Details

Autor(en) / Beteiligte

• De Rossi, A.
• Ribeiro, M.J.
• Labrincha, J.A.
• Novais, R.M.
• Hotza, D.
• Moreira, R.F.P.M.

Titel

Effect of the particle size range of construction and demolition waste on the fresh and hardened-state properties of fly ash-based geopolymer mortars with total replacement of sand

Ist Teil von

• Process safety and environmental protection, 2019-09, Vol.129, p.130-137

Ort / Verlag

Rugby: Elsevier B.V

Erscheinungsjahr

2019

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •The use of CDW as fine aggregate enhances the mortars’ mechanical properties.•Recycled fine aggregate completely replaces sand to produce geopolymer mortars.•Geopolymers can be produced using 75wt.% solid residues.•CDW does not act as binder in the geopolymerization process. This study seeks the valorization of industrial residues (fly ash and construction and demolition waste (CDW)) through the production of geopolymer mortars. The effect of the sand substitution by CDW and the influence of the particle size range of CDW fine aggregates on the fresh and hardened properties of the mortars were evaluated. Geopolymer mortars were produced using biomass fly ash waste and metakaolin as a binder, CDW as fine aggregates, and an alkali solution of sodium silicate and sodium hydroxide as activator. The geopolymer mortars were characterized in fresh state by the flow table test and in the hardened state through chemical, physical/microstructural analyzes. The mortars produced with CDW showed lower flowability when compared to the ones prepared with sand. The compressive and flexural strength of hardened mortars, respectively, obtained with residues were higher when compared to sand: 40MPa and 8.5MPa with CDW, against 23MPa and 3.1MPa for sand-based samples. It was observed that mortars developed with recycled aggregate and natural aggregate present similar chemical and mineralogical compositions. The superior results obtained in the mechanical properties of mortars produced with CDW are related to the recycled aggregate-geopolymer paste interface.