高掺量磷石膏水硬性胶凝材料组成设计与性能调节  

Composition Design and Property Regulation of High Content Phosphogypsum Hydraulic Cementing Material

作　　者：刘爱平 吴赤球 水中和[3] 吕伟 练九阳 LIU Aiping;WU Chiqiu;SHUI Zhonghe;LYU Wei;LIAN Jiuyang(School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;Hubei Changyao New Materials Co.,Ltd.,Yichang 443000,China;State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学材料科学与工程学院,武汉430070 [2]湖北昌耀新材料股份有限公司,宜昌443000 [3]武汉理工大学硅酸盐建筑材料国家重点实验室,武汉430070

出　　处：《硅酸盐通报》2024年第3期1003-1011,共9页Bulletin of the Chinese Ceramic Society

摘　　要：本文研究的水硬性磷石膏胶凝材料体系由80%(质量分数)磷石膏,以及少量矿渣、水泥、偏高岭土、粉煤灰、硅灰等辅助胶凝材料组成,借助力学性能试验数据与分子动力学(MD)模拟为超高掺量磷石膏体系组成设计提供依据,后续对该体系强度倒缩问题进行性能调节。结果表明,当磷石膏掺量固定时,辅助胶凝材料(SCM)的n(CaO)/n(SiO_(2)+Al_(2)O_(3))摩尔比接近1的样品力学性能结果最佳。分子动力学对模型原子表面积和孔结构分布的模拟结果与力学性能规律相符,孔结构越小时抗压强度越高;在原子尺度上,n(CaO)/n(SiO_(2)+Al_(2)O_(3))摩尔比接近1时O、Ca、Al及S原子表现出较高的扩散能力,可充分发挥碱激发与硫酸盐激发效应,同时使得OO、Al—O、Si—O键长增大而失稳水解,促进水化产物钙钒石的生成。最后,通过调节SCM的种类,在磷石膏-矿渣-水泥体系中复掺偏高岭土、硅灰及粉煤灰改善了90 d龄期强度倒缩的问题。基于化学组分设计配合比对大宗量利用磷石膏以及获得性能更好的胶凝材料具有重要意义。The hydraulic phosphogypsum cementing material system studied in this paper is composed of 80%(mass fraction)phosphogypsum and a small amount of auxiliary cementing materials such as slag,cement,metacaolin,fly ash and silica fume.Mechanical properties test and molecular dynamics(MD)simulation are used to provide a basis for the composition design of high content phosphogypsum system,and then the strength shrinkage of the system is adjusted.The results show that when the content of phosphogypsum is fixed,the n(CaO)/n(SiO_(2)+Al_(2)O_(3))molar ratio of the supplementary cementitious material(SCM)is close to 1,and the mechanical properties of the sample are the best.The results of molecular dynamics simulation on the atomic surface area and pore structure distribution of the model are consistent with the mechanical properties.The smaller the pore structure,the higher the compressive strength.On the atomic scale,O,Ca,Al and S atoms show high diffusion ability in molecular dynamics simulations with the molar ratio of n(CaO)/n(SiO_(2)+Al_(2)O_(3))close to 1,which can give full play to alkali and sulfate excitation effects,and at the same time,increase the bond length of O O,Al—O and Si—O,resulting in unstable hydrolysis and promote the formation of calcium vanadite as a hydration product.Finally,by adjusting the types of auxiliary cementing materials,adding metakaolin,wollastonite and fly ash into phosphogypsum-slag-cement system,the problem of strength shrinkage at 90 d age is improved.It is of great significance to design and use phosphogypsum based on chemical composition and obtain better cementing materials.

关 键 词：高掺量磷石膏 化学成分 分子动力学模拟 组成设计 性能调节 

分 类 号：TU526[建筑科学—建筑技术科学]