| Resumo : |
Concrete is the second most consumed material in the world; only water is consumed more than concrete. Therefore, several studies have searched for sustainable alternatives to reduce its use. Among these alternatives are the alkaliactivated binders, which it is generated from a mixture between a solid precursor and an alkaline activator. The alkaline activator tends to be an industrial product and hazardous to humans. Thus, there is the need to search for new activators. In this context, the present study aims to use the ash of the coffee husk as an alkaline activator, dividing the study into two works: the first is the production and the viability of the ash, and the second part aims the mechanical properties and microstructure of alkali-activated binders. In both works, it was possible to observe that the CHA is a material with high pH and solubility, and it is composed mainly by potassium carbonate and its optimum production temperature was 700 ºC. It was also observed in both works that the product formed when the ash is applied together with the blast-furnace slag is extremely homogeneous, dense, plane and composed mainly by calcite. It can be observed that the mortar formed by this mixture tends to gain strength with time and with the addition of CHA and the addition of 15% was the one that obtained the highest strength, being 40.9 MPa after 28 days. In addition, it was noted that the behavior and strength, when CHA is used, is very similar to that of industrial potassium carbonate. |