硫酸铝和偏铝酸钠对水泥浆体强度发展的影响机理  

Impact Mechanism of Aluminum Sulfate and Sodium Aluminate on Strength Development of Cement Mortars

作　　者：廖嘉欣 王健 孔祥明[1,2] 徐忠洲 周普玉 LIAO Jiaxin;WANG Jian;KONG Xiangming;XU Zhongzhou;ZHOU Puyu(Department of Civil Engineering,Tsinghua University,Beijing 100084,China;Advanced Building Functional Materials Innovation Center,Hebei-Tsinghua Development Research Institute,Langfang 056306,China;Shanxi Jiawei New Material Co.,Ltd.,Yuncheng 044200,China)

机构地区：[1]清华大学土木工程系,北京100084 [2]河北清华发展研究院先进建筑功能材料创新中心,河北廊坊056306 [3]山西佳维新材料股份有限公司,山西运城044200

出　　处：《建筑材料学报》2024年第12期1071-1080,共10页Journal of Building Materials

基　　金：运城市揭榜挂帅项目。

摘　　要：利用水化量热仪、热重分析仪、X-射线衍射仪、电感耦合等离子体发射光谱仪、压汞仪及扫描电镜等测试手段,建立了水泥浆体水化过程和力学性能之间的关系,揭示了硫酸铝(AS)和偏铝酸钠(NA)对水泥浆体强度发展的影响机理.结果表明:在相同掺量下,AS和NA对水泥浆体水化过程的影响和促凝早强机理完全不同,AS对水泥浆体硫酸盐平衡没有显著影响,但NA使水泥浆体成为欠硫体系,显著改变了体系的溶解沉淀平衡;水泥砂浆抗压强度的发展同时受硅相反应程度和浆体微结构建立过程的影响;水泥砂浆的早龄期强度不仅源自水泥水化的非晶相产物,钙矾石(AFt)和单硫型水化硫铝酸钙(AFm)等晶相产物也对早期强度有所贡献;与AFm相比,早期生成的AFt更有利于水泥浆体建立良好的早期固体网络结构,从而促进浆体后期强度的发展.Multiple techniques including calorimetry,thermogravimetric analysis,X-ray diffractometer,mercury intrusion porosimeter,inductively coupled plasma optical emission spectrometer and scanning electronic microscope were employed to establish quantitative relationships between hydration products and mechanical properties of cement mortars.The impact mechanisms of aluminum sulfate(AS)and sodium aluminate(NA)on the strength development of cement mortars was revealed.The results indicate that at the same dosage,AS and NA perform different mechanisms in affecting the early strength growth of cement mortars.AS does not significantly affect the sulfate equilibrium of the cement paste,whereas NA turns the cement paste into an under-sulfated system.NA significantly alters the dissolution-precipitation equilibrium of the cement paste.It is found that the compressive strength of cement mortars is affected by the hydration degree of silicate phase and the process of structure build-up.The early-age strength of mortar is not only derived from the amorphous hydration products,but also from the crystalline products such as ettringite(AFt)and monosulfoaluminate(AFm).Moreover,the formation of AFt in early stage other than AFm is more conducive to the establishment of a good early-stage solid network structure of cement paste,thus promoting the development of its later strength.

关 键 词：速凝剂 硫酸铝 偏铝酸钠 水化过程 强度发展 

分 类 号：TU528.01[建筑科学—建筑技术科学]