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<br />03300 - 4/22 <br />mix, a second size range need not be used. Such adjustments will be <br />considered refinements to the mix design and will not be the basis for extra <br />compensation to the CONTRACTOR. Concrete shall conform to the <br />requirements of this Section, whether the aggregate proportions are from the <br />CONTRACTOR's preliminary mix design, or whether the proportions have <br />been adjusted during the trial batch process. The trial batch shall be prepared <br />using the aggregates, cement, and admixture proposed for the project. The <br />trial batch materials shall be of a quantity such that the testing laboratory can <br />obtain 3 drying shrinkage, and 6 compression test specimens from each batch. <br />4. The determination of compressive strength will be made by testing 6-inch <br />diameter by 12-inch high cylinders; made, cured and tested in accordance with <br />ASTM C 31 and ASTM C 39. Three compression test cylinders will be tested <br />at 7 days and 3 at 28 days. The average compressive strength for the 3 <br />cylinders tested at 28 days for any given trial batch shall not be less than 125 <br />percent of the indicated compressive strength. <br />5. A sieve analysis of the combined aggregate for each trial batch shall be <br />performed according to the requirements of ASTM C 136. Values shall be <br />given for percent passing each sieve. <br />C. Field Tests <br />1. The responsibility to retain the services of an independent testing laboratory <br />shall be as defined in SECTION 01410. <br />2. The CONTRACTOR shall pay the cost of any additional tests and investigation <br />on WORK that does not meet the specifications. <br />3. Tests on pumped concrete shall be taken at the point of final placement. <br />4. Compressive Test: <br />a. Compressive test specimens shall be taken during construction from the <br />first placement of each class of concrete placed each day and for each <br />150 cubic yards or fraction thereof each day. <br />b. Each set of test specimens shall consist of 5 cylinders. Specimens shall <br />be made in accordance with ASTM C 31. Specimens shall be 6-inch <br />diameter by 12-inch high cylinders. <br />c. Compression tests shall be performed in accordance with ASTM C 39. <br />Two (2) cylinders shall be broken at 7 days and two (2) at 28 days, and <br />the remaining cylinder shall be held to verify test results, if needed. <br />d. The acceptance of the test results shall be the average of the strengths of <br />the two specimens tested at 28 days as per ACI 318. Evaluation and <br />acceptance of the concrete shall be per ACI 318, Chapter 5. <br />5. Slump Tests: One (1) slump test shall be taken per truckload in accordance <br />with ASTM C 143. <br />6. Air Content: Air content shall be determined for each compressive test taken in <br />accordance with ASTM C 231 or by ASTM C 173. <br />7. Aggregate testing shall be made every 12 months during construction to insure <br />continued compliance with these Specifications. <br />8. Concrete that fails to meet the ACI requirements and these Specifications is <br />subject to removal and replacement.