Stiffness and damping ratio of rubber-modified asphalt mixes: Potential vibration attenuation for high-speed railway trackbeds

This paper presents the first phase laboratory test results of a research p roject at the University of Kentucky. A number of resonant column tests wer e conducted to measure the stiffness and damping ratio of rubber-modified a sphalt (RMA) samples with different rubber contents and mixed by different methods. The measurements were conducted under a wide range of confining pr essures and shear strains to simulate the stress conditions that would be e xpected in a typical railway foundation. Data from the tests show that RMA has stiffness much higher than compacted soils while providing significantl y higher damping ratio than most soils under the same strain level. Therefo re, the results from this study indicate that RMA has great potential as a foundation material for high-speed railway trackbeds.