为研究水工混凝土吸水水分迁移及冻融劣化规律,对中低热水泥混凝土进行吸水及快速冻融试验, 同时采用核磁共振与工业CT(Computerized Tomography)进行过程监测,探讨分析水工混凝土在吸水过程中水分迁移、分布规律及冻融作用下内部孔隙结构的演化。结果表明,在吸水过程中,中低热水泥混凝土总体含水率持续增加,吸水48 h后基本达到饱和状态,低热水泥混凝土的吸水程度明显高于中热水泥混凝土;吸水时中热水泥混凝土中(0,0.1]μm的水分占比高于低热水泥混凝土,而其他较大尺寸水分占比均低于低热水泥混凝土;冻融期间低热水泥混凝土的总孔隙率和增幅均明显高于中热水泥混凝土;总体上中热水泥混凝土中>10 mm3的孔隙占比小于低热水泥混凝土,而其他较小范围孔隙占比大于低热水泥混凝土。
Abstract
To investigate the water migration and freeze-thaw deterioration of hydraulic concrete, water absorption and rapid freeze-thaw tests were conducted on low-heat cement concrete (LHCC) and moderate-heat cement concrete (MHCC). The testing process was monitored using nuclear magnetic resonance and industrial computerized tomography (CT) to explore and analyze the water migration and distribution in hydraulic concrete during water absorption, as well as the changes in internal pore structure under freeze-thaw action. The findings indicate that both LHCC and MHCC exhibit continuous increase of total water content during water absorption, with saturation being reached after 48 hours, and LHCC shows significantly higher water absorption capacity than MHCC. The proportion of moisture in 0-0.1μm range is higher in MHCC compared to LHCC, while all other larger sizes contain lower proportions of moisture compared to LHCC. During freezing and thawing, the total porosity in LHCC and its increment are notably higher than those in MHCC. Moreover, the percentage of pores larger than 10 mm3 in MHCC is lower than that in LHCC, while the percentage of pores of other smaller sizes is greater than that in LHCC.
关键词
水工混凝土 /
水分分布 /
冻融劣化 /
核磁共振 /
工业CT
Key words
hydraulic concrete /
moisture distribution /
freeze-thaw deterioration /
nuclear magnetic resonance /
industrial CT
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基金
国家自然科学基金项目(51902270);中国水利水电科学研究院流域水循环模拟与调控国家重点实验室开放基金项目(IWHR-SKL-201910);西京学院特区人才科研启动专项(XJ21T01)
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