USING ABSOLUTE VOLUME METHOD (EXAMPLE)
For a retaining wall, determine the mix proportions using the following specifications and conditions:
Required 28-day compressive strength (f'c)
= 3,000 psi
Maximum size aggregate
= 3/4-inch
Exposure condition
= moderate freeze-thaw exposure;
exposed to air
FM of fine aggregate
= 2.70
Specific gravity of portland cement
= 3.15
Specific gravity of fine aggregate
= 2.66
Specific gravity of coarse aggregate
= 2.61
Dry-rodded unit weight (DRUW) of coarse aggregate
= 104 lb/cf
DRUW of fine aggregate
= 103 lb/cf
Slump
= 3 inches
Cement
= Type IA
Estimate Air Content
Refer to Table 1-5, page 1-18.
Aggregate size = 3/4
Air-entrained concrete
Moderate exposure
Air content = 5 percent
Estimate Mixing-Water Content
Refer to Table 1-5.
Slump = 3 inches
Aggregate size = 3/4
Air-entrained concrete
Mixing water = 305 lb/cy
Determine Water/Cement Ratio
Check w/c ratios for strength, durability, and watertightness.
Strength.
Mix design strength = 3,000 psi
Specified compressive strength
Design strength (psi) = 3,000; w/c ratio (Table 2-2, page 2-4) = 0.46
EN5466
2-16
Previous Page
