Avaliação físico-química de cimentos Portland produzidos no Brasil, via Fluorescência por raios-X e resistência mecânica

Portland cement is the basic component of concrete. X-ray fluorescence spectroscopy is an established analytical technique used in cement plants throughout the world. A comparative study of the elemental constituents presents in Portland cements produced in Brazil was carried out via EDXRF analyses. The main elements identified and quantified in cement samples were Al, Ca, Fe, K, Si, S, Ti, Mn, Zn and Sr. The main components of cement are lime (CaO), silica (SiO 2 ), alumina (Al 2 O 3 ), iron oxide (Fe 2 O 3 ), magnesia (MgO), alkalis (Na 2 O and K 2 O ) and sulfates (SO 3 ). The components C 3 S, C 2 S, C 3 A and C 4 AF were calculated via Bogue’s formula. Mortar with water, cement and sand was produced for each cement brand, and analyses were performed in order to evaluate the mechanical compressive strength. The bodies were broken after curing over the following timeframes: 1, 3, 7, 28 and 91 days. The results from mechanical tests were correlated with the components found in the different cement brands. Our results indicate that initial compressive strength can vary greatly from one brand to another and the values for the Bogue’s potentials show large differences for C 3 S and C 2 S. It was showed by strength tests, how it is possible to predict the behavior of mortars made with these cements. Cements proved to be good for the manufacture of mortars and meet the Brazilian’s specifications.