CAJ | 학술논문

本文采用最大尺寸为1200mm×1200mm×200mm的楔入劈拉试件，利用光弹贴片法对混凝土预制缝的起裂、稳定扩展直至失稳破坏全过程进行了系统的研究.采用照相机及数码摄像机拍摄了光弹贴片所显示的裂缝扩展全过程，获得了各级荷载下各试件裂缝的亚临界扩展量.在此基础上，根据试验测得的起裂荷载Pini及最大荷载Pmax计算了混凝土起裂断裂韧度KiniIC及失稳断裂韧度KunIC.结果表明，混凝土KiniIC与试件高度无关，而当试件高度大于600mm时，所测得的KunIC也与试件高度无关，这说明混凝土双K断裂参数(KiniIC及KunIC)可以作为混凝土的材料参数.
본문채용최대척촌위1200mm×1200mm×200mm적설입벽랍시건，이용광탄첩편법대혼응토예제봉적기렬、은정확전직지실은파배전과정진행료계통적연구.채용조상궤급수마섭상궤박섭료광탄첩편소현시적렬봉확전전과정，획득료각급하재하각시건렬봉적아림계확전량.재차기출상，근거시험측득적기렬하재Pini급최대하재Pmax계산료혼응토기렬단렬인도KiniIC급실은단렬인도KunIC.결과표명，혼응토KiniIC여시건고도무관，이당시건고도대우600mm시，소측득적KunIC야여시건고도무관，저설명혼응토쌍K단렬삼수(KiniIC급KunIC)가이작위혼응토적재료삼수.
The wedge splitting specimens with maximum size 1200mm×1200×200mm are utilized to systematically investigate the crack initiation,stable propagation and unstable failure of concrete by means of photoelastic coatings.Using camera and digital video camera,the complete crack propagation process of concrete that appeared as interference fringes on the photoelastic coatings was recorded.On this basis,the propagation lengths under various loads are obtained.The crack initiation fracture toughness KiniIC and the unstable fracture toughness KunIC are determined according to the crack initiating load and the maximum load measured in the experiment.The result shows that the KiniIC is independent of the specimen height and so the KunIC when the specimen height reaches 600mm.Therefore,the double-K fracture parameter can be utilized as concrete material constant to describe the crack initiation,stable propagation and unstable failure of concrete structure.