基于楔入劈拉试验的橡胶混凝土软化本构模型

Softening constitutive model of rubber concrete based on wedge splitting-tensile test

为确定橡胶混凝土的软化本构模型,对2种缝高比和5种橡胶掺量的混凝土试件进行楔入劈拉试验研究和理论分析。依据试验结果,采用规范公式及能量守恒定律计算混凝土试件的断裂韧度和断裂能,并求解出PETERSSON、欧洲混凝土规范、XU和REINHARDT3种软化曲线的相关参数。根据3种软化本构关系得到黏聚韧度理论值,并与黏聚韧度试验计算值进行了对比分析。研究结果表明:掺入适量的橡胶集料可提高混凝土的断裂失稳韧度和断裂能;3种典型的混凝土软化模型均不能很好地描述橡胶混凝土的黏聚韧度;对XU和REINHARDT软化关系式进行修正后,得到了橡胶混凝土的软化本构模型,可用于研究橡胶混凝土材料的抗裂特性。

To determine the softening intrinsic model of rubber concrete,wedge splitting test studies and theoretical analyses were performed on concrete specimens with two seam height ratios and five rubber admixtures.Based on the test results,the fracture toughness and fracture energy of concrete specimens were calculated using the canonical formula and the law of energy conservation,and the relevant parameters of the three softening curves of PETERSSON,Euroconcrete Code,XU and REINHARDT were solved.The theoretical values of cohesive toughness were obtained based on the three softening instantonal relationships and compared with the calculated values of cohesive toughness tests.The results show that the softening instability and fracture energy of concrete can be improved by incorporating appropriate amounts of rubber aggregate;the three typical concrete softening models cannot describe the cohesive toughness of rubber concrete well;the softening intrinsic structure model of rubber concrete is obtained by modifying the softening relations of XU and REINHARDT,which can be used to study the cracking resistance of rubber concrete materials.