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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。
High ductility cementitious composites (HDCC) is a new type of fiber reinforced cement-based composites with properties of strain hardening, multi-slit cracking and high ductility. Its material design must obtain the toughness of the matrix, interfacial adhesion and Fiber characteristics of the three optimal combination, therefore, HDCC preparation must optimize the raw materials and optimize the mix to obtain the best material preparation techniques. Starting with the mix design, the influence of fly ash content and mortar ratio on the mechanical properties of HDCC was studied, and the material preparation technology under specific materials was optimized. The results show that the content of fly ash, the ratio of cement to sand and the curing conditions have a great influence on the tensile properties of HDCC. With the increase of fly ash content, the sand content decreases and the tensile strain increases. When the sand content is higher, the fracture toughness of the matrix is higher, and the corresponding ultimate tensile strain is smaller under the ultimate tensile stress of the matrix. However, the composite material still maintains a considerable strain as the stress decreases.