干湿循环作用下涂层对蒸养砂浆抗硫酸盐侵蚀防护性能的研究  

Protective Performance of Coatings Against Sulfate Erosion on Steam-Cured Mortar under Wet-Dry Cyclic Conditions

作　　者：杨博凯 叶汉青 陈学义 YANG Bokai;YE Hanqing;CHEN Xueyi(Nanjing Yangtze River Management Office,Nanjing 210006,China)

机构地区：[1]南京市长江河道管理处,江苏南京210006

出　　处：《中国水能及电气化》2025年第2期36-42,共7页China Water Power & Electrification

摘　　要：在我国西部盐碱地区,埋于地下的长距离输水管道预应力钢筒混凝土管(Prestressed Concrete Cylinder Pipe,PCCP)长期受到土壤中硫酸盐的侵蚀。为了提高PCCP管道在腐蚀环境中的耐久性,在实际工程中,一方面采用蒸汽养护的方式提高砂浆保护层养护期间的温度和湿度以加快水泥的水化速度,从而提高砂浆保护层的早期强度;另一方面通过在管道外壁涂装防腐涂层来阻止硫酸盐的侵入。文章采用干湿循环加速试验进程,通过测量抗压耐蚀系数、重量损失率以及微观形貌,对比研究蒸养和标养砂浆的抗硫酸盐侵蚀性能以及涂装三种不同厚度环氧煤沥青涂层后的耐久性。结果表明:在硫酸盐侵蚀下,抗压耐蚀系数和重量损失率随侵蚀龄期的变化均呈现出先增长后下降的趋势;与蒸养砂浆相比,标养砂浆的耐久性能较好;硫酸盐的侵蚀产物以钙矾石为主,同时伴有大量的硫酸钠晶体,正是这些侵蚀产物的不断生成,使砂浆密实度不断增加进而出现剥落。砂浆的耐久性随着涂装层数的增加而增强。In the saline-alkali regions of western China,long-distance water transmission pipelines,such as Prestressed Concrete Cylinder Pipes(PCCP),buried underground,are continuously subjected to sulfate erosion from the surrounding soil.To enhance the durability of PCCP pipelines in erosive environments,practical engineering solutions involve,on one hand,using steam curing to increase the temperature and humidity during the curing of the mortar protection layer,thereby accelerating the hydration rate of the cement and improving the early strength of the mortar;on the other hand,applying corrosion-resistant coatings on the outer surface of the pipeline to prevent sulfate intrusion.This paper uses wet-dry cyclic accelerated tests,measuring compressive erosion resistance coefficients,weight loss rates,and microscopic morphology,to compare and analyze the sulfate erosion resistance of steam-cured and standard-cured mortars,as well as the durability of three different thicknesses of epoxy coal-tar pitch coatings.The results show that:Under sulfate erosion,both the compressive erosion resistance coefficient and the weight loss rate exhibit an initial increase followed by a decrease over time.The durability of the standard-cured mortar is better than that of the steam-cured mortar.The erosion products of sulfate erosion are mainly ettringite,accompanied by a large number of sodium sulfate crystals.The continuous formation of these erosion products increases the density of the mortar,leading to spalling.The durability of the mortar improves with the increase in the number of coating layers.

关 键 词：PCCP管道 环氧煤沥青涂层 涂装层数 蒸养砂浆 

分 类 号：TV47[水利工程—水工结构工程]