Reviewing the properties of recycled concrete aggregates and iron slag in concrete

The demand for concrete has increased manifolds due to rapid urbanization and development across the globe. Natural fine aggregates (NFA) and natural coarse aggregates (NCA) constitute the majority of the volume of concrete and are mined from natural resources that lead to a massive impact on the planet. Concern about protecting and preserving natural resources has driven many researchers to work on innovative materials that can replace conventional aggregates without compromising the performance of concrete. Construction and Demolition (C&D) waste can be processed and upcycled to recycled concrete aggregate (RCA) and can successfully replace NCA. Iron slag (IS) is another by-product of the iron industry which is non-biodegradable and causes land abuse. IS has a particle size similar to NFA and can be an efficacious alternative to it. Many investigations have been conducted in the recent past to examine the effect of RCA and IS on concrete and support their use as NCA and NFA replacements respectively. The present article critically reviews the most of the available literature that investigates the influence of the RCA and IS on various properties (such as fresh, mechanical, durability and microstructural properties) of concrete. Also, the present state of art review, is an attempt to provide a single-valued source that summarizes the generalized trends, findings, research gaps, and future scope and potential of the iron slag and RCA based concrete. It has been inferred that use of RCA and IS up to precise level has successfully match with properties of conventional concrete.