Mechanical properties of recycled concrete made with different types of coarse aggregate

- Mechanical properties test for two types of recycled coarse aggregate concrete were performed and the the results were discussed.
- Equations of relationships between the compressive strength and flexural strength of recycled aggregate concrete were presented.
- Expressions of stress-strain curves for recycled coarse aggregate concrete were proposed.

One of the most important issues that determine many properties are the types of coarse aggregate in recycled concrete. This paper is arming to experimental study the influence of two different types of coarse aggregate (recycled crushed rock aggregate and recycled pebbles aggregate) on the mechanical properties of recycled concrete. The properties of these two types of recycled coarse aggregate (RCA) derived from waste concrete were investigated. Using these RCA and corresponding types of natural coarse aggregates, recycled concrete specimens according to different replacement percentage were produced and tested. Finally, Analysis and comparisons of the mechanical properties of RAC, including compressive strength, flexural strength, elastic modulus and Poisson's ratios etc., were made between these recycled concretes. The results show that different types of RCA have significant variance in mechanical properties. The recycled concrete containing crushed rock aggregate presents a lower relative strength and elastic modulus than that containing pebble aggregate while the toughness of them is contrary. The theoretical expression for stress-strain relationship and equations for the relationships between various strength of recycled concrete with each type of coarse aggregate are also presented.