Feasibility of Modified Sand Made by Using Desert and Recycled Sand in Structural Concrete: An Experimental Research

Abstract Even to date, the excessive mining of natural river sand is an unattempted issue. It is a global problem that impacts the river's ecosystem and the environment. This study has attempted to develop a new technique to modify vacant desert sand to replace 100% natural river sand. A technique is introduced in this study to modify desert sand by adding manufactured and recycled sand separately. Four new concrete mixes were prepared with developed modified sand. Additional four mixes were obtained when 12.5% ordinary Portland cement was replaced with silica fume. A detailed compressive strength was evaluated on 8 prepared mixes at curing ages of 3, 7, 28, 56, 91, and 360 days. The physical properties, such as density, absorption, and porosity, were evaluated at 28 days. The sulphuric acid attack was also studied to evaluate durability at 28, 56, 91, and 120 days. The developed concrete mixes with 12.5% silica fume at all curing phases revealed higher compressive strength than those without. The developed sustainable modified sand with 12.5% silica fume filled the pores and absorbed less water than the samples without silica fume. The modified sand with 12.5% silica fume revealed better density, water absorption, and voids and showed better resistance against 5% sulphuric acid solution than those without silica fume. It is concluded that all newly developed mixes showed satisfactory results. Moreover, the mix of (50% desert sand + 50% recycled sand) and 12.5% silica fume is the best sustainable mix for replacing 100% river sand and 12.5% cement from the concrete industry.