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.

沥青混凝土 (AC) 层顶部的水平拉伸应变被认为是分析自顶向下开裂 (TDC) 的路面最合适的响应。在这项研究中，根据路面的拉伸应变大小，探讨了车速、温度和非均匀老化模量对 TDC 的影响。利用一种新的分析方法，在具有水泥处理基层 (CTB) 和颗粒基层 (GB) 的路面中，计算厚薄 AC 层顶部和底部的响应。结果表明，临界拉伸应变出现在 AC 层的顶部和横向。低温下速度的变化会影响开裂的临界类型，而在中温和高温下，TDC 在分析的所有速度下都占主导地位。