碳酸钙晶须对混杂纤维增强高延性水泥基复合材料力学性能的影响

为了探究碳酸钙晶须对钢纤维/PVA混杂纤维增强高延性水泥基复合材料(HyFRHDCC)力学性能的影响,利用2%体积掺量的廉价碳酸钙晶须替代部分纤维,研究了不同纤维掺量HyFRHDCC的压缩性能和拉伸性能,利用扫描电子显微镜观察了HyFRHDCC的微观结构。研究结果表明,引入碳酸钙晶须能够提高HyFRHDCC的初裂拉伸应变和峰前压缩韧性;在1.5%PVA+0.25%钢纤维HyFRHDCC中掺入2%碳酸钙晶须可以改善材料的拉伸性能;当PVA纤维减少至1%时,HyFRHDCC出现了明显的应变软化行为。微观形貌分析发现,碳酸钙晶须能够通过裂纹偏转、晶须拔出以及裂缝桥联等微观机制改善HyFRHDCC的应变硬化行为。

Effect of calcium carbonate whisker on mechanical properties of hybrid fiber reinforced high ductility cementitious composites

To investigate the effect of calcium carbonate whisker on the mechanical properties of steel/PVA hybrid fiber reinforced high ductility cementitious composites(HyFRHDCC),2%volume content of cheap calcium carbonate whisker was used to replace the dosage of fibers.The compressive and tensile properties of HyFRHDCC with different fiber content were studied.The microstructure of HyFRHDCC was observed by scanning electron microscope.The results showed that the addition of calcium carbonate whisker could improve the tensile strain and pre-peak compressive toughness of HyFRHDCC.The usage of 2%calcium carbonate whisker in 1.5%PVA+0.25%steel fiber HyFRHDCC could improve the tensile properties of the specimens.When the dosage of PVA fiber was reduced to 1%,HyFRHDCC exhibited a significant strain softening behavior.Micromorphology analysis found that calcium carbonate whisker could improve the strain hardening behavior of HyFRHDCC through microscopic mechanisms such as crack deflection,whisker pull-out and crack bridging.