橡胶混凝土抗压性能及细观破坏机理研究

Study on Compressive Properties and Meso Failure Mechanism of Rubber Concrete

目的研究橡胶混凝土抗压性能及受压破坏机理,为橡胶混凝土路用提供理论基础.方法配制水灰比为0.35、0.40、0.45,橡胶掺量为0、10%、20%、30%的橡胶混凝土,进行轴心抗压强度试验;基于细观层次,将橡胶混凝土看作由砂浆、粗骨料、橡胶颗粒、砂浆-粗骨料界面和砂浆-橡胶颗粒界面组成的多相复合材料,建立橡胶混凝土细观数值模型,模拟不同橡胶掺量和不同水灰比的橡胶混凝土轴心抗压强度.结果随着橡胶掺量的增加,轴心抗压强度逐渐降低,强度损失逐渐增大;橡胶掺量相同时,水灰比越小,抗压强度越大;水灰比相同时,随着橡胶掺量的增加,应力应变曲线越来越平缓,峰值应力、初始弹性模量、峰值变形模量逐渐减小;橡胶掺量相同时,水灰比越小,峰值应力、初始弹性模量、峰值变形模量越大;抗压强度模拟结果与试验结果符合较好,验证了细观模型的正确性.结论砂浆与橡胶颗粒的界面区域对橡胶混凝土轴心抗压强度和破坏过程影响较大;骨料和砂浆界面性能约为砂浆的65%,橡胶和砂浆界面性能约为砂浆的35%.

The compressive properties and failure mechanism of rubber concrete are studied to provide theoretical basis for rubber concrete pavement.Rubber concrete with water cement ratio of respectively 0.35,0.40 and 0.45 and rubber content of respectively 0,10%,20%and 30%were prepared to conduct axial compressive strength test.In the mesoscopic level,rubber concrete can be regarded as a multiphase composite material composed of mortar,coarse aggregate,rubber particles,mortar-coarse aggregate interface and mortar-rubber particle interface.The mesoscopic numerical model of rubber concrete was built to simulate the axial compressive strength of rubber concrete with different rubber contents and water cement ratios.The results show that with the increase of rubber content,the axial compressive strength decreases and the strength loss increases.When the rubber content is the same,the smaller the water cement ratio is,the greater the compressive strength is.At the same water cement ratio,with the increase of rubber content,the stress-strain curve becomes more and more gentle,and the peak stress,initial elastic modulus and peak deformation modulus gradually decrease.When the content of rubber is the same,the smaller the water cement ratio is,the larger the peak stress,the initial elastic modulus and the peak deformation modulus are.The simulation results of compressive strength are in good agreement with the experimental results,which verify the correctness of the meso model.The interface area between mortar and rubber particles has a great impact on the axial compressive strength and failure process of rubber concrete.The interface performance of aggregate and mortar is about 65%of that of mortar,and that of rubber and mortar is about 35%of that of mortar.