碳化—硫酸盐侵蚀—干湿循环作用下水工混凝土耐久性研究与评价
发布时间：2018-12-15 09:02
【摘要】：近年来,混凝土材料在土木工程领域得到广泛应用,受服役环境的影响,众多混凝土结构未达到设计寿命而发生侵蚀破坏。在我国西北干旱扬黄灌区,水工混凝土建筑物同时受到碳化、硫酸盐侵蚀、干湿循环等作用,出现了不同程度的侵蚀破坏,灌区安全运行受到极大威胁。在灌区混凝土在多种侵蚀作用下,耐久性劣化机理尚不明确,劣化过程规律尚不清晰,水工混凝土材料层次的耐久性综合评价方法仍不够完善。因此,开展在碳化、硫酸盐侵蚀、干湿循环共同作用下的混凝土耐久性劣化规律研究与综合评价将更有学术价值与应用价值。本课题结合河南省高校科技创新人才支持计划项目“基于多场耦合作用的灌区水工混凝土结构耐久性研究”实施开展。以甘肃省景泰川电力提灌区(以下简称“景电灌区”)内的水工混凝土建筑物为研究对象,针对水工混凝土结构服役环境中的水样、土样和剥落残渣进行成分分析,揭示主要侵蚀作用及侵蚀介质;设计不同水胶比、粉煤灰掺量、引气剂用量的混凝土,进行室内加速劣化试验,揭示了混凝土的耐久性劣化过程;基于灰色关联理论和可拓评价理论,对各侵蚀阶段的混凝土耐久性进行了定量评价和定性评价,得出以下结论:(1)在碳化-硫酸盐侵蚀-干湿循环共同作用下,不同配合比混凝土的耐久性劣化过程整体上经历了稍有增强-缓慢下降-快速下降三个阶段。水胶比对混凝土的耐久性影响较为显著,水胶比越小,耐久性越强,劣化过程越慢。粉煤灰的掺加能够明显提高混凝土的耐久性,最优掺量在20%左右。引气剂的使用在一定程度上能够提高混凝土的耐久性。(2)以关联度值为依据将混凝土耐久性等级划分为“好、较好、中、较差、差”五个等级。在实验前期,各试验组混凝土耐久性关联度值在0.75以上,等级均在“Ⅱ”级以上,耐久性整体处于“较好”以上状态;在实验后期,各试验组混凝土耐久性关联度值在0.45以下,等级均在“Ⅴ”级以下,耐久性整体处于差的状态。通过碳化-硫酸盐侵蚀-干湿循环共同作用下混凝土耐久性劣化规律研究和综合评价,为干旱扬黄灌区水工混凝土结构的耐久性设计提供参考,对现有混凝土建筑物的运行维护与修缮提供了依据。
[Abstract]:In recent years, concrete materials have been widely used in the field of civil engineering. Under the influence of service environment, many concrete structures have not reached the design life and have been corroded and destroyed. In the arid Yellow River irrigation area of northwest China, the hydraulic concrete buildings are affected by carbonation, sulfate erosion and dry-wet cycle at the same time, which results in different degree of erosion and destruction, and the safe operation of the irrigation area is greatly threatened. Under the action of many kinds of erosion in irrigation area, the mechanism of durability deterioration is not clear, the law of deterioration process is not clear, and the comprehensive evaluation method of durability of hydraulic concrete material level is not perfect. Therefore, the research and comprehensive evaluation of durability deterioration law of concrete under the combined action of carbonation, sulfate erosion and dry-wet cycle will have more academic value and application value. This subject is carried out in combination with the project "durability study of hydraulic concrete structure in irrigation district based on multi-field coupling", which is supported by scientific and technological innovation talents in colleges and universities in Henan Province. Taking the hydraulic concrete buildings in Jingtai Electric Irrigation area (hereinafter referred to as Jingdian Irrigation area) as the research object, the composition analysis of water, soil and peeling residue in the service environment of hydraulic concrete structure is carried out. Reveal the main erosion and erosion medium; Concrete with different water / binder ratio, fly ash content and air entraining agent was designed, and accelerated deterioration test was carried out to reveal the durability deterioration process of concrete. Based on the grey relation theory and extension evaluation theory, the durability of concrete in each erosion stage is evaluated quantitatively and qualitatively. The following conclusions are drawn: (1) under the combined action of carbonation, sulphate erosion and dry and wet cycle, the concrete durability is evaluated quantitatively and qualitatively. The durability deterioration process of concrete with different mix ratio has experienced three stages as a whole: slight strengthening, slow descending and fast decreasing. The water / binder ratio has a significant effect on the durability of concrete. The smaller the water-binder ratio is, the stronger the durability is, and the slower the deterioration process is. The addition of fly ash can obviously improve the durability of concrete, and the optimum content is about 20%. The use of air-entraining agent can improve the durability of concrete to a certain extent. (2) according to the correlation value, the durability grade of concrete can be divided into five grades: "good, medium, poor and poor". In the early stage of the experiment, the concrete durability correlation degree of each test group is above 0.75, the grade is above "鈪，
本文编号：2380378
[Abstract]:In recent years, concrete materials have been widely used in the field of civil engineering. Under the influence of service environment, many concrete structures have not reached the design life and have been corroded and destroyed. In the arid Yellow River irrigation area of northwest China, the hydraulic concrete buildings are affected by carbonation, sulfate erosion and dry-wet cycle at the same time, which results in different degree of erosion and destruction, and the safe operation of the irrigation area is greatly threatened. Under the action of many kinds of erosion in irrigation area, the mechanism of durability deterioration is not clear, the law of deterioration process is not clear, and the comprehensive evaluation method of durability of hydraulic concrete material level is not perfect. Therefore, the research and comprehensive evaluation of durability deterioration law of concrete under the combined action of carbonation, sulfate erosion and dry-wet cycle will have more academic value and application value. This subject is carried out in combination with the project "durability study of hydraulic concrete structure in irrigation district based on multi-field coupling", which is supported by scientific and technological innovation talents in colleges and universities in Henan Province. Taking the hydraulic concrete buildings in Jingtai Electric Irrigation area (hereinafter referred to as Jingdian Irrigation area) as the research object, the composition analysis of water, soil and peeling residue in the service environment of hydraulic concrete structure is carried out. Reveal the main erosion and erosion medium; Concrete with different water / binder ratio, fly ash content and air entraining agent was designed, and accelerated deterioration test was carried out to reveal the durability deterioration process of concrete. Based on the grey relation theory and extension evaluation theory, the durability of concrete in each erosion stage is evaluated quantitatively and qualitatively. The following conclusions are drawn: (1) under the combined action of carbonation, sulphate erosion and dry and wet cycle, the concrete durability is evaluated quantitatively and qualitatively. The durability deterioration process of concrete with different mix ratio has experienced three stages as a whole: slight strengthening, slow descending and fast decreasing. The water / binder ratio has a significant effect on the durability of concrete. The smaller the water-binder ratio is, the stronger the durability is, and the slower the deterioration process is. The addition of fly ash can obviously improve the durability of concrete, and the optimum content is about 20%. The use of air-entraining agent can improve the durability of concrete to a certain extent. (2) according to the correlation value, the durability grade of concrete can be divided into five grades: "good, medium, poor and poor". In the early stage of the experiment, the concrete durability correlation degree of each test group is above 0.75, the grade is above "鈪，
本文编号：2380378
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