Contributing factors in the initiation of failure of asphalt concrete

Abstract

As long as the asphalt concrete pavement is under service, signs of failure usually initiate and the distress types start showing throughout the service life. The asphalt concrete pavement practices repeated tensile and shear stresses through the vehicular loading. In the present study, the contributing factors in the initiation of failure under repeated flexural stresses have been detected. Slab samples of Asphalt concrete have been prepared at the laboratory by implementation of three different percentages of asphalt binder contents. The specimens of Asphalt concrete beams were acquired from slab samples to subject them to dynamic flexural stresses at four consistent strain levels.. One part of the beam specimens were subjected to long term ageing, while another part practices moisture damage. Fatigue life testing was conducted on the asphalt concrete beam specimens. It was observed that specimens prepared at optimum binder content and tested under moderate strain level of 400 microstrain exhibit more resistance to the flexural stresses. However, specimens practicing ageing exhibit higher resistance to flexural stresses as compared with the control or the moisture damaged specimens. It was concluded that the resistance of asphalt concrete to the distress initiation reaches its peak value after two to three seconds from the start of the repeated loading, and then declines as the loading proceed.The contributing factors of initiation of failure are the moderate constant microstrain level of 400, the optimum binder content, and the durability issues.