Volume 12, No. 4, 2018
Received: 2018/09/12, Accepted:
Authors:
Ghazi Al-Khateeb; Omar Alqudah;
Abstract:
This study aims at investigating the influence of laboratory aging on the fatigue performance of asphalt mixtures prepared using the superpave method. In this study, one type of asphalt binder (PG64-10) and one type of aggregate (limestone) were used. Loose mixtures were short-term aged (STA) in a draft oven at 135C for 2 hours, 3 hours and 4 hours. Half of tested samples were long-term aged (LTA) in a draft oven at 85C for time periods of 3 days, 5 days and 7 days. Fatigue test was performed on test specimens using the Indirect Tensile Test (IDT) under stress-controlled mode. Four initial strain levels: 100, 200, 300 and 400, two test temperatures: 40 and 20C and one loading frequency: 10 Hz, were used and considered in the testing matrix of the study. Data analysis was conducted and fatigue curves were obtained for each case in this study. The effect of STA and LTA on fatigue life was investigated at the two test temperatures. It was found that the STA led to an increase in fatigue life at both test temperatures under stress-controlled mode in the IDT test.
Nevertheless, the fatigue life increased as the LTA period increased from 3 to 5 days, but then it was reduced for 7-day LTA. Findings of this study also showed that the fatigue life increased as the temperature increased from 20 to 40C. Control specimens (short-term aged for 2 hours) tested at 20°C were found to have the shortest
fatigue lives. On the other hand, specimens that were long-term aged for 5 days and tested at 40°C had the longest fatigue lives.
Keywords:
Fatigue cracking, Fatigue performance, Indirect tensile test, Aging, STA, LTA