胶凝材料与纤维种类对UHTCC性能的影响

Effect of cementitious materials and fiber types on performance of ultral high toughness cementitious composites

对12组超高韧性水泥基复合材料(UHTCC)进行流动性、抗压强度、劈裂抗拉强度和抗弯强度试验,探讨胶凝材料与纤维种类对UHTCC性能的影响。结果表明,单掺2.0%镀铜钢纤维时,抗压强度和劈裂抗拉强度最佳;镀铜钢纤维掺量的增加,拉压比、抗弯试验峰值荷载以及韧度因子明显增大,抗弯性能与韧性能力得到提升;随着硅灰掺量、镀铜钢纤维掺量增大以及聚丙烯纤维的掺入,拌合物的流动性变差;当水泥掺量为胶凝材料质量的70%,粉煤灰与硅灰掺量皆为15%时,拌合物流动性良好,有利于纤维发挥增韧作用;当镀铜纤维与聚丙烯纤维组合时,较单掺镀铜钢纤维,抗压强度与劈裂抗拉强度显著提升,特别是抗弯强度试验峰值荷载明显增大。

The fluidity,compressive strength,splitting tensile strength and flexural strength of 12 groups of ultra high toughness cement-based composites(UHTCC)were tested to investigate the effect of cementitious materials and fiber types on UHTCC performance.The results show that the compressive strength and splitting tensile strength are the best when the 2.0%copper-plated steel fiber is used alone.The increase of the amount of copper-plated steel fiber increases,the tensile-compression ratio,the peak load of the bending test and the toughness factor increase significantly.The bending resistance and toughness ability are improved.As the amount of silica fume,the amount of copper-plated steel fiber increases,and the incorporation of polypropylene fiber,the fluidity of the mixture deteriorates.When the cement content is a cementitious material 70%of the mass,when the fly ash and silica fume are both 15%,the fluidity of the mixture is good,which is beneficial to the fiber toughening effect.When the copper-plated fiber is combined with the polypropylene fiber,it is more than copper-plated steel fiber,compressive strength and splitting tensile strength are significantly improved,especially the peak load of the bending strength test is significantly increased.