Avaliação do desempenho do concreto com substituição parcial do cimento portland por cinza da combustão de carvão mineral

Abstract

The large availability of waste generated by the burning of coal at thermoelectric plants in Brazil to the electric power generation presents itself as a good alternative source in place of materials traditionally employed in various segments of the construction industry, and minimizes the damage to the environment. One of the alternatives is the partial replacement of Portland cement in the concrete composition of coal combustion waste. The products generated from burning coal are: the fly ash, bottom ash and slag. This work includes the analysis of the performance of concrete with partial replacement, by volume, of Portland cement by the coal combustion ash - CCCM at different levels (3%, 6% and 9%). Tests were held characterization of gray used, including XRD, XRM, SEM, laser particle size and the determination of the activity index pozzolanic with Portland cement, among others. Tests were carried out in the fresh State in concrete (slump test; specific mass and air content embedded) and hardened State (compressive strength, tensile strength by diametral compression and water absorption to 28 days). The results suggest that the use of CCCM showed satisfactory results in consistence on the fresh state and hardened state in the improvement of the compressive strength in the levels of 6% for a/c 0,45 and 9% for a/c 0,55, increased tensile strength in the level of 6% and decreased water absorption for a/c 0,55.