Cinza de biomassa rica em calcário como material carbonático em sistemas cimentícios de base Porthand.

Abstract

The use of alternative materials, in place of clinker, for the production of Portland cement has been extensively studied in order to reduce costs and minimize environmental damage. Biomass combustion processes for energy and / or heat generation produce ashes as a by-product, these ashes are rich in calcium, silica or silica-alumina compounds. The present work has the objective of investigating the influence of the use of the Algaroba ash (Prosopis Juliflora), rich material in calcium carbonate, in the mechanisms of hydration and formation of the main hydrated phases of Portland cement. Compositions with 5%, 10%, 15%, 20% and 40% of Algaroba ash were analyzed and compared to laboratory cement with 20% and 40% filler and commercial Portland cement with limestone filler (6-10% ), CPII-F. The physical and chemical characteristics of the raw materials were evaluated by specific surface area tests, real density by helium gas pycnometry, particle size distribution, X-ray diffraction, X-ray fluorescence, thermogravimetric analysis and scanning electron microscopy. The results evidenced the use of Algaroba ash as a potential alternative filler potential for application in the Portland based cement systems, this one showed predominance of compounds with calcium, CaCO3, alkali content within the standard, refined granulometry, high specific surface area, low density and absence of expansive oxides. In terms of chemical reactivity in the cement system, the standard hydrated compounds were identified for Portland cement in the cementitious systems with addition of ash, also acting on the influence of the formation of the carboaluminate phase. It was also observed that the alternative filler from the Algaroba ash acted similarly to the limestone filler in terms of C-S-H phase nucleation, ettringite stabilization and tendency to the formation of carboaluminates.