HIGH-COMPRESSIVE-STRENGTH CONCRETE Development of Concrete Mixtures

摘要

The information contained herein constitutes the second report on high-compressive-strength concrete. The first report, a review of the statu of the art, emphasized that a low water-cement ratio with con sequent high cement factor, proper curing conditions, and careful selection of materials would be required to consistently produce high compressive-strength concrete. Approximately 150 mixtures were made in this investigation to study and evaluate the effects of these and other factors, such as the size of test specimen, the size and type of coarse aggregate, the grading of the fine aggregate, the type of cement, and the type and quantity of water-reducing admixture. The results presented in this report indicate that a water-cement ratio of approximately 0.30, by weight, which generally requires the use of 10 bags of Portland cement per cubic yard of concrete, a limestone, quartzite, or traprock coarse aggregate, and continuous moist curing for at least 28 days are required to produce workable concrete with a compressive strength in excess of 10,000 psi at 90 days.