钢纤维聚合物水泥砂浆三点弯曲断裂特性研究  

Three-point bending fracture performance of steel fiber reinforced polymer modified cement mortar

作　　者：梅迎军[1] 魏河广 徐建平 樊文胜 

机构地区：[1]重庆交通大学土木建筑学院,重庆400074 [2]重庆交通建设(集团)有限责任公司,重庆400010 [3]江西省高速公路投资集团有限责任公司抚州至吉安高速公路项目建设办公室,江西南昌330000

出　　处：《西安建筑科技大学学报（自然科学版）》2013年第5期652-657,共6页Journal of Xi'an University of Architecture & Technology(Natural Science Edition)

基　　金：教育部博士点基金资助项目(20105522120001);重庆市科委科技攻关基金资助项目(2011GGC006);江西省交通厅科技基金资助项目(2012C0024)

摘　　要：通过对带有切口的砂浆试样进行三点弯曲试验测试,得到了质量掺量为0～18%的SBR(styrene-butadiene rubber,简称SBR)乳液改性水泥砂浆、体积掺量为0～0.9%的钢纤维砂浆和钢纤维聚合物改性水泥砂浆荷载-变形曲线及相应裂缝嘴张开位移(CMOD),并通过理论计算得到了砂浆的有效裂纹长度(aeff)、临界应力强度因子(Ks IC)及裂纹尖端张开位移(CTOD)等断裂特征参数.研究结果表明:钢纤维和聚合物乳液在单掺的情况下,均能改善砂浆的断裂性能,掺量越大,效果越好,且钢纤维对砂浆断裂性能的作用效果好于SBR乳液,SBR乳液和钢纤维复掺效果又明显优于单掺;与普通砂浆相比,钢纤维聚合物改性水泥砂浆临界荷载增加了32.3%～64.4%,临界荷载对应的变形增加了115.8%～209.2%,且荷载-变形曲线下降段更加平缓、饱满,荷载-变形曲线下降段甚至出现了二次峰值;与断裂能、有效裂纹长度、临界应力强度因子及裂缝嘴张开位移等断裂特征参数相比,采用裂纹尖端张开位移作为评价指标更能体现钢纤维和聚合物乳液对砂浆断裂性能作用效果的差异.The load-deformation curves and crack mouth open displacements （ CMOD ） of mortar were acquired by means of three-point bend test on notched mortar samples. Those mortars are named SBR latex modified cement （with the con- tent of 0-18%SBR, by weight of cement）, steel fiber reinforced mortar （with the content of 0-0.9% steel fiber, by volume of mortar）, steel fiber reinforced SBR latex modified cement mortar. Fracture parameters such as efficient crack length （ aeff ）, critical stress intensity factor （ Kic ） and crack tip open displacement （ CTOD ） were obtained from theo- retical calculation. The results show that the addition of steel fiber and SBR latex help improve fracture properties of mor- tar respectively, and the effect may increase the content of the SBR latex and steel fiber. Effect of steel fiber on fracture properties of mortar is superior to SBR latex, while compound addition of SBR latex and steel fiber is superior to employ respectively. Compared with blank mortar, critical load of steel fiber reinforced SBR latex modified cement mortar in- creased by 32.3 % -64.4 %, while corresponding deformation increased by 115.8 % -209.2 %. The descent segment of load-deformation curves for steel fiber reinforced polymer mortar falls gently, and there even appeared a secondary peak load. The adoption of CTOD in appraising the effect of SBR latex and steel fiber on the fracture performances of mortar is more efficient than fracture energy, aef~ , Kic and CMOD .

关 键 词：钢纤维 聚合物乳液 水泥砂浆 断裂参数 临界应力强度因子 裂纹尖端张开位移 

分 类 号：TU528.41[建筑科学—建筑技术科学] TU528.58