盐冻条件下FRP布加固混凝土粘结性能试验  

Bond Tests of Concrete Strengthened with FRP Sheet under the Salt Frozen Condition

作　　者：张延年[1] 常萍[1,2] 顾亚洁 郑怡 

机构地区：[1]沈阳建筑大学土木工程学院,辽宁沈阳110168 [2]南宁学院土木与建筑工程学院,广西南宁530200 [3]辽宁省建筑材料监督检验院,辽宁沈阳110032

出　　处：《沈阳建筑大学学报（自然科学版）》2015年第5期793-802,共10页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金项目(51078065);质检公益性行业科研专项项目(201210040);辽宁省高等学校优秀人才支持计划(LR2014015);重庆市科学计划项目(cstc2013yykf A30004)

摘　　要：目的研究FRP布加固混凝土在盐冻侵蚀下能否按预定要求起到应有的效果及其力学性能的变化.方法将混凝土试块进行25次、50次、75次和100次的盐冻处理,并采用试验机进行轴拉试验,对其试件的外观、极限承载力及粘结强度等指标进行对比分析.结果试验结果表明:盐冻时间越长越易从混凝土的浅层区发生拉断破坏或者从纤维布处破坏,进行100次盐冻处理的C20混凝土试件粘结强度平均值仅为0.890 MPa;C40混凝土试块经过100次盐冻处理后,粘结强度平均值仍达到3.944 MPa,其破坏形式为混凝土被拉断.结论在相同混凝土等级不同作用时间情况下,盐冻开始时对粘结强度的影响较大,后来变得不是很明显.在不同混凝土等级相同作用时间情况下,盐冻对较低等级混凝土影响较大,对较高等级混凝土影响较低,同时CFRP的正拉粘结强度远大于GFRP的粘结强度,CFRP的粘结强度较高.This paper studied the mechanical behavior of concrete reinforced with FRP cloth under the salt freeze-thawerosion condition and its application effect. Some specimens were salt frozen under 25,50,75 and 100 time cycle conditions and tested by axial tension. Dimensions,ultimate bearing capacities and adhesive strengths of specimens were comparatively analyzed. Results showthat the longer the salt frozen time is,the more easier the tensile failure occurs in the shallowarea of concrete or by fiber fabric. The bond strength average value of C20 concrete treated by salt freezing with 100 times is only 0. 890 M Pa and the bond strength average value of C40 concreteblock under the same treatment condition still reaches 3. 944 M Pa. Concrete damage form is tensile breaking. Conclusion is that for concrete with the same level,the salt freezing with different frozen time has an great influence on bond strength at the beginning. In contrast,for different level concrete specimens with same frozen time,the salt freezing has an great influence on the lower level ones. M eanwhile,the tensile adhesivity of CFRP is more higher than the adhesivity of GFPR.

关 键 词：混凝土试块 盐冻处理 极限抗拉强度 FRP布加固 粘结性能 

分 类 号：TU375.6[建筑科学—结构工程]