Sir I am working on how we can increase the strengths of concrete by adding admixture and so on. Can you please guide me?

First, you need to specify what is called "Assemble Inputs" including needed compressive strength, materials properties, exposure and so on.

Then, specify the required slump, max aggregate size, water and air content, water to cement ratio, cement content, coarse aggregate content, sand content, then you need to adjust moisture.

And please remember, what written above is how to design the concrete for the required strength. ADMIXTURE IS NOT a panacea for a poor mixture design or  sloppy concrete practice.

Admixture can modify the concrete properties for a better handling, transporting, curing and so on and also to reduce the cost.