纤维增强水泥基材料强度和微结构的影响因素研究

Influence Factors of Strength and Microstructure of Fiber Reinforced Cement-Based Materials

为了研究沙漠砂和PVA纤维的工程应用,采用单因素试验方案,探索了纤维长度、纤维掺量、粉煤灰掺量和砂类别等因素对纤维增强水泥基材料力学性能的影响,分析了抗压强度和劈裂抗拉强度、抗折强度之间的相关性,并利用扫描电镜和压汞仪探究材料内部结构。结果表明,随着纤维长度的变短和纤维掺量的增加,材料的抗压强度、劈裂抗拉强度和抗折强度均呈现增大的趋势且三者之间线性相关。随着粉煤灰掺量的增加,材料的抗压强度不断降低,劈裂抗拉强度和抗折强度先增大后降低,粉煤灰的掺入改善了纤维-水泥基体界面。与石英砂对比,使用沙漠砂制备的材料劈裂抗拉强度和抗折强度相对提高,沙漠砂由于较小的粒径造成了材料中大孔隙和中孔隙累积体积占比的增大。

In order to study the engineering application of desert sand and PVA fiber,a single factor test scheme was adopted to explore the influence of fiber length,fiber content,fly ash content and sand type on the mechanical properties of cement-based materials reinforced by fiber.The correlation between compressive strength,splitting tensile strength and bending strength was analyzed.The internal structure of the material was investigated by scanning electron microscopy and mercury injection.The results show that the compressive strength,splitting tensile strength and flexural strength of the material increase with the decrease of fiber length and the increase of fiber content,and there is a linear correlation among them.With the increase of fly ash content,the compressive strength of the material continuously decreases,splitting tensile strength and flexural strength first increase and then decrease,and the addition of fly ash improves the fiber-cement matrix interface.Compared with quartz sand,the splitting tensile strength and flexural strength of the material prepared from desert sand are improved.Due to the small particle size of desert sand,the proportion of the cumulative volume of medium and large pores in the materials increases.