SEAUPG Jacksonville, Florida November 14-16, 2017

Transcription

1 Florida Department of TRANSPORTATION Topics of Discussion Overview of APT Program ACCELERATED PAVEMENT TESTING RESEARCH Performance of Asphalt Pavements Constructed Using Different Compaction Levels November 217 Wayne A. Allick, Jr., P.E. Accelerated Pavement Testing Engineer State Materials Office Impact of Layer Thickness on Rutting Performance of Open Graded Friction Courses (FC-5) Impact of Asphalt Mix Segregation on Pavement Performance Summary 2 FDOT s APT Program Test Track housed at the State Materials Office 5 Lanes approximately 5 ft. long x 12 ft. wide 2 Lanes 15 ft. long x 12 ft. wide 2 Outdoor Test Pits FDOT s APT Program Loading performed using the Heavy Vehicle Simulator (HVS) Mark IV & Mark VI Models 3 Research Project Selection Environmental Control APT program is integrated with overall research effort Planning, development, and execution of research projects performed on an annual basis Research projects solicited from Central and District offices, FHWA, industry, and Florida Universities Heater elements attached to HVS test beam Maintain asphalt temperature at 12⁰F Asphalt temperature monitored at 2-inches below surface Florida Florida Department Department of of Transportation Transportation 5 6 1

2 Heavy Vehicle Simulator Uni-Directional Loading: 9 kips Super Single tire (Goodyear G286 A SS, 25/65R22.5) Wheel wander: -inches On-board laser profiler system Left Laser Right Laser Performance of Asphalt Pavements Constructed Using Different Compaction Levels Heating system 1, loaded repetitions per day 7 8 Asphalt In-Place Density Density Test Sections 12.5-mm NMAS PG Asphalt Mixture Asphalt Density Study Three densities were targeted 87%, 9%, and 93% ±.5% Tolerance 12.5-mm NMAS (Granite) PG polymer-modified binder 5 ft. long x 12 ft. wide test lane 12.5 mm w/ PG inch Milled Surface 1.5 inch limerock base 12 inch granular subbase 9 1 Establishing Rolling Patterns Test Track Construction Rolling Pattern Results: Steel Wheel Vibratory Roller 3ft. 12ft. Section 1 5ft. 1 ft. Section 2 5ft. 7 ft. Section 3 3ft. Approx. 22 VPM Approx..5 MPH % 89.6% 91.% 92.7% 92.9% % % 85.1% 9.% 9.6% 93.1% 92.9% Target: 87% Average: 86.3% Std.:.9% Target: 9% Average: 9.3% Std.:.6% Target: 93% Average: 92.9% Std.:.2%

3 IDT Tensile Strength Rutting Performance In general, rutting performance is improved with increasing in-place density for the typical 12.5 PG mixtures (granite) 13 1 Rutting Performance Additional Non-Destructive Testing Surface Texture Measurements Sand Patch Method Circular Texture Meter In-Place Density, MPD, & Friction (12.5 NMAS Granite) 1. 8 Change in Friction w/ traffic MPD (mm) FNR Impact of Layer Thickness on OGFC (FC-5) Rutting Performance. 2,, 6, 8, 1, HVS Pass Number 3 2,, 6, 8, 1, HVS passes 18 3

4 OGFC Test Sections OGFC Rutting Performance 2 16 FC 5 Layer Thickness vs. Rutting Avg. PG (.75 inch) Avg. PG (.75 inch) Avg. PG (1.25 inch) Avg. PG (1.25 inch) Avg. PG (2 inch) Avg. PG (2 inch) OGFC Thickness Study FC-5 (Friction Course) Two Binders: PG & PG Three layer thickness:.75, 1.25, and 2.-inches Rut Depth (mm) , 2, 3,, 5, 6, 7, 8, 9, 1, HVS Passes 19 Dense vs. OGFC (Texture & Friction) Field Permeability Testing 3. Change in Surface Texture w/ Traffic 8 Change in Friction w/ traffic 1. Clean and saturate the test location MPD (mm) FNR Fill the water container with continuous water supply 3. Remove the water source and measure the time of dropping water between the marked water levels.5. 2,, 6, 8, 1, HVS passes 3 2,, 6, 8, 1, HVS passes. Measure the water temperature then use drop time, and layer thickness to calculate field permeability index K (1.E 5 cm/s) 22 OGFC Permeability Results PG 76 22: Before and After Loading PG Before PG After 22, ,37 17,263 11,73 92,79 68,23 Permeability (1^-5 cm/s) PG 82 22: Before and After Loading 369,169 PG Before PG After 185,59 18,5 1,123 87,593 55,775 Impact of Segregation on Asphalt Pavement Performance.75 inch 1.25 inch 2 inch.75 inch 1.25 inch 2 inch Layer Thickness Layer Thickness 23 2

5 Asphalt Segregation Study Segregated Test Sections Quantify the impact of segregation on pavement performance Severe Segregation Asphalt Segregation Study Develop/refine methods to quantify segregation using texture measurements (CTM) 12.5-mm NMAS (Granite) PG polymer-modified binder 12.5 mm w/ PG inch Milled Surface No Segregation 5 ft. long x 12 ft. wide test lane 1.5 inch limerock base 12 inch granular subbase Non Destructive Testing Test Lane Construction Use nondestructive testing methods to quantify the presence of segregation in the field Circular Texture Meter TM2: wide spot laser Comparison between segregated and non segregated HVS loading areas Surface texture (MPD) Rutting performance Construct the areas with varying severity levels of segregation on test lane Quarter truck loads of asphalt Cycled screed heater on/off Cooler material introduced into paver Material sampling Construction Activity Test Track Construction Temperature Distribution before Compaction

6 Segregated Pavement Macrotexture Change in Surface Macrotexture Rutting Performance In-Place Density Rut Depth (mm) Segregated Segments Non segregated Segments Non segregated Segregated 33 3 Summary Summary Higher in-place density results in improved rutting & cracking resistance The surface macrotexture on dense graded asphalt pavement increases with traffic An FC-5 layer thicker than.75-inches reduces rutting performance FC-5 shows greater reduction in friction than dense graded after 1, HVS passes loaded at 9 kips The permeability of FC-5 reduces with increasing traffic Friction is not well correlated with surface macrotexture on dense graded asphalt pavements Rutting on segregated pavements is greater than on non-segregated pavement Segregated pavements have higher surface macrotexture than compared to non-segregated pavement

7 APT Summary APT is a critical component of FDOT s pavement research program Key to success is the careful selection of research projects that address critical issues Technology transfer is essential 37 7