镁质胶凝材料制备与分类、水化机理及耐久性能  

Preparation,classification,hydration mechanism and durability of magnesium-based cementing material

作　　者：胡捷 王艳 张少辉 常天风 孙琳琳 Hu Jie;Wang Yan;Zhang Shaohui;Chang Tianfeng;Sun Linlin(School of Materials Science and Engineering,Xi’an University of Architecture and Technology,Xi’an Shaanxi 710055,China;State Key Laboratory of Green Building in Western China,Xi’an Shaanxi 710055,China;School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an Shaanxi 710055,China)

机构地区：[1]西安建筑科技大学材料科学与工程学院,陕西西安710055 [2]西部绿色建筑国家重点实验室,陕西西安710055 [3]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《矿业科学学报》2023年第6期856-867,共12页Journal of Mining Science and Technology

基　　金：国家自然科学基金(51878549)。

摘　　要：镁质胶凝材料是基于活性MgO的一种新型胶凝材料,具有快凝、早强、耐火等特性,在修补、抢修等工程中具有显著优势。本文按照MgO煅烧温度及调和液种类,将镁质胶凝材料分为氯氧镁水泥、硫氧镁水泥和磷酸镁水泥,详细讨论并总结了它们的水化机理及耐久性能。氯氧镁水泥的水化实质是MgO、MgCl_(2)和H_(2)O三元体系水化;硫氧镁水泥水化过程由于游离MgSO4的存在导致硬化体系的强度较低;磷酸镁水泥由于MgO溶解放热及与磷酸盐之间剧烈反应放热的重叠导致水泥水化过快及放热过于集中。碳化会收缩镁质胶凝材料硬化基体中的毛细孔、优化内部孔结构,提高其强度及耐久性。镁质胶凝材料耐水性都较差,氯氧镁水泥耐水性差的原因目前并没有统一的认识;硫氧镁水泥耐水性差是因为未反应的MgO与水反应生成Mg(OH)_(2),引起体积膨胀、硬化基体开裂;磷酸镁水泥耐水性差是因为磷酸盐会导致水化产物及未反应的MgO溶解。Magnesium-based cementing material is a new type of cementitious material based on active MgO.It features rapid solidification,early strength and fire resistance,exhibiting significant advantages in repair and emergency repair projects.This study divided magnesium-based cementitious materials into three types according to the differences in calcination temperature of MgO and blending solution:mag-nesium oxychloride cement,magnesium oxysulfate cement,magnesium phosphate cement.We conducted detailed discussion and review of their hydration mechanism and durability.The hydration of magnesium oxychloride cement lies in the hydration of ternary system of MgO,MgCl_(2) and H2O.The hardened system of magnesium oxysulfate cement shows low strength due to the existence of free MgSO_(4) in the hy-dration process.The hydration rate of magnesium phosphate cement delayed owing to the overlapping of exothermic of MgO solution and sharp reaction between MgO and phosphate,which leads to excessive hydration and over-concentrated heat release.Carbonation reduces the pores contents,optimizes the in-ternal pore structure,and improves the strength and durability of magnesium-based cementitious materi-als.The magnesium-based cementitious materials have poor water resistance,among which no unified understanding has been reached as to the reasons for magnesium oxychloride cement.For magnesium oxysulfate cement,the unreacted MgO reacts with water to form Mg(OH)_(2),and the volume expansion leads to the cracking of the hardened matrix.In the case of magnesium phosphate cement,the phosphate can lead to the dissolution of hydration products and unreacted MgO.

关 键 词：镁质胶凝材料 氯氧镁水泥 硫氧镁水泥 磷酸镁水泥 水化机理 耐久性能 

分 类 号：TU528[建筑科学—建筑技术科学]