The scalar modulus: A novel parameter for predicting creep properties of asphalt mixtures

In this paper, we introduce a novel material parameter termed the 'scalar modulus,' conceived through the expansion of the elastic-viscoelastic correspondence principle. The extended principle and associated transformations open new avenues for applying this framework under non-constant strain rate conditions, particularly in scenarios like creep test. Through a combination of rigorous experimental observations and numerical analysis, we establish a crucial relationship between the creep rate/creep compliance rate and the 'seed property' known as the scalar modulus. This relationship proves to be distinctive for diverse asphalt compositions, temperatures, and loading conditions, effectively delineating the material's internal states. To validate the versatility of this novel concept, we conducted an extensive series of experiments on various asphalt concrete mixtures with varying aggregate types, gradation, air void content, binder content, and aging durations. The experimental approaches to obtain the scalar modulus encompasses Superpave IDT tests, uniaxial static creep tests under tension and compression, as well as both destructive and non-destructive creep tests. By thoroughly examining the scalar modulus and characterizing the material behavior under varying composition and conditions, we gain crucial insights into its creep behavior and its reaction to external mechanical loads.