Specifications include, but are not limited to: A. General Requirements: Air-entrained Portland cement plus an air-entraining admixture, fine and coarse aggregate, and fly ash or water-reducing admixtures – when required. The concrete mix proportions will be determined by the Department of Public Works and will be designed to have a slump of three (3) inches and an air content of between four (4) and seven (7) percent by volume when the concrete contains No. 1 and No. 2 coarse aggregates and between four-point-five (4.5) and eight (8) percent when the concrete contains only No. 1 coarse aggregate. 1. Cement: Cement shall meet the requirements of ASTM Designation C150. 2. Aggregates: Fine and coarse aggregate shall meet the requirements of the current Street Construction Specifications of the City of Milwaukee. 3. Admixtures: a. Air Entrainment: Air-entraining admixtures for concrete shall meet the requirements of ASTM Designation C260. The dosage rate shall be the amount necessary to meet the specified concrete air entrainment. b. Calcium Chloride: Calcium chloride admixture when used as a concrete accelerator shall be added in solution form. The maximum quantity of calcium chloride shall not exceed 2% by weight of the cement in the concrete (3.5 pints of 30% solution per sack of cement). The use of calcium chloride in concrete mixes will not be approved after May 15 and prior to September 15. Calcium chloride shall comply with the requirements of AASHTO Designation M144, Type L. c. Water-Reducing Admixture: Water-reducing admixtures shall meet the requirements of AASHTO Designation M194, Type A. Water-reducing retarding admixtures shall meet the requirements of AASHTO Designation M194, Type D. The specific type of admixture and rate of use will be determined on the basis of the atmospheric conditions, desired properties of the finished concrete and the manufacturer’s recommended rates to meet the requirements of AASHTO Designation M194.
