In-situ sampling of solid recovered fuel and recycling ashes for the production of sustainable binders

Abstract

Increasing waste generation and energy shortages are fueling interest in alternative fuels such as solid recovered fuels (SRFs), but limited studies address their compositional properties and potential for reuse in construction. This study involved in-situ sampling at SRF production/utilization facilities in Taiwan, with five sites substituting 30 %–80 % of their fossil fuels use with SRFs derive mainly from plastics, textiles, and waste wood. The net calorific values of SRFs ranged from 18.42 MJ/kg to 29.11 MJ/kg with textile-derived SRFs containing higher sulfur (3.23 %) and chlorine (0.03 %) levels. After incineration, SRF ashes showed increased concentrations of metals, notably Ca (0.09–30.2 %), followed by Si (4.17–18.95 %), and Fe (1.15–5.86 %). Metals such as aluminum and iron were found to be more concentrated after incineration. The compressive strength of ash-based binders increased with curing time, achieving 291 kgf/cm² at 30 % SRF ash content after 14 days. The study suggests that replacing approximately 10 % of cement with SRF ash and curing for 7 days optimizes viscosity, permeability, and compressive strength. These findings support the circular economy by repurposing SRF ashes for civil and environmental applications.