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为研究箍筋约束工程纤维增强水泥基复合材料(ECC)的受压性能,对12组共36个箍筋约束的配筋ECC圆形截面短柱进行了轴心受压试验,分析了箍筋屈服强度和间距、ECC强度与PVA纤维体积掺量对约束ECC应力-应变曲线的影响。结果表明:试件的破坏形态均为纵筋压屈、核心ECC压碎,由于PVA纤维的桥接作用,提高了柱的整体性,保护层ECC外鼓但并未剥落;提高箍筋屈服强度、减小约束箍筋间距、采用低强度ECC及增加PVA纤维体积掺量,约束ECC应力-应变曲线的下降段较为平缓,短柱的延性得到改善,相对于较强的箍筋约束作用,PVA纤维对约束ECC变形的影响则较小。基于试验结果的分析,提出了考虑有效约束指标与PVA纤维体积掺量的箍筋约束ECC峰值应力及其对应应变计算式,建立了约束ECC应力-应变全曲线方程,计算曲线与实测曲线吻合较好。
In order to study the compressive property of fiber reinforced cement-based composites (ECC) with stirrups restraint, 36 pairs of reinforced ECC circular cross-section short columns with a total of 36 stirrup restraints were subjected to axial compression test. Effect of yield strength and spacing, ECC strength and volume fraction of PVA fiber on constrained ECC stress - strain curve. The results show that the failure modes of the specimens are longitudinal bar buckling and core ECC crushing. Because of the bridging effect of PVA fiber, the integrity of the column is improved, while the protective layer ECC outer drum does not peel off. The yield strength of the stirrup is improved, In order to reduce the confinement stirrup spacing, the low-strength ECC and the increase of the volume content of PVA fiber were used to constrain the descending section of ECC stress-strain curve. The ductility of the short column was improved. Compared with the restraint effect of the stirrups, PVA fiber The impact of constrained ECC deformation is smaller. Based on the analysis of the test results, the peak stress of confined ECC and its corresponding strain calculation formula considering effective restraint index and volume content of PVA fiber are proposed, and the constrained ECC stress-strain total curve equation is established. The calculated curve is in good agreement with the measured curve it is good.