Enhanced mechanical and durability performance of dry mix concrete made with silica-coated aggregates

Abstract

This research work has focused on enhancing the mechanical and durability properties of M40 grade concrete by replacing natural granite coarse aggregates with silica-coated granite aggregates. The mix has been further improved by changing the order of mixing ingredients and by using a mechanically modifying binder. Improvement in the fresh state properties of all the mixes has been observed due to the formation of a lubricating layer over the aggregates as a result of the slurry coating compared to control concrete. Around 48% increase in 28 days’ compressive strength, 47% enhancement in flexural strength and 36% in tensile strength have been observed with the modified formulations. Furthermore, the enhanced formulation lowers the chloride penetration by 20% and water penetration by 80%. The dense interfacial transition zone of scanning electron microscopic images has shown that the use of silica-coated aggregates, along with mechanically modifying the binder and changing the order of mixing, has imparted superior mechanical and durability properties to the concrete compared to conventional methods.