Intrinsic properties and micro-crack characteristics of ultra-high toughness fly ash/steel slag based geopolymer

Abstract The ultra-high toughness fly ash/steel slag based geopolymer was prepared from fly ash and steel slag as the main raw materials. The results of tensile tests show that the suitable amount of steel slag is 21% in mass. The effects of different tensile strains and curing condition on the compressive strength, apparent density, tensile properties and micro-crack characteristics of geopolymer were studied through tensile tests. The self-healing characteristics of geopolymer were studied by preload. With the increase of strain, cracks number and cracks width are increasing. The crack number increases with the increase of age, and the cracks width decreases. High temperature curing improves the strength of geopolymer and reduces the cracks width, but it reduces the strain properties and compactness. The excellent self-healing effects are found. C-S-H gel and N-A-S-H gel are existed in the self-healing products.