| Resumo : |
Portland cement is a comprehensive material in the construction medium with various purposes, such as reinforced concrete. However, several factors in the production of Portland cement demand high energy expenditure and CO2 emissions, from the extraction of raw materials to the final production of Portland cement. Therefore, research in search of alternative methods and materials that can reduce not only the abusive extraction of raw materials, but also the reduction of environmental impacts generated in the production of Portland cement are extremely important. One way to achieve this objective would be the use of alkaline-activated binders (AAA), which are materials composed of a solid precursor and an alkaline activator, which, when reacted, have a hardened form like cement. This study seeks to analyze the properties of wood residue ash (WRM) rich in silicon, calcined at different temperatures (600, 75 and 900 °C) as a solid precursor with the use of sodium hydroxide (NaOH) as an alkaline activator in solution with water at different concentrations. Micro and macrostructural analyzes were carried out with traces varying between the CRM calcination temperature, Na+ concentration (6.5; 8; 9.5; 11 and 12.5 mol.kg-1), and low curing temperature ( 25°C) and high (60, 75 and 90°C) temperatures. Macrostructural studies based on chemical compression and retraction, on the other hand, for microstructural studies, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that using calcined wood residue ash (CRMC) with NaOH provides the formation of hydrated sodium silicate products (N-S-H), however, when using low Na+ concentrations and low ash calcination temperatures offer better properties for AAA, so that high concentrations of NaOH result in the extensive formation of porous structures of sodium carbonate (NaCO3), which reduces the mechanical strength of this AAA. |