The increasing amount of waste from the vulcanization industry has become a serious environmental challenge. Even the partial reuse of the steel contained in tires as dispersed reinforcement in the production of new building materials may contribute to reducing the environmental impact of this industry while supporting the principle of sustainable development. In this study, the concrete samples were made of Portland cement, tap water, lightweight perlite aggregates, and steel cord fibers. Two different addition of steel cord fibers (1.3% and 2.6% wt. of concrete, respectively) were used. The samples of lightweight concrete based on perlite aggregate with steel cord fiber addition showed a significant increase in compressive (18-48%), tensile (25-52%), and flexural strength (26-41%). Moreover, higher thermal conductivity and thermal diffusivity were reported after incorporating steel cord fibers into the concrete matrix; however, the specific heat values decreased after these modifications. The highest values of thermal conductivity and thermal diffusivity were obtained for samples modified with a 2.6% addition of steel cord fibers and were equal to 0.912 ± 0.002 W/mK and 0.562 ± 0.002 µm2/s, respectively. Maximum specific heat, on the other hand, was reported for plain concrete (R)-1.678 ± 0.001 MJ/m3 K.
Keywords: fresh mix properties; lightweight concrete; mechanical properties; microscope analysis; perlite aggregate; recycling; steel fiber.