Hi, does anyone know where and what to buy for sealing the exposed concrete driveway? My driveway looks dull and has some streaks of yellowish stuff (sand/mud) even after I washed it with pressure washer. During washing, a lot of the yellowish dirt comes off.

I am thinking of washing it again with the driveway detergent but I doubt it would help much. I think I need to seal it with some kind of sealant but have no idea of what product to use and where to get it. If anyone could tell me how to do it and where to get the stuff (especially in Calgary), I would greatly appreciate it. Thanks.