EFFECT OF THE SUBSTITUTION OF NATURAL AGGREGATE IN CONCRETE WITH RECYCLED AGGREGATES

ABSTRACT

This work intends to evaluate the (mechanical and durability) performance of concrete made with coarse recycled concrete aggregates (CRCA) obtained using crushing processes: primary crushing (PC).This analysis intends to select the most efficient production process of recycled aggregates (RA). The RA used here resulted from laboratory-made concrete (L). The evaluation of concrete was made with the following tests: compressive strength; Slump Test; Sieve Analysis Test; and water absorption by immersion. These findings contribute to a solid and innovative basis that allows the precasting industry to use without restrictions the waste it generates. On top of that, methods for improving RAC mechanical properties and long-term performance were summarized and categorized into three groups, i.e. (1) Reduction of recycled aggregate porosity (2) Reduction of old mortar layer on recycled aggregate surface, and (3) Property improvement without recycled aggregate modification (i.e. different concrete mixing design and addition of fiber reinforcement) Finally, future perspectives of RAC research focus was discussed, i.e. development of “green” treatment methods on recycled aggregates, further direction on nanoparticle application in RAC, and the establishment of database for RAC strength prediction.