青稞秸秆灰改性氯氧镁水泥砂浆防护钢筋混凝土的损伤特性

摘要/Abstract

摘要： 为了探究青稞秸秆灰改性氯氧镁水泥砂浆防护混凝土的耐久性损伤特性及劣化规律,制备了不同防护层厚度的钢筋混凝土试件,通过在盐卤侵蚀环境下恒电流通电加速锈蚀试验对钢筋的锈蚀劣化进行了测试分析。采用混凝土裂缝缺陷探测仪对混凝土侵蚀过程中的裂缝开展情况进行监测,基于交流阻抗分析与极化曲线拟合所得电化学参数,用以表征混凝土内部钢筋的锈蚀劣化情况。采用Weibull分布函数建立了氯氧镁水泥砂浆防护混凝土的耐久性损伤劣化数值模型。结果表明,在盐卤侵蚀环境下掺入青稞秸秆灰的氯氧镁水泥砂浆防护钢筋混凝土在通电648 h后,钢筋的腐蚀电流密度仍小于0.2 μA·cm^-2,处于低锈蚀状态,锈蚀发展较为缓慢; Weibull分布函数可以有效地用于青稞秸秆灰改性的氯氧镁水泥砂浆防护混凝土中钢筋锈蚀劣化的损伤程度预测。

关键词: 青稞秸秆灰, 氯氧镁水泥, 防护混凝土, 耐久性, 电化学分析, Weibull分布函数

Abstract: In order to investigate the durability damage characteristics and degradation law of highland barley straw ash modified magnesium oxychloride cement mortar protected concrete, reinforced concrete specimens with different thicknesses of protective layers were prepared. The corrosion degradation of steel bars was tested and analyzed by constant current accelerated corrosion test under salt brine erosion environment. The cracking situation of concrete during the erosion process was monitored by concrete crack defect detection instrument, and the electrochemical parameters obtained based on AC impedance analysis and polarization curve fitting were used to characterize the corrosion degradation of internal steel bars. A numerical model of durability damage degradation of magnesium oxychloride cement mortar protected concrete was established using Weibull distribution function. The results show that under salt brine erosion environment, the corrosion current density of steel bars in magnesium oxychloride cement mortar protected concrete with highland barley straw ash added is still less than 0.2 μA·cm^-2 after 648 h of current passing, indicating a low corrosion state and a slow corrosion development. The Weibull distribution function can effectively predict the degree of corrosion degradation of steel bars in highland barley straw ash modified magnesium oxychloride cement mortar protected concrete.

Key words: highland barley straw ash, magnesium oxychloride cement, protected concrete, durability, electrochemical analysis, Weibull distribution function

中图分类号:

TU526

崔丽君, 乔宏霞, 曹锋, 舒修远, 盛程辉. 青稞秸秆灰改性氯氧镁水泥砂浆防护钢筋混凝土的损伤特性[J]. 硅酸盐通报, 2024, 43(9): 3282-3293.

CUI Lijun, QIAO Hongxia, CAO Feng, SHU Xiuyuan, SHENG Chenghui. Damage Characteristics of Highland Barley Straw Ash Modified Magnesium Oxychloride Cement Mortar Protected Reinforced Concrete[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(9): 3282-3293.

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