experimental study on recycled concrete and the impact of waste manufacturing metallic fibers on its mechanical performance

This study investigates the properties of waste steel fiber reinforced recycled concrete (rc-wsf) aiming to develop sustainable concrete using demolition debris and steel fibers from machining chips. the research has two primary. to assess the impact of various percentages of recycled aggregates (ra) as replacements for natural aggregates (na) in conventional concrete and to evaluate the effect of incorporating waste steel fibers (wsf) into recycled concrete mixes. the experimental methodology involved producing and testing standard specimens in two phases: first, evaluating different ra percentages (25%-rc25, 50%-rc50, 75%-rc75) in natural concrete; second, studying the addition of wsf (0.4%, 0.6%, 0.8%) to selected recycled concrete mixes (rc25, rc50) from the initial phase. the tests included compressive and flexural tests with particular attention to the workability of fresh concrete. the results showed that replacing na with ra decreased compressive strength, flexural strength, and young’s modulus. however, for 25% and 50% ra replacements, the reduction in mechanical properties was less than 25% in general. low volume fractions of wsf (< 0.8%) significantly improved the mechanical performance of recycled concrete under compression and increased ductility in flexure. higher wsf content did not lead to further improvements. flexural tests on notched beams showed more than 30% increase in fracture energy for rc25 and rc50 reinforced with 0.4–0.6% wsf. these new results underscore the viability of rc-wsf in promoting sustainable building practices, offering significant insights into the adaptive behavior of recycled concrete and the advantageous roles of waste steel fibers in enhancing structural integrity.