Viabilidade de aplicação das cinzas da bacia de resíduos da termelétrica do Pecém no concreto

Abstract

The use of pulverized coal ash to produce energy generates by-products such as fly ash and bottom ash. Coal combustion residues are produced in great quantity and there are many issues related to it. Not only they pollute the environment and are potentially toxic substances, but also have relatively high disposal cost since they must be displaced in protected landfills. The coal ash produced by two power plants in Ceará, Brazil, called Pecém I and Pecém II, was the object of study in this research. A great amount of coal ash was produced during the power plants preliminary tests phase, which are heterogenous due to unstable burning processes in the furnaces. The purpose of this research is to study this residue by improving its quality through grinding until the particle is smaller than 0.15 mm, adding it into the concrete mixture and analyze its technical and environmental feasibility. Six concrete mixtures with different ash percentages and one control mixture were produced and investigated in this research. The w/ag ratio was 0.5 and kept constant in all mixtures, and coal ash replaced cement in volumes of 7.5% and 15%. Some properties of concrete have been determined such as unit weight, particle size distribution, x ray fluorescence, x ray diffraction, loss on ignition, leaching e solubility. The tests conducted in concrete were slump test, compressive strength, water absorption, void ratio, leaching and solubility tests. The results present that concrete mixtures have satisfactory compressive strength development and good environmental performance.