Footing volume: (1.25 ft)(8.5 ft)(75 ft) =' 96.9 cf
Total volume: 1,720.6 cf- 27 cf/cy = 63.7 cy
Step 2. Since the volume is 200 cubic yards or less, the waste factor is 10 percent.
Total volume + waste = (63.7 cy) (1.10) = 70.1 cy
Step 3. Determine the amounts of cement and aggregates needed.
Cement (7.05 sacks/cy) (70.1 cy)
= 494.2 sacks
Round this value up to 495 sacks since
you cannot order partial sacks.
CA (1,768 lb/cy) (70.1 cy)
= 123,937 lb or 61.9 tons
FA (1,083 lb/cy) (70.1 cy)
= 75,918 lb or 37.9 tons
Step 4. Determine the amount of water required for clean up and mixing.
Water required (495 sacks) (8 gal/sack) = 3,960 gallons
Summary of the amounts of materials to be ordered for the project--
Cement
= 495 sacks
Water
= 3,960 gallons
CA
= 62 tons
FA
= 38 tons
LESSON 2
PRACTICAL PROBLEM
Obtain the preliminary proportions for a one-cubic-yard concrete mix to be used in a reinforced-concrete retaining
wall to be constructed at Fort Leonard Wood, MO. The climate is severe, and a high-speed vibrator with a 250-
cfm air compressor is available. The concrete will be mixed using a M919 concrete mobile mixer, which can
handle a maximum size aggregate of 1 1/2 inches.
Specifications:
Strength at 28 days = 3,000 psi
Cement types available -- I, IA, III
Water available from a potable source
Fine aggregate
FM
SG*
BUW*
Percent Fines
Source A
2.50
2.65
120 lb/cf
4
Source B
2.95
2.60
125 lb/cf
6
2-45
EN5466
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