abstract
Lime slaker grits and biomass fly ash are solid wastes produced by the Kraft paper-pulp industry that are commonly disposed of in landfill. However, recent studies and European regulations discourage such disposal practices. This work investigates an alternative and innovative way to recycle and reuse these wastes in the production of green geopolymeric mortars intended for application in the construction industry. Here, biomass fly ash was used as the main source of alumino-silicate in the binder precursor (70 wt.% substitution to metakaolin), and grits (ranging from 1-12.5 mm, as provided by the industry) were reused as aggregate. Aggregate granulometry was also completed by using a commercial natural siliceous sand (<1 mm). Mortars using sand only were prepared for comparative reasons. The implemented mix was designed to investigate the influence of the grits on the mortar's properties such as its binder/aggregate ratio, workability, bulk density, water sorptivity, and compressive strength. At the same time, waste reuse was analysed in light of its limitations and potentialities. Moreover, in the pursuit of sustainability, the manufacturing process that was followed was highly cost-effective in ambient curing conditions (20 degrees C, 65% RH), which avoided the use of any external source of energy as commonly used in geopolymers processing. The achieved results proved that the combined use of these wastes, which to date has hardly been explored, along with ambient manufacturing conditions increases the material sustainability. The produced mortars are suitable for innovative applications in various fields, with a particular focus on construction and contribute to the circular economy.
keywords
METHYLENE-BLUE; CONCRETE; CEMENT; PERFORMANCE; EMISSIONS; REMOVAL; BINDERS; FRESH
subject category
Science & Technology - Other Topics; Environmental Sciences & Ecology
authors
Saeli, M; Senff, L; Tobaldi, DM; La Scalia, G; Seabra, MP; Labrincha, JA
our authors
David Maria Tobaldi
Researcher
João António Labrincha Baptista
Full professor
Luciano Senff
Post-Doc Fellowship
Manfredi Saeli
Post-Doc Fellowship
Maria Paula Seabra
Assistant Professoracknowledgements
This work is financed by Portugal 2020 through the European Regional Development Fund (ERDF) in the frame of the Operational Competitiveness and Internationalization Programme (POCI) in the scope of the project PROTEUS-POCI-01-0247-FEDER-017729 and in the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. David M. Tobaldi is grateful to Portuguese national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in number 4, 5 and 6 of article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.