短纤维及混杂纤维砂浆轴向拉伸试验研究

Experimental study on axial tension of short fiber or hybrid fiber reinforced mortar

采用自行设计的试验加载装置,对在砂浆中分别掺入钢纤维、PVA纤维以及同时掺入两种纤维的水泥基复合材料进行了直接拉伸试验,成功地获得了完整的应力-应变全曲线,数据采集采用动态应变测试系统,结果表明,在砂浆中掺入钢纤维,可以大大提高基体的抗拉强度及韧性,试件的最终破坏取决于钢纤维与基体之间的界面粘结强度;在砂浆中掺入PVA纤维对提高基体的抗拉强度有限,但却可以较大幅度地提高基体的韧性,试件的破坏是随着纤维的逐渐断裂而破坏。混杂纤维增强砂浆的破坏形式则是由基体、钢纤维、PVA纤维的材料特性共同决定。

A set of new testing scheme is adopted in this experiment, whole stress-strain curve of fiber-reinforeed mortar including three mixed style under direct tension is aquired. Dynamic strain testing system is used to collect Data. Experiment results show that tensile strength and toughness of mortar mixed steel fibers is largely increased. The last failure is determined by the interfacial adhesion strength between steel fibers and mortar. Although Tensile strength is only increased slightly, toughness of mortar mixed PVA fibers is strengthened largely, with crack spread, PVA fiber breaks one by one. when mortar is mixed with steel fibers and PVA fibers, failure properties of composites is decided by characteristic of two types of fiber.