应变硬化水泥基复合材料(SHCC)弯曲韧性研究  

Flexural toughness of strain Hardening cementitious composites(SHCC)

作　　者：田砾[1] 毛新奇[2] 李晓东[3] 赵铁军[1] 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]莱阳农学院,山东青岛266109 [3]青岛理工大学,山东青岛266033

出　　处：《混凝土》2006年第11期10-12,19,共4页Concrete

基　　金：国家自然科学基金资助项目(50378045)

摘　　要：砂浆、混凝土等水泥基复合材料易于开裂、耐久性低劣的主要原因是其抗拉强度低、韧性差。高模量聚乙烯醇(PVA)纤维的添加可以增强水泥基材料的韧性,使其呈现准应变硬化和多微缝开裂特性,从而显著改善结构的耐久性。通过四点弯曲试验研究了PVA纤维体积掺量分别为0、0.75%、1.5%的抗折强度,按照ASTM方法确定了SHCC的弯曲韧度指数,通过JCI方法得到了SHCC的弯曲韧性系数。结果表明,最大抗弯承载力和最大挠度均随纤维掺量的增加而增加,结果可由纤维增强材料的应变硬化特性来解释。同时,与数值模拟结果的比较也证实了上述结论。Durability of cement-based composites such as normal mortar or concrete is usually limited due to low tensile strength, poor toughness and hence low resistance with respect to crack formation. The experimental results indicate that high elastic modules Polyvinyl Alcohol （PVA） Fiber can enhance the ductility of the celncntitious composites. Hence, SHCC exhibits the typical behavior of strain hardening and multiple-crack that will increase the durability of RC structures marvelously. Flexural strength under four-point bending has been determined on samples made of fine mortar containing 0, 0.75%, and 1.5% of PVA fibers. The flexural toughness index according to ASTM method and the coefficient of the flexural toughness based on JCI method have been evaluated. It can be concluded that the maximum load bearing capacity and the maximum deflection ofcementitious composites under four-point bending increase with increasing PVA fiber content, This observation can be explained by pronounced Strain hardening of the fiber reinforced material. Comparison with numerical simulation confirms the obtained results.

关 键 词：耐久性 抗弯强度 聚乙烯醇(PVA)纤维 SHCC 应变硬化 韧度 

分 类 号：TU528.01[建筑科学—建筑技术科学]