Concrete Mix Ratios
Suggested
Concrete Mix Ratios: The strength of concrete varies
with the amount of cement and water in each yard. Trailered
Ready-mix concrete is not rated by pounds per square inch (PSI)
strength, but by the amount of cement sacks in each yard. The
following information represents a rule of thumb for trailered
ready-mix strengths and suggested uses.
Fence Posts: 4-sack mix (four 94# bags of cement per yard): This mixture has a PSI of between 200011 and 250011 and is recommended for things like setting fence posts.
Foot Traffic: 5-sack mix (five 9411 bags): PSI of between 2500# and 3000# and is recommended for things like walking surfaces such as sidewalks.
Auto Traffic: 6-sack mix (six 94# bags): PSI of between 300011 and 350011 and is recommended for things like driving surfaces such as driveways.
Cold Climate Tip: In areas of multiple freeze/thaw cycles, there should be 1 sack of cement added to each of these recommendations.