硅酸盐水泥中Ca^(2+)在不同浓度NH4+溶液中的溶解  

Dissolution of Ca^(2+) in Portland Cement in Different Concentrations of NH Solutions

作　　者：张立明 江羽习 梁高荣 范萌萌 

机构地区：[1]广西路建工程集团有限公司,广西南宁530001 [2]南宁市筑路技术与筑路材料工程技术研究中心,广西南宁530001 [3]广西交建工程检测咨询有限公司,广西南宁530001

出　　处：《大众科技》2021年第1期24-27,共4页Popular Science & Technology

基　　金：广西住建厅研究开发项目“稳定型橡胶沥青混合料关键技术及在市政道路示范应用研究”(桂建科[2019]9号);广西住建厅研究开发项目“高强沥青及沥青混合料路用关键核心技术研究及在市政道路工程中示范应用”(桂建科[2019]9号);南宁市兴宁区科技项目“高粘沥青及沥青混合料路用性能研究”(南兴发科[2019]23号);南宁市兴宁区科技项目“低收缩抗裂钢渣路面基层材料的研究与应用”(2020A06);南宁市科技项目“氧化石墨烯改性沥青及其混合料关键技术研究”(20201062)。

摘　　要：硅酸盐水泥在实际使用环境中常常面临复杂的外界服役环境,地下的众多离子均会影响水泥混凝土材料的耐久性。其中NH4+离子广泛存在于化工厂、下水管道等附近的混凝土设施中,硅酸盐水泥的性能也会因此发生变化。文章基于化学热力学方程对硅酸盐水泥中Ca2+离子在NH4+溶解的中浓度的变化情况进行研究,并通过EDTA滴定法测定硅酸盐水泥中Ca2+离子在NH4+离子中溶解的实际浓度。结果表明NH4+离子溶解水泥硬化体时,水泥硬化体中Ca2+离子的溶解浓度与溶液中的NH4+离子浓度存在一定关系,即硅酸盐水泥中Ca2+的浓度与NH4+离子浓度的对数函数成正比关系,并通过实验验证该函数的适用性。在该过程中发现随着NH4+离子的浓度增加,水泥硬化体中的水化形成的Ca(OH)2和未水化的硅酸三钙与硅酸二钙等均发生溶解。基于上述数据研究了水泥硬化体不同NH4+离子的浓度下的溶解机理。Portland cement are often faced with complex external service environment in the actual used environment, and many ions at underground will affect the durability of cement-based materials. Among them, NH4+ ions widely exist in concrete facilities near the chemical plants and sewer pipelines, and the properties of cement-based materials will change accordingly. Based on the chemical thermodynamic equation, the variation of Ca2+ concentration in the solution of NH4+ in cement-based materials was studied. The actual concentration of Ca2+dissolved in NH4+ ions in Portland cement was determined by EDTA titration. The results showed that when NH4+ ions dissolve cement hardening paste, the dissolution concentration of Ca2+ ions in cement hardening paste had a certain relationship with the concentration of NH4+ ions, that is, the concentration of Ca2+ in Portland cement is proportional to the logarithmic function of NH4+ ion concentration, and the applicability of this function is verified by experiments. In this process, it is found that with the increase of NH4+ ion concentration, Ca(OH)2 formed by hydration of harden cement paste and C3 S and C2 S unhydrated of harden cement paste were dissolved. Based on the above data, the dissolution mechanism of harden cement paste under different NH4+ ion concentration was studied.

关 键 词：酸盐水泥 热力学方程 NH4^(+) 溶解 

分 类 号：TQ172[化学工程—水泥工业]