Open AccessEvaluation of the long-term compressive strength development of the sewage sludge ash/metakaolin-based geopolymer
Author(s) -
Danilo Bordan Istuque,
Lourdes Soriano,
M.V. Borrachero,
J. Payá,
Jorge Luís Akasaki,
José Luiz Pinheiro Melges,
Mauro M. Tashima
Publication year - 2021
Publication title -
materiales de construcción
Language(s) - English
Resource type - Journals
eISSN - 1988-3226
pISSN - 0465-2746
DOI - 10.3989/mc.2021.13220
Subject(s) - metakaolin , compressive strength , geopolymer , materials science , microstructure , curing (chemistry) , mortar , composite material , fly ash
This paper aimed to evaluate the long-term compressive strength development of the sewage sludge ash/metakaolin (SSA/MK)-based geopolymer. SSA/MK-based geopolymeric mortars and pastes were produced at 25ºC with different SSA contents (0 - 30 wt.%). Compressive strength tests were run within the 3-720 curing days range. A physicochemical characterisation (X-ray diffraction and scanning electron microscopy) was performed in geopolymeric pastes. All the geopolymeric mortars presented a compressive strength gain with curing time. The mortars with all the SSA evaluated contents (10, 20, 30 wt.%) developed a compressive strength over 40 MPa after 720 curing days at 25ºC. The maximum compressive strength of the mortars with SSA was approximately 61 MPa (10 wt.% of SSA), similarly to the reference mortar (100% MK-based geopolymer). The microstructure analyses showed that the SSA/MK-based geopolymer presented a dense microstructure with N-A-S-H gel formation.