Effects of Rutted Surface on Near-Surface Pavement Response

Transcription

1 Effects of Rutted Surface on Near-Surface Pavement Response Guangming Wang, Ph.D., EIT; Dennis Morian, P.E. Quality Engineering Solutions, Inc Reynaldo (Rey) Roque, Ph.D., P.E. Department of Civil and Coastal Engineering University of Florida 2010 VT Pavement Evaluation 1

2 Outline Background Develop 2-D Axle-Tire-pavement Contact Model Investigate Rutted Surface on Near- Surface Pavement Response Conclusions & Recommendation 2010 VT Pavement Evaluation 2

3 Background Rutted Surface Affects Tire-Pavement Interaction Non-Uniform Contact Stress Top-Down Cracking and Instability Rutting 2010 VT Pavement Evaluation 3

4 Develop 2-D Axle-Tire-pavement Contact Model Modeling of Tire Tire to be modeled-goodyear 425/65R22.5 Components of a unisteel radial tire (Goodyear after 2004) 2010 VT Pavement Evaluation 4

5 2D-Tire Mesh Developed 2-D finite element tire model 2010 VT Pavement Evaluation 5

6 Modeling of 2-D Axle-Tire-Pavement Interaction Why need an axle? Unstable Structure Stable Structure 2010 VT Pavement Evaluation 6

7 Developed 2-D Axle-Tire-Pavement Model Flat Surface Rutted Surface 2010 VT Pavement Evaluation 7

8 Model Verification 50 Vertical Contact Stress (psi) Tire Lateral Distance (in.) Transverse Contact Stress (psi) Tire Lateral Distance (in.) 2010 VT Pavement Evaluation 8

9 Effects of Rutted Surface on Near-Surface Response 50 Vertical Contact Stress (psi) Flat -350 Rut Tire Lateral Location (in) Transverse Contact Stress (psi) Flat -80 Rut Tire Lateral Distance (in.) 2010 VT Pavement Evaluation 9

10 Effects of Rutted Surface on Near-Surface Response (Cont.) m Vertical Contact Stress (psi) % Slope 2% Slope % Slope 4% Slope Tire Lateral Distance (in.) Transverse Contact Stress (psi) % Slope 2% Slope -60 3% Slope 4% Slope Tire Lateral Distance (in.) 2010 VT Pavement Evaluation 10

11 Statistical Summary Table 1. Statistic results of the comparison of peak contact stresses Degree of Rutting Severity Items 0% 1% 2% 3% 4% Peak Vertical Contact Stress (psi) Increasing Percentage (Relative to Flat Surface) Peak Transverse Contact Stress (psi) Increasing Percentage (Relative to Flat Surface) 0% 16% 37% 47% 83% % 4% 24% 36% 47% 2010 VT Pavement Evaluation 11

12 Effects of Rutted Surface on TDC and Instability Rutting F x W = sinα α Forces acting on a tire on a side of a rut For one degree of inclination angle, a lateral force of lb/lb is produced in the downhill direction by the gravitational component. For radial tire, this lateral force might be responsible for creating rut or increasing severity of rut in asphalt pavement surface (Gillespie, TD. et al. 1993) VT Pavement Evaluation 12

13 Critical Locations for TDC and Instability Rutting Stress_yy/SIGMA-1 (psi) Transverse Bending stress Vs. Principal Tensile Stress Transverse distance to tire edge (in) Stress_yy SIGMA-1 Principal Tensile Stress SIGMA Depth (in) in to Tire Edge 0.62 in to Tire Edge 0.75 in to Tire Edge 0.90 in to Tire Edge 2010 VT Pavement Evaluation 13

14 Effects of Rutted Surface on TDC Flat Rut SIGMA-1 (psi) Distance to Tire Edge (in.) SIGMA-1 (psi) % Slope -40 2% Slope 3% Slope 4% Slope Distance to Tire Edge (in.) 2010 VT Pavement Evaluation 14

15 Effects of Rutted Surface on Instability Rutting Depth to AC surface(in) Maximum Shear Stress (psi)-425/65r Flat Rut 0.0 Maximum Shear Stress (psi) Distance to Surface (in.) % Slope 2% Slope 3% Slope 4% Slope 2010 VT Pavement Evaluation 15

16 Statistical Summary Table 2. Summary of Peak Principal Tensile Stress and Maximum Shear Stress Items Degree of Rutting Severity 0% 1% 2% 3% 4% Peak Maximum Shear Stress (psi) Increasing Percentage (Relative to Flat Surface) 0% 15% 26% 33% 38% Peak Principal Tensile Stress (psi) Increasing Percentage (Relative to Flat Surface) 0% 30% 60% 110% 150% 2010 VT Pavement Evaluation 16

17 Conclusions The developed 2-D axle-tire-pavement finite element contact model can successfully capture patterns of both vertical contact stress and horizontal shear contact stress distributions Comparing with flat AC surface, contact stresses induced on the rutted surface are more concentrated on the tire shoulder and decrease along the downhill direction. The more severity the rut, the higher the localized contact stress on the tire shoulder VT Pavement Evaluation 17

18 Conclusions (Cont.) Comparing with flat surface, both peak SIGMA-1 and maximum shear stress due to rutted surface are increased significantly. The more severity the rut, the greater propensity for TDC and the more severity for instability rutting 2010 VT Pavement Evaluation 18

19 Future Research Recommendation Need to develop 3-D tire-pavement interaction model to further investigate the effects of rutted surface on the near-surface pavement response 2010 VT Pavement Evaluation 19

20 Thank You 2010 VT Pavement Evaluation 20