不同掺合料对盐碱腐蚀条件下干湿循环后混凝土性能的影响  

INFLUENCES OF DIFFERENT ADMIXTURES ON CHARACTERISTICS OF CONCRETE AFTER DRYING-WETTING CYCLE UNDER THE SALINE CORROSION

作　　者：姚贤华[1,2] 冯忠居 管俊峰[2] 刘宁 赵雄章 杜海丽 YAO Xianhua;FENG Zhongju;GUAN Junfeng;LIU Ning;ZHAO Xiongzhang;DU Haili(School of Highway, Chang＇ an University, Xi＇ an 710064, China;School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou 450011, China;Institute of Qinghai Highway Scientific Research and Survey Design, Xining 810008, China;Construction Administration of Qinghai High Grade Highway, Xining 810008, China)

机构地区：[1]长安大学公路学院,西安710064 [2]华北水利水电大学土木与交通学院,郑州450011 [3]青海省公路科研勘测设计院,西宁810008 [4]青海省高等级公路建设管理局,西宁810008

出　　处：《工业建筑》2018年第3期6-10,30,共6页Industrial Construction

基　　金：国家自然科学基金面上项目(51779095);青海省交通科技项目(2014-07);郑州市科技攻关项目(153PKJGG111)

摘　　要：通过制备5组不同掺合料的混凝土配合比,研究混凝土腐蚀后的外观变化、质量损失率、相对动弹性模量、抗侵蚀系数,并采用扫描电镜（SEM）和能谱化学元素组成分析（EDX）研究了混凝土腐蚀后的微观结构变化。结果表明：掺有粉煤灰和矿渣的混凝土抗干湿循环能力比基准混凝土差,干湿循环60次后其相对动弹性模量降到了60%以下,干湿循环100次后,抗侵蚀系数从1.0降到了0.76;而掺有粉煤灰、硅灰和膨胀剂的混凝土循环120次后,其相对动弹性模量仍然在90%以上,干湿循环120次后,抗侵蚀系数也在0.95以上。微观结构变化表明：在粉煤灰和硅灰基础上加入膨胀剂,填补了混凝土的孔隙,是提高混凝土抗干湿循环能力的主要原因;氯离子的存在,减少了氯酸三钙（C_3A）被硫酸盐化学侵蚀而生成膨胀性物质钙矾石的机会,从而减轻了硫酸盐造成的结晶膨胀破坏作用。Five groups of concrete specimens with different admixtures were designed to study the appearance changes,mass loss rate,relative dynamic elastic modulus and corrosion-resistance coefficients and the microstructure corrosion mechanism of concrete was revealed by electron microscope scanning（ SEM） and Energy Dispersive X-Ray Spectroscopy（ EDX）. The results showed that the resistance to drying-wetting cycles for the concrete mixed with fly ash and slag even worse than normal concrete,the relative dynamic elastic modulus of the concrete was below 60% after 60 times of drying-wetting cycles,and also the corrosion-resistance coefficients of the concrete desreased from1. 0 to 0. 76 after 100 times of drying-wetting cycles; nevertheless,it was very significant to improve the corrosion resistance of the concrete in which to add fly ash,silica fume and the certain amount of expanding agent,the relative dynamic elastic modulus of the concrete was above 90% ,and also the corrosion-resistance coefficients of the concrete were above 0. 95 after 120 times of drying-wetting cycles. Microscopic mechanism studies had also shown that not only fly ash and silica fume were added in the concrete,but also the expanding agent,in order to fill in the pores of the concrete,which was a major cause of improving the resistance to drying-wetting cycles of the concrete. The chloride reduced the risk that C_3A was corroded by the sulfate and the expansibility material ettringite was generated. Thus,which alleviated the damage of the concrete for the sulfate crystallization.

关 键 词：混凝土 干湿循环 复合盐浸泡 抗侵蚀系数 相对动弹性模量 微观机理 

分 类 号：TU528[建筑科学—建筑技术科学]