Worn out car tires and plastic from food wrappings constitute a problematic waste. They pollute the environment and management of such waste is important both ecologically and economically as it protects the environment, and reduces the costs of acquiring components to produce different materials. In this article, the results of testing modified concrete are shown. The concrete was modified with a mixture of supplements in the form of the pre-mentioned materials. The car tires provided, upon processing, rubber granules SBR of the following fractions: 0÷1 mm, 0.8÷2 mm, 2÷4 mm. Plastics of polyethylene terephthalate were used in the form of PET flakes. Six concrete series were generated where 10% of the cement mass was replaced with the supplement mixture. Tests of the texture and compression strength of a modified concrete mixture were conducted after 7, 14, and 28 days. All the series of concrete shared satisfactory homogeneousness of decomposition in the particular components. The strength tests proved that the application of rubber granules SBR and PET flakes in the form of a supplement mixture obtains a concrete strength of about 40 MPa.