西藏高寒地区沥青路面防水防裂设计及疲劳寿命评价

Crack Prevention Design and Fatigue Life Evaluation of Highway Asphalt Pavement in Alpine Region

采用剪切、拉拔试验确定了粘层油选型和最佳用量,通过渗水试验、MTS疲劳试验、MMLS3加速加载试验等评价了路面的防裂效果,并对温度和荷载作用进行有限元分析。结果表明:采用1.1~1.3 kg/m2的90-A级沥青作为粘层油最佳,MTS试验加载至完全开裂时,铺设基布的次数是未铺基布的2.64倍,MMLS3试验加载60万次时,层底微应变仅为不铺基布方案的12.22%,有限元分析得出铺设防裂基布使层底应变降低28.38%,实体工程调查显示防裂基布使裂缝率降低了65.29%。铺设防裂基布后形成防水防裂应力吸收层,有助于延缓反射裂缝的发生,延长路面疲劳寿命。

This paper determines the type selection and optimum dosage of viscous oil using Shear and Drawing Test.The anti-cracking effect of pavement was evaluated by seepage test,MTS fatigue test and MMLS3 accelerated loading test.The finite element analysis of temperature and load is carried out.The results showed that The 90-A grade asphalt with 1.1~1.3 kg/m2 is the best choose.When MTS test is loaded to complete cracking,the number of laying substrates is 2.64 times that of unpaved substrates.When the MMLS3 test is loaded 600000 times,the micro-strain at the bottom of the layer is only 12.22%of that of the non-laying scheme.Finite element analysis shows that laying crack-proof base cloth reduces the strain of bottom layer by 28.38%.The investigation of physical engineering shows that the crack rate is reduced by 65.29%by the anti-crack base cloth.After laying crack-proof base cloth,a waterproof and crack-proof stress absorbing layer is formed,which helps to delay the occurrence of reflective cracks and prolong the fatigue life of pavement.