短碳纤维增强高性能混凝土的性能和机理研究

Understanding of Properties and the Mechanism of Short Carbon Fiber High-performance Concrete

为了改善高强混凝土由于水泥自缩、湿涨造成的脆性大、抗拉强度低,特别是应力——应变曲线的下降段不及普通混凝土的特点,本文以掺入短碳纤维为突破口,选取水胶比、砂率、短碳纤维的体积比、高效减水剂掺量四个因素作为变量,利用均匀设计安排试验,用SPSS软件对抗压强度和劈拉强度分别进行回归分析而得到回归方程,用MATLAB进行优化处理,进而求出最优配比。研究结果表明,短碳纤维的加入可明显改善混凝土的脆性,劈拉强度与抗压强度之比由原来的1/10～1/15增大到1/6～1/8,且拌合物的保水性、粘聚性也得到明显改善。最后用扫描电子显微镜观测了短碳纤维增强混凝土的微观结构,并从基理上进行了分析。

In order to improve the high-performance concrete quality with brittleness, low tensile strength, particularly the less descending branch in stress-strain curve compared with that of ordinary concrete. The breakthrough of this thesis lies in the mixture of short carbon fiber. Four factors such as water-binder ratio, volume ratio of short carbon fiber and blending value of high efficiency water-reducing admixture were selected as variable. Experiment was carried out by utilizing uniform design. Regression equation was established by regression analysis of the compression strength and the split tensile strength separately utilizing SPSS software. The process of optimization was obtained with MATLAB. The optimized ratio was acquired. Results of the research show that the brittleness of concrete is decreased significantly by adding short carbon fiber. And the radio of the split tensile strength and compression strength increases to 1/6-1/8 from 1/10-1/15. In addition, moisture retention and coherence of the high-performance concrete are improved. The microscope structure of short carbon fiber was studied through electron microscope.