Influence of Temperature and Pressure on the Dynamic Properties of Rubber-Modified Asphalt Concrete

Abstract

Results from a series of resonant column tests on two blends of rubber-modified asphalt under varying temperature and pressure conditions are presented. The blends of rubber-modified asphalt tested were samples of Type C, with a 20% rubber content, and Type E, with a 10% rubber content. A sample of conventional asphalt was tested for comparison purposes. These three samples were tested in a resonant column device for their shear moduli and damping ratios under various temperature and pressure conditions to simulate the range of loading environments expected in typical high-speed railway foundations. It is shown that as the rubber content of the asphalt blend increases, the shear modulus and damping ratio of the material increases; additionally, the shear moduli and damping ratios are strongly correlated to changes in temperature. The shear modulus and pressure are related as well, with the stiffness decreasing slightly as the confining pressure is increased; however, temperature effects tend to dominate the behavior of all of the asphalt mixes. Comparing these results to the data from five years ago, there has been little change in the shear moduli of the asphalt samples.