Influence of Flexural Stress Repetitions on Asphalt Concrete

The flexible pavement usually practices flexural stress repetitions of the mixed traffic loading through its service life. The deformation, flexural stiffness and the dissipated energy is expected to be different under various modes of loading. In the present assessment, slab samples of asphalt concrete were prepared at optimum binder requirement using the roller compaction. Beam specimens of and 62 mm width, 400 mm length, and 56 mm depth were extracted from the slab samples. Asphalt concrete beam specimens were tested under repeated flexural stresses at 20 º environment using the constant strain mode. Five levels of constant microstrain have been implemented as a target amplitude, (100, 200, 500, 700 and 1000) microstrain while a loading frequency of 5 Hz was used. The test process was terminated at 50 % reduction in the stiffness. Test results were analysed and assessed. It was observed that as the flexural stiffness increases, the permanent microstrain declines regardless of the microstrain level implemented. However, the deformation increases by (3, 8, 11, and 16) % when the microstrain level rises from 100 to 200, 500, 700, and 1000 respectively. The dissipated energy increases by (14, 16, 6, and 15.5) % when the microstrain level rises from 100 to 200, 500, 700, and 1000 respectively. The flexural stiffness declines by (53, 75, 79, and 84) % as the microstrain increases from 100 to 200, 500, 700, and 1000 respectively