配筋聚乙烯醇纤维增强水泥复合材料梁的曲率延性

Flexural ductility of steel-polyvinyl alcohol fiber reinforced cement composite beam

聚乙烯醇纤维增强水泥(Polyvinyl alcohol fiber reinforced cement, PVA/C)复合材料具有优越的受拉应变硬化特性,可显著提高结构的变形能力。本文以PVA纤维体积分数和受拉钢筋配筋率为研究参数,对6根配筋PVA/C梁和2根普通混凝土梁(RC)进行四点弯曲试验,并对其曲率延性进行了试验研究和理论分析。试验研究表明:配筋PVA/C梁的荷载-挠度(P-δ)关系曲线所包围的面积是C梁的1.64~2.43倍,证明配筋PVA/C梁有较好的持荷变形能力;在PVA纤维体积分数一定的情况下,试验梁的曲率延性系数随受拉钢筋配筋率的增大而减小;在受拉钢筋配筋率一定的情况下,配筋PVA/C梁的曲率延性系数是C梁的1.56~2.02倍,证明掺入PVA纤维显著提高了试验梁的延性。建立了配筋PVA/C梁曲率延性系数的计算公式,并分析了PVA纤维体积分数对受压区高度系数和曲率延性系数的影响,试验结果与计算结果吻合较好。

Polyvinyl alcohol fiber reinforced cement(PVA/C) composites have superior tensile strain hardening characteristics, which can significantly improve the deformation capacity of the structure. Based on the PVA fiber volume fraction and the reinforcement ratio, the four-point bending experiment of six steel reinforced PVA/RC beams and two ordinary concrete(C) beams was carried out, and the ductility of the steel reinforced PVA/RC beams was analyzed. The experimental research shows that the area surrounded by the load-deflection curve of the steel reinforced PVA/C beams is 1.64-3.71 times of the RC beam, which proves that the steel reinforced PVA/RC beams have better holding deformation ability. When the PVA fiber volume fraction is constant, the curvature ductility coefficient of the test beam decreases with the increase of the reinforcement ratios. In the case of a certain reinforcement ratio, the curvature ductility coefficients of the steel reinforced PVA/C beams are 1.56-2.02 times that of the C beam, which proves that the incorporation of PVA fiber significantly improves the ductility of the test beam. The calculation formula of the curvature ductility coefficient of the steel reinforced PVA/C beams was established, and the influence of the PVA fiber volume fraction on the ductility coefficient and the height coefficient of pressurized zone was analyzed. The test results are in good agreement with the calculated results.