矿物掺合料对混凝土中钢筋腐蚀进程的影响

发布时间：2018-05-08 12:18

本文选题：氯盐 + 硫酸盐　；参考：《南京理工大学》2017年硕士论文

【摘要】：长期处于滨海盐渍土环境下的混凝土结构遭受着硫酸盐和氯盐等环境因素的侵蚀作用,引起混凝土损伤和钢筋锈蚀,造成混凝土结构耐久性不足,从而导致结构的安全性降低,服役混凝土结构提前失效,严重影响了工程结构服役的安全性和可靠性。同时,掺加粉煤灰、矿渣、硅粉等矿物掺合料可制备性能优越的混凝土。因此,研究矿物掺合料对钢筋混凝土腐蚀进程的影响规律,对提高盐渍土环境下混凝土结构服役的安全性和可靠性意义重大。本文利用电化学测试方法,开展了不同矿物掺合料掺量和不同复掺比例钢筋混凝土腐蚀进程的试验测试,分析了不同矿物掺合料对钢筋混凝土在不同腐蚀环境下的腐蚀进程的影响规律,主要得到以下研究成果:(1)硫酸盐的存在一定程度上减缓试件在氯盐腐蚀环境下的腐蚀速率,在腐蚀后期试件腐蚀速率加快,且最终腐蚀程度更加严重。(2)单掺矿渣、粉煤灰和复掺粉煤灰/矿渣的水泥浆体-钢筋试件腐蚀速率均明显减小,抗氯盐和抗复合氯盐与硫酸盐腐蚀性能显著提高,粉煤灰复合水泥浆体-钢筋试件在单一氯盐和氯盐与硫酸盐耦合腐蚀环境下发生钢筋表面再钝化现象,其二次水化的产物对钢筋的钝化具有显著的促进作用。(3)20%矿渣对提高净浆-钢筋试件抗氯盐腐蚀性能优于抗复合氯盐与硫酸盐腐蚀性能;40%矿渣对提高净浆-钢筋试件的抗氯盐腐蚀性能优于抗氯盐与硫酸盐复合的腐蚀性能,但优势并不明显;20%矿渣掺量对提高净浆-钢筋试件抗单一氯盐腐蚀性能和抗复合氯盐与硫酸盐腐蚀性能均优于40%矿渣掺量。(4)10%粉煤灰掺量和20%粉煤灰掺量对提高净浆-钢筋试件的抗氯盐腐蚀性能和抗复合氯盐与硫酸盐腐蚀性能基本相当;10%粉煤灰掺量对提高净浆-钢筋试件抗单一氯盐腐蚀性能和抗复合氯盐与硫酸盐腐蚀性能均优于20%粉煤灰掺量,但优势均不明显。(5)10%粉煤灰和10%矿渣掺量的复合水泥净浆-钢筋试件的抗氯盐与硫酸盐复合侵蚀性能强于其抗单一氯盐侵蚀性能;而20%粉煤灰掺量和20%矿渣掺量的复合水泥净浆-钢筋试件的抗氯盐腐蚀性能和抗复合氯盐与硫酸盐腐蚀性能基本相当;20%粉煤灰掺量和20%矿渣掺量复合水泥净浆-钢筋试件抗氯盐腐蚀性能和抗复合氯盐与硫酸盐侵蚀性能均略优于10%粉煤灰掺量和10%矿渣掺量复合水泥净浆-钢筋试件。
[Abstract]:For a long time, the concrete structure in the coastal saline soil environment has been eroded by environmental factors such as sulfate and chlorine salt, which causes concrete damage and steel bar corrosion, resulting in insufficient durability of concrete structure, which leads to the reduction of structural safety. The failure of concrete structures in service has seriously affected the safety and reliability of engineering structures. At the same time, the addition of fly ash, slag, silica and other mineral admixtures can be used to prepare concrete with superior performance. Therefore, it is of great significance to study the influence of mineral admixtures on the corrosion process of reinforced concrete and to improve the safety and reliability of concrete structures in saline soil. In this paper, the corrosion process of reinforced concrete with different mineral admixtures and different admixtures has been tested by electrochemical method. The effects of mineral admixtures on the corrosion process of reinforced concrete under different corrosion conditions were analyzed. The following research results were obtained: 1) the presence of sulphate to some extent slowed down the corrosion rate of specimens under chloride corrosion environment. In the late stage of corrosion, the corrosion rate of specimens is accelerated, and the final corrosion degree is more serious. The corrosion rate of cement paste and steel bar specimens with fly ash and fly ash / slag is obviously reduced. The corrosion resistance to chlorine salt and complex chloride salt and sulfate was improved significantly. The repassivation of steel bar surface occurred in the environment of single chloride salt and chloride salt and sulfate coupling corrosion. The product of secondary hydration has a remarkable promoting effect on the passivation of steel bar. 20% slag can improve the corrosion resistance of clean paste and steel bar to chlorine salt than to compound chloride salt and sulfate. 40% slag can improve the corrosion resistance of clean paste and steel bar. The corrosion resistance of the parts is better than that of the compound of chlorine salt and sulfate. But the advantages are not obvious. 20% slag content is superior to 40% slag content, 10% fly ash content and 20% fly ash content in improving the corrosion resistance to single chloride salt and compound chloride salt and sulfate corrosion resistance of pure paste and steel bar specimen. The corrosion resistance of paste to steel bar and the corrosion resistance of compound chlorine salt to sulfate are basically equal to that of 10% fly ash on improving the corrosion resistance of pure paste steel bar to single chloride salt and complex chloride salt and sulfate corrosion. Energy is better than 20% fly ash, But the advantages of 10% fly ash and 10% slag were not obvious. The composite corrosion resistance of composite cement paste and steel bar with 10% slag was better than that of single chloride salt. The corrosion resistance of composite cement paste with 20% fly ash and 20% slag is similar to that of composite cement paste with 20% fly ash and 20% slag. The corrosion resistance of rebar specimens to chloride salt and the corrosion resistance of composite chloride salt and sulfate are slightly better than that of 10% fly ash and 10% slag mixed cement paste and reinforced concrete specimens.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【参考文献】