双裂缝混凝土试件断裂过程试验研究

为了研究不同缝间跨比值（RCSS）混凝土三点弯曲梁试件断裂参数变化规律,并探讨边缝的存在对跨中裂缝断裂特性的影响,以双K断裂理论为基础,设计制作了4组相同初始缝高比、不同缝间跨比值（0、0.1、0.15、0.2）的混凝土三点弯曲梁试件,研究跨中主裂缝起裂韧度和失稳韧度的变化规律.结果表明：起裂韧度随着缝间跨比值的增加而增大,均值从缝间跨比值为0到0.2增加了0.14MPa·m1/2;失稳韧度随着缝间跨比值的增加而减小,均值从缝间跨比值为0到0.2减小了0.09MPa·m1/2;这种变化使混凝土的韧性逐渐减小,脆性逐渐增加.

EXPERIMENTAL STUDY ON FRACTURE PROCESS OF DOUBLE-CRACK CONCRETE SPECIMEN

In order to study the change rule of concrete fracture parameters for different ratio of crack-spacing and span（RCSS）,and the influence of side crack on mid-span crack,four groups threepoint bending specimens with same initial crack-depth ratios and different RCSS（0、0.1、0.15、0.2）are designed and constructed base on double K fracture theory.The change rule of the initiation fracture toughness and the unstable toughness for mid-span crack is studied.The results showed that the initiation fracture toughness will increase as the RCSS increases,average increased by 0.14MPa · m1/2 when the RCSS changed from 0 to 0.2; and the unstable toughness will decrease as the RCSS increases,average decreased by 0.09MPa · m1/2 when the RCSS changd from 0 to 0.2.This change made the concrete toughness decreased gradually and brittleness increased gradually.