114 Section 2 Construction Materials
Estimating Volume
Ready-mix concrete is a type of concrete that is produced in a factory,
using carefully controlled proportions of Portland cement, aggregate, and
water to meet the specifications of the job. It is delivered to the work site in a
transit-mix truck. It is sold by the cubic yard, Figure 6-11. But form dimen-
sions are typically measured in feet and inches. Use the following formula
to calculate cubic yards when all dimensions are given in feet. Convert any
dimensions given in inches to feet before entering the numbers into this
formula.
thickness (feet) × width (feet) × length (feet)
= _____ cubic yards
27 ft.3/yd.3
Assume a concrete wall is being made that measures 6″ thick, 8′ tall,
and 56′ 9″ long. The first step is to convert all given dimensions from inches
to their equivalent in feet: 6″ = 0.5′ and 56′ 9″ = 56.75′. Now enter the dimen-
sions into the formula:
0.5′ × 8′ × 56.75′ = 227 cubic feet
= 8.4 cubic yards
27 ft.3/yd.3 27 ft.3/yd.3
S a f e t y Ti p
Wet concrete is highly alkaline and can cause chemical burns. Avoid contact
with the skin and eyes. Use waterproof gloves, kneepads, and boots. Safety
glasses or goggles are also highly desirable. If wet concrete comes in contact
with the skin, wash the area thoroughly.
Dry Portland cement is a very fine powder and should not be inhaled. Use a
dust mist respirator when working with this material.
cubic yard: A volume
measurement equal
to 27 cubic feet.
3′
3′
3′
1′
1′
1′
1′
1′
1′
1′
1′
1′
Figure 6-11. A cubic yard is 3′ × 3′ × 3′ or 27 cubic feet.