Waste Polyethylene terephthalate flakes modified by gamma rays and its use as aggregate in concrete

Severe environmental problems are generated by the excessive amount of waste Polyethylene Terephthalate (PET). A popular way to reuse it is to recycle as filler material in concrete technology. However, some mechanical properties decrease because of adhesion weakness between cement paste and waste polymers, when they are added. One alternative solution to deal with it is to use the radiation. In this respect, the influences of waste Polyethylene Terephthalate (PET) flakes and gamma radiation on strength, deformation capacity and elasticity modulus of cement based concrete were studied. In production, cement, water, gravel and sand were mixed. The sand was replaced with the PET flakes with 0.71, 1.4, 2.8 mm at 1, 2.5 and 5% in volume. Then, the specimens were subjected to 100, 150 and 200 kGy. Results present higher compressive strength (similar to 34%) and elasticity modulus (similar to 414%) for irradiated concretes when compared with those values obtained for reference specimen. However, deformation decreases about 88%. Such mechanical results were associated with the physicochemical characteristics induced by gamma rays on flakes and cement; which were evaluated by SEM, TGA, DSC and X-ray diffraction (XRD). (C) 2020 Elsevier Ltd. All rights reserved.