高掺量粉煤灰高延性水泥基复合材料的制备和性能

PREPARATION AND PROPERTIES OF HIGH DUCTILITY CEMENTITIOUS COMPOSITES WITH HIGH CONTENT OF FLY-ASH

高延性水泥基复合材料(high ductility cementitious composites,HDCC)是一种具有应变硬化、多缝开裂和高延性等特性的新型纤维增强水泥基复合材料,其材料设计必须取得基体韧度、界面黏结和纤维特性三者的最优组合,因此,HDCC的制备必须优选原材料和优化配合比,以取得最优的材料制备技术。从配合比设计入手,研究了粉煤灰含量、胶砂比等对HDCC力学性能的影响,优化了特定材料下的材料制备技术。结果表明:粉煤灰含量、胶砂比和养护条件对HDCC的拉伸性能均具有较大的影响。随着粉煤灰掺量的增大,砂含量的降低,拉伸应变增大。当砂含量较高时,基体开裂韧度较高,基体的极限拉伸应力下对应的极限拉伸应变较小,然而随着应力的下降,复合材料仍然能维持相当大的应变。

A high ductility cementitious composite （HDCC） is a developed sort of fiber reinforced composite with strain-hardening behavior, multi-crack and high ductility. To prepare the HDCC, it is necessary to optimize the mixture proportion and to gain the optimum combination of the toughness of matrix, interface properties and fiber performance. The effect of fly-ash content and the ratio of binder to sand on the properties of the HDCC were investigated based on the mixture design. The results show that fly-ash content, ratio of binder to sand and curing condition have an influence on the tensile properties of the HDCC. The tensile strain increases with the increasing of fly ash content and the decreasing of sand content. For the matrix with relative high crack toughness, the ultimate tensile strain of the HDCC is smaller, but the large strain can be maintained with the tardily descending stress.