Minutes - 19670807 - Laserfiche WebLink

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GS-3 CONCRETE. During the progress of the concrete work, the Contractor shall have a foreman experienced in such work at all times in charge of the work, who shall see that the concrete is properly and carefully mixed and placed as specified, and that the reinforcement, where required, is properly placed according to the plans, and undisturbed. All concrete shall be composed of Portland Cement, sand and broken stone or gravel. All proportions of materials specified shall be by measure, and shall be as directed by the Engineer, so as to produce a plastic. concrete of proper workability. PROPORTIONS: Concrete used in the building of the structures shal be in the approximate proportions given in the table below. All reinforced concrete shall be Class l and all other concrete shall be Class 2. Materials Per Cubic Yard of Concrete MaX. Water Size Cement Gals. Approx. Class Stone e s cement Water Aggre- Ratio Per 3ag -2 ate lbs l 1 1/2" 6.0 0.55 6.2 2 2. 3350 4.4 0.58 6.5 3666 The above table is intended to specifj the amount of cement per cubic yard of concrete and the water cement ratio with aggregate so graded that the mix will produce concrete of the desired workability, density and strength, and that strength on 28 day.test shall be not less than 3000 lbs. per square inch. The contractor shall provide such laboratory control as. to insure the concrete desired. As the work proceeds, the Contractor shall have the mplacedake compressive test for each 100 cu, yards MIXING AND PLACING: The amount of water specified per sack of cement s all include the moisture in the aggregate, which shall be measured by the Contractor by a method approved by the Engineer, and which shall determine accurately the weight of the moisture within 2 pounds per 100 pounds of aggregate. The Engineer may require that proportions be made by weight. Measuring devices whether for weight or volume shall all be made uniform so as to avoid variation,.in quantities determined upon.