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For watertight and chemical resistant concrete with a maximum <br />aggregate size of 1.5 inches, admixtures shall be used to entrain <br />4.5-5.5% of air by volume. Mix designs with a maximum <br />aggregate size of 1 inch shall contain 5-7% air by volume. <br />4.4.3 WATER REDUCING AGENTS <br />Water reducing admixtures may be used at the option of the <br />Contractor only with prior written authorization of the Engineer. <br />4.5 METAL REINFORCEMENT AND ACCESSORIES <br />The Contractor shall supply the reinforcing bars, welded wire fabric, tie <br />wire and bar supports. Reinforcement and accessories shall be free from <br />rust, scale, grease, clay, other coatings, or foreign substance which would <br />reduce the banding qualities. <br />4.5.1 BARS <br />Unless otherwise authorized by the Engineer, all reinforcing bars <br />shall be intermediate grade new billet steel conforming to ASTM <br />Standard A 615, Grade 60. At the discretion of the Engineer, bars <br />requiring special protection against adverse environmental condi- <br />tions shall be epoxy-coated in accordance with ASTM A 775. <br />4.5.2 WELDED WIRE FABRIC <br />All welded wire fabric shall be intermediate grade new billet steel <br />conforming to ASTM A 185. Minimum yield strength for welded <br />wire fabric shall be 60 ksi. At the discretion of the Engineer, <br />galvanizing shall be used to protect welded wire fabric when used <br />in concrete exposed to adverse environmental conditions. <br />4.5.3 TIE WIRE <br />Tie wire for securing reinforcement in place shall be annealed wire <br />of suitable quality no smaller than No. 16 gage. <br />4.5.4 BAR SUPPORTS <br />Supports shall be standard bright basic wires, or reinforcing bars, of <br />sufficient strength to carry the reinforcement they support. Wire <br />sizes and number of supports shall conform to specifications for <br />placing bar supports in the Manual of Standard Practice for Rein- <br />forced Concrete Construction. <br />4.6 CURING AIDS <br />When required by the Drawings, specifications, or Engineer; materials or <br />procedures for curing shall conform to one of the following: Liquid <br />Pigmented curing compounds--ASTM C 309; Waterproof paper--ASTM C <br />171. Other materials or procedures may be used with prior authorization <br />by the Engineer. <br />SPEC B -CONCRETE <br />PAGE 6 <br />