学术论文

      石灰石粉掺量对超高性能混凝土水化演变的影响

      Effects of limestone addition on hydration development of ultra-high performance concrete

      摘要:
      为制备生态型超高性能混凝土,采用不同体积掺量的石灰石粉(34%,54%和74%)降低超高性能混凝土(UHPC)中的水泥和硅灰用量,并研究石灰石粉对UHPC的抗压强度发展和水化演变的影响.试验结果表明:由于水泥中只含有少量的C3A,石灰石粉在UHPC中几乎不参与化学反应,只作为一种惰性的填充材料;与传统配合比相比,掺加54%石灰石粉不仅能改善拌合物的工作性,还能提高混凝土的抗压强度,56 d时,UHPC的抗压强度由155 MPa提高至170 MPa;由于填料稀释效应,水泥的水化程度由39.0%提高至66.2%.研究发现,过高掺量的石灰石粉会降低体系中活性组分的含量,因此石灰石粉最优掺量的确定需要满足体系内水泥与水含量的平衡关系,符合水泥完全水化理论要求,确保UHPC体系中具有足够的水化产物能够胶结其他颗粒材料.
      Abstract:
      The ecological ultra high performance concretes (UHPCs) with less amount of cement and silica fume were prepared by adding different levels of limestone (34%, 54% and 74% by volume).The effects of limestone on the compressive strength development and hydration evolution of UHPC were investigated.The experimental results show that the limestone is almost inert filler in the UHPC system due to the low amount of C3A in cement.Compared with the classical mix, the replacement of 54% limestone can improve the workability and compressive strength (from 155 MPa to 170 MPa at 56 d).In addition, the hydration degree of cement is increased from 39.0% to 66.2% due to the dilution effect of filler.However, the excessive addition of limestone can decrease the amount of reactive components.Therefore, the optimized amount of limestone addition should balance the relationship between cement and water,satisfy the fulfill hydration theory, and ensure the UHPC system to have enough hydration product to combine all particles.
      作者: 黄伟 孙伟
      Author: Huang Wei Sun Wei
      作者单位: 东南大学材料科学与工程学院,南京,211189
      年,卷(期): 2017, 47(4)
      分类号: TU528
      在线出版日期: 2017年8月15日