原料摩尔比对硫氧镁胶凝材料性能的影响

Influence of Molar Ratio on Properties of Magnesium Oxysulfate Cementitious Materials

研究了氧化镁-硫酸镁摩尔比n(MgO)/n(MgSO4),水-硫酸镁摩尔比n(H2O)/n(MgSO4)对硫氧镁胶凝材料性能的影响及其微观机理.结果表明:固定n(H2O)/n(MgSO4)为19∶1,n(MgO)/n(MgSO4)为14∶1时硫氧镁胶凝材料力学性能最优;n(MgO)/n(MgSO4)超过14∶1后,硫氧镁胶硬化浆体中剩余MgO和Mg(OH)2的含量会增大,使硬化结构疏松,从而降低其力学性能;固定n(MgO)/n(MgSO4)为14∶1时,n(H2O)/n(MgSO4)的增大会延缓硬化硫氧镁浆体中碱式硫酸镁相的生成,造成微观结构中产生大量孔隙,从而导致其力学性能下降.

Effects of n（MgO）/n（MgSO4）,n（H2 O）/n（MgSO4）on the properties and micro-structural mechanism of magnesium oxysulfate（MOS）cemented materials were investigated.The results show that the most optimal mechanical properties are obtained when n（H2 O）/n（MgSO4）is fixed to be 19∶1 and n（MgO）/n（MgSO4）equals to 14∶1.Micro-structural analysis shows that once n（MgO）/n（MgSO4）is over 14∶1,the content of residual MgO and Mg（OH）2 in hardened paste of MOS will increase,which will loosen the structure of the hardened MOS and reduce its mechanical properties;With the increase of n（H2 O）/n（MgSO4）the formation of basic-magnesium-sulfate phase in hardened MOS will be retarded,resulting in a large amount of pores in microstructure and decrease of mechanical properties,when n（MgO）/n（MgSO4）is 14∶1.