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cementitious content by weight of total cementitious materials when use in combination <br />with silica fume and /or metakaolin. <br />c. As an option for Slightly and Moderately Aggressive environments <br />ensure that there is at least 20% fly ash by weight and 40% Portland cement by weight <br />for mixes containing Portland cement, fly ash and slag. <br />(4) Type IP (MS): Ensure that the quantity of pozzolan in Type IP (MS) is in <br />the range of 15% to 40% by weight. <br />(5) Silica Fume and Metakaolin: <br />a. Cure in accordance with the manufacturer's recommendation and <br />approved by the Engineer. <br />b. Silica Fume - ensure that the quantity of cementitious material <br />replaced with silica fume is 7% to 9% by weight. <br />c. Meta kaolin-ensure that the quantity of cementitious material <br />replaced with metakaolin is 8% to 12% by weight. <br />346 -2.4 Coarse Aggregate Gradation: Produce all concrete using Size No. 57 or <br />Size No. 67 coarse aggregate. With the Engineer's approval, Size No. 8 or Size No. 89 may <br />be used either alone or blended with Size No. 57 or Size No. 67. The Engineer will consider <br />requests for approval of other gradations individually. Submit sufficient statistical data to <br />establish production quality and uniformity of the subject aggregates, and establish the <br />quality and uniformity of the resultant concrete. Furnish aggregate gradations sized larger <br />than nominal maximum size of 1.5 inch [37.5 mm] as two components. Ensure the <br />maximum coarse aggregate size does not violate the reinforcement spacing provisions <br />given for reinforced concrete in the AASHTO Standard Specifications for Highway Bridges. <br />346 -2.5 Admixture Requirements: Admixtures will meet the requirements of this <br />subarticle. Chemical admixtures not covered in this subarticle may be approved by the <br />Engineer. Submit statistical evidence supporting successful laboratory and field trial mixes <br />which demonstrate improved concrete quality or handling characteristics. <br />Do not use admixtures or additives containing calcium chloride (either in the <br />raw materials or introduced during the manufacturing process) in reinforced concrete. <br />346 -2.5.1 Water Reducer /Water Reducer Retardant Admixtures: Use water- <br />reducing admixture, Type A, or water - reducing and retarding admixture, Type D. Use in <br />accordance with the manufacturer's recommended dosage rate. <br />346 -2.5.2 Air Entrainment Admixtures: Use an air entraining admixture in all <br />concrete mixes except counterweight concrete. <br />346 -2.5.3 High Range Water Reducing and Viscosity Modifying Admixtures: <br />346- 2.5.3.1 General: The Contractor may propose the use of a Type <br />F or G admixture, meeting the requirements of Section 924, in all classes of concrete, <br />except for concrete used in drilled shafts. The use of High Range Water Reducing (HRWR) <br />admixtures in concrete mixes incorporating silica fume or metakaolin is mandatory. <br />346- 2.5.3.2 Flowing Concrete Admixtures for Precast /Prestressed <br />Concrete: The Contractor may propose the use of a Type I or Type II admixture, meeting <br />the requirements of Section 924. Produce flowing concrete mix with target slump of 9 <br />inches [230 mm]. The use of flowing concrete admixtures is limited to the construction of <br />precast /prestressed concrete products. Add the flowing concrete admixtures at the ready <br />mixed concrete production batch plant. <br />Submit the proposed flowing concrete mix design, containing <br />Type I or II admixture, and test data as specified herein and in 346 -6.2. <br />March 2007 01000 -90 03- 4122.D <br />