玄武岩纤维含氯盐补偿收缩混凝土抗碳化性能试验研究

发布时间：2018-06-03 12:35

本文选题：混凝土碳化 + 碳化周期　；参考：《安徽理工大学》2017年硕士论文

【摘要】：自从混凝土问世以来,混凝土就被建筑行业广泛的使用,但随着建筑行业的不断发展,混凝土耐久性问题也变得日益突出。为改善混凝土耐久性问题,通过在混凝土中掺入玄武岩纤维和HCSA型膨胀剂,使用内掺氯盐的方法来模拟海边混凝土常年受氯盐侵蚀的情况。试验中氯盐掺量分别为1 kg/m3、2kg/m3、3 kg/m3、4 kg/m3,HCSA型膨胀剂掺量分别为8%、10%、12%,玄武岩纤维掺量分别为0和3 kg/m3,共56组压拉强度试验。混凝土碳化试验参数选择压拉强度试验中较优的五组,进行了碳化试验。玄武岩纤维含氯盐补偿收缩混凝土压拉试验结果表明:当玄武岩纤维掺量和膨胀剂掺量相同时,混凝土的压拉强度值均随着氯盐掺量的增加而提高。与素混凝土相比,当氯盐掺量为4 kg/m3时,含氯盐混凝土、含氯盐补偿收缩混凝土、玄武岩纤维含氯盐补偿收缩混凝土的抗压强度值分别增加了 23.6%、25.1%和26.4%,劈裂抗拉强度值分别增加了 4.8%、8.8%和31.3%,因此玄武岩纤维的加入,对混凝土劈裂抗拉强度的改善要远大于对抗压强度的改善。此外,膨胀剂掺量为8%时,混凝土压拉强度值最好,这是由于合适的膨胀剂掺量能有效改善混凝土内部的微裂缝,从而提高混凝土的密实度,增强了混凝土的压拉强度值。玄武岩纤维含氯盐补偿收缩混凝土碳化试验结果表明:与素混凝土相比,当氯盐掺量、膨胀剂掺量和玄武岩纤维掺量分别为4 kg/m3、29.6 kg/m3和3 kg/m3时,混凝土压拉强度性能达到最佳,且此时抗碳化能力也较好;同时,试块在3 d、7d、14d和28 d时的抗碳化能力与素混凝土相比分别提高了 12.9%、19.7%、7.2%和5.8%。碳化周期为28 d时,最小碳化深度值为8.46mm。混凝土早期碳化速度高于后期碳化速度,主要是因为碳化早期的混凝土有利于碳化反应进行,生成大量的碳化产物CaCO3后,会附着在混凝土水化产物Ca(OH)2的表面,从而降低了混凝土的碳化速度。
[Abstract]:Since the advent of concrete, concrete has been widely used in the construction industry, but with the continuous development of the construction industry, the durability of concrete has become increasingly prominent. In order to improve the durability of concrete, by adding basalt fiber and HCSA type expansion agent into concrete, the method of adding chloride salt into concrete is used to simulate the perennial chloride corrosion of seaside concrete. In the experiment, the chloride content was 1 kg / m ~ (3) ~ 2 kg / m ~ (3) ~ 3 kg / m ~ (3) ~ 4 kg 路m ~ (3) ~ (-1) HCSA type dilatant was 8 ~ 10%, and the basalt fiber content was 0 and 3 kg / m ~ (3) respectively. 56 groups of compressive and tensile strength tests were carried out. The carbonation test parameters of concrete were selected five groups of which were better in compressive tensile strength test and carbonation test was carried out. The results of compressive and tensile tests show that when the content of basalt fiber and dilatant is the same, the compressive strength of concrete increases with the increase of chloride content. Compared with plain concrete, when the chloride content is 4 kg/m3, the concrete with chloride salt compensates for shrinkage. The compressive strength of basalt fiber reinforced concrete with chloride salt compensation is increased by 23.625% and 26.4% respectively, and the splitting tensile strength value increases by 4.880% and 31.3wt%, respectively, so the basalt fiber is added. The improvement of splitting tensile strength of concrete is much greater than that of compressive strength. In addition, when the amount of expansive agent is 8, the compressive tensile strength of concrete is the best, which is due to the fact that the appropriate amount of expansive agent can effectively improve the micro-cracks in concrete, thus increase the compactness of concrete and enhance the compressive tensile strength of concrete. The carbonation test results of basalt fiber containing chloride salt compensated shrinkage concrete show that the compressive and tensile strength of concrete is the best when the content of chlorine salt, expansion agent and basalt fiber is 4 kg / m ~ (3) 29.6 kg/m3 and 3 kg/m3, respectively, compared with plain concrete. At the same time, the carbonation resistance of the test blocks at 3 d ~ 7 d ~ (14 d) and 28 d was increased by 12.9% ~ 19.7% and 5.8%, respectively, compared with that of plain concrete. When the carbonization period is 28 days, the minimum carbonation depth is 8.46 mm. The rate of early carbonation of concrete is higher than that of later carbonation, mainly because the early carbonation of concrete is favorable to the carbonation reaction, and a large number of carbonation products, CaCO3, will attach to the surface of concrete hydration product Ca(OH)2 after the formation of a large number of carbonation products. Thus, the carbonation rate of concrete is reduced.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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