PVA-ECC的弯曲韧性方板法试验研究

Square plate method experimental study on bending toughness of PVA-ECC

主要研究了PVA纤维体积掺量对纤维增强水泥基复合材料(PVA-ECC)弯曲韧性的影响,对PVC纤维体积掺量分别为0%,0.5%,1.0%,1.5%,2.0%的PVA-ECC试件的抗压强度和方板法弯曲性能等进行试验研究,分析了PVA纤维在ECC中的作用机理,并对PVA-ECC方板进行能量评价。结果表明:PVA纤维体积掺量的改变对ECC材料的抗压强度影响甚微,PVA纤维体积掺量的增加对方板法弯曲韧性试验中ECC试件的初裂荷载影响不大,但峰值荷载有明显的提高,跨中挠度增加明显且裂缝宽度减小;PVA-ECC方板弯曲韧性随PVA纤维体积掺量增大而提高且体积掺量为2.0%时增韧的效果最佳。

The effect of PVA fiber volume on the bending toughness of Polyvinyl Alcohol Fiber Engineered Cementitious Composite(PVA-ECC) was mainly investigated. Under the volume contents of 0%, 0.5%, 1%, 1.5% and 2%, the compressive strength of PVA-ECC and its bending properties based on square plate method were measured respectively. The mechanism of PVA fiber in ECC was analyzed, and the energy of PVA-ECC square plate was evaluated. The results show that the change of PVA fiber volume fraction has little effect on the compressive strength of ECC material. The increase of PVA fiber volume fraction has little effect on the initial crack load of ECC specimen in the square plate bending toughness test, but the peak load is obviously increased, the mid span deflection is obviously increased and the crack width is reduced. The bending toughness of PVA-ECC square plate increases with the increase of PVA fiber volume fraction and the toughening effect is the best if the volume fraction is 2.0%.