CaCO_3晶须对钢-聚乙烯醇混杂纤维增强水泥基复合材料板弯曲性能的影响

将廉价的微米级CaCO_3晶须引入毫米级钢纤维与聚乙烯醇(PVA)纤维混杂纤维增强水泥基复合材料(HyFRCC),研究CaCO_3晶须对HyFRCC薄板力学性能、破坏形态和尺寸效应的影响,并使用SEM观察HyFRCC微观形貌。试验结果显示,引入晶须后,HyFRCC薄板呈现出良好的弯曲性能及比梁式试件更优良的假性应变硬化和多缝开裂特征,且可以更有效地减小尺寸效应对抗弯强度的影响。微观形貌观察证实掺加晶须后,混杂纤维体系可以在不同尺度上发挥多层次阻裂作用。研究认为,由廉价的CaCO_3晶须部分替代钢纤维和PVA纤维制备的HyFRCC呈现出对板式构件良好的适应性,实现了力学性能优化和经济性提高的双重目标。

Influence of CaCO3 whisker on flexural behavior of steel-polyvinyl alcohol hybrid fiber reinforced cement matrix composite slabs

Cheap micron grade CaCO3 whisker was incorporated into the millimeter grade steel fiber and polyvinyl alcohol (PVA)fiber hybrid fiber reinforced cement-based composites (HyFRCC).The influence of CaCO3 whisker on mechanical behaviors,failure pattern and size effect of thin HyFRCC slabs was studied.The micro morphology of the composites was observed using SEM.The experimental results show that the thin slabs demonstrate good flexural performance,better pseudo strain hardening and multiple cracking behaviors than beams with addition of whisker.And the HyFRCCs including CaCO3 whisker are more efficient in reducing the size effect sensitivity on flexural strength.The micromorphology observation verifies that the hybrid fiber system incorporating CaCO3 whisker can inhibit the crack propagation at different scales.The study indicates that the steel fibers and PVA fibers can be replaced partly with cheap CaCO3 whiskers to produce HyFRCC,which shows good adaptability to fabricate slab element.And the dual goals of mechanical performance optimization and economy efficiency increase are both achieved.