接触溶蚀条件下混凝土游离钙离子固化效果研究  

Study on Curing Effect of Free Calcium Ions in Concrete under Contact Corrosion Conditions

作　　者：蒋雅君[1] 林利达 喻良敏 郑屹 曹丹阳 JIANG Yajun;LIN Lida;YU Liangmin;ZHENG Yi;CAO Danyang(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Chengdu Yanghua Yuandong New Materials Science and Technology Co.,Ltd.,Chengdu 610213,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]成都扬华源动新材料科技有限公司,四川成都610213

出　　处：《铁道学报》2024年第6期189-198,共10页Journal of the China Railway Society

基　　金：成都扬华源动新材料科技有限公司研发项目(2018H0468)。

摘　　要：为研究将硅灰和硅酸钠作为掺合料内掺后的喷射混凝土在接触溶蚀条件下析出钙离子的规律,在不同掺量下制备了单掺和复掺混凝土试块,开展30 d去离子水浸泡试验,测试溶液中的钙离子浓度、溶液pH值的变化情况,并结合SEM等微观检测对接触溶蚀过程进行研究。结果显示:单掺硅灰试块在不换水条件下的钙离子溶出量大大低于空白组,换水条件下30 d内3%、5%、7%掺量组较空白组平均溶出钙离子总重依次减少73.29%、69.65%、69.26%;单掺硅酸钠后,不换水条件下3%掺量的试块钙离子溶出量也能得到明显的降低,换水条件下30 d内1%、3%、5%掺量组较空白组平均溶出钙离子总重依次减少9.22%、20.53%、29.96%;将单掺组中固化效果良好的3%掺量硅灰和5%掺量硅酸钠复掺入混凝土后,不换水条件下浸泡溶液初始钙离子浓度仅为20~30 mg/L,从第18天左右溶液游离钙离子清零,换水条件下复掺试块较空白组平均溶出钙离子总重减少约85%。In order to study the rule of calcium ion precipitation in shotcrete mixed with silica fume and sodium silicate as admixtures under contact dissolution conditions,single mixed and double mixed concrete test blocks were prepared under different admixtures.A 30-day deionized water immersion test was carried out to test the changes in calcium ion concentration and pH value in the solution and study the contact corrosion process in combination with microscopic detection such as SEM.The results show that the dissolution amount of calcium ions in the single doped silica fume test block is significantly lower than that in the blank group under the condition of not changing water.The average total weight of dissolved calcium ions in the 3%,5%and 7%doping groups decreases by 73.29%,69.65%and 69.26%respectively compared with the blank group within 30 days under the condition of water change.After single addition of sodium silicate,the dissolution amount of calcium ions in the sample with 3%dosage can also be significantly reduced without water change.The average total weight of dissolved calcium ions in 1%,3%and 5%dosage groups is 9.22%,20.53%and 29.96%less than that in the blank group within 30 days in the case of water change.After the addition of 3%silica fume and 5%sodium silicate,which have good curing effect,into concrete,the initial calcium ion concentration of immersion solution is only 20~30 mg/L under the condition of not changing water.The free calcium ions in the solution are cleared to zero from about the 18th day.Compared with the blank group,the average total weight of dissolved calcium ions in the double mixed test block in the case of water change decreases about 85%.

关 键 词：隧道工程 喷射混凝土 碳酸钙结晶 钙离子析出 接触溶蚀 

分 类 号：U457.2[建筑科学—桥梁与隧道工程]