再生微粉掺量对超高性能混凝土力学性能影响研究

将再生微粉(RCP)取代硅灰制备超高性能混凝土(UHPC),研究了再生微粉取代率对UHPC性能的影响。结果表明:再生微粉取代率为0~45%时,随取代率的增加,UHPC的流动性逐渐降低,收缩逐渐减少,强度逐渐降低;再生微粉取代率从0增大到45%时,UHPC的流动度降低了30%,收缩率下降了44.5%,抗压强度降低了12.9%,抗折强度下降了13.2%。微观分析表明,用再生微粉取代硅灰作为外掺料对UHPC水化产物影响不大,再生微粉的颗粒为不规则形态,且粒径整体偏大是UHPC性能变化的主要原因。

Effect of recycled fine powder content on mechanical properties of UHPC

Ultra-high performance concrete(UHPC)was prepared by replacing the recycled fine powder with silica fume,and the influence of the proportion of recycled fine powder replacing silica fume on the physical and mechanical properties of UHPC was studied.The results show that when the replacement rate of recycled fine powder is 0~45%,as the replacement rate increases,the fluidity of UHPC mortar gradually decreases,the shrinkage gradually decreases,and the strength gradually decreases.UHPC mortar fluidity decreased by 30%,shrinkage rate decreased by 44.5%,compressive strength decreased by 12.9%,flexural strength decreased by 13.2%.Microscopic experiments show that the use of recycled fine powder instead of silica fume as an admixture has little effect on the hydration products of UHPC.The irregular shape of particles of the recycled fine powder and the larger overall particle size is the main reason for the change in UHPC performance.