砂胶比对混杂纤维增强机制砂砂浆弯曲及压缩性能的影响

Influence of sand-cement ratio on the mechanical properties of hybrid fiber reinforced mortar with manufactured sand

以钢纤维、聚乙烯醇纤维(PVA)、CaCO3晶须组成不同纤维体系,并将其掺入以环保经济的机制砂为骨料的水泥砂浆中,探究不同纤维体系对机制砂混凝土硬化物力学性能的影响,以及在不同砂胶比下机制砂水泥基体与各纤维体系的适应性。试验结果显示,钢纤维、PVA纤维、CaCO3晶须分别在宏观、细观、微观3种尺度发挥其增强增韧作用,在不同纤维体系下,随着体系中纤维种类的增多,试件的抗弯性能逐渐提高,即SPW体系抗弯性能最好;而抗压性能则以SP体系最优。在基体适应性方面,砂胶比改变对机制砂水泥基体与纤维体系的协同工作性会产生影响:在S体系中,0.45砂胶比机制砂水泥基体与纤维体系协同性最好,表现出的力学性能最优;在SP及SPW体系中,0.50砂胶比机制砂水泥基体与纤维体系协同工作性更好。研究认为,以机制砂替代不可再生的河砂作为骨料,根据实际工程需要选用不同纤维体系及砂胶比,既能满足工程安全性的要求、也能实现经济环保的目的。

Steel fiber,PVA fiber and CaCO3 whisker were used to form different fiber systems,which were incorporated into cement mortar with environment-friendly and economic manufactured sand as aggregate.This experiment explored the influence of different fiber systems on the mechanical properties of manufactured sand concrete,as well as the adaptability of manufactured sand cement matrix with different sand-binder ratios and various fiber systems.The results show that Steel fiber,PVA fiber and CaCO3 whisker play their strengthening and toughening roles at different scales respectively.With the increase of fiber types,the flexural performance of the specimens gradually improved,that is,the SPW system had the best flexural performance.As for compressive property,SP system shows the best performance.In terms of matrix adaptability,in S system,the best synergetic effect of sand-cement matrix with fiber system is 0.45 sand-cement ratio while in SP and SPW systems,the 0.50 sand-cement ratio cement matrix show better adaptability.The study indicates that the requirements of engineering safety,inexpensive and environmental protection could be meeted when choose manufactured sand instead of nonrenewable river sand,appropriate sand-cement ratio and suitable fiber system.