The discrete and continuous retardation and relaxation spectrum of warm mix crumb rubber modified asphalt mixtures

Abstract

To study the linear viscoelasticity of crumb rubber modified asphalt mixtures before and after adding the warm mix additive. The methods of obtaining the discrete and continuous spectrum are presented. The discrete spectrum of asphalt mixtures can be obtained from complex modulus test results according to the generalized Maxwell and the generalized Kelvin model. Similarly, the continuous spectrum of asphalt mixtures can be obtained from the complex modulus test data by the inverse integral transformation. The results show that the discrete spectrum and the continuous spectrum have similar shapes, but the magnitude and position of the peak spectrum is different. The continuous spectrum can be considered as the limiting case of the discrete spectrum.