Incorporação de cinzas de caldeira em elementos construtivos a base de concreto

Abstract

Civil construction is one of the industries with the greatest impact on natural resources due to the high consumption of raw materials that, in addition to producing a huge amount of waste, are often deposited irregularly. Thus, one of the particularities of the civil construction industry is the search for new materials and technologies to reduce environmental degradation, the consumption of raw materials and at the same time reduce the costs of the final product. Thus, the objective of this work was to evaluate the incorporation of boiler ashes based on eucalyptus chips in partial replacement of Portland cement for the production of concrete-based constructive elements. Using different concentrations of residues (0%, 5%, 10% and 15%) instead of cement, some tests were carried out to characterize the ash, such as: determination of pH, electrical conductivity, granulometric composition, organic impurities, specific mass and pozzolanic index. Regarding the aggregates, the specific mass and granulometric composition of the fine and coarse aggregates were characterized, in addition to the determination of the organic impurities of the fine aggregate. The evaluation of the fresh state of the concrete and the compressive strength were carried out. In view of the results, it was verified that the incorporation of eucalyptus chip ash directly influences the consistency of the concrete in its fresh state, since its slump decreased proportionally to the incorporated content. The analysis of the pozzolanic index showed that the ash does not have pozzolanic potential. The results of the resistance tests show that the replacement of cement by ash does not provide an increase in resistance.