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为探究含粗骨料超高性能混凝土单轴拉伸韧性及增强增韧机理,采用单轴拉伸法,研究含粗骨料超高性能混凝土的单轴拉伸性能;采用X射线计算机断层扫描技术和图像分析法,并引入纤维分散系数和纤维取向系数,对单轴拉伸试验后超高性能混凝土中钢纤维的真实分布进行表征;阐明了钢纤维分布与粗骨料、钢纤维分布与混凝土拉伸韧性之间的关系。试验结果表明,钢纤维以粗骨料为中心环绕分布;粗骨料对钢纤维分布具有不利影响,粗骨料掺量越大,粒径越大,纤维分散性越差,超高性能混凝土单轴拉伸韧性越低;钢纤维分布与超高性能混凝土单轴拉伸强度及韧性密切相关,随着纤维分散系数和取向系数的增大,超高性能混凝土单轴拉伸强度、韧性指数以及拉压比相应增大,韧性增强。
In order to explore the uniaxial tensile toughness and the toughening mechanism of the ultrahigh-performance concrete with coarse aggregate, the uniaxial tensile method was used to study the uniaxial tensile properties of the ultrahigh-performance concrete with coarse aggregate. The X- Technology and image analysis were introduced. The fiber distribution coefficient and fiber orientation coefficient were introduced to characterize the true distribution of steel fiber in the ultra-high performance concrete after uniaxial tensile test. The distribution of steel fiber and the distribution of coarse aggregate, Relationship between tensile toughness of concrete. The results show that the steel fiber is distributed around the coarse aggregate. The coarse aggregate has an adverse effect on the distribution of the steel fiber. The larger the coarse aggregate content, the larger the particle size and the poorer the fiber dispersion. The ultrahigh performance concrete single The lower the tensile toughness of the shaft; the distribution of the steel fiber is closely related to the uniaxial tensile strength and toughness of the ultra-high performance concrete. With the increase of the fiber dispersion coefficient and the orientation coefficient, the uniaxial tensile strength and toughness index of the ultrahigh- Tension and compression than the corresponding increase in toughness increased.