Influence of cement type and chemical admixtures on the durability of recycled concrete aggregates

This study investigates the effect of replacement of natural aggregates with recycled concrete aggregates on the durability of concrete. Three different combinations of cement and chemical admixtures were considered, and the produced mixtures were assessed for their durability performance. The obtained results show a significant increase in the porosity of the mixtures with increasing in the percentage of recycled sand substitution, whereas the porosity increase was less pronounced for the natural gravel substitution. In addition, increasing the percentage substitution of recycled aggregates results in a decrease in density. However, this decrease is more pronounced in the case of substitution with recycled sand than for recycled gravel. Finally, the diffusion depth of the chloride ions increases with the increase of recycled gravel, regardless of the cement/admixture couple. This rise is less pronounced than in the case of concrete made with recycled sand.