磷酸氢二钾提高硅酸镁水泥早期强度的机理  

Mechanism of K2HPO4 Improving Early Strength of Magnesium Silicate Hydrate Cements

作　　者：冷迪飞 李相国 吕阳 李能 LENG Difei;LI Xiangguo;LV Yang;LI Neng(State Key Laboratory of Silicate Materials for Architectures,School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;State Key Laboratory Incubation Base for Green Processing of Chemical Engineering,School of Chemistry and Chemical Engineering,Shihezi University,Shihezi 832000,Xinjiang,China)

机构地区：[1]武汉理工大学材料科学与工程学院,硅酸盐建筑材料国家重点实验室,武汉430070 [2]石河子大学化学化工学院,化工绿色过程省部共建国家重点实验室培育基地,新疆石河子832000

出　　处：《硅酸盐学报》2025年第3期531-538,共8页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金面上项目(52172024);兵团重点领域科技攻关计划项目(2023AB013-03)。

摘　　要：硅酸镁水泥(MSHC)较慢的早期水化速率是限制该种水泥应用规模的主要因素。通过X射线衍射(XRD)精修,29Si核磁共振谱(NMR),扫描电子显微镜(SEM)与密度泛函理论计算探讨了磷酸氢二钾(DKP)加速MSHC水化的机理,证实DKP的引入能够诱导胶凝性更强的水化硅酸镁(M-S-H)结构更快的生成,从而显著提高MSHC的早期强度以及后续强度,其1、3、7、14 d和28 d分别提高3.25、13.78、22.23、34.58 MPa和37.96 MPa。硅酸镁水泥水化产物的XRD精修,^(29)Si NMR,SEM与密度泛函理论计算证实,DKP诱导生成了高杨氏模量和低泊松比的M-S-H,即Superhydrous Phase B。强调这样一种思路,即合适的外加剂能够诱导胶凝性更强的M-S-H结构更快的生成,从而提高水合硅酸镁水泥的水化速度和早期强度,进一步拓展水合硅酸镁水泥的应用范围。Introduction Magnesium silicate hydrate(M-S-H)cement is a low-carbon cementitious material.This paper discusses the mechanism of dipotassium phosphate(DKP)accelerating the hydration of hydrated magnesium silicate cement,and confirms that the introduction of DKP accelerated the formation of M-S-H gel due to the alkali induction effect and K-struvite seed crystal induction effect.This improves the compressive strength and subsequent strength of hydrated magnesium silicate cement,which can increase 3.25,13.78,22.23,34.58 MPa and 37.96 MPa at the age of 1,3,7,14 d and 28 d,respectively.Meanwhile,different additives can induce the formation of different M-S-H crystal phases.The acceleration of the hydration process by these additives is confirmed through X-ray diffraction(XRD),^(29)Si nuclear magnetic resonance spectroscopy(NMR),scanning electron microscopy(SEM)and density functional theory calculations.M-S-H is the main source of strength for hydrated magnesium silicate cement,and this paper also emphasizes that suitable additives can induce a faster formation of M-S-H structures with stronger cementitious properties,thereby improving the hydration rate and early compressive strength of magnesium silicate hydrate cements,and further expanding the application range of magnesium silicate hydrate cements.Methods MgO:SF mass ratio for preparing MSHC samples was 40:60(i.e.,the amount of substance was 1:1),the water/cement(w/c)ratio was 0.45,the SHMP content was 1%(mass fraction)of the total solid mass,and the samples were all cured at 25℃and 95%RH for 28 d.When the samples were cured at different ages(i.e.,1,3,7,14 d and 28 d),they were broken into small pieces with the particle sizes of 1-3 cm and soaked in isopropyl alcohol to stop their further hydration.The broken samples were dried in a vacuum drying oven at 40℃until there was no more mass loss.The crystal phases of the samples were determined by a model Empyrean Rietveld X-ray diffractometer(XRD,Malvern Panalytical Co.,The Netherlands).The morphology of the samp

关 键 词：硅酸镁水泥 核磁共振谱 X射线衍射精修 加速水化 密度泛函理论 磷酸氢二钾 

分 类 号：TU528.44[建筑科学—建筑技术科学]