基于DIC方法的地聚合物混凝土断裂过程分析  

Investigation of Fracture Process in Geopolymer Concrete with Digital Image Correlation Method

作　　者：谢子令[1] 周华飞[1] 杨克家[1] 孙林柱[1] 

机构地区：[1]温州大学建筑工程学院,浙江温州325035

出　　处：《建筑材料学报》2015年第6期982-987,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(51108348;51178356);浙江省教育厅项目(Y201121074);温州市科技计划项目(S20140010)

摘　　要：为了量化研究地聚合物混凝土断裂过程参数的演化过程,采用数字图像相关(digital image correlation,DIC)方法及夹持引伸计法对含初始缺口粉煤灰基地聚合物混凝土试样在三点弯曲加载过程中的裂缝口张开位移(CMOD)、裂尖张开位移(CTOD)及裂缝扩展长度进行测试与计算分析.结果表明:DIC测试的裂缝口张开位移与夹持引伸计测试值吻合较好,试样经历了起裂、裂缝的稳态和亚稳态扩展及失稳破坏阶段;基于DIC测试的裂尖张开位移与基于弹性等效的理论计算吻合较好,但基于DIC裂缝扩展长度的测试值与弹性等效裂缝扩展长度的计算值之间存在较大偏差,导致这一差别的主要原因是由于地聚合物混凝土与水泥混凝土一样存在断裂过程区.To investigate the fracture behavior of fly ash geopolymer concrete,three-point bending tests of fly ash geopolymer concrete samples were carried out.The digital image correlation（DIC）method was proposed to measure the crack-mouth-opening displacements（CMOD）,crack-tip-opening displacements（CTOD）,as well as the crack extension length.For the purpose of cross validation,the extensometer was also employed for crack measurement.The results show that the fracture process can be separated into four different stages,i.e.crack initiation stage,crack stable extension stage,crack sub-steady extension stage,and crack unstable extension stage.The values of CMOD measured by the two methods matched very well with each other,which helps to validate the effectiveness of DIC method.In addition,the values of CTOD measured by DIC show good agreement with the results calculated from the elastic equivalent crack method.However,the crack extension length measured by DIC is much larger than the calculated results.It is attributed to the formation of fracture process zone in the front of the crack tip,which has also been observed in cement concrete.

关 键 词：地聚合物混凝土 数字图像相关方法 断裂过程区 裂缝扩展 

分 类 号：TU526[建筑科学—建筑技术科学]