Preparation of Self-compacting Ultra-high Toughness Cementitious Composite

A self-compacting ultra-high toughness cementitious composite （UHTCC） reinforced by discontinuous short polyvinyl alcohol （PVA） fibers, which exhibits self-compacting performance in the fresh state and strain-hardening and multiple cracking behavior in the hardened state, was developed through controlling flow properties of fresh mortar matrix at constant ingredients concentrations determined by micromechanical design and ensuring uniform fibers dispersion. The superplasticizer was utilized to adjust its flow properties in the fresh state. A series of flow tests, including deformability test, flow rate test, and self-placing test, were conducted to characterize and quantify the fluidity performance of fresh mortar matrix and self-compactability of fresh UHTCC. It is revealed that the utilization of superplasticizer is efficient in producing the fresh mortar matrix with desirable fluidity and the resulting self-compacting UHTCC. In addition, results of four point bending tests on the developed self-compacting UHTCC confirm the insensitivity of mechanical performance of self-compacting UHTCC to the presence of external vibrations as well as the flexural characteristics of deformation hardening and multiple cracking.

基于向量式有限元的超高韧性水泥基复合材料叠合剪力墙非线性分析

超高韧性水泥基复合材料(UHTCC)具有抗拉性能好、裂缝宽度可控、耐久性强以及受拉应变硬化特征等优点,克服了传统水泥基复合材料的易开裂破坏的缺点,适合于受拉混凝土构件或裂缝要求高的混凝土构件。剪力墙是一种抗震性能良好的结构构件,但其边缘为拉压破坏的易损区域,采用超高韧性混凝土材料替换传统混凝土可望获得更优异的抗震性能。基于求解结构非线性行为的向量式有限元(VFIFE)方法,采用自开发程序模拟分析超高韧性水泥基复合材料剪力墙拟静力推覆全过程。模拟结果表明,超高韧性水泥基复合材料具有优异的抗拉性能及韧性性能,可以有效改善剪力墙开裂后的工作性能,从而提高构件的抗震性能,因此具有重要的工程应用价值。