Cement production contributes to about 7% of the global CO2 emissions into the atmosphere. As per the Paris agreement there is a need to reduce the amount of emissions into the atmosphere to meet the targets put forth by various countries around the world pertaining to climate change. Many researchers have carried out investigations on replacing the cement completely or partially with different industrial by-products (which are popularly known as supplementary cementitious materials). In this present study, an investigation of experimental work was carried out to find the suitability of fly ash use and micro silica as supplementary cementitious materials. In the present work, cement was partially replaced with fly ash and micro silica as binary and ternary replacements in different proportions by the weight of cement and the optimum proportions were determined. Also, to further enhance the sustainability of concrete, the recycled concrete aggregates were used as natural aggregates fly ash in the concrete. The recycled concrete aggregates were treated by acid treatment technique and were used in the concrete. The M70 grade high-strength concrete mix was considered in this experimental study and was analyzed for compressive, split tensile, flexural strengths at a 28 days curing period. The results of M70 grade concrete with treated recycled aggregates in various replacement levels was compared with conventional concrete mix with natural aggregates. Based on the experimental results, it was concluded that the recycled aggregates with acid treatment technique have shown similar strength properties compared to that of the natural aggregate concrete.