环氧沥青混凝土抗疲劳层对柔性基层长寿命沥青混凝土路面结构的影响

Influence of epoxy asphalt concrete anti-fatigue layer on structure of perpetual asphalt concrete pavement with flexible base

开发了一种适用于道路工程的新型环氧沥青,基于拉伸试验、黏度试验和荧光显微技术评价了其抗拉强度、断裂伸长率、黏度随时间增长规律和微观固化机理;设计了AC-13C环氧沥青混凝土,评价了其路用性能和疲劳特性,分析了普通沥青混凝土、SBS改性沥青混凝土与环氧沥青混凝土作为抗疲劳层材料对柔性基层长寿命沥青混凝土路面结构厚度与疲劳寿命的影响。试验结果表明:开发的环氧沥青抗拉强度为2.47 MPa,断裂伸长率为2.65,满足环氧沥青抗拉强度不小于1.5MPa、断裂伸长率不小于2的技术要求;环氧沥青黏度增长到1Pa·s的时间为54min,54min后,黏度迅速增大,因此,施工时环氧沥青混凝土的拌和、运输与摊铺总时间应控制在54min内;根据环氧沥青混凝土疲劳方程反推出当其疲劳寿命为10亿次时的疲劳应变极限为333με;相对于普通沥青混凝土和SBS改性沥青混凝土,环氧沥青混凝土抗疲劳层路面结构的疲劳寿命分别增大了2.92×10~5、4.39×10~3倍,沥青层厚度分别减小了18、10cm;环氧沥青的微观固化机理为环氧树脂与固化剂在沥青中逐渐从点到线、由线到网形成交联的三维网状结构。

A kind of new epoxy asphalt for road engineering was developed.Based on tensile test,viscosity test,and fluorescence microscope technology,the tensile strength,breaking elongation,changing rules of viscosity with time,and microscopic curing mechanism of epoxy asphalt were evaluated.The epoxy asphalt concrete AC-13 C was designed,and its road performances andfatigue characteristics were evaluated.When common asphalt concrete,SBS modified asphalt concrete and epoxy asphalt concrete were taken as anti-fatigue layers,the influences of antifatigue layers on the structural thickness and fatigue life of perpetual asphalt concrete pavement with flexible base were analyzed.Test result shows that the tensile strength of epoxy asphalt is2.47 MPa and the breaking elongation is 2.65,which satisfies the technical requirement that the tensile strength is not less than 1.5 MPa and the breaking elongation is not less than 2.The time needs 54 min when the viscosity of epoxy asphalt reach to 1 Pa·s,after 54 min,the viscosity increases rapidly,so the total time for mixing,transportation,and paving should be controlled within 54 min in construction.The fatigue strain limit is 333μεwhen the fatigue life is 1 billion times according to the fatigue equation of epoxy asphalt concrete.Compared to common asphalt concrete and SBS modified asphalt concrete,when epoxy asphalt concrete is taken as anti-fatigue layer,the fatigue life of perpetual asphalt concrete pavement increases by 2.92×10~5 times and 4.39×10~3 times respectively,and the thickness decreases 18 cm and 10 cm.The microscopic curing mechanism of epoxy asphalt is that epoxy resin and hardener form cross-linked and three-dimensional network structure from point to line and from line to net in asphalt.