Increased interest in rational approaches to flexible pavement design, rather than the usual empirical methods, has brought about an urgent need for a better understanding of the material properties involved. In this study, laboratory equipment capable of providing reliable measurements of the material properties for asphaltic concrete mixes, under variable stress and temperature conditions has been developed. The basic material properties obtained from these measurements are the resilient modulus (MR) and dynamic Poisson's ratio (v), which are the required inputs for the elastic analysis of flexible pavement structures. Tests have indicated that temperature is the main parameter affecting the resilient modulus of asphaltic concrete mixes, with deviator stress and confining pressure secondary in effect. Based on tests performed on a few samples, the dynamic Poisson's ratio was found to increase with temperature from about 0.24 at 10ºC (50ºF) to approximately 0.46 at 42ºC (108ºF). Confining pressure was found to have little or no effect on the dynamic v. Analysis using a linear elastic flexible pavement computer programme has indicated a significant reduction in...a mix with a higher MR value. This demonstrates the advantage of utilizing the structural analysis approach to flexible pavement design for more efficient use of materials.

Master of Engineering (ME)