Development of a low-carbon binder based on raw, ground, and carbonated waste paper fly ash

Abstract

The formulation of an eco-binder only makes sense if the technical and environmental suitability of new waste material have been assessed. This study focuses on the recovery of three sets of waste paper fly ash (WPFA): raw, ground, and carbonated, as the main component of an eco-binder. The effect of the partial replacement of ordinary Portland cement (OPC) with WPFAs is studied from a mechanical and environmental point of view. The results show that raw WPFA contributes to the development of compressive strength, especially for low substitution rates (10 and 20%). Grinding results in improved compressive strength, fineness, and stability (at high substitution rates), and also accelerated setting kinetics. Natural carbonation is an effective and low-cost solution that has been proposed to treat WPFA before incorporation into the cementitious matrix. The carbonation contributes to delaying the setting and improving the stability of the matrix. Furthermore, the process of carbonation has been observed to have a beneficial impact on the stabilization of barium through the reduction of its leaching potential, which can contribute to the environmental sustainability of the eco-binder. In conclusion, the replacement of OPC with 20% of carbonated WPFA can save significant amounts of greenhouse gas emissions (27.29%).