Assessment of treated recycled concrete aggregates on the properties of recycled-aggregate-self-compacting concrete

Abstract:

To improve the recycled concrete aggregates (RA) quality for using in self-compacting concrete (SCC), the effect of four alternative treatment methods of RA with two sources on the fresh and hardened properties of RA-SCC were evaluated. The result shows that the RA sources and parent concrete strength has great influence on the quality and properties of RA. While after the pretreatment of RA, the RA qualities from different sources are improved and the performance difference of RA-SCC becomes small. The presoaking in the water glass dispersion and cement-fly ash slurry can significantly improve self-consolidating characteristics of fresh RA-SCC. The thermal expansion method, low-concentration acid dissolution method and water glass dispersion method provide denser and connected microstructures leading to the significant improvement in tensile strength, dry shrinkage resistance and frost resistance of RA-SCC. Most enhancement methods have a limited effect on compressive strength and modulus of elasticity.