Preparation and performances of foamed hydraulic lime

•Foamed HLs was appropriate for CO2 capture and in-situ solidification.•Foamed HLs has good thermal insulation performance.•Accelerated carbonation curing can improve the Thermal insulation performance.•Accelerated carbonation curing can reduce the pore diameter of foamed HLs. Hardened hydraulic lime with proper strength, high porosity and large carbonation capacity is considered to be an ideal candidate for CO2 adsorption and in-situ solidification. In this study, hydraulic lime (HL) was obtained by mixing of hydrated lime (Ca(OH)2, CH) and white Portland cement (WPC). Foamed HLs with dry bulk densities of 300 kg/m3 and 600 kg/m3 were prepared in order to increase the CO2 permeability in hardened matrix. Then, CO2 was rapidly captured by foamed HLs to form CaCO3 due to the air-hardening reaction. Results indicated that the CO2 captured capacity and the thermal insulation performance of foamed HLs was increased, but the compressive strength was reduced with the increase of CH in HLs. Carbonation rate was further accelerated under accelerating carbonation condition. Pore size of foamed HLs was refined with the cement hydration and carbonation process, which was beneficial to the increase of compressive strength and thermal insulation performance of foamed HLs. It is expected that foamed HLs could be used as building insulation materials with superior capacity and rate for CO2 adsorption and solidification.