PVA纤维增强混凝土的弯曲韧性

为了掌握具有高强度和弹性模量的聚乙烯醇纤维(PVA)增强混凝土的抗弯韧性,对PVA纤维混凝土的弯曲韧性进行了系统试验,测定了不同纤维掺量纤维混凝土梁的荷载—挠度全曲线。基于美国ASTM方法,分析了PVA纤维增强混凝土的弯曲韧性。研究表明:PVA纤维可显著提高混凝土抗弯韧性和变形能力,纤维掺量为0.78kg/m3、1.0kg/m3和1.3kg/m3时,韧性指数I5分别比素混凝土提高2.89、2.82和3.24倍,I10分别比素混凝土提高4.33、5.08和6.29,I30分别比素混凝土提高7.91、7.98和8.83。在纤维体积率相同情况下,PVA纤维混凝土抗弯韧性高于聚丙烯纤维混凝土;PVA纤维使混凝土由脆性破坏变为延性破坏。

Flexural Toughness of Polyvinyl Alcohol (PVA) Fiber Reinforced Concrete Beams

The polyvinyl alcohol fibers a new type fiber. In order to study the flexural toughness of PVA fiber reinforced concrete, the flexural toughness experiments of concrete with PVA fibers, and PP fiber are made at the same time, and the load deflection curve of all beams are obtained. Based on the ASTM method,the flexural toughness of concrete with PVA,PP fibers are all analyzed. The experimental results indicate that the PVA fiber can improve the flexural toughness and the deformation ability of concrete beams. The flexural toughness index I5 and I10 of concrete with PVA fiber are 3. 24 and 6. 29 times higher than that of the plain concrete respectively. For the same fiber volume ratio of 0. 1% ,the flexural toughness index of PVA fiber reinforced concrete is higher than that of concrete with PP fiber. PVA fibers can improve the toughness and deformation ability of concrete remarkably, and the failure mode is changed from brittle to ductile fracture.