活性混合材对改性硫氧镁胶凝材料性能的影响

Effects of Active Admixtures on Properties of Modified Magnesium Oxysulfate Cemented Materials

为了进一步提高硫氧镁胶凝材料的性能,研究了活性混合材(粉煤灰、矿渣粉)分别对柠檬酸改性硫氧镁(CMOS)胶凝材料、柠檬酸/水玻璃复合改性硫氧镁(SCMOS)胶凝材料性能的影响及机理.结果表明:粉煤灰和矿渣粉均可以明显提高CMOS胶凝材料的抗折强度和耐水性,尤其是其后期抗折强度提高最多;掺加10%粉煤灰或10%矿渣粉,均可以进一步提高SCMOS胶凝材料的力学性能和耐水性,其中SCMOS胶凝材料的28d浸水软化系数可达0.85以上.微观分析表明:粉煤灰和矿渣粉的微集料填充效应,使得CMOS、SCMOS胶凝材料的硬化结构更加密实;粉煤灰和矿渣粉均可以延缓CMOS、SCMOS胶凝材料硬化结构中碱式硫酸镁相的形成,减少硬化体系中氢氧化镁相的生成量;另外,粉煤灰或矿渣粉还可以延迟体系的水化进程并降低其水化热峰值.

In order to improve the properties of magnesium oxysufate cemented material,the effects of active admixture such as fly ash and slag powder on citric acid modified magnesium sulfate(CMOS)cemented materials and citric acid/sodium silicate modified magnesium sulfate(SCMOS)cemented materials were investigated.The results show that fly ash and slag powder can improve the flexural strength and water resistance of CMOS cemented materials,especially the late flexural strength increases mostly.Adding 10%fly ash or slag powder further improves the mechanical properties and softening coefficient of SCMOS cemented materials and specifically the corresponding 28d-immersed softening coefficients increases to be over 0.85.The micro-analyzing results show that the filling effect of fly ash or slag powder makes the hardening structure of CMOS and SCMOS cemented materials more compact;fly ash or slag powder can delay the formation of basic magnesium sulfate phases and decrease the formation of Mg(OH)2 in the hardened structures.It was found that fly ash or slag powder can postpones the hydration process of CMOS and SCMOS cemented material,and reduce its peak of hydration heat.