Mechanical and physical properties of eco-friendly recycled plastic concrete (RPC)

In this research, an Eco-friendly Recycled Plastic Concrete (RPC) having good workability, low density, thermal isolation characteristics, and can be used in structural applications has been engineered. One reference mixture in addition to nine RPC mixtures were studied, where the plastic granules were used as a partial replacement of sand and/or gravel by volume. The studied parameters were the replacement ratios of fine and coarse aggregates by plastic granules; the replacement ratios were: 1) 100, 80, and 60 % from sand; 2) 50, 40, and 30 % from gravel; and 3) 100, 80, and 60 % from sand simultaneous with 30 % from gravel. The effect of incorporating plastic on the physical, mechanical, and thermal properties of the newly developed RPC mixtures have been investigated experimentally via thirty concrete standard cubes (150 x 150 x 150 mm), thirty concrete standard cylinders (150 x 300 mm), and 30 S-shape prisms. A statistical analysis on the test results was carried out using commercial software to determine the optimum proportions of the studied RPC mixtures. The criteria were to maximize the required strengths and to minimize the required density and thermal conductivity. The conducted optimum sand/gravel replacement ratios were 30 % for sand and 80 % for gravel, which were similar to the replacement ratios of Mixture 8 in the current research. This optimum mixture has a unit weight of 1900 kg/m3 and a compressive strength of 27.7 MPa, which were found to meet the limits of structural light weight concrete according to ACI 213R-14 and supports both structural and environmental benefits.