由小尺寸试件确定混凝土的断裂韧度与拉伸强度  

DETERMINATION OF FRACTURE TOUGHNESS AND TENSILE STRENGTH OF CONCRETE USING SMALL SPECIMENS

作　　者：管俊峰 姚贤华 白卫峰 陈记豪 付金伟 GUAN Jun-feng;YAO Xian-hua;BAI Wei-feng;CHEN Ji-hao;FU Jin-Wei(School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China)

机构地区：[1]华北水利水电大学土木与交通学院,河南郑州450045

出　　处：《工程力学》2019年第1期70-79,87,共11页Engineering Mechanics

基　　金：国家自然科学基金面上项目(51779095;51679092);郑州市科技攻关项目(153PKJGG111;153PKJGG109)

摘　　要：该文利用骨料最大粒径dmax=10 mm,试件高度W依次为60 mm、80 mm、100 mm、140 mm、160 mm,厚度B=40 mm的小尺寸三点弯曲梁试件,来确定无尺寸效应的混凝土断裂韧度KIC与拉伸强度ft。区别于现有尺寸效应模型关注于"绝对尺寸W",该文提出"相对尺寸W/dmax"的概念,分析了骨料颗粒对有限尺寸试件断裂破坏的影响机理,进而将骨料最大粒径dmax与离散度参数?引入修正的边界效应模型的解析表达式中,发展建立了离散颗粒断裂模型,进而给出了由实验室条件下小尺寸试件(W=60 mm～160 mm和B=40 mm)的峰值荷载Pmax同时确定混凝土材料参数—KIC和ft的实用方法。进而分析了不同试件组合和不同峰值荷载时裂缝扩展量取值对材料参数确定的影响规律,建立了混凝土材料破坏的完整曲线,给出了满足线弹性断裂力学条件的混凝土试件理论最小尺寸,并基于确定的材料参数对各试件的峰值荷载进行了成功预测。。A simple method is presented for determining the material parameters of concrete KIC and ft using the small specimens in laboratory,in which the maximum aggregate of the concrete dmax=10mm,the specimens depth W=60mm,80mm,100mm,140mm and160mm,and the specimens width B=40mm.Compared to existing size effect models,only linked to specimen size W,the concept“relative size W/dmax”is proposed.The roles of aggregate size on fracture of finite size specimens were analyzed,and the maximum aggregate dmax and discrete numberβare included in the analytic solution expression of the improved Boundary Effect Model,named discrete particle fracture model.The different combination conditions of tested specimens and different fictitious crack growth at peak loading are adopted to determine the influence law of KIC and ft.The whole fracture failure curves of the concrete material are obtained.The theoretical minimum concrete specimen size meeting the condition of linear elastic fracture mechanics is obtained.And the peak loads of every specimens are predicted successfully based on the determined material parameters.

关 键 词：混凝土 小尺寸试件 相对尺寸 准脆性断裂 断裂韧度 拉伸强度 

分 类 号：TU528[建筑科学—建筑技术科学]