粉煤灰加剧半浸泡混凝土硫酸盐侵蚀的研究  

Accelerating Effect of Fly Ash on Damage of Concrete Partially Immersed to Sulfate Environment

作　　者：刘赞群[1] 李湘宁[1,2] 侯乐[1] 施斌林 邓德华[1] 

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]遵义市住房和城乡建设局,贵州遵义563000 [3]中铁八局集团第一工程有限公司,重庆400053

出　　处：《建筑材料学报》2017年第3期439-443,448,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(51378508)

摘　　要：在20℃,相对湿度60%的环境中,将粉煤灰掺量(质量分数)为10%,20%,30%的水泥净浆试件与纯水泥净浆试件半浸泡在质量分数为10%的硫酸钠溶液中进行侵蚀试验.结果表明:粉煤灰掺量30%的试件浸泡60d后在水分蒸发区全部断裂,而纯水泥净浆试件浸泡6个月后才全部断裂;掺入粉煤灰的试件水分蒸发区生成更多的钙矾石和石膏,并且生成量随着掺量的增加而增多,说明粉煤灰与硫酸钠发生了化学反应,其活性成分被水分蒸发区形成的高浓度硫酸盐离子激发使其比纯水泥净浆更不稳定、更容易破坏.Pure cement and fly ash ＋ cement pastes with replacement rates （by mass） of 10%, 20% and 30% were partially immersed in 10% sodium sulfate solution under environment condition of 20 ℃ and 60% RH. The results show that the evaporation zone of 30% fly ashcement paste is severely broken af- ter 60 days immersion, but pure cement paste is damaged until 6 months immersion. The XRD and DTG- TG analysis results indicate that more expansive crystals of ettringite and gypsum are generated in evapora- tion zone of fly ashcement paste, and more fly ash is added the more ettringite and gypsum crystals are generated. These expansive products are generated due to the pozzolanic activity of fly ash activated by the higher concentration of Na2SO4 solution caused by the accelerating effect of fly ashcement paste.

关 键 词：粉煤灰 混凝土 硫酸盐化学侵蚀 物理盐结晶 加剧破坏 

分 类 号：TU528.01[建筑科学—建筑技术科学]