长寿柔性基层沥青路面的极限应变

The design of long-life flexible pavements is often based on strain control, including controlling the horizontal tensile strain at the bottom of the asphalt layers and the vertical compressive strain at the top of subgrade soil. The current endurance limits of the strains were obtained under laboratory test conditions and have constant values. However, in situ strains at the critical locations are affected by the interactions between load configuration, load size, asphalt layer thickness, temperature, and asphalt aging status, exhibiting seasonal fluctuations and long-term trends. To obtain the approximate ranges of endurance strain limits, the mechanical responses of two heavy-duty traffic roads: the 35-year-old TuenMun Road and 36-year-old Tolo Road, were calculated. The results indicate that the maximum tensile strain at the bottom of the asphalt layer and compressive strain at the top of the subgrade soil for the newly constructed TuenMun Road at high temperatures are 376×10^-6 and 562×10^-6, respectively. At low temperatures, the strains decline to 87×10^-6 and 249×10^-6, respectively. For the Tolo Road, the maximum asphalt layer strain and subgrade soil strain at high temperature are 149×10^-6 and 324×10^-6, respectively. At low temperatures, these strains decline to 50×10^-6 and 156×10^-6, respectively. The strains corresponding to the asphalt layer and subgrade soil significantly decrease as the asphalt ages. On-site observations indicate that after 36 years of use, the TuenMun Road has developed sporadic fatigue damage, while the Tolo Road has no fatigue damage. Because the strains at the critical locations are affected by many factors, such as load configuration, load magnitude, asphalt layer thickness, temperature, and asphalt aging state, these factors should be considered in long-life flexible pavement design.