强辐照作用下水泥浆体微结构与抗氯离子侵蚀性能研究  

Study on Microstructure and Resistance to Chloride Ingress of Cement Paste Under Intense Ultraviolet Irradiation

作　　者：汪伟 范志宏[1,2,3] 赵家琦 杨海成 WANG Wei;FAN Zhihong;ZHAO Jiaqi;YANG Haicheng(CCCC Fourth Harbor Engineering Institute Co.,Ltd.,Guangzhou 510230,China;Key Laboratory of Harbor&Marine Structure Durability Technology of Transport Industry,Guangzhou 510230,China;Observation and Research Base of Transport Industry of Long-term Performances of Marine Infrastructure,Zhanjiang 524000,Guangdong,China)

机构地区：[1]中交四航工程研究院有限公司,广州510230 [2]水工构造物耐久性技术交通行业重点实验室,广州510230 [3]海洋基础设施长期性能交通运输行业野外观测研究基地,广东湛江524000

出　　处：《材料导报》2024年第21期124-130,共7页Materials Reports

摘　　要：以南海为代表的远海海洋服役环境恶劣,具有高温、高湿、高盐、高辐照的环境特点。现有研究表明辐照会改变水泥浆体的组成与结构,但对水泥浆体耐久性的影响常被忽略。为阐明强辐照作用对水泥浆体微结构与抗氯离子侵蚀性能的影响,本研究利用紫外线耐气候试验箱进行加速模拟实验,并与水养、室内环境进行对比分析,表征了不同条件下水泥的浆体吸水率、碳化深度、物相组成、孔结构与氯离子固化能力,并在紫外辐照-干湿循环耦合作用条件下进行了氯离子侵蚀实验。结果表明,辐照时间由500 h增加至1500 h,浆体的最可几孔径由135.8 nm增大至283.8 nm,孔隙率由25.0%增大至29.5%,孔结构劣化,氯离子扩散通道增加。同时,强辐照造成AFm、水化硅酸钙凝胶(C-S-H)等水化产物碳化分解,导致水泥浆体的氯离子固化量由51.9 mg/g下降至23.9 mg/g。此外,长期辐照耦合干湿循环作用产生的温度应力会增大浆体开裂的风险,裂纹会显著降低浆体的抗氯离子侵蚀能力。The service environment to concrete structures in far sea represented by the South China Sea is harsh,with the characteristics of high temperature,high humidity,high salt content and intense ultraviolet irradiation.Existing studies have shown that irradiation can change the composition and structure of cement paste,but the effects on the durability of cement paste is easy to ignore.In order to clarify the effects of irradiation on the microstructure and resistance to chloride attacks of cement paste,the accelerated simulation experiment was carried out by using ultraviolet climate chamber,and compared with water curing and room environment.The capillary water absorption,carbonation depth,phase composition,pore structure and chloride binding capacity of cement paste under different conditions were characterized,and the chloride ingress experiment was carried out under the coupling condition of dry-wet cycle and irradiation.The results show that with the irradiation time increases from 500 h to 1500 h,the most probable pore diameter of the paste increases from 135.8 nm to 283.8 nm,the porosity increases from 25.0%to 29.5%,the pore structure deteriorates,and the chloride diffusion channel increases.At the same time,intense irradiation caused the carbonation decomposition of hydration products such as AFm and C-S-H,resulting in the chloride binding capacity of cement paste decreased from 51.9 mg/g to 23.9 mg/g.In addition,the temperature stress caused by long-term irradiation coupled with dry-wet cycles will increase the cracking risks of paste and the crack will significantly deteriorate the resistance to chloride attacks.

关 键 词：辐照作用 干湿循环 微结构 氯离子固化能力 抗氯离子侵蚀 

分 类 号：TU528[建筑科学—建筑技术科学]