机制砂混凝土的抗硫酸盐侵蚀研究

发布时间：2018-06-10 03:29

本文选题：机制砂混凝土 + 硫酸盐侵蚀　；参考：《福州大学》2013年硕士论文

【摘要】：天然砂在短期内作为一种不可再生资源,正面临着日益短缺的趋势,因而机制砂必然将广泛应用于今后的工程建设中。但是机制砂由于颗粒表面粗糙尖锐、多棱角,并且在颗粒内部微裂纹多、空隙率大、级配不良,对混凝土的性能特别是耐久性能会产生不良影响。硫酸盐侵蚀作为混凝土耐久性的重要内容,一直受到国内外研究者的广泛关注。目前对机制砂混凝土的硫酸盐侵蚀研究还比较少,因而本文较全面地研究了机制砂混凝土的抗硫酸盐侵蚀性能。具体工作和主要结论如下：1、采用抗折劣化系数、抗压劣化系数和质量变化率三个评价指标研究了不同机制砂掺量混凝土的抗硫酸盐侵蚀性能。研究表明：机制砂和天然砂互掺提高了混凝土的抗硫酸盐侵蚀性能,随着机制砂掺量的增加,抗硫酸盐侵蚀性能呈现出先上升后下降的趋势,当机制砂掺量为50%时,抗硫酸盐侵蚀性能最佳。2、采用上述评价指标研究稻壳灰(RHA)对机制砂混凝土抗硫酸盐侵蚀性能的影响。研究表明：稻壳灰提高了机制砂混凝土的抗硫酸盐侵蚀性能,并且随着稻壳灰细度的减小和掺量的增加,这种效果也更好。各种活性掺合料的抗硫酸盐侵蚀性能优劣依次为：硅灰稻壳灰粉煤灰。3、采用氮气吸附法测得机制砂混凝土的孔结构相关参数,从微观上研究了孔结构与机制砂混凝土抗硫酸盐侵蚀的关系。研究表明：机制砂和天然砂互掺、稻壳灰的掺加都细化了混凝土的孔径分布,减小了平均孔径,改善了孔结构,提高了混凝土的抗硫酸盐侵蚀性能。4、基于FHH方程得到表面分形维数D,建立表面分形维数与机制砂混凝土抗硫酸盐侵蚀性能的线性关系。研究表明：表面分形维数越大,机制砂混凝土的抗硫酸盐侵蚀性能也越高。5、设计0.2、0.4、0.6三种弯拉应力水平,研究应力水平对机制砂混凝土的抗硫酸盐侵蚀影响。研究表明：弯拉应力加速了混凝土的硫酸盐侵蚀,应力越大,这种加速作用也越明显。
[Abstract]:Natural sand, as a non renewable resource in the short term, is facing the trend of increasing shortage. Therefore, the mechanism sand will be widely used in future engineering construction. However, the mechanism sand can be widely used in future engineering construction. However, the mechanism sand, due to the rough surface of the particle, has many edges and corners, and has many micro cracks in the particles, the air gap rate is large, the gradation is bad, and the performance of the concrete is especially resistant to the concrete. Long performance will have a bad effect. As an important content of concrete durability, sulphate erosion has been widely concerned by researchers at home and abroad. At present, the study on sulfate erosion of mechanism sand concrete is still relatively small. Therefore, the sulfate corrosion resistance of mechanism sand concrete is studied in this paper. The specific work and main conclusion are made in this paper. The following are as follows: 1, the anti sulphate erosion performance of concrete with different mechanism sand content is studied by the three evaluation indexes of anti deterioration coefficient, compression deterioration coefficient and mass change rate. The study shows that the interaction of mechanism sand and natural sand improves the sulfate corrosion resistance of concrete. With the increase of the content of the mechanism sand, the sulfate corrosion resistance is increased. The performance showed a tendency to increase first and then decline. When the content of the mechanism sand was 50%, the optimum.2 was the resistance to sulfate attack. The effect of rice hull ash (RHA) on the sulfate corrosion resistance of mechanism sand concrete was studied. The study showed that rice husk ash improved the sulfate corrosion resistance of mechanism sand concrete. The reduction of the fineness of the shell ash and the increase of the amount of admixture are also better. The corrosion resistance of various active admixtures is in turn: silica ash rice husk ash fly ash.3, the pore structure related parameters of mechanism sand concrete are measured by nitrogen adsorption method, and the sulfate corrosion resistance of pore structure and mechanism sand concrete is studied from microcosmic. The study shows that the mixing of the mechanism sand and the natural sand, the addition of the rice husk ash can refine the pore size distribution of the concrete, reduce the average pore size, improve the pore structure, improve the sulfate corrosion resistance of concrete.4, get the surface fractal dimension D based on the FHH equation, and establish the surface fractal dimension and the mechanism of sulphate corrosion resistance of the mechanism sand concrete. The linear relationship of performance shows that the greater the fractal dimension of the surface, the higher the corrosion resistance of the mechanism sand concrete is.5, the design of three kinds of flexural stress levels of 0.2,0.4,0.6 and the effect of the stress level on the sulfate corrosion resistance of the mechanism sand concrete. The study shows that the bending stress accelerates the sulfate erosion and stress of concrete. The greater the acceleration, the more obvious it is.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528

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