火山灰质粉对砂浆性能与微结构的影响

Effects of pozzolan powder on properties and microstructure of mortar

为加强我国区域火山灰资源利用,为工程建设提供优质建筑原材料,选取泸定桥、泸霍两地典型火山灰弃岩资源磨制成火山灰材料,研究不同种类和粒径的火山灰质材料基本特性。采用火山灰等质量取代水泥制备火山灰-水泥砂浆,分析火山灰对水泥砂浆力学性能与微观结构的影响及机理。结果表明,随着火山灰粒径(d50)的降低,砂浆各个龄期的抗压强度和火山灰活性指数升高,但浆体的流动性降低。掺入火山灰会导致浆体的孔隙率增大和孔结构粗化。当火山灰粒径相似时,泸定桥组砂浆的28d活性指数小于泸霍组。此外,蒸汽养护可以促进各组砂浆的抗压强度和活性增长。

In order to strengthen the utilization of typical pozzolans resources and provide high-quality building raw materials for corresponding engineering construction,the typical pozzolan abandoned rock resources in Ludingqiao and Luhuo are selected to be ground into pozzolan materials.The basic properties of pozzolanic materials of different types and particle sizes are studied.The pozzolan-cement mortar is prepared by replacing cement with pozzolan,and the influence and mechanism of pozzolan on the mechanical properties and microstructure of cement mortar are analyzed.The results show that with the decrease of pozzolan particle size(d50),the compressive strength and pozzolanic activity index of mortar at each age increase,however the fluidity of the slurry decreases.The addition of pozzolan results in increased porosity and coarsening of the pore structure of the paste.When the particle sizes of the pozzolans are similar,the 28-day activity index of the mortar of the Ludingqiao group is smaller than that of the Luhuo group.In addition,steam curing can promote the growth of compressive strength and activity of each group of pozzolan-cement of mortars.