Use of Reclaimed Foundry Sand (RFS) as Fine Aggregate in Mortars and Concrete

Annually around 100 MT of sand is expensed by metal casting industries across the world. This results in the generation of huge quantity of used sand often addresses as reclaimed foundry sand or waste foundry sand. This sand is disposed after multiple use. However, similar composition can be seen in disposed RFS and conventional sand. Currently, around 28% of disposed RFS are being used in building construction-related applications, while the rest of material is disposed as landfill, causing impacts on environment and ecological system. Due to lack of availability of Natural Sand, manufactured sand is produced from quarries and is widely used in construction as an alternative to river sand. With extensive mining of granite quarries, cost of M-sand is also escalating. These concerns of availability and cost of basic materials have led the direction towards utilization of recycled/ industrial waste materials. These alternate fine aggregates are silica enriched and inert exhibiting possibilities for partial to complete replacement to sand in making mortar or concrete. In this article, Reclaimed foundry sand (RFS) is used as alternative to conventional fine aggregate. Chemical, mineralogical properties of RFS is explored and compared with M Sand. Micro-structure investigation indicated silica concentration in RFS was of the order 72%. Properties of cementitious products made with partial replacement of M-sand by RFS are also investigated. Use of RFS as a substitute to M-Sand, limited to 20% and 40% in mortar and concrete respectively in comparable strength properties. Shear bond strength of masonry triplets was found ranging between 0.14 and 0.18 MPa for mortars made with 20% replacement of M-sand by RFS.