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研究了M/P比值(重烧氧化镁与磷酸盐的质量比)对磷酸镁水泥水化历程的影响,采用水化热动力学结合水化产物、微观形貌变化探讨了M/P比值对磷酸镁水泥水化作用机理。结果表明:增大M/P比值,会显著降低水化时吸热峰及放热峰的峰值。根据磷酸镁水泥水化放热速率的变化特点,可将水化放热过程划分为KH_2PO4水解期、MgO溶解期、Mg(H_2O)62+增长期、MgKPO4·6H_2O增长加速期、MgKPO4·6H_2O增长减速期以及稳定期6个阶段。Knudsen与Kondo的水化动力学公式对于磷酸镁水泥水化体系的最终放热量及半衰期预测以及水化动力学研究具有良好的适用性,拟合相关系数高达0.99以上。M/P比值由2:1增至6:1,最终放热量及半衰期呈逐渐减小的趋势。磷酸镁水泥的水化是由结晶成核过程直接进入扩散过程,改变M/P比值,主要会对Mg(H_2O)62+增长期、MgKPO4·6H_2O增长减速期以及水化稳定期产生影响。在第Ⅰ~Ⅳ阶段,反应物浓度及游离水含量变化是影响水化行为的主要原因。在第Ⅴ、Ⅵ阶段,水化体系中剩余MgO产生的隔断作用及反应物浓度的变化共同决定了水化速率。
Abstract：The influence of M/P ratio(mass ratio of magnesia to phosphate) on the hydration processes of magnesium phosphate cement(MPC) was investigated. The mechanism was analyzed via the hydration kinetic combined with the variation of hydration production and microstructure. The results show that increasing M/P ratio can decrease the peak value of endothermic valley and exothermic peaks of the hydration. The hydration of MPC is divided into six stages, i.e., hydrolyzation of KH_2PO4, dissolution of MgO, growth of Mg(H_2O)62+, accelerating growth of MgKPO4·6H_2O, decelerate growth of MgKPO4·6H_2O and stable period according to the change regulation of hydration evolution rate of MPC. The final heat release and half-life of MPC can be predicted by the Knudsen hydration equation, and the Kondo hydration equation can be applied for the hydration kinetic. The Pearson correlation coefficient of the fitting is > 0.99. The final heat and half-life of MPC decreases when the M/P ratio increases from 2:1 to 6:1. The hydration of MPC varies from nucleation and crystal growth process to diffusion process directly. The M/P ratio mainly affects the growth of Mg(H_2O)62+, decelerates the growth of MgKPO4·6H_2O. The concentration of reactant and free water are the primary reasons for altering the hydration behavior of MPC. The partition function of residual MgO and the reactant concentration in hydration system determine the hydration behavior of MPC when the hydration proceeds into stage Ⅴ and stage Ⅵ.
[1]YANG Q,ZHANG S,WU X.Deicer-scaling resistance of phosphate cement-based binder for rapid repair of concrete[J].Cem Concr Res,2002,32(1):165–168.
[2]QIAO F,CHAU C K,LI Z.Property evaluation of magnesium phosphate cement mortar as patch repair material[J].Constr Build Mater,2010,24(5):695–700.
[3]SEEHRA S S,GUPTA S,KUMAR S.Rapid setting magnesium phosphate cement for quick repair of concrete pavements—characterisation and durability aspects[J].Cem Concr Res,1993,23(2):254–266.
[4]MESTRES G,GINEBRA M P.Novel magnesium phosphate cements with high early strength and antibacterial properties[J].Acta Biomater,2011,7(4):1853–1861.
[5]KLAMMERT U,VORNDRAN E,REUTHER T.Low temperature fabrication of magnesium phosphate cement scaffolds by 3D powder printing[J].J Mater Sci:Mater Med,2010,21(11):2947–2953.
[6]SINGH D,WASH A S.Phosphate bonded structural product from high volume wastes[P].US patent,5 846 894.1998:6.
[7]QIAO F,CHAU C K,LI Z.Calorimetric study of magnesium potassium phosphate cement[J].Mater Struct,2012(45):447–456.
[8]KRSTULOVI?R,DABI?P.A conceptual model of the cement hydration process[J].Cem Concr Res,2000,30(5):693–698.
[9]阎培渝,郑峰.水泥基材料的水化动力学模型[J].硅酸盐学报,2006,34(5):555–559.YAN Peiyu,ZHENG Feng.J Chin Ceram Soc,2006,34(5):555–559.
[10]KNUDSEN T.On particle size distribution in cement hydration[A]//In:Proceedings of 7th International Congress on the Chemistry of Cement,Vol I[C].Paris:1980:1–170.
[11]KONDO R,UEDA S.Kinetics of hydration of cement[A]//In:5th International Conference on the Chemistry of Cement,SessⅡ-4[C].Tokyo,1968:203–208.
[12]文静,余红发,吴成友,等.氯氧镁水泥水化历程的影响因素及水化动力学[J].硅酸盐学报,2013,41(5):588–596.WEN Jing,YU Hongfa,WU Chengyou,et al.J Chin Ceram Soc,2013,41(5):588–596.
[13]SUGAMA T,KUKACKA L E.Magnesium monophosphate Cements derived from diammonium phosphate solutions[J].Cem Concr Res,1983,13(3):407–416.
[14]SOUDéE E,PéRA J.Mechanism of setting reaction in magnesia-phosphate cements[J].Cem Concr Rcs,2000,30(2):315–321.
[15]YOU Chao,QIAN Jueshi,QIN Jihui,et al.Effect of early hydration temperature on hydration product and strength development of magnesium phosphate cement(MPC)[J].Cem Concr Res,2015,78:179–189.
[16]DING Zhu,DONG Biqin,XING Feng,et al.Cementing mechanism of potassium phosphate based magnesium phosphate cement[J].Ceram lnt,2012,38(8):6281–6288.
[17]BAMFORD C H,TIPPER C F H,COMPTON R G.Comprehensive Chemical Kinetics[M].Amsterdam:Elsevier,1985:3–45.
[18]傅彩霞,沈文霞,姚天扬.物理化学[M].四版,北京:高等教育出版社,2003:505–1090.
[19]邹亚莉.新型早强磷酸镁水泥的实验研究和工程应用[D].上海:上海交通大学,2010.LUO Yali.Experimental study on magnesium phosphate cement with high early strength and its applications(in Chinese,dissertation).Shanghai:Shanghai Jiaotong University,2010,50–53.
[20]YANG Quanbing,WU Xueli.Factors influencing properties of phosphate cement-based binder for rapid repair of concrete[J].Cem Concr Res,1999,29(3):389–396.
[21]HOUSTON P L.Chemical Kinetics and Reaction Dynamics[M].New York:Mc Graw-Hill Companies,2001:34–83.
基本信息:
DOI：10.14062/j.issn.0454-5648.2017.08.13
中图分类号:TQ172.1
引用信息:
[1]戴丰乐,汪宏涛,丁建华,等.氧化镁与磷酸盐质量比对磷酸镁水泥水化历程的影响[J].硅酸盐学报,2017,45(08):1144-1152.DOI:10.14062/j.issn.0454-5648.2017.08.13.
基金信息:
国家自然科学基金项目(51272283)
2017-07-23
2017-07-23
2017-07-23