水玻璃对硫氧镁胶凝材料强度稳定性和耐水性的影响

Effects of Sodium Silicate on Strength Stability and Water Resistance of Magnesium Oxy Sulfate Cemented Materials

摘要:

为了进一步提高硫氧镁（MOS）胶凝材料的强度稳定性和耐水性，研究了不同掺量水玻璃对MOS胶凝材料力学性能和耐水性能的影响，并采用X射线衍射（XRD）、热重（TG）和扫描电镜（SEM）分析了水玻璃对MOS胶凝材料性能影响的机理.结果表明：水玻璃可以有效降低MOS胶凝材料浆体在水中的分散性，明显提高MOS胶凝材料强度的长期稳定性；水玻璃掺量为轻烧氧化镁粉质量的05%～10%时，MOS胶凝材料硬化体在水中的质量损失率和强度损失率最低，抗折强度和抗压强度最高；掺加0.5%水玻璃的MOS胶凝材料硬化体系中稳定的碱式硫酸镁相含量增多，无胶凝性Mg(OH)2相的含量明显减少，硬化体结构更加密实；水玻璃会加快MOS胶凝材料的吸热反应，使反应体系中H+浓度增加，促进生成晶相更为稳定的碱式硫酸镁相.

Abstract:

In order to improve the strength stability and water resistance of magnesium oxy sulfate(MOS) cemented materials, the influence of sodium silicate of different content on performance and mechanism of MOS cemented materials was investigated and also TG, XRD and SEM techniques were adopted to analyze the corresponding influencing mechanism. The results show that sodium silicate can effectively reduce the dispersion of MOS cemented materials in water, and obviously improve the long term strength stability. When the content of sodium silicate is 05%10% of light burnt MgO mass, the strength loss rate of hardened MOS cement paste in the water is the lowest, compressive and flexural strength reaches the highest. In the hardened system of MOS cemented materials with 05% sodium silicate, the content of fibrous basic magnesium sulfate phase increases, that of flake Mg(OH)2 phase decreases obviously, and the corresponding hardened structure tended to be more compact. The analysis of the hydration reaction of MOS cemented materials shows that sodium silicate can accelerate the endothermic reaction in the system of MOS cemented materials, increase the concentration of H+ in the reaction system and eventually produce more stable alkaline magnesium sulfate with better gelatinization.