Preparation and performances of foamed hydraulic lime

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/m(3) and 600 kg/m(3) 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. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Hardened hydraulic lime is considered as ideal material for CO2 adsorption and in-situ solidification. Foamed HLs with different densities were prepared to increase CO2 permeability and capture capacity. Results showed increased CO2 capture capacity and thermal insulation performance, but decreased compressive strength with higher CH content.