盐雾湿润–干燥循环作用下水泥砂浆氯离子扩散特性  

Chloride Diffusion Properties of Cement Mortar Under Salt Spray Wetting-Drying Cycle

作　　者：元强[1,2] 王玉曼 张凯 张嘉嘉 饶惠明 陈其强 张锋 张志鹏 YUAN Qiang;WANG Yuman;ZHANG Kai;ZHANG Jiajia;RAO Huiming;CHEN Qiqiang;ZHANG Feng;ZHANG Zhipeng(School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Research Center of High-speed Railway Construction Technology,Changsha 410075,China;Shandong CSCEC Urban Development Co.,Ltd,Jinan 250014,China;Southeast Coastal Railway Fujian Co.Ltd.,Fuzhou 350013,China;China Railway Nanchang Group Co.,Ltd.,Nanchang 330103,China)

机构地区：[1]中南大学土木工程学院,长沙410075 [2]高速铁路建造技术国家工程研究中心,长沙410075 [3]山东中建城市发展有限公司,济南250014 [4]东南沿海铁路福建有限责任公司,福州350013 [5]中国铁路南昌局集团有限公司,南昌330002

出　　处：《硅酸盐学报》2023年第11期2805-2813,共9页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划(2022YFB2602604)。

摘　　要：盐雾湿润-干燥循环作用下,处于潮汐区、浪溅区、大气区等近海地区的海工混凝土耐久性加速劣化,内部钢筋锈蚀风险增高。考虑配合比、干湿比和暴露时间等参数影响,基于盐雾湿润-干燥循环试验,结合分层磨粉-电位滴定的测试方法,对近海环境水泥基材料中氯离子扩散规律展开研究。结果表明:盐雾湿润-干燥循环作用下,砂浆内氯离子的沉积与传输主要受干湿比、水胶比和暴露时间等影响,其中,水胶比的影响最为显著,干湿比对其影响较小。氯离子峰值浓度C_(max)与有效扩散系数D_(eff)随着砂浆水胶比的增大而增加。提高粉煤灰掺量、增加干湿循环次数后,C_(max)呈现典型先增高后降低的趋势。随着暴露时间的延长,D_(eff)减小;随着粉煤灰掺量的增加,D_(eff)先增后减。选用较低水胶比混凝土,引入粉煤灰可有效延缓氯离子的侵蚀速率,进而提升结构的耐久性能。The deterioration of the durability of marine concrete and the degree of corrosion of internal steel bars in the tidal,splash and atmospheric zones are often serious in salt spray wetting and drying cycle.The diffusion of chloride in cement-based materials was investigated at different parameters(i.e.,mix ratio,dry-wet ratio,and exposure time)by a cycle test of salt spray wetting and drying and a test method of layered grinding and potentiometric titration.The results show that the deposition and transport of chloride ions in mortar are primarily affected by salt spray wetting-drying cycle,dry-wet ratio,water-binder ratio,and exposure period.The influence of water-binder ratio is dominant,while the influence of dry-wet ratio is slight.The maximum concentration of chloride C_(max)and the effective chloride diffusion coefficient D_(eff)increase as water-binder ratio improves.C_(max)firstly increases and subsequently declines as fly ash amount and frequency of dry-wet cycles increase.D_(eff)decreases as exposure time increases.D_(eff)firstly increases and subsequently reduces as fly ash content increases.Low water-binder ratio and use of fly ash can effectively postpone chloride erosion,thereby enhancing the durability of structures.

关 键 词：近海地区 干湿循环 氯离子传输 有效扩散系数 耐久性 

分 类 号：TU528[建筑科学—建筑技术科学]