MgO搭配合比式对无机聚合物硬化浆体体积变形及微观结构的影响

摘要

Geopolymer is a novel type of low carbon,environmentally friendly cementitious material,which possess the characteristics of quick setting early strength.However,the large volume shrinkage is the main reason for limiting its application.The effects of the collocation of different reactive MgO on the volume shrinkage and microstructure of geopolymer hardened pastes were studied.The results indicated that the collocation of MgO with 60 s and 220 s could improve the early strength of geopolymer hardened pastes,and the shrinkage value of the hardened pastes were the lowest.Mg(OH)2 formed with the addition of MgO,which compensated the contraction of geopolymer.%无机聚合物制备过程中能耗和碳排放较低、环境相容性好,且具有早期强度高、结构致密性和较好的耐腐蚀性等特点.但与硅酸盐水泥相比,存在收缩大、易开裂等缺陷,严重影响了无机聚合物的应用.通过采用不同活性的氧化镁进行搭配,研究了无机聚合物硬化浆体的体积变形及微观结构的变化.结果表明,不同养护制度下,活性MgO不同搭配合比式对无机聚合物胶砂力学性能影响显著;不同活性MgO搭配的无机聚合物干燥收缩在不同养护制度下表现不同,MgO活性为60、220 s搭配时制备的硬化浆体的收缩值均最低,硬化浆体的改善效果也最好;不同活性MgO搭配加入到无机聚合物胶凝材料中会影响无机聚合物水化放热的快慢和总的放热量;MgO加入到无机聚合物中与水反应生成了Mg(OH)2,从而改善无机聚合物的收缩性能.