Innovative Recycling of Lime Slaker Grits from Paper-Pulp Industry Reused as Aggregate in Ambient Cured Biomass Fly Ash-Based Geopolymers for Sustainable Construction Material

Manfredi Saeli, Luciano Senff, David Maria Tobaldi, Giada La Scalia, Maria Paula Seabra and João Antonio Labrincha
Additional contact information
Manfredi Saeli: Department of Materials and Ceramics Engineering, Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
Luciano Senff: Department of Mobility Engineering, Federal University of Santa Catarina, 89218-000 Joinville, Brazil
David Maria Tobaldi: Department of Materials and Ceramics Engineering, Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
Giada La Scalia: Department of Engineering, University of Palermo, Viale delle Scienze, Bld 8, 90128 Palermo, Italy
Maria Paula Seabra: Department of Materials and Ceramics Engineering, Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
João Antonio Labrincha: Department of Materials and Ceramics Engineering, Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal

Sustainability, 2019, vol. 11, issue 12, 1-15

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 °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: construction; geopolymer concrete; biomass fly ash; lime slaker grits; recycling; paper-pulp industry (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2019
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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