ECC修复既有RC梁正常使用阶段的裂缝研究

Study on the crack of reinforced concrete beams repaired with ECC during the normal working stage

基于工程纤维增强水泥基复合材料(ECC)修复既有钢筋混凝土梁的弯曲性能试验,主要分析了聚乙烯醇(PVA)纤维体积掺量、修复层厚度和损伤参数对修复梁裂缝形态、间距及宽度的影响。研究结果表明:外贴ECC能显著改善既有混凝土梁的裂缝形态,随着PVA纤维掺量和修复层厚度(合理范围内)的增加,修复梁的裂缝宽度和间距均得到明显改善;损伤参数较大的修复梁,ECC层对裂缝的改善效果不太明显。基于试验与理论分析,建立了ECC修复既有钢筋混凝土(RC)梁裂缝的计算模型,研究结果可为ECC材料在修复工程中的应用提供参考。

Based on the bending performance test of existing reinforced concrete beams repaired with engineered fiber reinforced cementitious composites(ECC), the effects of volume fraction of PVA fibers, repair layer thickness and damage parameters on the crack distribution, spacing and width of the repaired beams are analyzed. The results show that the crack distribution of the existing concrete beams is significantly improved by applying ECC, and the crack width and spacing of the repaired beams are significantly improved with the increase of volume fraction of PVA fibers and repair layer thickness(within a reasonable range). The improvement effect of ECC layer on cracks is less obvious for repaired beams with larger damage parameters. Based on the experimental and theoretical analyses, a computational model of cracks for concrete beams repaired with ECC is established, and the results of the study can provide reference for the application of ECC materials in repair projects.