水泥路面上超薄沥青罩面主被动抗反射裂缝应用研究

Application Research on Active and Passive Anti-reflective Cracks on Ultra-thin Asphalt Overlay of Cement Pavement

针对旧水泥混凝土路面加铺超薄沥青罩面易产生反射裂缝的问题,设计了一种特定的主被动结合的抗反射裂缝路面结构形式。借助FORTRAN软件编写的DLOUD子程序,在ABAQUS建立的道路模型上模拟车辆动载作用。研究了水泥板底局部注浆、水泥板底脱空和加铺结构层厚度组合参数变化对水泥板接缝处应力强度因子的影响。通过模拟车辆荷载、温度应力以及车辆荷载和温度耦合场3种加载条件进行力学分析,揭示了该结构模式防反射裂缝的理论原因,使用光纤光栅传感器实测接缝处力学响应数据加以验证。研究结果表明:采取板底局部注浆的主动方式,对限制旧水泥路面板的显性位移,减弱板间接缝处的应力集中具有高效率。在车辆荷载和温度耦合场中实测横向水平最大应变相较于板底脱空降低了77.5%。1 cm的碎石应力吸收层与2.5 cm的超薄沥青罩面层组合的被动结构层,有效地阻碍了反射裂缝的扩展与传递。

In view of the fact that the ultra-thin asphalt overlay on the old cement concrete pavement was easy to bring about reflective cracking,the specific active and passive combination of anti-reflective crack pavement structure was designed in this paper.With the help of the DLOUD subroutine written by FORTRAN,the dynamic load of the vehicle was simulated on the road model established by ABAQUS.The effect of parametric variation including the local grouting at the bottom of the cement slab,the vacancy of the bottom of the cement slab and the thickness combine of the overlay structure on the stress intensity at the seam of the cement slab was studied.By simulating three loading conditions of vehicle load,temperature stress,and load-temperature coupled field,the mechanical analysis revealed the theoretical reasons for the anti-reflective cracking of the structure mode,which was verified by the measured mechanical response data of using fiber grating sensor on the seam.The results show that the active method of local grouting at the bottom of the slab is efficient in limiting the apparent displacement of the old cement pavement slab and reducing the stress concentration at the seam of the slab.The measured horizontal maximum strain is reduced by 77.5%compared with the vacancy of the bottom of the cement slab in the vehicle-mounted and temperature-coupled field.The passive structure layer composed of 1 cm gravel stress absorption interlayer and 2.5 cm ultra-thin asphalt overlay can effectively prevent the propagation and transmission of reflective cracks.