高性价比混杂纤维工程水泥基复合材料的力学性能研究

Mechanical Properties of High Cost Performance Hybrid Fiber Engineered Cementitious Composites

为提高工程水泥基复合材料(ECC)的经济适用性,并保证其较好的拉伸延性,研究了PVA-ECC的制备方法,配制出性价比较高的PVA-ECC,为实际工程提供更多的材料选择。首先基于ECC的微观力学模型和多尺度结构特征,确定ECC配合比的优化方向。然后通过设计12组不同配合比的ECC试件单轴压缩试验和单轴拉伸试验,研究硅灰、水泥/粉煤灰比、水胶比、PVA纤维种类和CaCO_(3)晶须对ECC力学性能的影响,确定了混杂纤维水泥基复合材料的较优配合比。最后通过价值工程法对比分析本文制备的混杂纤维水泥基复合材料的经济价值,并根据其成本和性能,提出了三种具有代表性的配合比:低成本、拉伸延展性相对较低、单掺国产PVA纤维的H12;中等成本、拉伸延展性相对较高、复掺两种PVA纤维的H11;高成本、高拉伸延展性、复掺日产PVA纤维和CaCO_(3)晶须的H8。本研究可为实现力学性能优化和经济性提高的双重目标提供数据参考。

In order to improve the economic applicability of engineered cementitious composites(ECC)and ensure its good tensile ductility,the preparation method of PVA-ECC was studied,and PVA-ECC with high cost performance was prepared to provide more material selection for practical engineering.Firstly,based on the micro-mechanical model and multi-scale structural characteristics of ECC,the optimization direction of ECC mix ratio was determined.Then,the uniaxial compression test and uniaxial tensile test were carried out by designing 12 groups of ECC specimens with different mix ratios.The effects of silica fume,cement-fly ash ratio,water-binder ratio,PVA fiber type and CaCO_(3) whisker on the mechanical properties of ECC were studied,and the optimal mix ratio of hybrid fiber cement-based composites was determined.Finally,the economic value of the hybrid fiber engineered cementitious composites prepared in this paper was compared and analyzed by the value engineering method.According to its cost and performance,three representative mix ratios were proposed:H12 with low cost,relatively low tensile ductility and reinforced by domestic PVA fibers,H11 with moderate cost,relatively high tensile ductility and reinforced by hybrid PVA fibers and H8 with high cost,high tensile ductility and reinforced by Japanese PVA fibers and CaCO_(3) whisker.This study can provide data reference for achieving the dual goals of mechanical performance optimization and economic improvement.