高抗折硫氧镁基无机复合胶凝材料的制备及其机理

为了制备具有高抗折性能的硫氧镁基胶凝材料, 分别研究了不同掺量硅灰取代轻烧氧化镁粉对柠檬酸改性硫氧镁(CMOS)胶凝材料性能的影响及机理. 结果表明: 掺加硅灰之后, 制备的柠檬酸改性硫氧镁胶凝材料抗折抗压强度均得到了提高. 当硅灰取代掺量在5%~10%质量分数时, 柠檬酸改性硫氧镁胶凝材料各个龄期的力学性能最优, 其中, 28d抗折强度达到了22~23 MPa左右, 这比相同水灰比条件下普通硅酸盐水泥P.O42.5的抗折强度提高了238%. 研究还发现, 硅灰取代掺量在5%~10%质量分数范围时, 所制备的硫氧镁基胶凝材料的耐水系数达到了0.85以上, 表明该高抗折硫氧镁基胶凝材料具有较高的耐水性, 完全适用于受水浸泡或处于潮湿环境的重要结构中.

Preparation and mechanism of magnesium oxysulfate based inorganic cementitious material with high flexural strength

In order to prepare magnesium oxysulfate cementitious material with high flexural properties, the effects of different amount of silica fume instead of light burned magnesia powder on citri-acid-modified magnesium oxysulfate (CMOs) cementitious materials were investigated. The results show that the compressive strength of CMOs materials is improved by adding silica fume. When the dosage of silica fume is 5%-10%, the optimum mechanical properties of CMOs cemented materials are obtained at different ages. At age of 28 days, its flexural strength reaches 22-23MPa which increases by 238% comparing with ordinary Portland cement P.O42.5 under the same water cement ratio condition. The results also shows that when replacement content is 5%-10%, the softening coefficient of the prepared CMOs cementing material is more than 0.85, which indicates that prepared CMOs cemented materials has much higher water resistance and it could be adopted in some key structures soaking in water or in wet environment.