The effects of nominal maximum aggregate size (NMS), coarse aggregate type, fine aggregate angularity (FAA), and gradation types on HMA rutting performance were evaluated using the Purdue Laboratory Wheel Track Device (PURWheel).
Correlation between PURWheel and Indiana Department of Transportation/Purdue University (INDOT/Purdue) Accelerated Pavement Tests (APT) was used as an initial step to field pavement rutting performance evaluation. Test results showed that PURWheel and APT are well correlated. This is positive because the traffic loading andcompaction method used in the prototype scale APT is essentially identical to field conditions.
The rutting performance of 9.5 and 19 mm mixtures and that of limestone and granite mixtures was not statistically different. Analysis of the data revealed that adequate performance could be obtained with mixture gradations plotting above (ARZ), through (TRZ), and below (BRZ) the restricted zone. FAA significantly impacted the rutting performance in PURWheel tests. However, mixtures incorporating very high FAA values did not perform better than those incorporating typical (≈ 45) FAA values.