CRC+AC复合式路面结构中AC层的裂缝扩展

Crack Propagation in AC Layer of Continuously Reinforced Concrete Composite Asphalt Pavement

针对CRC+AC复合式路面结构的特点和现有研究的不足,运用断裂力学理论和有限元法,对AC层的受力进行了计算和分析,对AC层裂缝的产生和扩展机理进行了研究。计算了AC层荷载型和温度型裂缝的尖端应力强度因子,研究了裂缝扩展时期、裂缝长度、结构层厚度、模量等因素对AC层裂缝扩展的影响规律。研究结果表明:AC层裂缝的扩展时期对扩展强度有一定的影响;增加AC层的厚度对裂缝扩展尤其是对AC层底面裂缝的扩展能起到很好的延缓作用;CRC层厚度对AC层裂缝扩展的影响很小或基本没有影响;随着AC层模量的增加,AC层温度裂缝的扩展强度线性增加,荷载裂缝的扩展强度变化不大;其他结构层的厚度和模量对AC层裂缝的扩展强度基本没有影响。研究结果可为CRC+AC复合式路面的合理设计提供参考依据。

Aimed at the structure characteristics and the flaws of existing studies of CRC ＋ AC composite pavement, fracture mechanics theory and finite element method were used to calculate and analyze the stress state of AC layer to investigate the mechanism of formation and propagation of cracks in AC layer. The stress intensity factors of load crack and temperature crack were calculated, the effects of propagation period, crack length, structure thickness and modulus on the crack propagation were analyzed. The results show that （1） propagation period has a certain effect on propagation strength of AC layer; （2） increasing thickness of AC layer could postpone crack propagation, especially the crack propagation in undersurface of AC layer; （3） the thickness of CRC layer has minimal or little effect on the crack propagation; （4） the propagation strength of temperature crack increases linearly with the increase of the modulus of AC layer, but load crack changed not significantly; （5） the moduli and thicknesses of other structural layers have little effect on the crack propagation. The results could provide a basis for rational design of CRC ＋ AC composite asphalt pavement.