高性能PVA纤维增强水泥基复合材料的弯曲行为

高韧性的PVA-HPFRCC具有很高的能量吸收能力,但强度通常较低。本文采用工业废料(粉煤灰、硅灰等)替代部分水泥来制备高强度的PVA-HPFRCC,并研究粉煤灰、硅灰掺量以及PVA纤维体积掺量对高强度HPFRCC的弯曲行为的影响。研究结果表明:大掺量粉煤灰替代水泥可有效改善HPFRCC的应变-硬化特性,当粉煤灰掺量达到胶凝材料重量的60%时,其应变-硬化特性发挥的最为明显;增加PVA纤维体积掺量可提高HPFRCC的抗弯承载力和达到极限荷载时的变形能力,硅灰则降低了HPFRCC的韧性。

FLEXURAL BEHAVIOR OF HIGH PERFORMANCE PVA FIBER REINFORCED CEMENT COMPOSITES

PVA-HPFRCC with high toughness has high energy absorption capability,but the strength is often relatively low.In this paper,large quantities of fly-ash and silica fume are used to prepare PVA-HPFRCC with high strength.The influence of fly-ash and silica fume content as well as PVA fiber content on flexural behavior of high-strength HPFRCC is studied.The results show that strain-hardening performance of HPFRCC can effectively be improved by using cement replacers in the form of fly-ash.When the fly-ash content reached 60% by weight of cementitious materials,the strain-hardening performance of HPFRCC is the most distinct.The flexural capacity and deformation capacity of HPFRCC under ultimate load increase with the increasing of PVA fiber content.Silica fume leads to less ductile behavior of HPFRCC.