Best concrete mix for slabs

Start with a 4,000 PSI mix in 80 lb bags. For a slab you want a mix rated around 4,000 PSI, poured at least 2 in thick (4 in for anything driven on), and 80 lb bags cut the bag count and mixing time.

• Quikrete Concrete Mix (80 lb) — the default all-purpose slab mix; easy to find and forgiving to work with.
• Sakrete 80 lb Concrete Mix — same job, slightly stiffer slump, good if you're finishing by hand.
• Sakrete Fast-Setting — for small slabs you need to walk on the same day; sets in about 30 minutes, so mix small batches.
• PSI-4000 mix — best value per bag if you're buying a pallet for a bigger pour.

Skip countertop and 10 lb patch bags for a structural slab.