A review on the characterization and use of ISF slag as fine aggregate in cement concrete

Abstract

Imperial smelting furnace (ISF) slag is one among many other materials when dumped as such can cause serious environmental damage due to the presence of the heavy metals in it. This article presents a review of the available scientific literature and identifies the current trends and research gap regarding the utilisation of ISF slag in the production of concrete and mortars. Based on this state of the art, it can be concluded that ISF slag can be safely used to replace around 50% of conventionally used fine aggregate for the production of concrete. Such a concrete is both corrosion and acid resistant as well. At 60% utilisation of ISF, the durability parameters of the concrete mixes reduce. However, properties like flexural strength and pull-off strength have been noted to be within acceptable limits. Due to the rough texture of ISF particles, the interfacial transitional zone (ITZ) formed between ISF slag and cement particles is denser and hence the water absorption reduced by 20–25% in mixes with 60% ISF slag. It was also understood that ISF slag’s interaction with cement hydration in delaying the setting and hardening process can be avoided if the slag particles are coarser than 0.3 mm. Additionally, the heavy metals found in ISF slag are effectively bound in the cement matrix, hence protecting the environment from heavy metal contamination. On the negative side, mixes showed reduced resistance to abrasion when ISF slag was used as fine aggregate even at 10% utilisation. Hence from this study it can be concluded that ISF slag can be safely used to replace 50% of fine aggregate to produce durable concrete with appropriate mechanical performance. On such usage, the mining and environmental problems associated with dumping of ISF can be effectively resolved hence making the zinc industry more sustainable.