Evaluation of the long-term compressive strength development of the sewage sludge ash/metakaolin–based geopolymer

• Autor(a) principal: Istuque, D. [UNESP]
• Data de Publicação: 2021
• Outros Autores: Soriano, L., Borrachero, M. V., Payá, J., Akasaki, J. L. [UNESP], Melges, J. L.P. [UNESP], Tashima, M. M. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.3989/MC.2021.13220; http://hdl.handle.net/11449/222239
• topic: Alkali-activated cement; Compressive strength; Metakaolin; Mortar; Scanning electron microscopy

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.