Depends upon the concrete.
Siloxane and silane compounds are water repellant pore blockers. Since they enter the pores and obstruct other molecules entry they also help reduce oil staining or paint penetration.
However really good concrete has no pores so they have little effect.
Since they are colourless they are particularly useful on more porous building materials like brickwork or blockwork.
The liquids are somewhat toxic so stringent safety precautions need to be taken on application, particularly indoors.