SHCC修复既有混凝土梁在持续荷载作用下的裂缝试验研究  

Experimental investigation on the cracks of existing concrete beams repaired with SHCC under sustained load

作　　者：胡春红[1] 司斌[1] 

机构地区：[1]河南理工大学土木工程学院,河南焦作454000

出　　处：《混凝土》2017年第2期15-20,共6页Concrete

基　　金：国家自然科学青年基金(51208183);河南省科技攻关研究项目(132102310312);河南理工大学博士基金(B2014-063)

摘　　要：应变硬化水泥基复合材料(SHCC)在拉伸荷载作用下,具有应变硬化和多微缝开裂的特性,其极限拉应变可达到3%以上。通过5根SHCC修复梁和1根未修复的对比梁,对SHCC修复既有混凝土梁在四点弯曲持续荷载作用下裂缝的发展情况进行了试验研究。主要考察了修复层厚度、黏结面粗糙度、SHCC龄期等因素对修复梁的裂缝间距、裂缝宽度的影响规律和作用机理。对比分析了试验梁在持续荷载作用下裂缝的出现、发展与分布规律。试验结果表明,与对比梁相比,修复梁的裂缝条数增多、间距减小;最大裂缝宽度与平均裂缝宽度均减小,且最大裂缝宽度扩大系数有所降低;SHCC层呈现出多裂缝开裂形态,平均裂缝宽度可控制在100μm左右。说明SHCC对于提高修复构件的耐久性极为有利,是一种有效的修复材料。试验结果可为实际工程提供理论依据和指导。Strain hardening cementitious composite （ SHCC ） has strain-hardening and multiple micro-cracking characteristics with anultimate tensile strain exceeding 3% under uniaxial tensile load.Research on crack development of reinforced concrete beams repaired withSHCC was done through four-point bending sustained load test of five repaired beams and a contrast beam.The influence of interfaceroughness, thickness of repair layer and age of SHCC on crack was mainly investigated.The occurrence, development and distribution rulesof cracks of two materials （concrete and SHCC ） were analyzed.The results indicated that the crack number increased and crack spacingdecreased in repaired beams compared with the contrast beam.Meanwhile,introducing SHCC material into repairing not only could reducethe maximum and average crack width, but also decrease the increscent coefficient of maximum crack width.In addition, the SHCC layerpresented a multiple crack pattern,and the average crack width could be controlled at about 100 μm.It shows that SHCC is highlyadvantageous to improve the durablity of repaired structure, so it is an effective repair material.The test results can provide theoretical basisand guidance for practical engineering.

关 键 词：应变硬化水泥基复合材料 混凝土 修复 裂缝 持续荷载 

分 类 号：TU528.01[建筑科学—建筑技术科学]