摘要
碱式硫酸镁水泥(Basic magnesium sulfate cement,BMSC)是一种以外加剂技术为核心的新型镁质胶凝材料,主要由轻烧氧化镁、不同结晶水的硫酸镁、矿物掺合料与化学外加剂一起混磨而成,使用时与普通硅酸盐水泥一样加水拌和即可。碱式硫酸镁水泥具有氯氧镁水泥轻质、快凝、高强、耐磨的优点,且不易吸潮反卤。BMSC的主要水化产物5Mg(OH)2·MgSO 4·7H 2O相(5·1·7相)的溶解度仅为0.034 g/100 g水,与硅酸盐水泥基本处于同一量级,远低于氯氧镁水泥,在建筑保温材料等领域可以广泛取代氯氧镁水泥。碱式硫酸镁水泥的抗折强度约为同强度等级硅酸盐水泥抗折强度的2~3倍,且其耐久性能、护筋性能与普通硅酸盐水泥相当。同时,BMSC混凝土具有较大的刚度和良好的抗震性能,其抗弯拉及抗冲击荷载性能均优于同等级普通硅酸盐水泥混凝土,尤其是开裂荷载比同强度、同配筋的普通混凝土大10%,因此其在结构工程领域也有良好的应用前景。更重要的是,用于制备碱式硫酸镁水泥的轻烧氧化镁的煅烧温度较低,使BMSC满足了建筑节能和环境保护的要求,有望成为未来核心高性能生态友好型水泥,具有巨大的发展潜力。本文概述了碱式硫酸镁水泥的性能特点,综述了其制备方法及水化过程,对比分析了碱式硫酸镁水泥、氯氧镁水泥和硫氧镁水泥的微观结构与性能的差异,阐明了镁质原料中α-MgO的含量和活性、α-MgO/MgSO 4及H 2O/MgSO 4的配料物质的量比、化学外加剂种类及掺量对碱式硫酸镁水泥微观结构及性能的影响。在此基础上,从原料及制备工艺等方面提出了进一步提升碱式硫酸镁水泥性能的措施,并展望了碱式硫酸镁水泥未来的研究方向。
B asic magnesium sulfate cement(BMSC)is a new type of magnesium cementitious material with the core of admixture technology.It is mainly made up of lightly burned magnesia,magnesium sulfate,mineral admixture of different crystal water and chemical admixture.It is used in the same way as ordinary Portland cement.Basic magnesium sulfate cement has similar advantages with magnesium oxychloride cement,such as light weight,fast setting,high strength,wear resistance,and is not easy to absorb moisture and anti-halogen.The solubility of its main hydration product 5Mg(OH)2·MgSO 4·7H 2O phase(5·1·7 phase)is only 0.034 g/100 g water,which is basically the same as Portland cement,much lower than magnesium oxychloride cement,which can widely replace magnesium oxychloride cement in the field of building insulation materials.In addition,the BMSC’s flexural strength is 2—3 times than that of the Portland cement at the same strength grade,and its durability and reinforcement protection performance is similar to Portland cement.Besides,BMSC concrete has large rigidity,good seismic performance and its bending,tensile and impact resistance performance are better than that of the Portland cement concrete at the same grade,which also has a good application prospect in the field of structural engineering.More importantly,the calcination temperature of light burned magnesia used to prepare BMSC is low,which makes BMSC meet the requirements of building energy conservation and environmental protection,and is expected to become the core high-performance eco-friendly cement in the future with great development potential.In this paper,the preparation and hydration process of BMSC are reviewed.The microstructure and performance difference of BMSC,magnesium oxychloride cement and magnesium oxysulfate cement are compared and analyzed.The effects of content and activity ofα-MgO in the magnesium materials,the proportioning molar ratio ofα-MgO/MgSO 4 and H 2O/MgSO 4,the type and dosage of chemical admixture on the microstructure and properties of BMSC are clarified.On this basis,measures to furtherly improve the performance of BMSC are proposed from the aspects of raw materials and preparation processes.
作者
王爱国
楚英杰
徐海燕
刘开伟
马瑞
董伟伟
孙道胜
WANG Aiguo;CHU Yingjie;XU Haiyan;LIU Kaiwei;MA Rui;DONG Weiwei;SUN Daosheng(Anhui Key Laboratory of Advanced Building Materials,Anhui Jianzhu University,Hefei 230022,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第13期13091-13099,共9页
Materials Reports
基金
国家自然科学基金(51778003)
高性能土木工程材料国家重点实验室开放课题(2018CEM002)
安徽省高等教育人才项目(皖教高[2014]11号文)
高校优秀中青年骨干人才国内外访学研修项目(gxfxZD2016134)
安徽建筑大学校引进人才及博士启动基金项目(2018QD60)。
关键词
碱式硫酸镁水泥
5·1·7相
微观结构
提升技术
basic magnesium sulfate cement
5·1·7 phase
microstructure
improvement technology
