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• In addition to the requirements specified herein, epoxy-coated seven-wire prestressing steel strand shall be grit <br /> impregnated and filled in conformance with the requirements in ASTM Designation:-A 882/A 882M,including Supplement <br /> I,and the following: <br /> A. The coating material shall be on the Department's list of approved coating materials for epoxy-coated strand, <br /> available from the Transportation Laboratory. <br /> B. The film thickness of the coating after curing shall be 381 µm to 1143 µm. <br /> C. Prior to coating the strand, the Contractor shall furnish to the Transportation Laboratory a representative 230-g <br /> sample from each batch of epoxy coating material to be used. Each sample shall be packaged in an airtight <br /> container identified with the manufacturer's name and batch number. <br /> D. Prior to use of the epoxy-coated strand in the work, written certifications referenced in ASTM Designation: <br /> A 882/A 882M, including a representative load-elongation curve for each size and grade of strand to be used and a <br /> copy of the quality control tests performed by the manufacturer,shall be furnished to the Engineer. <br /> E. In addition to the requirements in Section 50-1.10, "Samples for Testing," four 1.5-m long samples of coated strand <br /> and one 1.5-m long sample of uncoated strand of each size and reel shall be furnished to the Engineer for testing. <br /> These samples,as selected by the Engineer,shall be representative of the material to be used in the work. <br /> F. Epoxy-coated strand shall be cut using an abrasive saw. <br /> G. All visible damage to coatings caused by shipping and handling, or during installation,including cut ends, shall be <br /> repaired in conformance with the requirements in ASTM Designation: A 882/A 882M. The patching material shall <br /> be furnished by the manufacturer of the epoxy powder and shall be applied in conformance with the manufacturer's <br /> written recommendations. The patching material shall be compatible with the original epoxy coating material and <br /> shall be inert in concrete. <br /> • All bars in any individual member shall be of the same grade,unless otherwise permitted by the Engineer. <br /> • When bars are to be extended by the use of couplers, the assembled units shall have a tensile strength of not less <br /> than the manufacturer's minimum guaranteed ultimate tensile strength of the bars. Failure of any one sample to meet this <br /> requirement will be cause for rejection of the heat of bars and lot of couplers. The location of couplers in the member shall <br /> be subject to approval by the Engineer. <br /> • Wires shall be straightened if necessary to produce equal stress in all wires or wire groups or parallel lay cables that <br /> are to be stressed simultaneously or when necessary to ensure proper positioning in the ducts. <br /> • Where wires are to be button-headed,the buttons shall be cold formed symmetrically about the axes of the wires. <br /> The buttons shall develop the minimum guaranteed ultimate tensile strength of the wire. No cold forming process shall be <br /> used that causes indentations in the wire. Buttonheads shall not contain wide open splits, more than 2 splits per head, or <br /> splits not parallel with the axis of the wire. <br /> • Prestressing steel shall be protected against physical damage and rust or other results of corrosion at all times from <br /> manufacture to grouting or encasing in concrete. Prestressing steel that has sustained physical damage at any time shall be <br /> rejected. The development of visible rust or other results of corrosion shall be cause for rejection, when ordered by the <br /> Engineer. <br /> • Epoxy-coated prestressing steel strand shall be covered with an opaque polyethylene sheeting or other suitable <br /> protective material to protect the strand from exposure to sunlight, salt spray,and weather. For stacked coils,the protective <br /> covering shall be draped around the perimeter of the stack. The covering shall be adequately secured; however, it should <br /> allow for air circulation around the strand to prevent condensation under the covering. Epoxy-coated strand shall not be <br /> stored within 300 in of ocean or tidal water for more than 2 months. <br /> • Prestressing steel shall be packaged in containers or shipping forms for the protection of the steel against physical <br /> damage and corrosion during shipping and storage. Except for epoxy-coated strand,a corrosion inhibitor which prevents rust <br /> or other results of corrosion, shall be placed in the package or form, or shall be incorporated in a corrosion inhibitor carrier <br /> type packaging material, or when permitted by the Engineer, may be applied directly to the steel. The corrosion inhibitor <br /> shall have no deleterious effect on the steel or concrete or bond strength of steel to concrete. Packaging or forms damaged <br /> from any cause shall be immediately replaced or restored to original condition. <br /> • The shipping package or form shall be clearly marked with a statement that the package contains high-strength <br /> prestressing steel,and the type of corrosion inhibitor used,including the date packaged. <br /> • Prestressing steel for post-tensioning which is installed in members prior to placing and curing of the concrete,and <br /> which is not epoxy-coated,shall be continuously protected against rust or other results of corrosion,until grouted,by means <br /> of a corrosion inhibitor placed in the ducts or applied to the steel in the duct. The corrosion inhibitor shall conform to the <br /> provisions specified herein. <br /> • When steam curing is used, prestressing steel for post-tensioning shall not be installed until the steam curing is <br /> completed. <br /> • Water used for flushing ducts shall contain either quick lime(calcium oxide) or slaked lime(calcium hydroxide)in <br /> the amount of 0.01-kg/L. Compressed air used to blow out ducts shall be oil free. <br /> Contract No. 10-OM7104 <br /> 26 <br />