Estimated Quantity: 500 cubic yards – delivered; 500 cubic yards - City truck. Bid price per cubic yard. The mix shall conform to the following design: The concrete mix design for these items shall conform to the 2024 Iowa Statewide Urban Design and Specifications (SUDAS) Section 7010 and the current City of Davenport Supplemental Specifications to Iowa SUDAS. 1. Compressive Strength not less than 3,000 psi in 72 hours; not less than 4,000 psi in 28 days. 2. Minimum Cement: 660 lbs. per cubic yard. 3. Water/Cement ratio: 0.42 lb./lb. maximum 4. An approved water reducing agent conforming to ASTM C-494 shall be used. 5. The use of calcium chloride accelerator shall not be allowed unless specifically approved by the requesting agency. 6. All Portland Cement Concrete used shall be treated with an air-entraining admixture conforming to ASTM-C260 in proper amounts to obtain 7% +/- 1.5% air entrainment in the final mixture per Iowa SUDAS Section 7010. All ready-mixed concrete shall meet the requirements of the latest ASTM specification for Ready-Mix Concrete, designation C-94. All aggregates incorporated into ready-mix Page 3 of 8 concrete shall conform to IDOT Specifications Section 4115 and Materials I.M. 409, Source Approval for Aggregates. 7. Ready-mix concrete shall be mixed for a minimum of 70 revolutions, at a speed designated by the manufacturer. If upon arrival at the work site the slump of the concrete is less than specified, an additional five (5) gallons of water to bring the slump to within required limits may be injected into the mixer to produce a workable mix. The watercement ratio shall not be exceeded. The drum shall be turned an additional 30 revolutions (more if necessary), at mixing speed, to achieve uniformity.
