Fig. 5 shows the modulus of elasticity of concretes that were
investigated at 28, 60, and 90 days. The results showed that the
modulus of elasticity of all concretes increased with the increase
of compressive strength. However, the elastic modulus of recycled
aggregate concrete with and without GBA was lower than that of
CON concrete by approximately 19% when the compressive
strengths of both concretes were the same. Some researchers reported
that the recycled aggregate concrete has the modulus of
elasticity lower than that of the conventional concrete by approximately
25–26% [9,29]. The modulus of elasticity of concrete not
only depends on the compressive strength of concrete but also
on the bonding between aggregates and cement pastes also has
significant influenced on the modulus of elasticity of concrete,
especially at the early age of concrete [30]. Therefore, the results
indicated that the use of GBA could not improve the modulus of
elasticity of recycled aggregate concrete.