基于应变硬化能量比值法对PVA-FRCC弯曲韧性的研究

Research on flexural toughness for PVA-FRCC by strain hardening energy ratio method

本文对比分析各国规范以及国内外学者对弯曲韧性评价方法的研究,基于欧洲材料与结构联合会(RILEM TC162-TDF)标准,依据聚乙烯醇纤维增强水泥基复合材料(PVA-FRCC)荷载挠度曲线的变化特征,提出采用纤维提供能量与水泥基材料提供能量比值的方法,即变形硬化能量比值法,对PVA-FRCC进行弯曲韧性评价。该方法计算方便,能反映PVAFRCC的应变硬化特点,较好地适用于PVA-FRCC的弯曲韧性评价。采取该方法对PVA-FRCC四点弯曲试验梁进行韧性计算,分析了国产纤维与进口纤维对韧性的影响。结果表明:PVA纤维的加入明显提高了复合材料的弯曲韧性,而弯曲韧性随纤维掺量的增加而增加;纤维总掺量一定时,进口纤维掺量比例越大,其弯曲韧性越好。

The flexural toughness evaluation methods from domestic and foreign standards and scholars studies are compared,and the strain hardening energy ratio method is proposed base on the RILEM TC 162-TDF standard and the characteristics of polyvinyl alcohol fiber reinforced cementitious composites（ PVA-FRCC） load deflection curves. This method uses the energy ratio provided by fiber and cementitious composites to evaluate the toughness of PVA-FRCC.It needs simple calculation and can express the strain hardening characteristics of PVA-FRCC so that it fits well for the PVA-FRCC evaluation. The method is used for the calculation of the toughness of PVAFRCC four-point bending beams,in order to analysis the differences between Japan-fiber and China-fiber. The results show that the use of fiber significantly increased the flexural toughness of cementitious composites while the flexural toughness changes with the fiber dosage. And when the total fiber dosage is constant,the lager the Japanfiber dosage ratio is,the better the flexural toughness gets.