Utilização de cinzas de termelétrica na confecção de blocos de concreto para alvenaria

Abstract

Combined with the extensive generation of waste, the construction industry is a vast explorer of the existing natural resources and, consequently, it is seen as one of the main protagonists of the projects deactivated in the environmental context. In this context, the researchers of the area seek to mitigate these impacts through the application of industrial waste in the products used by the sector. Generation of energy in Brazil has as main hydropower criterion, but, among non-renewable sources, thermoelectric companies that use coal as the object of burning have growth potential already established by the Brazilian federal government. In the global context, mineral coal has 41% of energy demand, so study about the waste from thermoelectric power plants is quite pertinent. Two by-products of coal burning were used in the present study, with application pairing of masonry concrete: fly ash as partial replacement of Portland cement and the bottom ash as partial replacement of conventional fine aggregate. The substitutions were carried out in bulk, compensating for the specific mass, in isolation (10%, 20% and 30% of fly ash; 5%, 10% and 15% of bottom ash) and joint (10% fly ash and 5% bottom ash; 20% fly ash and 10% bottom ash; 30% fly ash and 15% bottom ash) for blocks made by vibro pressing, with verification of the consistency in the fresh state of the dry concrete by the modified Vebe consistometer and the axial compressive strength, water absorption and modulus of elasticity in the hardened state. Statistical analysis showed that the influence of the substitutions is notorious in some levels, but in others, there is similarity with the reference blocks and maintenance of the limits established in the pertinent regulations. Thus, environmentally sustainable products were achieved without compromising their physical-mechanical characteristics.