Uso de cinza de casca de arroz para obtenção de blocos de concreto para pavimentação

Abstract

Considering the importance of recycling agricultural waste, such as the one originated from the utilization of the rice husk as source of energy, the rice husk ashes (RHA), in this study it was researched the use of RHA on the production of concrete blocks for pavements, seeking to obtain an alternative product for companies of the branch. The ash used had its origin in the burning of the rice husk at a temperature of 550ºC and it was characterized concerning moisture levels, carbon levels and granulometry. Due to its granulometry, the RHA was inserted in substitution to the medium thick sand, in the percentages of 5% and 10%, in mass. In search for reality in production, the concrete blocks with and without the RHA were made by a company of such branch, existing in Pelotas, RS, and they were tested regarding water absorption levels, void ratio, mechanical resistance to compression and abrasion resistance. Besides that, it was also verified the effects of adding RHA on the final tonality of the block, aiming the possibility of reducing the use of inorganic dye (pigments) and a possible cost reduction of this aspect. The result showed to be possible to attain blocks with RHA with the proposed quantities, but only the blocks with 5% replacement met the ABNT NBR 9781:2013 requirements.