Seal Coat Research Project Construction Report 1996-98

Status: Complete
Report Date: 01/07/2000

Summary:

At the Minnesota Road Research Project (Mn/ROAD), asphalt concrete mixtures were used to evaluate both warm and cold temperature material properties with selected text methods and a wide range of testing parameters. These parameters were selected to approximate different levels of environmental conditions, traffic speeds, traffic loads, and, in certain cases, confining pressures. The underlying theories used to calculate stress and strain from various loading configurations also were rigorously evaluated to determine the appropriateness of comparing results from one testing configuration to another. Mn/ROAD mixtures were evaluated as the first step in linking laboratory measurements and test method selection to live traffic pavement responses and performance. A comparison of axial and diametral testing using harmonic loading showed that experimental results did not agree with theory. That is, the complex deviatoric modulus determined for diametral testing should have been less than the Young's modulus determined from testing axially loaded samples. This was not the case. This suggested that a further examination of the sample instrumentation, testing variability, and the possibility of anisotropic mixture behavior due to particle orientation during compaction are needed to resolve these differences. Other findings indicated that the influence of load duration is minimized as the test temperature decreases, there was little influence in rest period times in repeated loading tests on modulus, and confining pressure only had a significant influence on modulus above about room temperature.

Final Deliverables:

Report #2000-03