Análise do desempenho mecânico e acústico de blocos vazados de concreto com adição de resíduos de estação de tratamento de água

Abstract

Among the main producers of solid waste stand out the Water Treatment Plants (WTP) and the construction industry. This work aims to evaluate the mechanical and acoustic performances of concrete hollow blocks for sealing with the addition of WTPS (Water Treatment Plant Sludge), as an alternative of appropriate final disposal for the residue. To achieve the objective of this work, the characterization of the raw materials of concrete, cement CP II-F-32, sand, gravel and WTPS was performed, later a base trace was defined for the reference concrete, the granulometry of the residue was chosen and the composite with better mechanical performance and acoustic insulation was selected for the manufacture of hollow concrete blocks. The mass concrete trace, adopted as a reference, was 1: 4.95: 4.05: 0.58 (cement: sand: gravel: water/cement). The concrete composites were produced with 1%, 2%, 3%, 4% and 5% of WTPS in relation to the concrete mass, whose granulometry of this was the pass-through in the sieve of 6.3 mm and retained in the 4.8 mm. Through statistical analyses, it was found that the composites with 3% of WTPS presented mean values of resistance, density and loss of sound transmission higher than the other contents analyzed. Regarding water absorption, it was proved that the different levels of WTPS didn’t influence the water absorption of concrete. For the void indexes, the concrete with 3% obtained a lower percentage compared to 1%, 2%, 4% and 5%. In view of the results presented in this work, concrete hollow blocks were produced with 3% WTPS, since their performance in relation to physical, mechanical and acoustic properties was higher than the others. The blocks with residue were approved in relation to the dimensional analyses, certifying the production with their quality according to NBR 6136 (2016), in addition, the block with 3% of residue presented average resistance (7.01 MPa) 11.09% higher than the reference block. In general, blocks with residue presented lower water absorption and void index than conventional ones, percentages equivalent to 3.96% and 9.66%. The acoustic performance for the loss of average sound transmission of blocks with 3% WTPS was higher than conventional at frequencies from 2000 to 3000 Hz and from 3000 to 3500 Hz. Thus, based on all the tests and analyses developed in this work, it is concluded that the incorporation of WTPS in concrete hollow blocks, without structural purpose, is feasible and positively impacts the environment, besides corroborating for an appropriate destination and applicability of this type of waste.