A. Maldonado-Alameda, A. Alfocea-Roig, J. Formosa, J. Giro-Paloma, J.M. Chimenos
https://doi.org/10.3390/app10124129
Applied sciences, 2020, 10, 12, 1-15
Quartile Q2, Impact 2.679
The concern about the large amount of weathered bottom ash (WBA) produced in waste-to-energy plants (WtE) has caused an increased search for alternatives to reduce their environmental impact. The present study aims to provide an added value through the WBA valorization from municipal solid waste incineration (MSWI) for its use as a sole precursor for developing alkali-activated binders (AABs). Alkali-activated weathered bottom ash binders (AA-WBA) were formulated with a liquid-to-solid ratio of 1.0 and using sodium silicate (80 wt.%) and NaOH (20 wt.%) at different concentrations (2, 4, 6, and 8M) as alkali-activator solutions. AA-WBA were cured at room temperature to extend their applicability. The effect of the alkali-activator solution molarity on the final properties of the AA-WBA was evaluated. The physicochemical characterization by XRD, FTIR, and SEM evidenced the presence of the typical phases (calcium silicate hydrate and gehlenite) of C-(A)-S-H gel. Leaching concentrations of As, Cu, and Mo exceed the acceptance in landfills for inert waste, while the leaching concentration of Sb exceeds the one for non-hazardous waste. The structure of the binders depends on the alkalinity of the activator, obtaining better results using NaOH 6M in terms of microstructure and compressive strength (6.7 MPa). The present study revealed that AA-WBA for non-structural purposes can be obtained. The AA-WBA formulation contributes to the WBA valorization and development of low-carbon cements; therefore, it is an encouraged alternative to ordinary Portland cement (OPC). Considering the amounts and costs of the WBA, sodium silicate, NaOH, and water, the total cost of the developed formulations is comprised in a range between 137.6 and 153.9 €/Tn.
Funding
The research leading this project has received funding from the Spanish Government (BIA2017–83912- C2–1-R). This work has been partially funded by a Catalonian research Grant (FI-DGR 2017).
Research category: Environment and Construction
Projects associated: Desarrollo sostenible de cementos activados alcalinamente a partir de escorias de incineración de residuos municipales (BIA2017–83912- C2–1-R)
Doctoral Thesis related: Alkali-activated binders based on municipal solid waste incineration bottom ash