Properties of concrete replaced with different percentages of recycled aggregates

Abstract

The main objective of this study is to implement ecological and sustainable principles in the design of concrete mixes by partially replacing normal aggregates with recycled aggregates. Different proportions of recycled coarse aggregates were used to produce normal strength concrete mixes with compressive strength of 40 MPa. The percentages of recycled aggregates used were 20%, 40%, 60%, and 100%. In addition, concrete mixes with 100% normal aggregates were prepared to act as benchmark mixes. The tests conducted to verify the mechanical and physical properties of the concrete mixes were compressive strength tests, slump tests, and water permeability tests. Test results indicated that the workability of concrete was either improved or remained unchanged in the early stages of the concrete life due to the usage of recycled aggregates in different ratios of replacement. In addition, using 20 and 40% recycled aggregates resulted in adequate compressive strength compared to normal concrete. On the other hand, the compressive strength drastically reduced when 60 and 100% recycled aggregates were used compared to that with normal aggregates. Finally, the use of recycled aggregates did not impact the concrete ability to resist water penetration.