Sustainable Utilization of Dumped Concrete Wastes as Fine Aggregates in Concrete – An Experimental Study

Dumped construction waste (municipal solid waste) is a major threat to the environment in recent times due to its abundance in generation resulting from increased construction activities. Perhaps, the scarcity of construction materials is also alarming due to urbanization necessitating an alternative suitable material. Concerning the above complications, this research encompasses the sustainable use of concrete fractions of the construction waste as a suitable replacement for natural fine aggregate (NFA) termed fine recycled aggregate (FRA). However, the use of FRA disrupts the concrete properties due to a weak interfacial transition zone (ITZ) ensuing from the adherence of cement particles and finer dust particles. This study investigates the effective utilization of FRA through the mortar mixing approach (MMA) technique with varying percentages of FRA. The optimum proportion of FRA as a substitute to NFA was observed to be 30%, with an increase in the concrete strength by 7.85%, while it decreased by 23.5% with 100% of FRA at 28 days. Through MMA, the strength of concrete was increased by 9.93%, while it is decreased by 19.45% with 100% of FRA at 28 days. The stiff concrete matrix developed as a result of MMA tends to strengthen the ITZ and improve the strength of concrete.