Deterioration Model of Asphalt Concrete under Environmental Influence

Abstract

Asphalt concrete experiences vehicular load repetitions and environmental influence throughout its design and service life. The deterioration of the pavement initiate at the early stages of loading. Development of a pavement deterioration model is important to understand the rate and cause of the deterioration regarding the ingredient materials, structural design, and environment. The model may be used in the decision of maintenance strategy and its priorities. In the present work, asphalt concrete mixtures were prepared at optimum binder requirement, and compacted by laboratory roller into a slab samples. Beam specimens were obtained from the slab sample and subjected to dynamic fatigue test using three constant strain levels at hot and cold environment. The deterioration in the flexural stiffness was monitored and modelled. It was concluded that at failure, the flexural stiffness decline by (92, 77.2, and 88) % while the fatigue life of asphalt concrete increase by (15.6, 14, and 233) % for specimens practicing constant strain levels of (250, 400, and 750) microstrain respectively when the testing environment changes from cold to hot (5 to 30) ℃. The developed power mathematical models exhibit high coefficients of determination (R²) when the specimens are tested at cold environment of 5℃, while the models exhibit an acceptable (R²) when the specimens are tested at hot environment of 30℃. The intercept declines as the constant strain level increase. However, the slope increases in general as the constant strain level rises. On the other hand, the intercept under cold environment of 5℃ is higher than that under hot environment, while the slope is lower.