Environmentally Friendly Concrete Block Production: Valorization of Civil Construction and Chemical Industry Waste

Abstract In the present work, a study was carried out on the dosage of wastes from civil construction (concrete and plaster) and chemical industry (tannery sludge) in mixtures for the production of concrete blocks. The characterization of the materials used was performed employing X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The influence of the different residues in the blocks properties was evaluated from the tests of compressive strength, traction in bending, water absorption and leaching test. The results indicated that the concrete blocks produced for paving with addition of residues did not obtain gains in the values of mechanical resistance to compression and traction in bending when compared with blocks made with standard raw material. However, the blocks produced with construction waste obtained satisfactory results for use in street paving after 7 days of concrete curing, reaching values between 36.54 MPa and 44.6 MPa for the mentioned properties. It was also observed that these values increase to 21.4% within 28 days of cure. The blocks produced with plaster showed values between 37.03MPa and 39.85MPa after 28 days of curing, allowing their use for paving streets. On the other hand, the blocks produced with residues from the chemical industry had lower strengths, reaching a maximum power of 29.36MPa after 28 days of curing. In addition, it was also noted that the blocks produced with recycled concrete showed an improvement in performance with a recycled quantity 50%.