沥青路面防水抗裂功能层缓解反射裂缝的数值分析

沥青路面的反射裂缝,主要是由半刚性基层无法避免的温缩及干缩裂缝导致应力集中过大而引起的,车辆荷载、较大的环境温差变化以及渗水导致反射裂缝道面破坏的不利因素。在半刚性基层和柔性面层之间设置防水抗裂功能层,可以有效缓解路面结构的应力集中现象,延缓反射裂缝的产生与扩展速度。采用有限元方法模拟易发反射裂缝的实际环境,对设置及未设置防水抗裂功能层的路面结构进行温度-荷载耦合力学对比分析,发现沥青路面下面层的荷载应力、温度应力以及应力强度因子都有较大幅度的降低,并且计算了防水抗裂功能层厚度、模量对路面结构应力、弯沉和强度因子的影响。结果表明：一般防水抗裂功能层的模量越小,效果更加明显;在合理范围内增加防水抗裂功能层的厚度能够更加有效地预防反射裂缝病害;适当控制基础模量可以防止反射裂缝的产生。

Numerical Analysis of Anti-Crack Layer Reflect-Crack Alleviation in Asphalt Pavement

Reflective crack in asphalt Pavement is mainly produced by too much stress concentration,which is caused by inevitable temperature and drying shrinkage cracks in the semi-rigid base structure. Besides,vehicle load,the large temperature change and water seepage cart become the unfavorable factors of this kind of damage. The waterproof and anti-crack layer between semi-rigid base and flexible layer can effectively alleviate the stress concentration phenomenon and delay the generation and propagation velocity of reflective crack. Finite element method is used to simulate the actual environment that easily results in reflective cracks. The temperature-load coupling force is analyzed and＇contrasted in pavement with and without waterproof and anti-crack layer. It is found that the load stress, temperature stress and stress intensity factor have significantly reduced after the pavement structure improvement. The influence of modulus and thickness of the waterproof and anti-crack layer is also calculated. The results showed that generally the modulus of waterproof and anti-crack layer is smaller,the effect is more obvious ; increasing thickness of waterproof an＇d anti-crack layer is very useful to prevent the generation of reflective cracks ; appropriate control on foundation modulus can also take effect.