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配比参数对UHPC流动性及抗压强度的影响试验研究
作者：樊俊江，於林锋，韩建军
（上海市建筑科学研究院，上海 200032）
摘要：提出了与超高性能混凝土（UHPC）特点相适应的体积法配比计算方法，研究了硅灰掺量、粉煤灰掺量、钢纤维体积掺量、水胶比4个配比参数对UHPC流动性及抗压强度的影响规律及机理。结果表明：硅灰和钢纤维对UHPC的抗压强度有较为明显的改善作用，但掺量过大时会引起流动性的大幅下降，带来强度增长边际效应；30%以内掺量的粉煤灰对UHPC的抗压强度无显著影响。水胶比过低时UHPC的流动性损失较大，UHPC在成型过程中引入缺陷的概率增大，抗压强度并未出现提高。硅灰和钢纤维对UHPC抗压强度的增强机理在于钢纤维阻碍了受压过程中裂缝的扩展，硅灰的存在增大了UHPC浆体与钢纤维间的界面粘结力，从而提高了钢纤维阻滞裂缝扩展的能力。
关键词：硅灰；粉煤灰；钢纤维；水胶比；UHPC；抗压强度
中图分类号：TU528.31 文献标识码：A 文章编号：1001-702X（2019）04-0005-04
Experimental study on influence of ratio parameters on UHPC fluidity and compressive strength
FAN Junjiang，YU Linfeng，HAN Jianjun
（Shanghai Research Institute of Building Science，Shanghai 200032，China）
Abstract：The calculation method based on material volume which is suitable to ultra high performance concrete UHPC is put forward. The influence of silica fume proportion，fly ash proportion，steel fiber volume proportion，water binder ratio to UHPC fluidity and compressive strength is studied，and the influence mechanism of those factors is also analyzed. Result shows that silica fume and steel fiber can obviously improve the compressive strength of UHPC，however when their proportion is too much，it will sharply reduce the fluidity of UHPC. When the proportion of fly ash is within 30%，it dose not obviously affect the compressive strength of UHPC. When the water binder ratio goes too low，the fluidity of UHPC also obviously decline which lead to no increase in compressive strength. The existence of steel fiber impedes the expansion of cracks during the compression process，silica fume improves the interfacial bonding force between UHPC paste and steel fiber which improves the ability of steel fiber to block the crack growth.
Key words：silica fume，fly ash，steel fiber，water binder ratio，UHPC，compressive strength