Technical Info

Rectangle:

Volume = l x w x h (or d) in Feet
  For Cubic Yards ÷ 27 Cubic Feet

For Example:

A foundation 230 lineal ft. long, 8' high and 10" thick
230' x 8' x (10" ÷ 12 = .833') = 1,532.72
1,532.72 ÷ 27 = 56.77 cubic yards

Flatwork - Driveway 20' long, 12' wide, and 4" thick.
20' x 12' x (4" ÷ 12 = .333') = 79.9 ÷ 27 = 2.96 yards needed

Footing - 230' lineal feet, 20" wide, and 10" thick
230' x (20" ÷ 12 = 1.66') x (10" ÷ 12 = .833') = 318.03 ÷ 27 = 11.7 yards needed

Cylinder:

Volume =  r²h = 0.7854d²h in Feet
  For Cubic yards ÷ by 27 Cubic Feet

For Example:

A sonet tube 28" in diameter, 19' high
.7854 x (28" ÷ 12 = 2.33' x 2.33' = 5.43') x 19' =
81.03 ÷ 27 = 3.00 cubic yards.

If a single gallon of water is added to a cubic yard of properly designed 3000 psi concrete mix.

• The slump is increased about one inch.
• The compression strength is cut by as much as 200 psi.
• The effect of 1/4 sack of cement is wasted.
• The shrinkage potential is increased by 10%.
• The freeze-thaw resistance is decreased by 20%.
• The resistance to attack by de-icer salts is decreased.

As an example of the relationship between temperature and setting time of concrete, let's assume that the concrete sets in approximately 6 hours at 70^oF (21^oC). Here's what might be expected at other temperatures.