基于非接触式观测技术的再生骨料混凝土断裂性能分析  

FRACTURE PROPERTIE ANALYSIS OF RECYCLED AGGREGATE CONCRETE BASED ON DIGITAL IMAGE CORRELATION TECHNIQUE

作　　者：吴恺云 罗素蓉[1] 郑建岚[1,2] WU Kai-yun;LUO Su-rong;ZHENG Jian-lan(College of Civil Engineering,Fuzhou University,Fuzhou,Fujian 350116,China;College of Engineering,Fujian Jiangxia University,Fuzhou,Fujian 350108,China)

机构地区：[1]福州大学土木工程学院,福建福州350116 [2]福建江夏学院工程学院,福建福州350108

出　　处：《工程力学》2022年第3期147-157,共11页Engineering Mechanics

基　　金：国家自然科学基金项目(52078139);国家自然科学基金海峡联合基金重点支持项目(U1605242)。

摘　　要：采用非接触式观测技术(DIC)和传统电测法,对不同再生粗骨料取代率(0%、30%、50%、70%、100%)的混凝土进行三点弯曲梁断裂性能试验,得到双K断裂参数、裂缝口张开位移(CMOD)、裂缝尖端张口位移(CTOD)、裂缝扩展长度(Δa)以及裂缝扩展路径,验证DIC非接触观测技术的有效性。结果表明:当再生骨料取代率为100%时,起裂韧度和失稳韧度分别下降了15.81%和15.39%;随着再生骨料取代率的增大,PCMOD、P-CTOD、P-Δa曲线下降段斜率增大;DIC方法能够有效捕捉到裂缝的扩展过程,并且与夹式引伸计测得的CMOD值二者吻合良好;CTOD的DIC实测值和公式计算值变化趋势较为一致;在试验结果的基础上,通过P/P_(max)与Δa/Δac的关系拟合曲线,可以获得不同再生骨料取代率的试件在不同荷载下的Δa估算值。Three point bending fracture tests of recycled aggregate concrete beams with different recycled coarse aggregate replacement ratio(0%,30%,50%,70%,100%)have been carried out,with results analyzed by digital image correlation(DIC)method and the traditional electrometric method.The double-K fracture parameters,crack-mouth-opening displacement(CMOD),crack-tip-opening displacement(CTOD),crack extension length(△a)and fracture growth path were obtained,and the validity of DIC method was verified.The results show that when the replacement rate is 100%,the crack initiation fracture toughness and unstable fracture toughness of recycled aggregate concrete decrease by 15.81%and 15.39%,respectively.With the increase of the replacement rate of recycled aggregate,the slopes of the descending sections of P-CMOD,P-CTOD and P-△acurves increase.DIC method can effectively capture the fracture propagation process.The CMOD values measured by DIC method and clip type extenometer are in good agreement.The variation trends of DIC measured value and formula-calculated value of CTOD are relatively consistent.Based on the test results,the estimated values,△a,of specimens with different replacement rates of recycled aggregate under different loads can be obtained by fitting the curve between P/P_(max) and△a/△ac.

关 键 词：再生混凝土 断裂性能 DIC非接触式观测技术 再生骨料取代率 裂缝扩展 

分 类 号：TU528[建筑科学—建筑技术科学]