Avaliação das propriedades do concreto devido à incorporação de lodo de estação de tratamento de água

Abstract

The objective of the present study was to evaluate technically the use of different rates of sludge from a Water Treatment Plant when incorporated to concrete fabrication as partial substitute of fine aggregate, thus decreasing the generation of this environmental pollutant, which is originated by sanitation companies. In the present study, test specimens of concrete containing 5% and 10% of sludge in substitution of sand, with the reference trace of 1:1,69:2,69 to cement, sand and crushed stone were made. The sludge used for concrete production was from a Water Treatment Plant partially responsible for the water treatment of Curitiba, where aluminium sulphate is used as coagulant. Firstly, a physical-chemical characterization of the collected sludge was performed determining the pH, analysing the temperature, turbidity, COD, TS, humidity rate and specific mass. Secondly, the characterisation of the aggregate was made in order to determine the reference trace to the present study; for this reason, tests for particles size, characteristic maximum dimension, fineness module, specific mass, unitary mass and fine material. Posteriorly, test specimens were made with dimensions of (100 x 200) mm and with the respective content of sludge to be incorporated. Considering the results, only sample with 5% of WTS sludge showed satisfactory conditions of resistance and axial compression when compared with the reference concrete with resistance loss of only 1,9 MPa. Therefore, the concrete made with the substitution of 5% of small aggregate may be used for non-structural finality, considering only the mechanical properties of the material because it is not possible to state about its durability.