CHAPTER II, SECTION 1
to undertake physical tests of construction
materials and to assure physical compliance
with specifications. The primary function of the
Field Inspection Section was to assure that all
work performed andall materials used complied
with approved plans and specifications.
The Test Section was composed of a Test
Engineer and from one to three Test Labora-
tory Assistants, depending on the work load.
This staff was responsibile for operating the
Test Laboratory at Elmer for the testing of
such materials as aggregate, cement, concrete,
and other materials requiring control in construction.
Figure 2-5.
Aggregates for concrete mixes were composed of crushed coral rock with the addition of
fine coral beach sand. Past experiences at the
Proving Ground showed coral deposits had wide
variations in their specific gravities and in their
percentages of absorption. The testing of these
two factors and control of mixes were important
in the economical production of 2500 and 3500
psi concrete. Tests, during the REDWING
Operation, of approximately 250 samples bore
out these wide variations as indicated in the
following results.
California Bearing Ratio Test
TEST AND INSPECTION
Operating as a part of the Engineering
Division, the Test and Inspection Department
was divided into two distinct sections: Materials
Testing and Field Inspection. The primary
function of the Materials Testing Section was
A.
ENIWETOK ATOLL
Type of
Aggregate
Unit Weight
Pounds Per
Cubic Foot
(Dry)
Course
Fine
78.5 to 86.5
91.5 to 102.0
B.
Per Cent of
Absorption in
Saturated
Surface
(Dry)
3.76 to 5.4
2.4 to 7.77
Specific Gravity
of Saturated
Fineness Modules
Surface
(Dry)
2.49 to 2.60
—
2.28 to 2.67
2.71 to 3.71
2.60
2.45 to 2.55
—
2.54 to 3.48
BIKINI ATOLL
Course
Fine
81.0 to 85
TT to 91.5
2.10
3.60 to 5.90
SPECIFICATIONS FOR AGGREGATE GRADATION WERE AS FOLLOWS:
Laboratory Sieve
Square Openings
Percentage by
Weight Passing
ow
100
70-100
55-85
50-80
40-70
30-60
20-50
10-30
0-15
1 16”
1"
4”
34"
#4
#10
#40
+200
Page 2-6