海洋环境下混凝土中腐蚀离子传输与结合研究

发布时间：2018-01-21 17:32

  本文关键词： 混凝土 氯离子 硫酸根 海洋环境 结合能力 表面区浓度　出处：《青岛理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：混凝土耐久性问题是当今世界各国海洋工程所面临的最严峻问题之一，海洋环境中高浓度的氯离子和硫酸根离子是引起钢筋锈蚀及混凝土保护层损伤破坏的主要因素。本文通过海洋暴露试验，室内模拟试验系统研究不同腐蚀环境、不同类型混凝土的氯离子结合能力、混凝土表面氯离子浓度演变规律。以及不同类型、不同海洋腐蚀区域混凝土中硫酸根反应量及表面区硫酸根离子演变规律。研究的主要内容及相关结论如下： （1）本文通过海洋环境（大气区、浪溅区、潮汐区、海沙区）及室内模拟环境暴露试验，研究了海洋不同区域、混凝土中矿物掺合料类型及掺量、腐蚀龄期对混凝土氯离子结合能力的影响。试验结果表明：海洋环境下，混凝土氯离子结合能力会在一段龄期内出现下降，随后会随龄期的增长而提高。矿粉掺量为30%或者粉煤灰掺量为15%~30%时，混凝土氯离子结合能力最高；室内环境条件下，置于1%Nacl中的混凝土粉末，其氯离子结合量会随浸泡龄期的延长而增加； （2）本文通过实海暴露试验及室内试验系统研究了矿物掺合料、腐蚀龄期、腐蚀区域对混凝土表面区氯离子浓度的影响。试验结果表明：室内模拟获得的试验结果演变规律与实海暴露一致。海洋环境条件下，掺加适当掺量矿物掺合料可以降低混凝土表面区氯离子浓度。混凝土表面区氯离子浓度关系为：海沙区潮汐区浪溅区大气区。当矿粉掺量为30%时，混凝土表面氯离子浓度最低。混凝土表面区氯离子浓度随腐蚀龄期增加而呈指数增加。适量硫酸根离子存在对混凝土中氯离子的侵入有促进作用。 （3）本文在实海暴露试验基础上，系统研究了矿物掺合料、腐蚀龄期、腐蚀区域对混凝土硫酸根反应量的影响。试验结果表明：掺加矿粉可以有效的减小混凝土与硫酸根的反应量，，降低量最多为10%；掺加粉煤灰可以最多减小混凝土与硫酸根反应量的13%。混凝土与硫酸根反应系数会随龄期增长保持在0.96~0.99之间；海洋不同腐蚀区域混凝土硫酸根离子反应量大小为：潮汐区海沙区浪溅区≈大气区。 （4）本文研究了室内环境下混凝土粉末与硫酸根的反应以及混凝土表面区硫酸根离子演变规律。试验结果表明：当矿粉掺量在50%以上时，可使混凝土抗硫酸根侵蚀性能增强。粉煤灰最佳掺量与腐蚀溶液类型有关。混凝土粉末与硫酸根的反应量会随着龄期的增加而提高。复合溶液中当氯离子浓度较低时能够阻碍硫酸根的侵入。
[Abstract]:The durability of concrete is one of the most serious problems in marine engineering all over the world. The high concentration of chloride ion and sulfate ion in marine environment are the main factors that cause the corrosion of steel bar and the damage of concrete protective layer. In this paper, different corrosion environments are studied by marine exposure test and laboratory simulation test system. The chloride binding capacity of different types of concrete, the evolution law of chloride ion concentration on the surface of concrete, and different types of concrete. The amount of sulfate reaction and the evolution law of sulfate ion in concrete of different marine corrosion areas. The main contents and relevant conclusions of the study are as follows: 1) in this paper, the types and contents of mineral admixtures in concrete in different areas of the ocean are studied by means of marine environment (large air area, splash area, tidal zone, sea sand area) and indoor simulated environmental exposure test. The effect of corrosion age on the chloride binding capacity of concrete. The experimental results show that the chloride binding capacity of concrete will decrease in a certain period of time under the marine environment. When the amount of mineral powder is 30% or the amount of fly ash is 15 ~ 30, the chloride binding capacity of concrete is the highest. Under indoor conditions, the chloride binding capacity of concrete powder placed in 1 NaCl will increase with the prolongation of immersion age. 2) in this paper, the mineral admixture and corrosion age are studied by the real sea exposure test and laboratory test system. The effect of corrosion zone on chloride concentration on concrete surface. The experimental results show that the experimental results obtained by indoor simulation are consistent with those of real sea exposure. The concentration of chloride ions in concrete surface can be reduced by adding appropriate mineral admixture. The relationship of chloride ion concentration on concrete surface is as follows: tidal zone in sea sand area, large air area in wave splash area, and when the amount of mineral powder is 30%, the concentration of chloride ion in concrete surface area can be reduced. The concentration of chloride ion on concrete surface is the lowest. The concentration of chloride ion in concrete surface increases exponentially with the increase of corrosion age. The presence of appropriate sulfate ion can promote the invasion of chloride ion in concrete. 3) on the basis of real sea exposure test, the mineral admixture and corrosion age are systematically studied in this paper. The experimental results show that the addition of mineral powder can effectively reduce the amount of reaction between concrete and sulfate radical, and the maximum reduction amount is 10%; The addition of fly ash can reduce the reaction amount of concrete and sulfate at most 13%. The coefficient of reaction between concrete and sulfate can be kept between 0.96 and 0.99 with the increase of age. The amount of sulfate ion reaction of concrete in different corrosion areas of the sea is as follows: tidal zone, sea sand area, splash area, 鈮

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