Impact of Ageing on Strength Parameters of Asphalt Concrete

Abstract

Ageing of asphalt concrete pavement causes loss of volatiles and decline the flexibility of the mixture. In the present investigation, an attempt has been made to assess the impact of short and long-term ageing process on the tensile, shear, and Marshall properties of asphalt concrete. The susceptibility of the asphalt concrete to testing temperature was also monitored. Asphalt concrete mixtures were prepared at optimum binder content. Extra specimens were also prepared at 0.5 % binder higher and lower than the optimum. The mixtures were subjected to short-term ageing. Marshall specimens were prepared and subjected to long-term ageing. Control mixtures without agĀeing process were prepared for comparison. The strength properties were determined. It was concluded that at optimum binder content, the indirect tensile strength of asphalt concrete increases by (7.3, and 27.4) % , the punching shear strength increases by (25.6, and 223.8) % while the Marshall stability increases by (21.2, and 29.7) % and the Marshall stiffness increases by (38.6, and 143.1) % for mixtures practicing short-term ageing and short and long-term ageing process respectively as compared with the control mixture. At (25, 40, and 60) °C testing temperatures, the indirect tensile strength of asphalt concrete increases by (7.3, and 27.4) % (23.7, and 94) % and (131.8, and 353.6) % for mixtures practicing short-term ageing and short and long-term ageing process respectively as compared with the control mixture. The tensile strength of asphalt concrete is highly susceptible to the testing environment.