摘要
氧化镁水泥基材料因其独特的体积膨胀特性,在补偿收缩、提升抗裂性能和耐久性方面表现出显著优势,但其水化速率慢、过度膨胀导致的力学性能损失等问题制约了工程应用。基于此,系统阐述了纳米化改性、纳米材料复合优化、固废协同利用及多膨胀剂协同作用等改性策略的研究进展。研究表明:纳米化氧化镁(50nm~100nm)通过增大比表面积(80m^(2)/g~120m^(2)/g)可加速水化反应,使28d抗压强度提升15%~20%,凝结时间缩短10min~20min。采用纳米材料,如纳米SiO_(2)(0.5wt%)优化界面过渡区结构,提升抗裂等级并降低干湿循环质量损失率至3.2%。通过将生物炭与或其他固废(如粉煤灰)复合可进一步提升氧化镁水泥基材料的耐久性能及内部湿度梯度,减少水泥石收缩。使用有机改性剂(如乙酸铵)可改善氢氧化镁的微观形态,由板状转变为更致密的棒状,从而改善孔结构,增强水泥基材料的耐久性。使用其他膨胀剂(如UEA)与氧化镁的协同作用可实现全龄期收缩补偿,为60d普通混凝土断裂韧性的1.09倍。
This paper systematically reviews the research progress on modification strategies,including nanoscale modification,composite optimization of nanomaterials,synergistic utilization of solid wastes,and the combined action of multiple expansion agents.The results show that nanosized MgO(50nm~100nm)can accelerate the hydration reaction by increasing the specific surface area(80m^(2)/g~120m^(2)/g),which improves the 28-day compressive strength by 15%~20%and shortens the setting time by 10min~20min.The incorporation of nanomaterials,such as nano-SiO_(2)(0.5wt%),enhances the anti-cracking performance and reduces the mass loss in the interfacial transition zone during dry and wet cycling by optimizing its structure,achieving a reduction of 3.2%.The durability properties and internal moisture gradient of MgO cementitious materials can be further improved by incorporating biochar or other solid wastes(e.g.,fly ash),thereby reducing cement paste shrinkage.The use of organic modifiers(e.g.,ammonium acetate)improves the micro-morphology of magnesium hydroxide from a plate-like form to a denser rod-like form,which improves the pore structure and enhances the durability of cementitious materials.The synergistic effect of combining other expansion agents(e.g.,UEA)with MgO can achieve full-age shrinkage compensation and improve the fracture toughness of 60d ordinary concrete by 1.09 times.
出处
《砖瓦》
2025年第8期24-28,共5页
Brick-tile
关键词
氧化镁
纳米材料
固体废弃物
有机改性
膨胀剂
magnesium oxide
nanomaterial
solid waste
organic modification
expansive agent
