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I I I I I I I I I I I I I I I I I I I cementitious content by weight of total cementitious materials when use in combination with silica fume and/or metakaolin. c. As an option for Slightly and Moderately Aggressive environments ensure that there is at least 20% fly ash by weight and 40% Portland cement by weight for mixes containing Portland cement, fly ash and slag. (4) Type IP (MS): Ensure that the quantity of pozzolan in Type IP (MS) is in the range of 15% to 40% by weight. (5) Silica Fume and Metakaolin: a. Cure in accordance with the manufacturer's recommendation and approved by the Engineer. b. Silica Fume-ensure that the quantity of cementitious material replaced with silica fume is 7% to 9% by weight. c. Metakaolin-ensure that the quantity of cementitious material replaced with meta kaolin is 8% to 12% by weight. 346-2.4 Coarse Aggregate Gradation: Produce all concrete using Size No. 57 or Size No. 67 coarse aggregate. With the Engineer's approval, Size No.8 or Size No. 89 may be used either alone or blended with Size No. 57 or Size No. 67. The Engineer will consider requests for approval of other gradations individually. Submit sufficient statistical data to establish production quality and uniformity of the subject aggregates, and establish the quality and uniformity of the resultant concrete. Furnish aggregate gradations sized larger than nominal maximum size of 1.5 inch [37.5 mm] as two components. Ensure the maximum coarse aggregate size does not violate the reinforcement spacing provisions given for reinforced concrete in the AASHTO Standard Specifications for Highway Bridges. 346-2.5 Admixture Requirements: Admixtures will meet the requirements of this subarticle. Chemical admixtures not covered in this subarticle may be approved by the Engineer. Submit statistical evidence supporting successful laboratory and field trial mixes which demonstrate improved concrete quality or handling characteristics. Do not use admixtures or additives containing calcium chloride (either in the raw materials or introduced during the manufacturing process) in reinforced concrete. 346-2.5.1 Water Reducer/Water Reducer Retardant Admixtures: Use water- reducing admixture, Type A, or water-reducing and retarding admixture, Type D. Use in accordance with the manufacturer's recommended dosage rate. 346-2.5.2 Air Entrainment Admixtures: Use an air entraining admixture in all concrete mixes except counterweight concrete. 346-2.5.3 High Range Water Reducing and Viscosity Modifying Admixtures: 346-2.5.3.1 General: The Contractor may propose the use of a Type F or G admixture, meeting the requirements of Section 924, in all classes of concrete, except for concrete used in drilled shafts. The use of High Range Water Reducing (HRWR) admixtures in concrete mixes incorporating silica fume or metakaolin is mandatory. 346-2.5.3.2 Flowing Concrete Admixtures for Precast/Prestressed Concrete: The Contractor may propose the use of a Type I or Type II admixture, meeting the requirements of Section 924. Produce flowing concrete mix with target slump of 9 inches [230 mm]. The use of flowing concrete admixtures is limited to the construction of precast/prestressed concrete products. Add the flowing concrete admixtures at the ready mixed concrete production batch plant. Submit the proposed flowing concrete mix design, containing Type I or II admixture, and test data as specified herein and in 346-6.2. March 2007 01000-90 03-4122.0