Table 1. Design Specification for Illinois 9.5 mm Mix for Local Road Overlays, Slow Traffic

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1 CE 330L Student Lab Manual Superpave TM Mix Design PART A Pre-Labratry Preparatin Intrductin This manual utlines the steps necessary t design, prepare and evaluate a ht mix asphalt (HMA) specimen using the Superpave TM (Superir Perfrming Asphalt Pavements) mix design methd and criteria. Superpave TM has been recently adpted by many state highway departments, replacing the Marshall and the Hveem methds fr asphalt mix design. This manual includes the fllwing parts. A. Prject parameters, aggregate blending, asphalt binder selectin, and material prperties. B. Preparatin f the ht mix specimen. C. Validatin f the final mix results. D. Appendix with supprting data and lab wrksheets. Related tpics f asphalt binder prperties and selectin, equipment calibratin and perfrmance testing are nt part f this dcument. Students wishing t learn mre abut the ttal Superpave TM prcess can cntact the instructr fr a list f additinal resurces. Design Criteria Superpave mix design requires many aggregate and asphalt cement prperties t be evaluated and selected t meet a particular set f standards. In Illinis, as in mst states, certain characteristics f the final mix design have been adpted and must be used fr certain prjects. T reduce detail wrk that is beynd the scpe f CE330L, many f the prperties have already been selected. The fllwing prcedures are based n the selected prperties. The specificatins given in Table 1 are presented t highlight the primary design target values necessary fr apprval f the mix under IDOT s criteria fr the IL 9.5 mm mix designatin nly. Fr ther mixes, refer t apprpriate surces fr the target values. Table 1. Design Specificatin fr Illinis 9.5 mm Mix fr Lcal Rad Overlays, Slw Traffic Parameter Target Value Equivalent Single Axle Lads (ESAL s) <0.3 millin Required Initial Density, N initial 5 Required Design Density, N design 30 Required Maximum Density, N max 42 Vids in Mineral Aggregate (VMA) 13.0% minimum (mdified IDOT) Percent (%) Air Vids (Va) 4.0 % Vids Filled with Asphalt (VFA) 65-78% Dust/AC rati 1.0 maximum Maximum percentage f G N initial 89% Maximum percentage f G N max 98% (Nte: G mm is the theretical maximum specific gravity f the mix.) Safety Cnsideratins This lab experiment invlves wrking with ht aggregates and ht liquid asphalt at temperatures f up t abut 350 F. The asphalt ignitin ven will be perating at abut 1100 F. Als, there is risk that sme f the materials culd stain yur clthing, s plan t wear apprpriate clthing. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001,2007 6/2/2009 Page A1 f 2

2 Superpave Asphalt Mix Design CE 330L Student Lab Manual Part A In additin t the standard lab safety requirements, yu are required t bring and wear the fllwing safety items: safety glasses lng pants shes that cmpletely cver yur feet In additin t the items abve, yu will be prvided with heat-resistant glves, Kevlar sleeves, a lab cat and face shield as needed fr certain peratins in the lab. Prcedures A key step in the prcedure fr designing a Superpave mix is t select apprpriate amunts f standard aggregate gradatins t achieve a well-graded, dense mix. Thugh yu have already tested the aggregates in a previus experiment, we will use standardized results in the actual mixing prcedures t reduce variatins in the final mix since each grup will share their HMA mix design results with the ther grups. Testing was perfrmed t find the gradatin characteristics f the materials stckpiled fr this lab. Table A1 shws the gradatins required fr the IL 9.5mm mix. Table A2 shws the restricted zne thrugh which the particle size distributin curve must nt pass. Table A3 shws the results f the sieve and specific gravity tests fr the fur standard aggregate gradatins stckpiled fr this lab. Table A4 shws the standardized aggregate prprtins fr the Superpave HMA mix design t be used in the experiment. Step 1 Refer t Table A4 which shws the percentage f each aggregate gradatin t be used t make a 7,000-gram batch. Cmpute the mass f each aggregate per this table. [Nte that the standard mix design prcedure fr the CA-16 material is t presrt and place int individual buckets t separate the larger particle sizes (3/8 inch thrugh #30). This is dne t reduce the effects f particle size segregatin n the final mix design. Using this methd, the mass f each particle size gradatin t be used frm the CA-16 stck is given in the table. Hwever, if reasnable precautins have been taken t prevent particle size segregatin, the CA-16 des nt need t be presrted. Yur instructr will let yu knw which methd t use fr this lab.] Cmplete the table by cmputing the ttal mass f each aggregate required. The ttal shuld add t 7,000 grams. Step 2 Superpave uses the 0.45 pwer chart fr pltting the mix gradatin (Figure A1). Using the results f yur grup s sieve tests, plt the ttal batch percentages fr each sieve size f the cmbined aggregates n the 0.45 pwer chart. Verify that the batch gradatin is within the cntrl pints and ut f the restricted zne (see Tables A1 and A2). Fr the purpse f this experiment, mentin any deviatins in yur reprt. NOTE: In actual practice the aggregate used fr the trial batch must be within the gradatin parameters f the 0.45 pwer chart in rder t prceed. If it desn t meet the parameters, then the mix designer must adjust material percentages, recalculate the batch percentages, and plt the resulting new batch gradatin. Step 3 Having successfully btained the trial batch gradatin percentages, make a batch f asphalt mix. Fr specific instructins n hw t make the asphalt mix refer t Part B f this manual. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001,2004 6/2/2009 Page A2 f 2

3 Superpave Asphalt Mix Design - Part B Labratry Prcedures fr the Preparatin f HMA Test Specimens Materials The fllwing materials will be used in the specimen prductin. Perfrmance Graded Asphalt Binder Curse Aggregate Fine Aggregate Mineral Filler Equipment The fllwing equipment will be utilized in the specimen prductin. Ovens, thermstatically cntrlled Mechanical Mixer, 10 qt. Flat bttm metal pans Metal Scp, spatula, and spns WD-40 r ther light lubricating fluid Puring pt, fr heating and dispensing liquid asphalt binder Thermmeters t measure F Balances, 8 kg capacity Heat resistant glves, Kevlar sleeves Yellw lumber crayn, fr specimen identificatin marking Paper disks, 6 inches, fr gyratry cmpactin Gyratry Cmpactr with cmputer (fr cmpacting and recrding specimen data) Definitins Althugh students shuld be familiar with the basic terminlgy f the asphalt mix design prcess frm lecture, the fllwing definitins are prvided fr ease f reference as these are used thrughut the manual. Asphalt Binder: the asphalt cement used t mix and bind the aggregate and mineral filler. Curse Aggregate: rck particles generally larger than the #4 sieve. Fine Aggregate: sand, silt, and clay particles generally smaller than the #4 sieve but larger than the #200 sieve. Mineral Filler: dust size particles used t fill small vids in the ht mix asphalt specimen. Gyratry Cmpactr: a piece f equipment used t cmpact the asphalt mix design specimen at a specified pressure, angle f tilt, and revlutin cycles. N design, Design Gyratins: the number f gyratins fr the particular mix design specimen. Crrespnds t the cmpactin at the end f the pavements design life. This is where the ptimum asphalt cntent is determined crrespnding t 4% air vids. N init : the number f gyratins at which the specific gravity must nt exceed 89 percent f Gmm. Crrespnds t the expected cmpactin at the time f the pavement s cnstructin. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page B1 f 3

4 Superpave Asphalt Mix Design Part B CE 330L Student Lab Manual N max : the number f gyratins at which the specific gravity must nt exceed 98 percent f Gmm. Crrespnds t the maximum recmmended density. Warning: The asphalt mix design specimen prcedure invlves the use f heavy aggregates and ht asphalt liquid. Students shuld fllw all lab safety prcedures t avid injury. Prcedures The fllwing steps utline the basic prcedures in the HMA specimen prductin. These basic steps are taken frm Asphalt Institute. (1996). Superpave Mix Design: Superpave Series N. 2 (SP-2). U.S.A. Sme adjustments were made t help fit the sequence t ur alltted lab schedule. Materials Step 1 Cmplete the pre-lab exercise described in Part A t determine the batch weights f curse and fine aggregate, mineral filler and asphalt t be used fr the HMA specimen prductin. Carefully weigh ut the required aggregate sizes and place in separate cntainers. Put the aggregate in the ven and heat fr 1 hur at 165+/-3 C (329+/-5 F). Step 2 After preheating, remve the materials frm the ven as yu need them. Avid allwing anything t cl befre mixing. Cmbining and Mixing Step 3 Place the CA-16 aggregate int the mechanical mixing bwl. D NOT add the FA-20 r MF materials yet. Place the pre-measured FA-01 (sand) in a heated bwl n the electrnic balance. Tare the bwl with the sand. Frm a bwl in the sand t hld the liquid asphalt. Carefully add the cmputed mass f liquid asphalt t the sand. If t much asphalt is added, remve the extra with a small scp r spn. Add the sand and asphalt t the aggregate already in the mixing bwl. Munt the mixing bwl n the mixer. Turn the mixer n (lw speed setting f 1) and mix until mst f the asphalt is distributed. Turn the mixer ff. Add the remaining aggregate fines. Turn the mixer n and mix the batch until all the aggregate is fully cated with the asphalt binder. Peridically turn the mixer ff and lightly scrape the material sticking t the sides f the bwl r upper prtin f the mixing wisp. Turn the mixer ff. Step 4 Remve all the specimen materials frm the mixer and place mixture nt tw shallw metal pans. Spread mixture t an even thickness and place in the ven fr 1 hur at 165 C. This time in the ven is dne t simulate shrt-term aging that ccurs during the actual HMA prductin and transprtatin phases prir t cmpactin. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page B2 f 3

5 Superpave Asphalt Mix Design Part B CE 330L Student Lab Manual Cmpactin In this sequence, yu will make a cmpacted HMA specimen. The gyratry cmpactr will mnitr the cmpactin pressure, sample height and number f gyratins. This data will be displayed during the cmpactin phase and saved t a file n the cmputer. The cmputer prgram will stp the gyratry cmpactr at the specified endpint, which fr ur lab will be after N max gyratins f 42. Step 5 While the mixture is aging in the ven, prepare the gyratry cmpactr fr use. Cnnect the cmputer t the gyratry cmpactr via the COM1 serial prt. Prepare the cmputer sftware that perates and cllects the data frm the cmpactr. Fr this peratin, verify the cmpactin pressure f 600 kpa, cmpactin mld inclinatin angle f 1.25, and enter the N max = 42 int the sftware at the apprpriate lcatin n the screen. Place the cmpactin mld and mld bttm in the ven fr 60 minutes at the 165 C temperature. Step 6 Remve the mixture and the cmpactin mld frm the ven at the same time. Spray a thin layer f a light lubricant (eg. WD-40) t cat the inside f the mld. Next, place a paper filter disk n the bttm plate f the mld. Using a scp r spatula, measure apprximately 4,500 grams f the specimen mixture int a preheated bwl. IMPORTANT: Recrd n the datasheet the actual mass f HMA t be placed in the mld. Then dump the mix int the mld in ne smth peratin. Finally, gently level the tp f the HMA specimen and place anther paper filter disk n tp f the specimen mixture in the mld. D NOT tamp the lse HMA. Step 7 Place the mld with the specimen int the gyratry cmpactr and click the Start buttn n the gyratry cmpactr prgram screen. During the cmpactin prcess, the cmputer will mnitr the specimen height, the cmpactin pressure, tilt angle and number f gyratins. The prgram will stp the test nce reaching the designated N max gyratins. Be sure the cmpactin angle stays within 0.10 f the 1.25 target angle. If it varies, stp the cmpactr temprarily by lifting the guard dr. This will stp the rtatin s yu can insert the handle t adjust the tilt angle. Then remve the handle, clse the dr and allw the cmpactin prcess t cntinue. Step 8 Once the cmpactin is cmplete, remve the mld frm the center hld. Center the mld ver the tp f the extractin pistn n the cmpactr base. Press the extractin buttn n the cmpactr and extrude the specimen frm the mld. Let the specimen cl enugh s that it des nt crumble r distrt when carefully handled. Use a small fan t speed the cling prcess. Remve the paper disks and, using a lumber crayn r chalk, mark the tp f the specimen with yur lab grup number fr future identificatin. Prceed t Part C fr Validatin test prcedures. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page B3 f 3

6 Superpave Asphalt Mix Design - Part C Validatin Prcedures and Reprt Requirements fr the Prepared HMA Test Specimens Intrductin The final step in the Superpave mix design methd is t determine if the trial batch meets the specificatins. Fllw the steps in the sectin belw t determine Va, VMA, and VFA. These are the last criteria that the mix design must meet. Having met these remaining criteria, yu will have successfully cmpleted a prper Superpave mix design. Prcedures Vlumetrics In rder t determine if the trial batch meets the Design Criteria, the mix needs t be tested t determine whether the target values have been met fr the particular gradatin chsen. The fllwing prcedures highlight the final prcess f the mix design. The results will determine whether the mix meets the specified design criteria. HMA Maximum Theretical Density, G mm Refer t AASHTO T 209 (ur masses used are equivalent t the masses in T 209) HMA Bulk Specific Gravity, G mb Refer t AASHTO T 166 Methd A( ur masses are equivalent t the masses in T 166) NOTE: Sak specimen in 25 +/- 1ºC fr 10 +/- 1 minutes befre reading the immersed mass. Cmbined Bulk Specific Gravity f Aggregate Blend, G sb When the ttal aggregate trial blend cnsists f aggregates with different specific gravities, which is usually the case, then the Bulk Specific Gravity fr the blend must be calculated using: G sb = P 1 + P P n P 1 + P P n G 1 G 2 G n Where, G sb = bulk specific gravity f ttal aggregate blend P 1, P 2, P n = individual percentages by mass f aggregate G 1, G 2, G n = individual specific gravities f aggregate Aggregate Percentage by Mass, P s Ttal percentage by mass f the batch by the ttal mass f the aggregate. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, 2007 Page C1 f 2

7 Superpave Asphalt Mix Design Part C CE 330L Student Lab Manual Calculatins Using the abve values, substitute int the fllwing equatins t determine VMA, Va and VFA. Prperty VMA = 100 (G mb * P s )/G sb Target Value 13.0%, minimum Va = 100 * (G mm G mb )/G mm 4.0% VFA = 100 * (VMA Va)/VMA 65% - 78% Reprt Requirements After cmpleting the lab wrk, yu must submit a reprt summarizing what yu learned. The data cllected by yur grup as well as thers shuld be included in the reprt. The reprt shuld be in frmal frmat and include the fllwing sectins in the bdy (abut 3 pages, single-spaced): Intrductin Brief histry f HMA Mix Design (include basic descriptin f Marshall methd, including what parameters were measured, advantages and disadvantages f the methd fr mix design.) Brief descriptin f Superpave methd, and hw it is believed t be superir t the Marshall methd. Outline f Superpave prcedures as perfrmed in ur lab (n need t include detailed step-by-step prcedures.) Summary f results frm lab wrk (recmmended asphalt cntent with expected air vids and VMA.) Cmpare the results f the vlumetric analysis with the target values given in Table A-1 in Part A. Fr each specified parameter, state whether r nt the prpsed mix design satisfies that specified target criteria. In the appendix, include the fllwing: Data (raw data frm yur grup s wrk, end results, i.e. G mm, G mb frm the ther grups results.) Sample calculatins fr aggregate gradatin, specific gravity and mix vlumetrics. Use the Superpave Vlumetrics Wrksheet as a guide. Plt each aggregate gradatin n its wn semilg gradatin chart. Pltted 0.45 pwer chart (use Figure App-1) fr the cmbined aggregate gradatin. Plt the fllwing curves in separate charts aligned vertically n ne page shwing Asphalt Cntent (AC) percentage n the x-axis vs. the vlumetric values listed belw. Draw and label the prjectin lines yu use t find the fllwing crdinates: 1. Percent Air Vids (AV). Draw line frm Air Vids axis t find the ptimum AC at 4% AV. 2. Percent Vids in Mineral Aggregate (VMA). Draw a line representing the required VMA minimum and indicate the pint n the VFA curve crrespnding t ptimum AC. 3. Percent Vids Filled with Asphalt (VFA). Draw lines representing the minimum and maximum limits f VFA and indicate the pint n the VFA curve crrespnding t ptimum AC. Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, 2007 Page C2 f 2

8 Superpave Asphalt Mix Design Student Lab Manual Appendix Appendix Table A1. IDOT 9.5 mm Aggregate Gradatin Cntrl Pints Sieve Percent Passing Designatin Size Min Max mm 1/2" /8" N N N N N N N Table A2. IDOT 9.5 mm Mixture Restricted Zne Sieve Percent Passing Designatin Size Min Max mm N N N N Table A3. CE Dept. Labratry Aggregate Gradatins Sieves Percent Passing Designatin Size CA-16 FA-01 FA-20 MF mm 1/2" /8" N N N N N N N Specific Gravity Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page A-1 f 4

9 Superpave Asphalt Mix Design Student Lab Manual Appendix Table A4. Batch Requirements frm Aggregate Stckpile 7,000-g Batch Requirements Percentage f Each Gradatin CA-16 FA-01 FA-20 MF Sieve Designatin 1/2" 3/8" N. 4 N. 8 N. 16 N. 30 N. 50 N. 100 N. 200 TOTAL Mass f graded particles needed (g) (retained n the sieve) (Subtract the sum f the masses abve frm the ttal mass f CA-16 required t find the mass f particles passing the #30 sieve) Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page A-2 f 4

10 Superpave Asphalt Mix Design Student Lab Manual Appendix Figure A1. Superpave 0.45 Pwer Chart 100 Superpave 0.45 Pwer Chart fr IDOT 9.5-mm Mix IDOT Upper Limit Theretical Maximum Density Percent Passing Restricted Zne IDOT Lwer Limit Cmplete this chart by adding the gradatin curve cmputed fr the cmbined aggregate mix. Be sure yur curve stays inside the upper and lwer limits and utside the restricted zne Grain size (in mm) raised t the 0.45 Pwer Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page A-3 f 4

11 Superpave Asphalt Mix Design Student Lab Manual Appendix Figure A2. HMA Specimen Prductin Flwchart BEGIN #1 Heat aggregate & asphalt t specified temperature. #2 Remve aggregate and asphalt frm vens. #3 Place prprtined aggregates & asphalt int mixer. Mix until aggregate is fully cated. #4 Place HMA mix in ven fr 1 hur at 165 C (329 F). #5 Prepare the gyratry cmpactr. Place mlds in ven fr 60 minutes. #6 Remve mix & mlds frm ven. Place mix int mld. #7 Center mld in cmpactr. Start cmpactr. Let run t Nmax. #8 Remve mld. Extract specimen. Let cl. I.D. specimen. END Department f Civil Engineering, Suthern Illinis University Edwardsville 2001, /14/2007 Page A-4 f 4

12 SUPERPAVE VOLUMETRICS LAB WORKSHEET Name: Grup: Enter the sample mass, SGC gyratins and crrespnding sample heights W m g Mass f cmpacted sample "puck" N init h. init mm N des h. des mm d 150. mm Mld diameter N max h. max mm NOTE The subscripts refer t the three main gyratin levels as fllws: init => initial, des => design, max => maximum Specify Asphalt Cement Cntent (as a percentage f the aggregate mass),p b P b % P b = Specify Specific Gravity f Asphalt, G b G b G b = Calculate Aggregate Percentage by Mass, P s 100 P s 100. % P s = % 100 P b Calculate Cmbined Bulk Specific Gravity f Aggregate Blend, G sb P 1 G 1 P 2 G 2 P 3 G 3 P 4 G 4 P 1 P 2 P 3 P 4 G sb G sb = P 1 P 2 P 3 P 4 G 1 G 2 G 3 G 4 Calculate Theretical Maximum Specific Gravity f HMA Mix fr this grup's mix, G mm Mass f HMA added t Pycnmeter, A A. g Mass f HMA and Pycnmeter filled with Water, E E. g Mass f Pycnmeter filled with Water at the same temperature as fr E D G mm. g A A D E G mm = 2/28/2007 Superpave Vlumetrics Wrksheet.mcd Page 1 f 4

13 Calculate Effective Specific Gravity f Aggregate fr this Grup's mix, G se_i 100 P b G se_i i = yur grup number G se_i = 100 P b G mm G b Calculate Average Effective Specific Gravity f Aggregate fr all Grups' mixes, G se_avg G se_avg ΣG se_i N mixes N mixes = the number f mixes frm which the individual G se-i values cme frm G se_avg = Calculate Adjusted Theretical Maximum Specific Gravity f HMA Mix fr this grup's mix based n the average G se_avg, G mm_adj 100 G mm_adj P s G se_avg P b G b Calculate Bulk Specific Gravity f Cmpacted HMA Mix, G N max = Mass f HMA puck in water, C C. g Mass f saturated-surface-dry HMA puck in air, B B. g Mass f dried HMA puck in air, F F g F G mb G mb = B C Calculate cmpacted sample vlume π. d 2. h init V. cm 3 m_init V m_init = mm 3 π. d 2. h des V. cm 3 m_des mm 3 π. d 2. h max V. cm 3 m_max mm 3 Calculate bulk specific gravity V m_des = V m_max = W m W m W m G mb_max_est V m_max 1. g cm 3 G mb_des_est V m_des 1. g cm 3 G mb_init_est V m_init 1. g cm 3 G mb_max_est = Calculate crrectin factr C G mb C = G mb_max_est 2/28/2007 Superpave Vlumetrics Wrksheet.mcd Page 2 f 4

14 Calculate relative cmpactin G mb_init G mb_des G mb_max CG.G mb_init_est G mb_init N init = CG.G mb_des_est G mb_des N des = CG.G mb_max_est G mb_max N max = Calculate crrected G mb %G mm_init 100. G mb_init % V a_init 100 %G mm_init G mm_adj %G mm_des 100. G mb_des % V a_des 100 %G mm_des G mm_adj %G mm_max 100. G mb_max % V a_max 100 %G mm_max G mm_adj Calculate Vids in Mineral Aggregate in Cmpacted Mix, VMA VMA init 100 VMA des 100 VMA max 100 G. mb_init P s G sb % VMA init = % G. mb_des P s G sb % VMA des = % G. mb_max P s G sb % VMA max = % Calculate Percentage f Air Vids in Cmpacted Mix, V a G V a_init 100 G. mm_adj mb_init % V a_init = % G mm_adj G V a_des 100 G. mm_adj mb_des % V a_des = % G mm_adj G V a_max 100 G. mm_adj mb_max % V a_max = % G mm_adj Calculate Percentage f Vids Filled with Asphalt in Cmpacted Mix, VFA VFA init 100 V. VMA init a_init % VFA init = % VMA init VFA des 100 V. VMA des a_des % VFA des = % VMA des VFA max 100 V. VMA max a_max % VFA max = % VMA max 2/28/2007 Superpave Vlumetrics Wrksheet.mcd Page 3 f 4

15 SUMMARY % Asphalt in mix P b = % Bulk Sp. Grav f Aggregate G sb = Average Effective Sp. Grav f Aggregate G se_avg = Theretical Max. Sp. Grav., adjusted based n all mixes G mm_adj = Gyratins N init = N des = N max = Bulk Sp. Gravity G mb_init = G mb_des = G mb_max = % f Max Sp. Gravity %G mm_init = % %G mm_des = % %G mm_max = % % Air Vids V a_init = % V a_des = % V a_max = % % Vids Filled with Asphalt VFA init = % VFA des = % VFA max = % % Vids in Mineral Aggregate VMA init = % VMA des = % VMA max = % 2/28/2007 Superpave Vlumetrics Wrksheet.mcd Page 4 f 4