitudinal joint spalling. While the PCI values for the four test sections differed somewhat, the main conclusion drawn from this procedure is that all sections were rated as Poor and, as their condition worsened, they were in need of rehabilitation. 4.3 Pavement Analysis Software Procedure The modulus of elasticity of the concrete slab, E c, and the modulus of subgrade reaction, k ef, were calculated using the ACPA s Pavement Analysis Software. This NDT backcalculation software requires deflection data gathered by the FWD along with the radius of the load plate, existing slab thickness, and Poisson s ratio of the concrete. Since data collected by the FWD was affected by transverse cracking the results of this analysis pertaining to the subgrade were not as representative as the DCP data. The averages of these two calculated values were later used in Section 4.5 for overall pavement modeling.

76 76 The existing slab thickness of 9 in and the 5.9 in load plate radius were used as inputs. A Poisson s ratio for the concrete was assumed to be 0.15 which is the typical average value for this pavement. (Huang, 2004) For each of the three impact loads used as inputs the corresponding deflections in mils for D f0, D f2, D f4, and D f5 were required. From this information averages for the k ef (pci) and E c (ksi) were calculated and reported. Figure 4.4 shows the user s interface for the pavement analysis program. It should be noted that the load plate radius input of 5.9 in, not 5.91 in, is not erroneous but rather the ability of the program to only accept a radius value with a resolution of 0.1 in. Figure 4.4 Pavement Analysis Software User Interface. 4.4 Pavement Analysis Software Results Due to the previously mentioned discrepancies in the FWD data, both with the load cell failure and transverse cracking, the NDT backcalculation could not be completely conducted as anticipated. When entering the data generated by the heavy impact loadings from September, 2004 the E c would max out at 10,000 ksi for each drop, as shown in Figure 4.5, thus giving an overestimated average E c. Because of this it was

77 77 assumed that the moderate impact loadings of the testing conducted on generated more reasonable results. Unfortunately, on this date only Sections 1 and 2 were completely tested; one third of Section 3 and none of Section 4 were covered. Figure 4.5 Pavement Analysis Software Output for Heavy Impact Loading. Throughout each of the three tested sections ten different locations were chosen based on varying D f0 values. These ten points spanned the length of the section and encompassed low, medium, and high D f0 deflections. The results of this procedure are displayed in Table 4.4. Section 2 had the highest concrete modulus of elasticity along with the lowest modulus of subgrade reaction. The lowest E c was in Section 3, which Table 4.4 Results of Pavement Analysis Software. Section Average k ef (pci) Average E c (ksi) Total Average

78 78 was predictable due to the fact that this section was in worse condition than all other sections. Because of its better condition and greater average thickness it could be predicted that Section 4 would have yielded the highest modulus of elasticity. The average modulus of elasticity for all sections was ksi which falls very near the mean of the expected range of 3000 to 6000 ksi, while the average k ef value of pci was also within the expected range of 130 to 170 pci. (Huang, 2004) 4.5 Rigid Pavement Design Program Procedure The Rigid Pavement Design Program, available as a free download on the Federal Highway Administration website as part of the Long Term Pavement Performance Program, is a Microsoft Excel spreadsheet that automates the design and analysis procedures for improved guidelines for Portland cement concrete pavements. (FHWA, 1999) This program makes use of the equations outlined in the 1998 Supplement to the AASHTO Guide for Design of Pavement Structures, Part II- Rigid Pavement Design and Rigid Pavement Joint Design. (FHWA, 1999) The macro-enabled spreadsheet has the ability to determine a required PCC thickness for either JRCP, jointed plain concrete pavement (JPCP), or continuously reinforced concrete pavement (CRCP). A final outputted design thickness, in inches, is dependant upon varying climatic, material, traffic, reliability, and soil condition input values. Since the program reports a single value for slab thickness based on numerous inputs the backcalculation of certain variables based on the existing thickness is impossible. The necessary thickness of concrete given the existing conditions and time span, however, was calculated. This process is summarized in the following paragraphs.

79 79 Estimates were made for a number of values because of the vast amount of input variables for which no firm data was available. The assumed input values for the program s general input screen are listed in Table 4.5 and described after it. Input assumptions for more specific areas of the program will be displayed and described in the same fashion, while all of the input screens are available in Appendix K. Table 4.5 Estimated General Input Values. PARAMETER INPUT VALUE Initial Serviceability Index 4.5 Terminal Serviceability Index day Mean Modulus of Rupture 700 psi Poisson's Ratio 0.15 Elastic Modulus of Base 30,000 psi Design Thickness of Base in Slab-Base Friction Factor 1.5 Reliability Level 95% Overall Standard Deviation 0.34 Mean Annual Wind Speed 12.1 mph Mean Annual Air Temperature 47.6 ºF Mean Annual Precipitation 37.5 in Initial and terminal serviceability indices correspond, respectively, to the condition of the pavement just after placement and at the desired point of rehabilitation or replacement. A serviceability index is determined from measurements of roughness and distress and ranges from 0 to 5, with 5 denoting the highest level of serviceability. An initial serviceability index of 4.5 was established for rigid pavements through the AASHO Road Test and was assumed for this analysis. The terminal serviceability was estimated to be 1.8 due to the poor condition of the roadway. As this is the point where rehabilitation should begin, and since there was none, this value was derived by underestimating the AASHTO suggested value of 2.5 or 2.0. (AASHTO, 1986)

80 80 The two material properties assumed for the concrete were the 28-day mean modulus of rupture and Poisson s ratio. Poisson s ratio was taken to be 0.15, which is typical for concrete, since this was the value assumed for the pavement analysis software analysis. This Poisson s ratio yielded the NDT backcalculated average E c of ksi and average k ef of pci in Section 4.4, which were also required for this section. A 28-day mean modulus of rupture was estimated to be 700 psi as this is another generally accepted value for PCC and it is also the default value within the program. The elastic modulus of the base material was estimated by using the program s suggested values for aggregate bases. An average value of 30,000 psi was taken from the range between 15,000 and 45,000 psi. The base design thickness of inches was determined from the NYDOT subsurface exploration logs as explained in Chapter 2. A slab-base friction factor of 1.5 was used for analysis coming from the recommended AASHTO value for crushed stone. (AASHTO, 1986) The AASHTO Design Guide states that the reliability of a pavement designperformance process is the probability that a pavement section designed using the process will perform satisfactorily over the traffic and environmental conditions for the design period. (AASHTO, 1986) Utilizing this concept, a suggested reliability value for rigid pavement design is usually taken as 95%. A standard deviation estimation often used for rigid pavements, when the variance of projected future traffic is considered is 0.34 and was used in this analysis. (AASHTO, 1986) The rigid pavement design program contains a library of climatic properties to be used when designing a pavement in various regions of the United States. The closest data entry to Olean, NY was for Buffalo, NY. From this database, the mean annual wind

81 81 speed of 12.1 mph, mean annual air temperature of 47.6 ºF (8.67 ºC), and the mean annual precipitation of 37.5 in were selected. Table 4.6 refers to the estimated input values required for the traffic calculation within the program. Given the AADT values of 11,900 veh/day for 2004 and 8,100 veh/day for 1994 an AADT of 4000 veh/day was estimated for 1972, thus giving the twoway AADT of 8000 veh/day. An 8.75% annual growth rate was calculated to bring this 4,000 AADT to the most current 11,900 veh/day over a period of 34 years. The percentage of trucks in the design lane was simply assumed while an even 50/50 split between trucks traveling east, the design direction, and west was also assumed. As suggested by the NYDOT information the highest percentage of trucks in traffic, 25%, was used for analysis to simulate the worst case scenario. Load equivalency factors for passenger cars, of 0.002, and five axle tractor semitrailers, of 1.09, for rural interstates were used to calculate the total ESALs accumulated during the design period. (Garber and Hoel, 2002) Table 4.6 Estimated Traffic Input Values. PARAMETER INPUT VALUE Two-Way Daily Traffic (ADT) 8,000 veh/day % of Trucks in Design Lane 80% % of All Trucks in Design Direction 50% Annual % Growth 8.75% Passenger Car Load Equivalency Factor Axle Tractor Semitrailer Load Equivalency Factor 1.09

82 82 Due to the lack of actual data many of the inputs used to check the pavement s susceptibility to joint faulting were selected as the given default values, as shown in 1 Table 4.7. A dowel diameter of 1 8 inches was chosen since this is the Portland Cement Association s recommended dowel size for a 9 in thick concrete slab. (Huang, 2004) Table 4.7 Estimated Faulting Check Input Values. PARAMETER INPUT VALUE Dowel Diameter in Modulus of Dowel Support 1,500,000 psi/in Modulus of Elasticity of Dowel Bar 29,000,000 psi PCC Thermal Expansion Coefficient 6 6 *10 /ºF Annual Temperature Range 94 ºF PCC Drying Shrinkage Coefficient strain Applied Wheel Load 9,000 lbf Percent Transferred Load 28% Mean Annual Freezing Index 1,028 ºF-days AASHTO Drainage Coefficient 0.95 The default values for modulus of dowel support of 1,500,000 psi/in, and the modulus of elasticity of the dowel bar of 29,000,000 psi, were selected. These are both typical moduli values for steel reinforcement. The PCC thermal expansion coefficient of 6 *10 6 /ºF is the AASHTO recommended value for concretes with gravel as coarse aggregate. (AASHTO, 1986) The PCC drying shrinkage coefficient of strain was also recommended by AASHTO for concrete that has an indirect tensile strength of 700 psi. (AASHTO, 1986) An annual temperature range of 94 ºF was taken from 2005 data for the Bradford, NY regional airport located 54 miles from the project site, shown in Figure 4.6. ( Season Weather, 2006) The program s default tire wheel load value of 9,000 psi was also selected, while a mean annual freezing index of 1,028 ºF-days was taken from the table included in the program for Buffalo, NY. The input for the

83 83 AASHTO drainage coefficient, 0.95, was also found as a choice within the program from a suggested range of for a pavement with edge drains, coarse-grained subgrade, a non-permeable base, and in a wet precipitation zone. A lower than average value was selected since steep slopes exist on the right side of the eastbound direction and some of the drains were clogged causing water to pond. Finally, the program uses a value of 0.5, or 50%, to denote perfect load transfer at a joint. A percentage of transferred load was calculated by taking the average load transfer efficiency for each section, averaging these four values, and then dividing by two to get 28%. Figure 4.6 Daily High and Low Temperatures for 2005 at Bradford, NY Regional Airport. ( Season Weather, 2006) 4.6 Rigid Pavement Design Program Results After executing the FHWA Rigid Pavement Design Program with the previously discussed input parameters a calculated slab thickness of inches was determined. The required thickness for the 34 year service life is effectively 6.5 inches higher than the actual 9 inches of the existing pavement. Figure 4.7 shows the plot generated by the

84 84 program for slab thickness with the added arrows highlighting the difference between the existing and calculated thicknesses. The slab thickness of inches is capable of withstanding the million equivalent single axle loads (MESALs) generated over the 34 year design period, while the existing 9 inch-thick pavement could only carry a design traffic of 1.5 MESALs. Pavement Thickness vs Design Traffic 100 Design Traffic (MESALs) Pavement Thickness Pavement Thickness (in) Figure 4.7 Calculated Pavement Thickness vs. Design Traffic, 34 Year Analysis. The pavement designed by the program would, however, be prone to faulting. A critical mean joint faulting value of 3.30 mm (0.13 in) was required for doweled pavement with joints spaced greater than 25 ft apart. The designed pavement failed the faulting check as it had a joint faulting value of 4.32 mm (0.17 in). If a larger drainage coefficient is used, such as the maximum suggested value for non-permeable bases of 1.10, the faulting calculates to 3.56 mm (0.14 in), which exceeds this faulting check by

85 mm (0.01 in). The difference between these joint faulting predictions and those measured by the Georgia digital faultmeter shows the overall good condition of the joints. Because of the large amount of MESALs in this situation the previous claim that faulting is mainly induced by traffic loads is substantiated. The implementation of better base materials would additionally help reduce the likelihood of joint faulting. The rigid pavement design program was also used to analyze this pavement assuming it was designed for a 20 year service life, as is typical for concrete pavements. All input values for the 20 year analysis were the same as for the 34 year analysis. During this 20 year time period MESALs would have accumulated resulting in a required pavement thickness of in, just over 4 inches greater than the constructed pavement. This suggests that either the pavement was under designed, or the estimated input parameters were not quite accurate. Judging by both the amount of assumed inputs and the documented condition of the pavement a combination of both of these factors is most likely. This inch-thick pavement would also not be subjected to joint faulting. The 3.30 mm (0.13 in) critical mean joint faulting was higher than the predicted value of 2.54 mm (0.10 in). A summary of the comparison between the results of the two analysis periods is shown in Table 4.8. Table 4.8 Comparison of Rigid Pavement Design Program Service Life Analyses. Analysis Period Concrete Design Thickness (in) Difference in Existing Thickness (in) Accumulated MESALs Joint Faulting Check (in) Predicted Joint Faulting (in) Pass Faulting Check (Y/N) 20 years YES 34 years NO

86 86 Chapter 5 Conclusions and Recommendations 5.1 Conclusions The results of distress surveys performed on I-86 corroborated the background information provided by the NYDOT. Numerous types of distresses were observed throughout the length of the four test sections surveyed on the 34 year old jointed reinforced concrete pavement. Of those recorded, high severity transverse cracks and high severity corner breaks were the most prevalent in the sections and were also the most detrimental to the condition of the pavement. Section 3 consistently had more severe distresses than all other sections. This became evident when the PCI was calculated for each section. Although all sections were rated Poor, the PCI of Section 3 was much lower than those of the other test sections, which were comparable to one another. The conventional unbonded overlay section, Section 1, should provide a good base condition for testing since its PCI value was the same as Section 2 and very close to Section 4. Data gathered by the Falling Weight Deflectometer during two series of tests also showed the extent of transverse cracking. The fluctuation of D f0 values and the range in spreadability for both test dates illustrated the effect these distresses had on the pavement. Joint conditions on this pavement, meanwhile, were as expected for a pavement of this age. Joint support ratios at all but one of the tested joints fell within the criteria required to deem them acceptable. Load transfer efficiency as a whole was fairly low for this pavement, but this was adversely affected by the state of the dowel bars. These were

87 87 found to be in poor condition having lost some cross sectional area due to severe rusting and the protective coating peeling off. Results of the dynamic cone penetrometer testing further singled out the condition of Section 3 being worse than the remaining three tested sections, although not as pronounced as in the distress surveys or PCI calculations. The subgrade stiffness in this section as a whole was less than that of the other test sections. As stated in the NYDOT geotechnical report settlement has occurred along this roadway indicating subsurface deficiencies. The results of the DCP testing show that the distresses found in Section 3 may potentially be the product of a deficient subgrade. Using the American Concrete Pavement Association s Pavement Analysis Software and select Falling Weight Deflectometer data the material properties of the concrete and subgrade were computed. This non-destructive testing backcalculation procedure reported values within the expected ranges for the modulus of subgrade reaction and the elastic modulus of concrete. Using backcalculation the average concrete elastic modulus of Section 3 was the lowest of all sections, which was caused by the greater amount of transverse cracking affecting the data collected by the Falling Weight Deflectometer. The average modulus of subgrade reaction of Section 3 was found to be higher than that of Section 2. This again can be attributed to the presence of transverse cracking affecting the analysis program since this differs from the results of the dynamic cone penetrometer. Average material property results obtained from the Pavement Analysis Software were used, along with other input parameters, to model the existing pavement in the FHWA Rigid Pavement Design Program. Analyzing the pavement using a typical 20

88 88 year design period showed that the major problem was not entirely the original design itself. The potentially unforeseen growth in traffic volume, including the high percentage of trucks, over the additional fourteen years of use caused severe deterioration. The decreased serviceability of the pavement was then most likely the result of an overextended service life. This outcome correlates directly with the majority of the severe distresses in this pavement being primarily traffic load related failures. Furthermore, the program showed the pavement should have been 6.5 inches greater than its existing thickness in order to be serviceable at its present age of 34 years. 5.2 Recommendations Comparing the observed conditions of the pavement to previously conducted research has allowed for other predictions about the future of this project to be made. When employing the crack and seat method on JRCP it is emphasized that the steel reinforcement is broken as well. If this is not achieved the slab will continue to act as a single layer and likely reflect cracks onto the overlay. (Carpenter et. al., 1989) It can be assumed that the steel reinforcement in Section 3 was probably not ruptured after assessing the condition of the pavement after cracking and seating. This may be the cause for earlier reflective cracking in the overlay as compared to the other test sections. The thickness of the full asphalt concrete overlay used in Section 4 slightly exceeded the better performing pavement cited in the ACPA rubblizing source. (ACPA, 1999) Assuming no other factors severely affect pavement behavior, this section could be expected to perform somewhat similarly.

89 89 Analysis involving the data gathered by this full forensic investigation has created a firm basis upon which each of the forthcoming rehabilitation procedures can be studied. All distresses and their magnitudes in the test sections have been logged and categorized. Calculating the PCI using this data will allow for comparisons to be drawn between the existing pavement and eventually the overlayed pavement. The properties of the existing pavement structure, which will become the underlying base and subbase materials, have been calculated and can then be used in further examination of the pavement. The use of the same analysis programs and procedures as those applied in this project for comparison is suggested, although others may also be employed for verification.

90 90 References Ahlrich, R. C. Performance and Structural Evaluation of Cracked and Seated Concrete. Transportation Research Board 1215 (1989): American Association of State Highway and Transportation Officials (AASHTO). AASHTO Guide for Design of Pavement Structures. Washington: American Association of State Highway and Transportation Officials, American Society for Testing and Materials (ASTM). Road and Paving Materials; Vehicle-Pavement Systems. 77 vols. Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys. West Conshohocken: ASTM International, Automated Pavement Distress Collection Techniques. Consultant Kenneth H. McGhee. National Cooperative Highway Research Program (NCHRP) Synthesis 334. Washington: Transportation Research Board, Cafiso, Salvatore and Alessandro Di Graziano. Road Surface Distress and Driving Performance. Transportation Research Board 83 rd Annual Meeting Compendium of Papers. CD-ROM. Transportation Research Board Carpenter, Samuel H. and Michael I. Darter. Field Performance of Crack and Seat Projects. Transportation Research Board 1215 (1989): Cox, Wendell and Jean Love. The Best Investment a Nation Ever Made. American Highway Users Alliance, June, May 2006 < Edwards, William F., Roger L. Green, and James C. Gilfert. Implementation of a Dynamic Deflection System for Rigid and Flexible Pavements in Ohio. Publication Number FHWA/OH-89/020. Columbus: Ohio Department of Transportation, Federal Highway Administration (FHWA). Distress Identification Manual for the Long- Term Pavement Performance Program. Publication Number FHWA-RD Washington: Federal Highway Administration, June, Federal Highway Administration (FHWA). Rigid Pavement Design Software: A New Tool for Improved Rigid Pavement Design. Publication Number FHWA-RD Washington: Federal Highway Administration, May, Garber, Nicholas J. and Lester A. Hoel. Traffic and Highway Engineering. Pacific Grove: Brooks/Cole, 2002.

91 91 Huang, Yang H. Pavement Analysis and Design. Upper Saddle River: Pearson Prentice Hall, Ohio Department of Transportation (ODOT). Pavement Design and Rehabilitation Manual. Columbus: Ohio Department of Transportation, January, Rubblizing of Concrete Pavements: A Discussion of its Use. American Concrete Pavement Association (ACPA) (1998). Sargand, Shad M., William Edwards, and Huntae Kim. Determination of Pavement Layer Stiffness on the Ohio SHRP Test Road Using Non-Destructive Testing Techniques. Publication Number FHWA/OH-2002/031. Columbus: Ohio Department of Transportation, Season Weather Averages for Bradford Regional (KBFD). Weather Underground. 12 April, 2006 < FD&StateCode=NY&SafeCityName=Olean&Units=none&IATA=BFD&lastyear =on&normals=on>. Webster, S. L., R. H. Grau, and T. P. Williams. Description and Application of Dual Mass Dynamic Cone Penetrometer. Vicksburg: United States Army Corps of Engineers, 1992.

92 92 APPENDIX A NYDOT SUBSURFACE LOG DATA CONDUCTED

93 Figure A.1 Subsurface Exploration Log, Station

94 94 APPENDIX B DISTRESS MAPS CONDUCTED and

95 95 SECTION 1 CONDUCTED Figure B.1 Section 1 Distress Map, 0 to 100. Figure B.2 Section 1 Distress Map, 100 to 200.

96 96 Figure B.3 Section 1 Distress Map, 200 to 300. Figure B.4 Section 1 Distress Map, 300 to 400.

97 Figure B.5 Section 1 Distress Map, 400 to

98 98 SECTION 2 CONDUCTED Figure B.6 Section 2 Distress Map, 0 to 100. Figure B.7 Section 2 Distress Map, 100 to 200.

99 99 Figure B.8 Section 2 Distress Map, 200 to 300. Figure B.9 Section 2 Distress Map, 300 to 400.

100 Figure B.10 Section 2 Distress Map, 400 to

101 101 SECTION 3 CONDUCTED Figure B.11 Section 3 Distress Map, 0 to 100. Figure B.12 Section 3 Distress Map, 100 to 200.

102 102 Figure B.13 Section 3 Distress Map, 200 to 300. Figure B.14 Section 3 Distress Map, 400 to 500.

103 103 SECTION 4 CONDUCTED Figure B.15 Section 4 Distress Map, 0 to 100. Figure B.16 Section 4 Distress Map, 100 to 200.

104 104 Figure B.17 Section 4 Distress Map, 200 to 300. Figure B.18 Section 4 Distress Map, 300 to 400.

105 Figure B.19 Section 4 Distress Map, 400 to

106 106 APPENDIX C NORMALIZED D f0 PLOTS

107 107 Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure C.1 Normalized Section 2 FWD D f0 Deflections, Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure C.2 Normalized Section 3 FWD D f0 Deflections,

108 Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure C.3 Normalized Section 1 FWD D f0 Deflections, Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure C.4 Normalized Section 3 FWD D f0 Deflections,

109 109 APPENDIX D REVISED NORMALIZED D f0 PLOTS

110 110 Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure D.1 Revised Normalized Section 2 FWD D f0 Deflections, Normalized Load Sensor Deflection (D f0 ) Section Vertical Deflection (mils/kip) Drop 1 Drop 2 Drop Distance (m) Figure D.2 Revised Normalized Section 3 FWD D f0 Deflections,

111 111 APPENDIX E AVERAGE SPREADABILITY PLOTS

112 112 Section 1 Average Spreadability Average Spreadability (%) SPR % Distance (m) Figure E.1 Section 1 Average Spreadability, Section 2 Average Spreadability Average Spreadability (%) SPR % Distance (m) Figure E.2 Section 2 Average Spreadability,

113 113 Section 3 Average Spreadability Average Spreadability (%) SPR % Distance (m) Figure E.3 Section 3 Average Spreadability, Section 4 Average Spreadability Average Spreadability (%) SPR % Distance (m) Figure E.4 Section 4 Average Spreadability,

114 114 Section 1 Average Spreadability Average Spreadability (%) "3 cracks under sensors" SPR % Distance (m) Figure E.5 Section 1 Average Spreadability, Section 2 Average Spreadability Average Spreadability (%) SPR % 50 "heavily patched area" Distance (m) Figure E.6 Section 2 Average Spreadability,

115 115 Section 3 Average Spreadability Average Spreadability (%) SPR % 50 "plate near small crack" Distance (m) Figure E.7 Section 3 Average Spreadability,

116 116 APPENDIX F GEORGIA DIGITAL FAULTMETER PLOTS

117 117 Extent of Transverse Crack Faulting Section Number of Cracks Number of Cracks to <0 No Faulting >0 to 5 5 to to to 20 Categories of Fault Severity (mm) 20 to to to 35 Figure F.1 Extent of Transverse Crack Faulting, Section 2. Section 4 Transverse Crack Faulting Profile Transverse Crack Faulting (mm) Distance (m) Figure F.2 Transverse Crack Faulting Profile, Section 2.

118 118 Section 2 Transverse Joint Faulting I-86 Eastbound Olean, NY Dropoff (mm) Faulting Joint Number Figure F.3 Faulting of Transverse Joints, Section Section 4 Transverse Joint Faulting I-86 Eastbound Olean, NY Dropoff (mm) Faulting Joint Number Figure F.4 Faulting of Transverse Joints, Section 4.

119 119 Lane-to-Shoulder Dropoff Section 3 Point Distance (m) Dropoff (mm) Figure F.5 Lane-to-Shoulder Dropoff, Section 3. 0 Lane-to-Shoulder Dropoff Section 4 Point Distance (m) Dropoff (mm) Figure F.6 Lane-to-Shoulder Dropoff, Section 4.

120 120 APPENDIX G DYNAMIC CONE PENETROMETER BLOWS VERSUS DEPTH PLOTS

121 121 NY I-86 East Bound Station Depth (mm) blow Blows Figure G.1 Blows vs. Depth, Station NY I-86 East Bound Station Depth (mm) blow Blows Figure G.2 Blows vs. Depth, Station

122 122 NY I-86 East Bound Station Depth (mm) blow Blows Figure G.3 Blows vs. Depth, Station NY I-86 East Bound Station Depth (mm) blow Blows Figure G.4 Blows vs. Depth, Station

123 123 NY I-86 East Bound Station Depth (mm) blow Blows Figure G.5 Blows vs. Depth, Station NY I-86 East Bound Station Depth (mm) blow Blows Figure G.6 Blows vs. Depth, Station

124 124 NY I-86 East Bound Station blow Depth (mm) Blows Figure G.7 Blows vs. Depth, Station NY I-86 East Bound Station Depth (mm) blow Blows Figure G.8 Blows vs. Depth, Station

125 125 NY I-86 East Bound Station Depth (mm) blow Blows Figure G.9 Blows vs. Depth, Station NY I-86 East Bound Station Depth (mm) blow Blows Figure G.10 Blows vs. Depth, Station

126 126 NY I-86 East Bound Station Depth (mm) blow Blows Figure G.11 Blows vs. Depth, Station NY I-86 East Bound Station Depth (mm) blow Blows Figure G.12 Blows vs. Depth, Station

127 127 NY I-86 East Bound Station Depth (mm) blow Blows Figure G.13 Blows vs. Depth, Station

128 128 APPENDIX H DYNAMIC CONE PENETROMETER PENETRATION INDEX VERSUS DEPTH PLOTS

129 129 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.1 PI vs. Depth, Station NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.2 PI vs. Depth, Station

130 130 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.3 PI vs. Depth, Station NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.4 PI vs. Depth, Station

131 131 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.5 PI vs. Depth, Station NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.6 PI vs. Depth, Station

132 132 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.7 PI vs. Depth, Station NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.8 PI vs. Depth, Station

133 133 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.9 PI vs. Depth, Station NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.10 PI vs. Depth, Station

134 134 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.11 PI vs. Depth, Station NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.12 PI vs. Depth, Station

135 135 NY I-86 East Bound Station Depth (mm) PI PI (mm/blow) Figure H.13 PI vs. Depth, Station

136 136 APPENDIX I DYNAMIC CONE PENETROMETER MODULUS OF RESILIENCE VERSUS DEPTH PLOTS

137 137 NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.1 Modulus of Resilience, Station NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.2 Modulus of Resilience, Station

138 138 NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.3 Modulus of Resilience, Station NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.4 Modulus of Resilience, Station

139 139 NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.5 Modulus of Resilience, Station NY I-86 East Bound Station Mr Depth (mm) Mr (ksi) Figure I.6 Modulus of Resilience, Station

140 140 NY I-86 East Bound Station Mr Depth (mm) Mr (ksi) Figure I.7 Modulus of Resilience, Station NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.8 Modulus of Resilience, Station

141 141 NY I-86 East Bound Station Mr Depth (mm) Mr (ksi) Figure I.9 Modulus of Resilience, Station NY I-86 East Bound Station Depth (mm) Mr Mr (ksi) Figure I.10 Modulus of Resilience, Station

142 142 APPENDIX J PAVEMENT CONDITION INDEX DISTRESS SUMMARY SPREADSHEETS

143 143 Table J.1 Distresses and Deduct Values, Section 2. LTPP Distress Type ASTM Distress Type Severity # Slabs Affected Density (%) Deduct Value Description Corner Break 1 22 M Corner Break 1 22 H Transverse Cracking 4 28 L Transverse Cracking 4 28 M Transverse Cracking 4 28 H Scaling 8b 36 L Scaling 8b 36 M Patch/Patch Deterioration (Small) L Patch/Patch Deterioration (Large) L Joint Seal Damage - 26 M SUM: 133 Table J.2 Corrected Deduct Values, Section 2. # DEDUCT VALUES m TDV q CDV Description Table J.3 Distresses and Deduct Values, Section 3. LTPP Distress Type ASTM Distress Type Severity # Slabs Affected Density Deduct Value Corner Break 1 22 L Corner Break 1 22 H Transverse Cracking 4 28 L Transverse Cracking 4 28 M Transverse Cracking 4 28 H Longitudinal Joint Spalling 6 39 H 1 4 Transverse Joint Spalling 7 39 H Scaling 8b 36 L Patch/Patch Deterioration 32 (Small) L 8 2 Patch/Patch Deterioration 16 (Large) L 4 4 Joint Seal Damage - 26 M Joint Faulting - 25 L SUM: 156

144 144 Table J.4 Corrected Deduct Values, Section 3. # DEDUCT VALUES m Total q CDV Table J.5 Distresses and Deduct Values, Section 4. LTPP Distress Type ASTM Distress Type Severity # Slabs Affected Density Deduct Value Description Corner Break 1 22 M Corner Break 1 22 H Longitudinal Cracking 3 28 L Transverse Cracking 4 28 L Transverse Cracking 4 28 M Transverse Cracking 4 28 H Longitudinal Joint Spalling 6 39 H Scaling 8b 36 L Patch/Patch Deterioration (Small) L 9 2 Patch/Patch Deterioration 4 (Large) L Patch/Patch Deterioration 4 (Large) H 1 7 Joint Seal Damage - 26 M Lane/Shoulder Dropoff - 27 L SUM: Table J.6 Corrected Deduct Values, Section 4. # DEDUCT VALUES m Total q CDV

145 145 APPENDIX K RIGID PAVEMENT DESIGN PROGRAM INPUT SCREENS

146 Figure K.1 Rigid Pavement Design Program General Input Form, 34 Year Test. 146

147 Figure K.2 Rigid Pavement Design Program Faulting Check, 34 Year Test. 147

148 Figure K.3 Rigid Pavement Design Program Traffic Inputs, 34 Year Test. 148

149 Figure K.4 Rigid Pavement Design Program General Input Form, 20 Year Test. 149

150 Figure K.5 Rigid Pavement Design Program Faulting Check, 20 Year Test. 150

151 Figure K.6 Rigid Pavement Design Program Traffic Inputs, 20 Year Test. 151