低真空条件对混凝土中介质迁移性能的影响  

Effect of low vacuum condition on medium migration performance in concrete

作　　者：刘梦晶 谢友均[1] 上官明辉 龙广成[1] 高策 LIU Mengjing;XIE Youjun;SHANGGUAN Minghui;LONG Guangcheng;GAO Ce(School of Civil Engineering,Central South University,Changsha 410000,China;China Railway Engineering Design and Consulting Group Co.Ltd.,Beijing 100055,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410000 [2]中铁工程设计咨询集团有限公司,北京100055

出　　处：《中南大学学报（自然科学版）》2023年第9期3535-3543,共9页Journal of Central South University:Science and Technology

基　　金：湖南省重点研发计划项目(2020SK2005);中国中铁股份有限公司科技研究开发计划项目(2021-重大-09);中南大学中央高校基本科研业务费专项资金资助项目(2022ZZTS0621)。

摘　　要：为探索低真空条件对混凝土中介质迁移性能的影响规律,保障低真空管道等严酷环境下混凝土结构服役性能,首先,通过模拟低真空环境条件,研究了经低真空条件处理的混凝土气体渗透性、毛细吸水性和氯离子渗透性能;其次,分析了粉煤灰、硅灰、消泡剂和吸水树脂(SAP)等外加剂对低真空条件下混凝土中气体、离子、水介质迁移性能的影响规律;最后,基于灰色关联理论,探讨了各因素与混凝土中介质迁移性能的关联度。研究结果表明:低真空条件对混凝土气体渗透性和毛细吸水性产生显著不利影响,复合掺入粉煤灰、硅灰及消泡剂可较好地降低混凝土气体渗透性和毛细吸水性,并且提高混凝土抗氯离子渗透性能,但复合掺入SAP对混凝土抗渗性改善作用较低;低真空条件处理会显著增加混凝土的水分蒸发量,扩大孔结构,从而导致其抗介质迁移性能比标准养护的差。复合掺入粉煤灰、硅灰及消泡剂可制得适用于低真空条件的高抗介质迁移性能的混凝土。In order to explore the influence of low vacuum condition on the migration performance of media in concrete and ensure the service performance of concrete structures in harsh environments,such as low vacuum pipelines,firstly,by simulating low vacuum environmental condition,the gas permeability,capillary water absorption,and chloride ion permeability of concrete treated under low vacuum condition were studied.Secondly,the influence rules and corresponding mechanisms of admixtures such as fly ash,silica fume,anti-foaming agent,and water absorbing resins on the migration performance of gas,ions,and water in concrete under low vacuum condition were analyzed.Finally,based on the grey correlation theory,the correlation between each factor and the media migration performance in concrete was discussed.The results show that low vacuum condition has significant adverse effects on concrete gas permeability and capillary water absorption.The composite addition of fly ash,silica fume and anti-foaming agent can effectively reduce the gas permeability and capillary water absorption of concrete and improve the chloride ion permeability of concrete.However,the composite addition of SAP has a relatively small effect on improving the permeability of concrete.Low vacuum condition significantly increases the water evaporation of concrete,expands the pore structure and leads to poorer resistance to medium migration compared to standard curing.Concrete with high resistance to medium migration suitable for low vacuum condition can be prepared by combining fly ash,silica fume and anti-foaming agent.

关 键 词：混凝土 低真空条件 介质迁移 气体渗透性 毛细吸水性 氯离子渗透性 

分 类 号：TQ178[化学工程—硅酸盐工业]