Volume 31, Issue 6 (November 2003)
Design and Performance of the HEART Wheel Load Simulator
Rutting of hot mixed asphalt (HMA) pavement has been considered a major pavement problem in many countries. Many researchers have tried to predict rutting or permanent deformation in the laboratory. Wheel-tracking devices have been used to evaluate rutting resistance from laboratory testing of HMA over the past several decades. Several studies showed high correlation of pavement performance between the highway and the laboratory results by wheel-tracking tests. Various wheel-tracking devices are available with different testing conditions, like variable temperature and loading conditions. Existing wheel-tracking devices developed by different institutes have some shortcomings such as nonlinear loading speed on the test specimen, fixed wheel path, impossibility of simulating underlayer effects, and so on. Therefore, the HEART Wheel Load Simulator (HWLS) was developed to improve the results the pavement engineers needs. The HWLS is capable of testing various thickness specimens, 50–700 mm, estimate rutting performance by both shear failure and further compaction of pavement substructure, and observe realistic rutting patterns by changing the wheel path using random variables or scattering. In addition, the HWLS has a linear loading speed capability using an oil compressor. Linear kneading compaction was added as an additional function so that it can be used to study rutting behavior under various compaction efforts, especially for conventional flexible pavement. This paper covers an outline of HWLS, calibration of the device, comparison of HWLS with existing wheel-tracking devices, and different behaviors of rutting resistance of typical HMA concrete under lateral distribution of traffic loading.