硅酸盐与硫铝酸盐复合水泥孔隙液相pH值变化研究

Study on the variation of pH value of pore solution of composite cement composed with Portland cement and sulphoaluminate cement

为了解硅酸盐水泥与硫铝酸盐水泥复合之后性能变化的原因,通过对复合水泥孔隙溶液的pH值进行研究,探讨了pH值变化与性能之间的内在联系。研究表明,孔隙溶液pH值变化与强度有良好相关性,水化3h后复合水泥pH值在SAC掺量为20%-80%之间出现波谷,水化剧烈并开始大量放热,后期强度也出现明显波谷区,其中以其掺量为60%时pH值和后期强度最低;当SAC或PC掺量为0%-20%时,复合水泥孔隙溶液pH值和强度相对于纯的SAC或PC而言基本没有变化,甚至还会稍微提高,这对降低水泥生产成本和提升水泥性能具有积极意义。

The internal relations between pH value variation and properties of the PC ＋SAC composite cement were investigated by means of pH value study of their pore solution. The properties changes of the PC ＋SAC composite cement were also studied. The results indicated that the strength of composite cement had a good relativity with the pH value variation of pore solution. The pH value would come to a valley after 3h hydration when the content of SAC was between 20% and 80%, and the composite cement hydrated vigorously and released a lot of heat. The later strength showed a valley bottom too, in which the pH value and later strength showed a lowest value if the amount of SAC approach to 60%. The pH value and strength of the composite cement would nearly or even surpass that of the pure SAC or PC, if either SAC or PC content was in the range of 0%-20%. This has positive significance to reduce cement production costs and improve cement performance.