Concrete Mix Design Reference Chart (PSI by Application)

Concrete Mix Design by Application

PSI (pounds per square inch) is the compressive strength of cured concrete at 28 days. Using the wrong PSI is a code violation and a liability.

PSI Reference Table

Application	Min PSI	Notes
Sidewalks, patios	2,500	Most residential flatwork
Driveways	3,000	Must resist vehicle loads
Garage floors	3,000-3,500	Oil and chemical exposure
Structural slabs	3,500-4,000	Engineer typically specifies
Foundations	3,000-4,000	Check local code
High-strength structural	5,000+	Commercial, bridges

Water-Cement Ratio

Lower water-cement ratio = stronger concrete. Never add extra water at the job site to make a mix more workable. Use a plasticizer (water reducer) instead.

Air Entrainment

In freeze-thaw climates, specify air-entrained concrete for all exterior flatwork. 5 to 7% air content is standard.