考虑骨料体积含量影响的混凝土准脆性断裂预测模型及应用  

QUASI-BRITTLE FRACTURE MODEL AND APPLICATION ON CONCRETE CONSIDERING AGGREGATE VOLUME CONTENT EFFECT

作　　者：徐平[1] 胡晓智[2] 张敏霞[1] 马金一 XU Ping;HU Xiao-zhi;ZhANG Min-xia;MA Jin-yi(School of Civil Engineering,Henan Polytechnic University,Jiaozuo,Henan 454003,China;School of Mechanical and Chemical Engineering,University of Western Australia,Perth Australia,WA 6009)

机构地区：[1]河南理工大学土木工程学院,河南焦作454003 [2]西澳大学机械与化学工程学院

出　　处：《工程力学》2018年第10期75-84,共10页Engineering Mechanics

基　　金：国家自然科学基金项目(U1404527;51508166);河南省交通厅科技项目(2016Y2-1);河南省博士后基金项目(169440)

摘　　要：基于对准脆性断裂边界影响模型参数的分析,该文将平均骨料粒径d_(ave)引入模型中,得到了考虑骨料体积含量及尺寸影响的混凝土准脆性断裂预测模型。模型中的有效裂缝与特征裂纹的比值,明确表征了三分点加载单边切口梁(SENB)试件的尺寸及初始缝长度变化时服从的断裂失效准则;模型中d_(ave)及分散系数β_(ave)将影响最大荷载P_(max)作用下临界微裂纹扩展区的平均虚拟裂纹长度Δa_(fic)。通过SENB试件在P_(max)时的受力分析,得到了临界正应力s_n、有效裂缝长度a_e、拉伸强度f_t及断裂韧度KIC之间的关系式。通过Amparano的试验结果,当afic为0.8~1.4倍d_(ave)时,采用混凝土准脆性断裂模型能较好预测混凝土拉伸强度及断裂韧度。通过对Δa_(fic)=1.2d_(ave)时模型得到的预测曲线与试验结果的对比,证明了模型计算结果的可靠性。考虑骨料体积含量影响的混凝土准脆性断裂模型能基于RILEM规范中三分点加载SENB试验预测混凝土断裂韧度与拉伸强度。Based on the analysis of parameters in a Boundary Effect Model,the average aggregate size dave has been introduced into the model.Whereafter,the quasi-brittle fracture prediction model on concrete considering aggregate volume content and size effect has been proposed.The ratio of effective notch length to characteristic crack length in this model can clarify the fracture failure criterion of the specimens as the variation of the dimension and initial notch length for single edge notched beams(SENB)in three-point-bending tests.The fictitious crack length in critical crack growth region at Pmax will be determined by the dave and dispersion coefficientβave in this model.Based on the stress analysis of the SENB at Pmax,the relationship between critical nominal strengthσn and effective notch length ae and tensile strength ft and fracture toughness KIC has been obtained.According to the experiment results performed by Amparano,the tensile strength and fracture toughness could be predicted well by the fracture model with the average fictitious crack lengthΔafic=(0.8~1.4)dave.The reliability and applicability of the fracture model proposed have been confirmed by the comparison of the prediction curves derived by the fracture model atΔafic=1.2 dave with the experiment results.According to the three-point-bending tests with SENB proposed by RILEM,tensile strength and fracture toughness can be predicted by the quasi-brittle fracture prediction model on concrete considering aggregate volume content effect.

关 键 词：边界影响模型 准脆性断裂 混凝土骨料 断裂韧度 拉伸强度 

分 类 号：TU528.1[建筑科学—建筑技术科学] O346.11[理学—固体力学]