Compósito de cimento alcalino ativado à base de metacaulim com adição de resíduo de casca de café

Abstract

Growing concern about the environmental impact of the production of conventional materials has driven the search for innovative alternatives in the construction industry. Alkali-activated cements (AAC) have emerged as a promising solution due to their mechanical properties and the possibility of reducing dependence on conventional cement. Coffee husk (CC), an agro- industrial waste, has been incorporated into the study as an additive in AACs, with the aim of adding value to this material by exploiting its reactive potential. This study investigated the use of SC in different proportions and grain sizes, combined with metakaolin (MK) and activating solutions of two different molarities of sodium hydroxide (8 and 10 mol/L) in conjunction with sodium silicate. The physical, mechanical, chemical and microstructural properties of the composites were analyzed. Evaluations carried out after 7 days of curing showed that optimized proportions of SC, combined with the appropriate alkaline solution, resulted in mechanical strengths comparable to those of conventional cement. In addition, the presence of potassium in the CC contributed as an additional alkaline activator, intensifying the polymerization reactions. These findings show the potential of FACs based on MK and CC as viable alternatives for structural applications, promoting the use of agro-industrial waste and innovation in the formulation of construction materials.