Effects of ageing, temperature and frequency-dependent properties of asphalt concrete on top-down cracking

The horizontal tensile strain at the top of asphalt concrete (AC) layer is considered as the most appropriate response of pavement for analysing Top-down cracking (TDC). In this study, influence of vehicle speed, temperature and non-uniform aging modulus on TDC are explored according to tensile strain magnitudes at the pavement surface. Utilizing a new analysis approach, the responses are computed at top and bottom of thick and thin AC layers in pavements with cement-treated base (CTB) and granular base (GB). The results demonstrate that critical tensile strain arises at the top of AC layer and in transverse direction. Variations of speed at low temperature affect the critical type of cracking, while at intermediate and elevated temperatures TDC is dominant at all speeds analysed. It is shown that modulus gradient induced by aging is an influencing factor in TDC which causes critical location of TDC to vary at the surface significantly.