Mechanical properties of the concrete containing recycled fibers and aggregates

Mixed Recycled Aggregates (MRA) is a mixture of recycled concrete and masonry materials. These kinds of aggregates have lower strength and higher water absorption than natural aggregates. Therefore, the concrete with recycled aggregates has lower strength than the concrete with natural aggregates. Using the steel fibers recovered from waste tires in the concrete with recycled aggregates improves the mechanical properties of this concrete as well as solving the environmental problem of these waste steel wires. In this study, the effect of recycled steel fibers on the mechanical properties of normal concrete and the concrete with recycled aggregate are investigated. Additionally, the effect of fibers on the reduction of concrete pavement thickness is studied. The replacement percentage of natural coarse aggregates with these aggregates is 0, 50 and 100%, with fiber percentage being 0.5 and 1% of concrete volume. Main results indicate that by adding recycled fibers into the concrete with recycled aggregates lead to the production of structural concrete by 50% replacement of aggregates. Moreover, adding recycled fibers by 0.5 and 1% of concrete volume reduces the thickness of concrete pavement for the amount of 8 and 16%, respectively.