Steel slag-based geopolymer foamed concrete (SSGFC) provide a promising value-added and carbon-neutral strategy for the re-utilization of SS, and the strength and physical properties of SSGFC are essential to its practical application. Therefore, this study proposes to use emulsified asphalt (EA) to improve the pore structure, compressive strength, water resistance and thermal insulation properties SSGFC. Firstly, different contents of EA were added into the foaming solution to prepare modified foam, and then SSGFC samples were prepared by using modified foam and steel slag-based geopolymer. The fresh properties, microstructure, pore structure, reaction products and physical properties of SSGFC samples were investigated. The results indicate that EA can reduce the fluidity and settlement value of the paste and increase the setting time. The addition of EA leads to a decrease in hydration products, but it can reduce the average pore diameter of the SSGFC and improve its pore diameter distribution. The SSGFC sample prepared by modified foam with 10 % EA showed the best physical properties. Compared with the control group, its compressive strength increased by 21.4 %, water absorption decreased by 16.5 %, and thermal conductivity decreased by 31.3 %. Therefore, EA shows significant potential to enhance the performance of SSGFC, thus providing reliable support for its practical applications.

Aimed to address the low utilization rate of steel slag (SS) and its challenge in resource utilization in China, this study developed ternary geopolymers made by high-content (50%) SS together with fly ash (FA) and granulated blast furnace slag (GBFS). The effects of GBFS content (0–40%) and curing methods (water curing, standard curing, sealed curing, and heat curing) on the working performance and microstructure of geopolymers were investigated. Microscopic analysis such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM) were utilized to investigate the hydration process and products of geopolymers under different curing conditions and GBFS content. The results indicated that when the GBFS content increased from 0% to 40%, the fluidity of the mixture decreased by 11.7%, the initial setting time of the geopolymer slurry decreased by 76%, and the geopolymer mortar's 28d compressive strength increased from 31.9 MPa to 60.6 MPa. At room temperature, the geopolymer mortar's 28d compressive strength was higher under standard curing (70.8 MPa) compared to water curing (57.5 MPa) and sealed curing (68 MPa). The geopolymer mortar cured at 60 °C for 24 h exhibited the highest 28d compressive strength (76.3 MPa). However, excessively high curing temperatures or prolonged durations led to more shrinkage cracks and reduced the compressive strength. The microscopic analysis revealed that the main gel products of ternary geopolymer were C-(A)-S-H gel. The amount of gel products is directly related to the strength of geopolymers. The developed ternary geopolymer has the potential to promote the large-scale utilization of SS in the concrete industry, making a significant contribution to sustainable development.