J. E. F. Nascimento.; NASCIMENTO, J. E. F.; http://lattes.cnpq.br/4847030348850402; NASCIMENTO, Jônatas Elim Maciel Frutuoso do.
Résumé:
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.
