纤维混凝土复合材料的制备及力学性能的研究

Research on preparation and mechanical properties offiber reinforced concrete composite materials

通过在混凝土中添加聚乙烯醇纤维,制备出一系列不同纤维含量(0,1%,2%和3%)(体积分数)的纤维混凝土复合材料。采用力学性能测试、流动性能测试、吸水性能测试和FT-IR分析等,对该纤维混凝土复合材料的抗压强度、劈裂抗拉强度、弹性模量、流动性能、吸水率和物相结构等进行了研究。结果表明,随着聚乙烯醇纤维掺量的增加,纤维混凝土复合材料7和28 d的抗压强度、劈裂抗拉强度以及弹性模量均呈现出先增大后降低的趋势,当纤维含量2%(体积分数)时,复合材料7和28 d的抗压强度、劈裂抗拉强度以及弹性模量均达到最大值。随着纤维掺量的增加,纤维混凝土复合材料的坍落扩展度径向长度逐渐降低,纤维掺入后导致了混凝土复合材料的流动性减小,当纤维含量为3%(体积分数)时,坍落径向长度最小为585 mm。随着纤维掺量的增加,纤维混凝土复合材料的吸水率呈现出先降低后升高的趋势,当纤维含量为2%(体积分数)时,纤维混凝土复合材料的吸水率最低为22.1%。掺入的聚乙烯醇纤维影响了水化反应,阻碍了Ca^(2+)在基体中的扩散,聚乙烯醇纤维在基体中形成了致密的薄膜网状结构,使得混凝土复合材料的各组分之间的连接能力增强,从而改善了纤维混凝土的韧性和强度。

A series of fiber reinforced concrete composites with different fiber contents(0,1vol%,2vol%and 3vol%)were prepared by adding polyvinyl alcohol fiber into concrete.The compressive strength,splitting tensile strength,elastic modulus,fluidity,water absorption and phase structure of the fiber reinforced concrete composites were studied by mechanical property test,flow property test,water absorption test and FT-IR analysis.The results showed that with the increased of polyvinyl alcohol fiber content,the compressive strength,splitting tensile strength and elastic modulus of fiber reinforced concrete composites at 7 and 28 d increased first and then decreased.When the fiber content was 2vol%,the compressive strength,splitting tensile strength and elastic modulus of the composites reached the maximum at 7 and 28 d.With the increased of fiber content,the slump expansion and radial length of fiber reinforced concrete composites gradually decreased,and the fluidity of concrete composites decreased after fiber addition.When the fiber content was 3vol%,the minimum slump radial length was 585 mm.With the increased of fiber content,the water absorption of fiber reinforced concrete composites decreased first and then increased,when the fiber content was 2vol%,the minimum water absorption of fiber reinforced concrete composites was 22.1%.The added polyvinyl alcohol fiber affects the hydration reaction and hinders the diffusion of Ca^(2+) in the matrix,polyvinyl alcohol fiber formed a dense film network structure in the matrix,which enhanced the connection ability between the components of concrete composites,and improved the toughness and strength of fiber reinforced concrete.