Failure Mechanism of Asphalt Concrete under Various Testing Modes

Abstract

The behavior of asphalt concrete in fatigue process is critical for its durability and sustainability study. Black-top substantial combination was ready with ideal fastener necessity, and compacted by rollers in a chunk form. Bar examples were acquired from the piece tests and tried under powerful flexural stresses and disappointment phases of black-top cement were evaluated utilizing consistent pressure and steady strain methods of stacking. The deterioration stages of flexural stiffness, cumulative dissipated energy, phase angle, and permanent deformation were monitored. It was observed that at failure, lower flexural stiffness could be detected under constant strain while the deformation, phase angle, and energy dissipation were higher under constant stress mode of test. At failure, the flexural stiffness of asphalt concrete under constant strain is lower by 66.6 % than that under constant stress, while the fatigue life of asphalt concrete under constant strain is longer than that of specimen under constant stresses by 10.1 folds. The energy dissipation at failure reaches (10 ^-7 and 10 ^{- 0.5}) MJ/m³ after (45 and 500) seconds for specimens practicing constant stress and constant strain respectively. The phase angle is higher under constant strain as compared with that under constant stress and fluctuates between (30 and 45) degrees under constant strain while it fluctuates between (1 and 8) degrees under constant stress. The deformation at failure under constant strain is higher by 132 folds than that of constant stress mode of testing.