Influence of foundry sand residues on the fresh and hardened properties of mortars produced with Portland cement

Resumen

The foundry sand waste (FSW) derives from moulds used in the metallurgical industries. The present experimental study was developed to evaluate the influence of the use of FSW on concrete properties. The mixtures were produced with cement CPV-ARI-RS, water reducing admixture, FSW, natural and crushed aggregates. The properties on the fresh state were evaluated by means of flow table test and the determination of the air content. On the hardened state, compressive strength tests were performed. The initial results show that the use of FSW leads to an increase in the air content and cracking, caused by expansive reactions. As a result of that, a reduction in the compressive strength was noticed. In order to define the origin of the presented trends, a complementary study was developed using FSW with different compositions. However, regardless the composition of the FSW, the obtained results present trends which are similar to the ones observed previously. Finally, considering the materials herein used, the addition of FSW in concrete is considered inadequate because this leads to a decrease not only in the compressive strength, but also in the durability of the material.