通过不同PVA纤维体积率在3d、7d、14d、28d、56d、90d及120d龄期的立方体抗压强度试验,得到纤维体积率和龄期对PVA纤维增强水泥基复合材料立方体抗压强度变化规律的影响并建立了预测模型。结果表明,PVA纤维的掺入不能增加立方体的抗压强度,但可以提高抗压强度前期的增长速率,增强前期强度,弥补了粉煤灰的掺入导致PVA-FRCC立方体抗压强度前期不足的缺陷。并且,PVA纤维具有阻裂作用。龄期影响着抗压强度的增长速率在整个过程中的变化。所建立的PVA纤维增强水泥基复合材料立方体抗压强度预测模型,拟合优度较好,误差较小,并具有收敛性,符合PVA纤维增强水泥基复合材料抗压强度的发展规律。
The compressive strengths of PVA fiber reinforced cement-based composites(PVA- FRCC) cube specimens with different fiber volume rate in the ages of 3d, 7d, 14 d, 28 d, 56 d, 90 d and 120 d are carried out to study the influence law of fiber volume rate and ages on the compressive strength of the specimens, and the prediction models are established. The results show that the addition of PVA fiber can't improve the compressive strengths of the PVA- FRCC cube specimens, but it can improve the growth rate of compressive strengths of the PVA- FRCC cube specimens in the early stage, meanwhile, adding fly ash can make up for the compressive strength deficiency of the PVA- FRCC cube specimens in the early stage. In addition, PVA fiber has the crack resistance effect. Ages affect growth rate changes of compressive strengths of the PVA- FRCC cube specimens during the whole process. The established model has goodness of fit, small errors and convergence, and the results from forecasting model conform to the development law of compressive strengths of the PVA- FRCC cube specimens.