高韧性纤维增强水泥基复合材料的单轴拉伸力学性能
Uniaxial Tensile Mechanical Properties of High Ductile Fiber Reinforced Cementitious Composites
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摘要: 试验研究了3种纤维掺量聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)的单轴拉伸力学性能及纤维掺量对ECC力学性能的影响规律,探讨了裂缝扩展宽度与轴拉应力的关系,分析了ECC拉伸断裂能与特征长度.结果表明:当纤维掺量由0.308%提高到0.462%时,PVA-ECC的断裂能提高128%,特征长度提高146%,最大拉应变提高128%.PVA-ECC的断裂能和最大拉应变比聚丙烯纤维混凝土分别提高209%和3 614%.表明PVA纤维具有良好的阻裂增韧效用,显著提高了ECC的抗裂性能和变形能力,ECC在单轴拉伸荷载下能实现应变硬化和多重裂纹开裂.Abstract: Uniaxial tensile test of three ratios polyvinyl alcohol fiber reinforced cementitious composites(PVA-ECC) and the influence regularity on the mechanical properties of ECC under different fiber content were studied in this paper.The relationship of crack width and tensile stress was researched.Tensile fracture energy and characteristic length were discussed.The result indicates that from 0.308% to 0.462% of PVA fiber in volume,fracture energy,characteristic length and maximum tensile strain for PVA-ECC improve by 128%,146% and 128% respectively.The fracture energy and maximum strain of PVA-ECC increase by 209% and 3 614% respectively comparing with that of polypropylene fiber reinforced concrete.PVA fiber has good resistivity and toughening effect,and significantly improves the cracking resistance and deformability for ECC.ECC shows strain-hardening and multiple cracking performances in uniaxial tensile test.