Ecological bricks from dimension stone waste and polyester resin

•A new ecological brick was developed with good thermal stability.•The resistance of the brick was 350% higher than that established by NBR 8492.•The new ecological brick was developed with a fire resistance.•In the water absorption test the brick had a lower value than specified in NBR 8492. In this work, the viability of using dimension stone (limestone) waste by mixing them with polyester resin to produce a new type of ecological brick, in the model of soil-cement bricks, was tested. First, limestone waste were characterized by infrared spectroscopy (FTIR), thermogravimetry/derivative thermogravimetry analysis (TG/DTG), X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF) and scanning electron microscopy (SEM). Second, the polyester resin was analyzed by FTIR and TG/DTG. Then the materials were mixed manually in a plastic beaker with the aid of a glass stick, and the limestone/polyester composites were compounded in ratios of 70/30, 80/20, 85/15 and 90/10 (weight percentage). The amount of curing agent (methyl ethyl ketone peroxide, MEKP) used for each composition was 0.6, 0.4, 0.3 and 0.2 mL, respectively. After the mixing step, the specimens were cylindrically shaped for the compression test (ASTM D695). The 70/30 composite presented the highest compressive strength, with a value of approximately 54 MPa, followed by 80/20, 85/15 and 90/10. The 90/10 composite, despite presenting a lower result than the other composites, achieved the value required by the standard at 600%, and its use will imply a lower cost due to the use of only 10% resin, plus the benefit of 90% waste no longer discarded in the environment. Due to these factors, the 90/10 composite was selected to be produced in real scale (prototype) and properly characterized. The bricks thus obtained were submitted to tests of compression (NBR 8492), water absorption (NBR 8492), TG/DTG and flammability (ASTM D635). The compressive strength of the limestone/polyester (90/10) brick was 280% and 350% higher when compared to the soil-cement brick and to the requirements for building bricks, respectively. The mean value of water absorption for the soil-cement brick was approximately 16.3%, close to the limit required by the standard (20%). In contrast, the value for the limestone/polyester (90/10) ecological brick was only 4%. The flammability test results showed that pure polyester resin has a tendency to propagate flames, but in the limestone/polyester (90/10) ecological brick, no propagat