Volume 15, No. 2, 2021
Received: 2021/04/02, Accepted:
Authors:
Khalid A. Ghuzlan; Ghazi G. Al-Khateeb; Monther A. Khader;
Abstract:
Fatigue cracking is considered one of the major distresses that occur in asphalt pavements, which can decrease the expected service life of this type of pavements. This study aimed at investigating the effect of aging, strain level, modification and temperature on the fatigue behavior of asphalt binders. To achieve the objectives of this
study, a 60/70-penetration grade asphalt binder having a superpave performance grade of PG 6416 and 4% Styrene-Butadiene-Styrene (SBS) modification was used in this study. Unmodified and modified asphalt
binders were aged using the rolling thin-film oven (RTFO) test and pressure aging vessel (PAV). The PAV aging was conducted for four periods: 0, 20, 40 and 60 hrs, providing four PAV-aged asphalt binders named as: PAV0, PAV20, PAV40 and PAV60, respectively. Asphalt binders were tested using the dynamic shear rheometer (DSR) at a single loading frequency (10 Hz), four different temperatures (22, 25, 28 and 31C) and four strain levels (5, 10, 15 and 20%). Findings of the study showed that increasing the aging period generally decreased the fatigue life of unmodified asphalt binders, particularly at lower temperatures (22 and 25C). However, at higher temperatures (28 and 31C), the fatigue life for 60-hr aging period was higher than that for 40-hr aging. The SBS modification increased the fatigue life of asphalt binders and showed an opposite trend to that of the unmodified asphalt binders at low temperatures. The strain level increase decreased the fatigue life for both unmodified and SBS-modified asphalt binders. However, the fatigue life reduction was higher at
low strain levels. The effect of temperature on the fatigue life agreed with literature; the increase in the temperature resulted in a decrease in the fatigue life of asphalt binders for all aging periods and strain levels.
Keywords:
Asphalt binder, Fatigue, Strain level, Extended aging, Modification