Interpretation of x-ray images to investigate the viability of incorporating poly (Ethylene-co-vinyl acetate) (eva) waste in portland cement

Abstract

EVA (poly(ethylene-co-vinyl acetate)) is a copolymer widely used in the Brazilian footwear industry, where approximately 18% of the EVA remains as waste, principally after the cutting out of insoles. EVA wastes cannot be recycled or reused for the original purpose, but it may be possible to add them to Portland cement to produce concrete for non-structural applications in constructions. This work presents an analytical technique based on the interpretation of X-ray images to assess the spatial distributions of these wastes within concrete test specimens. Evaluation was made of the feasibility of using this technique to study the incorporation of the wastes. Test specimens of concrete were produced according to Brazilian technical standard ABNT-NBR 5738, using a sand/gravel/cement ratio of 3:2:1, where EVA replaced part of the gravel content (10, 20, 50, and 70% of the total gravel volume). Analysis of front projection X-ray images of the specimens showed that the waste was homogeneously incorporated throughout the entire material, as required for concrete. The results of compressive strength tests showed that for samples containing up to 20% of EVA waste, the compression resistance remained almost unchanged, while incorporation of 50 or 70% of waste led to decreases of up to 64% in the resistance.