ANSWERS TO PRACTICAL PROBLEM
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
Coarse
aggregate
Type
SG
BUW
MSA*
Percent Fines
Source A
Gravel
2.85
110 lb/cf
2" (-)
0.5
Source B
Gravel
2.60
95 lb/cf
1" (-)
1.0
Source C
Gravel
2.70
103 lb/cf
1/2" (-)
1.3
1.
Select cement type.
a.
Availability
b.
Climate
c.
Specifications
1A
2.
Select aggregates.
a.
Fine aggregate
(1)
Fineness modulus
2.50
(2)
Specific gravity
2.65
(3)
BUW
120 pcf
(4)
Percent fines
4
b.
Coarse aggregate
(1)
Maximum size aggregate allowable for the project:
1/5 x T = 1/5 x 8" = 1 3/5"
1/3 x D = 1/3 x 15" = 5"
3/4 x MCS = 3/4 x 2" = 1 1/2"
MSA for mixing equipment = 1 1/2"
MSA for the project (smallest of above) = 1 1/2"
(2)
Chosen aggregate
Type Gravel (Source B)
MSA l inch
Specific gravity 2.60
Bulk unit weight 95 pcf
Percent fines 1.0
2-29
EN5466
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