New Damage Parameter for Fatigue Analysis of Asphalt Binders in Linear Amplitude Sweep Test

Abstract

The fatigue resistance of two conventional and two polymer modified binders using a new definition of failure in the linear amplitude sweep (LAS) test was assessed in this study. Viscoelastic continuum damage (VECD) theory was used to determine the relationship between number of cycles to failure (Nf) and strain level (γ). Experimental investigation at 10°C, 20°C, and 30°C was conducted on the asphalt binders to validate the proposed theory and compare it with the analysis used in the conventional LAS test. The ratio (R) of difference in pseudo stress-strain and true stress-strain area to the area of pseudo stress-strain curve is proposed as a quantifiable parameter of damage. The new definition of failure was found to offer better correlation between damage and the stored potential energy compared with the LAS test. The results evidently justify the applicability of the new damage parameter, which can be used easily with the conventional LAS test protocol. © 2020 American Society of Civil Engineers.