地聚物混凝土耐久性研究进展

Research progress on the durability of geopolymer concrete

地聚物是近年来发展起来的一种新型无机胶凝材料,其不仅实现了工业固废的资源再利用,还减少了能源消耗及温室气体排放,被认为是有潜力替代普通硅酸盐水泥的一种绿色胶凝材料。针对地聚物混凝土的耐久性问题,从耐化学侵蚀性(耐盐和耐酸)、抗碳化性、抗氯离子渗透性以及抗冻性4个方面对比总结了地聚物混凝土和硅酸盐水泥混凝土的耐久性能。研究发现,与硅酸盐水泥混凝土相比,地聚物混凝土有着更优异的耐化学侵蚀性、抗氯离子渗透性以及抗冻性,但有着稍低的抗碳化性能。然而,因地聚物原材料的多样性,各体系地聚物混凝土的微观结构、力学特性及劣化机理有所差异,致使其耐久性也存在较大区别。在环境的侵蚀下,地聚物混凝土的劣化机理主要归因于水化产物的溶解、膨胀性产物的形成、裂缝的产生以及孔隙率的增加。

Geopolymer is a new type of inorganic cementitious material developed in recent years.It not only realizes the resource reuse of industrial solid wastes,but also contributes to the reduced energy consumption and greenhouse gas emissions,and is considered a green cementitious material with the potential to replace ordinary Portland cement(OPC).To address the durability of geopolymer concrete,this paper compared and summarized the durability performance of geopolymer concrete and cement-based concrete from four aspects,namely,the resistance to chemical attack(salt and acid resistance),carbonation,chloride penetration,and frost resistance.It was found that geopolymer concrete exhibited superior chemical resistance,chloride penetration resistance,and frost resistance,but slightly lower carbonation resistance than cement-based concrete.However,due to the diversity of raw materials,the microstructure,mechanical properties,and deterioration mechanisms were different for each type of geopolymer concrete,thereby resulting in large differences in their durability.Under these environmental attacks,the deterioration mechanisms of geopolymer concrete were mainly attributed to the dissolved hydration products,the formed expansion products,the generated cracks,and the increased porosity.