This work presents about the determination of the mechanical properties (compression, split tensile and flexural tests) of the specimens (cubes, cylinders, and beams). The specimens are of M60 grade high strength concrete which includes ground granulated blast furnace slag (10 %, 20 %, 30 % and 40%) and Fly ash (10 %, 20 %, 30 % and 40%) to obtain the desired strengths and properties. Finally, we used in combination of fly ash and ground granulated blast furnace slag in different percentages as replacement of cement and concrete was prepared. We used SP430-Sulphonated Naphthalene Polymers as a superplasticizer for better workability for high-performance concrete. Dosage for superplasticizers is same for all mix proportions. We cast concrete cubes, beams, and cylinders and are kept for curing for a period of 28days. The tests are conducted after 7, 14 and 28 days of curing period. To obtain such desired strength that cannot be obtained from conventional concrete and by the current method, a large number of trial mixes with different percentages of fly ash and different percentages of ground granulated blast furnace slag are required to select the desired combination of materials that meet the required strength.