Compressed earth blocks stabilized with glass waste and fly ash activated with a recycled alkaline cleaning solution

• Autor(a) principal: Rivera, Jhonathan
• Data de Publicação: 2021
• Outros Autores: Coelho, João Diogo, Silva, Rui André Martins, Miranda, Tiago F. S., Castro, Fernando, Cristelo, Nuno
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/69549
• topic: Alkali activated cements; Earth construction; Glass waste; Soil stabilisation; Sustainability; Science & Technology

Sustainable alternatives are increasingly demanded as a sound response, from the construction industry, to the worldwide growing concerns with the environment. Such effort is justifiable by the degree of the contribution of this human activity to the problem, and it has thus propelled the development of a major trend in terms of funded research. The study reported in this paper focused on the physical-mechanical properties of compacted earth blocks formed by a common Portuguese silty clay (as the mineral skeleton), stabilized with a sustainable alkali activated cement exclusively produced from wastes and residues, including coal fly ash and glass waste, in a 50/50 wt ratio combination, and activated with an alkaline solution from the aluminium industry, using activator/precursor weight ratios of 0.50, 0.57 and 0.75. After optimising the alkaline activated cement (AAC), the AAC/Soil blocks were fabricated, using the response surface method to define their composition based on curing periods of 28 and 180 days at controlled ambient temperature. Uniaxial compressive strength (UCS) and several durability tests were performed, and the material was characterised using FTIR and SEM. The results evidenced the effectiveness of the alkaline cementing agent in forming a binding matrix for the soil particles. An average compressive strength of 17.23 MPa, in unsaturated conditions, was obtained for the blocks. The newly formed soil-binder structure was very capable to withstand wetting and drying cycles, ice-thaw cycles and erosion. The microstructure of the material was further analysed, using scanning electron microscopy and energy dispersive spectroscopy. The results demonstrated the real possibility of using this type of cement as a viable alternative to traditional soil stabilisation binders used in earth construction.