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