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1070-1 GENERAL.

Steel reinforcement shall be stored on blocking a minimum of 12 inches above the ground and shall be protected at all times from damage; and when placed in the work shall be free from dirt, dust, loose mill scale, loose rust, paint, oil, or other foreign materials.

1070-2 DEFORMED STEEL BAR REINFORCEMENT FOR STRUCTURES.

Deformed steel bar reinforcement shall conform to the requirements of ASTM A615 for Grade 60. Tolerances for bending and cutting during fabrication shall be in accordance with the "Manual of Standard Practice" published by the Concrete Reinforcing Steel Institute. Bars shall be bent cold to the details shown on the plans.

1070-3 COLD DRAWN STEEL WIRE AND WIRE FABRIC.

Cold drawn steel wire to be used as spirals or in fabricated form for the reinforcement of concrete shall meet the requirements of ASTM A82.

Welded wire fabric shall conform to ASTM A185.

1070-4 REINFORCING STEEL BAR SUPPORTS.

All wire bar supports shall be made of smooth cold drawn industrial quality basic wire having a minimum tensile strength of 65,000 psi, except when the legs of the bar supports are in contact with the forms, the entire leg of the bar support shall be stainless steel wire or a minimum thickness of 1/4" stainless steel at points of contact with the forms. The stainless steel wire shall meet the requirements of ASTM A493 except the minimum chromium content shall be 16 percent and the minimum tensile strength shall be 95,000 psi. Wire sizes, height tolerance, and leg spacing for wire bar supports shall be in accordance with the requirements listed in the current "Manual of Standard Practice" published by the Concrete Reinforcing Steel Institute.

In lieu of stainless steel wire for the legs of bar supports at points of contact with the forms, the legs may be cold drawn steel wire plastic protected in accordance with the current "Manual of Standard Practice" published by the Concrete Reinforcing Steel Institute, except that plastic protection shall be provided by dipping or by premolded plastic tips. Plastic legs molded to the top wire will not be permitted.

1070-5 PRESTRESSING STRAND.

Prestressing strands for use in prestressed concrete shall consist of 7­wire strands, stress relieved after manufacture to remove internal stresses. The size and the grade of the strand shall be as shown on the plans. Strands shall conform to the requirements of AASHTO M203 except that a specimen for test purposes may be required from each reel of cable instead of each 20 ton production lot.

A standard color marking every 100 ft. on the strands will be required. The standard color markings shall be white for 270K stress relieved strand, green for low relation strand, and a double marking of green and red for special low relation strand.

1070-6 DOWELS AND TIE BARS FOR PORTLAND CEMENT CONCRETE PAVEMENT.

Dowel bars shall be smooth plain round steel bars and shall conform to the requirements of ASTM A615, Grade 60. Dowel bars with burred ends will not be accepted. A tolerance of 1/4" will be permitted from the dowel length required by the plans. A straightness tolerance of 0.075" from a straight line will be permitted.

All dowel bars shall be epoxy coated in accordance with AASHTO M284 and these provisions. The coating thickness shall be 7 to 13 mils after curing. Coated bars will be taken by the Engineer from the production run on a random basis at the point of coating application for test, evaluation, and check purposes. The Engineer will determine the sampling and testing schedule for the number and frequency of tests for thickness of coating, adhesion of coating, and holidays. A minimum of one bar for each 20 coated will be tested by the Engineer for holidays and coating thickness. A minimum of 2 bend tests shall be performed by the Contractor for each 8 hours of production coating or any fraction thereof for determining that adhesion and flexibility of the coating meets specification requirements. Payment will not be made by the Department for coated bars selected for testing and evaluation purposes at the point of coating application. All coated bars will be inspected by the Engineer at both the coating and fabrication shops. A Type 1 Certified Mill Test Report shall be furnished and shall be attached to a completed Department of Transportation reinforcing steel certification Form Number 913 for all reinforcing bars to be coated before cleaning and coating operations, of the time and location where the work will be performed.

Dowel assemblies for supporting dowel bars shall be of rigid construction capable of holding the dowel bars in proper position during placing of concrete, and shall be of such design as to permit unrestricted movement of the pavement slab. Wire for dowel assemblies shall meet the requirements of ASTM A82. The dowel assembly shall hold the dowels in the required position within a tolerance of 1/4 inch in vertical and horizontal planes. The dowel assembly shall have been approved by the Engineer in writing prior to use.

Dowel bars and the entire dowel assembly shall be coated with a wax base coating which has been approved by the Engineer. The coating shall be applied by dipping or spraying. The wax coating on the dowel bars shall be of uniform thickness sufficient to allow the dowel to be pulled from the concrete as provided in AASHTO T253 and M254. The Contractor shall furnish to the Department for testing 1 dowel basket assembly for each 200 assemblies to be incorporated into the project.

Tie bars shall be deformed bars conforming to the requirements of ASTM A615 for Grade 40 or Grade 60.

1070-7 REINFORCEMENT FOR BLOCK MASONRY.

Reinforcement for block masonry shall be a prefabricated truss type unit consisting of at least 2 parallel rods connected to a continuous cross rod which is shaped in an alternating diagonal pattern. The unit shall be fabricated from No. 9 gage uncoated wire which meets all applicable requirements of ASTM A82.

1070-8 EPOXY COATED REINFORCING STEEL.

(A) General:

Coaters of epoxy coated reinforcing steel will be required to establish proof of their competency and responsibility in accordance with the Concrete Reinforcing Steel Institute's Fusion Bonded Epoxy Coating Applicator Plant Certification Program. Registration and certification of the plant or shop under the CRSI Program and submission of the valid annual certificate to the State Materials Engineer will be required prior to beginning any coating. The same requirement will apply to coaters subcontracting work from the coater directly employed by the contractor.

Each coater and/or fabricator of epoxy coated reinforcing steel shall also be approved by the Engineer prior to coating or fabricating bars. Approval shall be based upon: (a) the coating applicator and/or fabricator establishing and maintaining an effective quality control program and (b) the coating applicator having equipment for cleaning, coating, and/or fabricating that will produce coated material that conforms to these specification requirements. Requests for approval must transmit a well defined quality control program and be directed to the State Materials Engineer. Before Department approval is issued, the condition of equipment proposed for use by a company in blast cleaning, coating and/or fabricating material will be evaluated by the Engineer for determining if the equipment is capable of producing a coated product that will conform to the specifications. A list of NCDOT approved epoxy coating and/or fabricating companies can be obtained from the State Materials Engineer.

(B) Coating Materials:

The epoxy resin powder shall be approved by the Engineer prior to use. A list of prequalified powder sources may be obtained from the State Materials Engineer.

Prequalified products other than those now approved for use may be submitted to the State Materials Engineer for approval.

The powdered resin shall be of any color that provides contrast to the corroded or uncorroded surface of the steel. The material shall be of the same quality as that used for prequalification tests and as represented by test reports forwarded to the State Materials Engineer.

The manufacturer of the epoxy resin shall supply to the coating applier information on the resin that he considers essential to the proper use and performance of the resin as a coating. The manufacturer of the resin shall also furnish the coating applier a written certification signed by a responsible officer of the company that the material furnished for coating the reinforced steel is the same formulation as that for which test reports were previously submitted to the State Materials Engineer.

With each batch of coating material, a written certification shall be furnished by the coating applier to the Engineer which properly identifies the batch number, material, quantity represented, date of manufacture, name and address of manufacturer, and includes a statement that the supplied coating material is the same composition as that prequalified.

(C) Patching Material:

Patching or repair material that is compatible with the coating, inert in concrete and has been prequalified and approved shall be made available by the epoxy resin manufacturer. The material must be suitable for making repairs with a minimum dry film thickness of 6 mils on damaged areas of the coating. Each coater, fabricator, and contractor shall have a copy of the manufacturer's written instructions for application of the patching material and the instructions are to be closely followed during coating damage repairs.

(D) Reinforcing Steel:

Steel reinforcing bars to be coated shall meet the requirements of ASTM A615, Grade 60 and shall be free of contaminates such as oil, grease, and paint. The bars shall be free of surface irregularities that will produce holidays in the coating. The coater shall visually inspect the bars to avoid coating bars containing such surface irregularities. If the coater fails to detect surface irregularities that produce holidays in the coating, the holidays shall be patched with six (6) mils of patching material as specified in Section 1070­8(G), or may be rejected at the discretion of the Engineer.

(E) Surface Preparation of Bars:

Reinforcing steel surfaces to be coated shall receive a very thorough blast (near white) cleaning. The appearance of the surface after cleaning shall correspond to Standard ASTM D2200 and the pictorial standards of Steel Structures Painting Council Specifications VIS 1, degree of cleaning SSPC­SP10. A suitable anchor pattern profile shall be produced by the cleaning media. A target profile depth of approximately one third the coating thickness shall be considered a suitable anchor pattern.

The coating shall be applied to the cleaned surface as soon as possible after cleaning. Any formation of rust blooms on the cleaned bars are to be removed by blast cleaning before application of the coating. However, in no case shall the coating be delayed more than 8 hours after cleaning unless otherwise permitted by the Engineer. At the time of coating, the surface characteristics of the steel shall be as described above.

After blast cleaning, and before application of the coating, all visible traces of grit and dust shall be removed from the bars.

(F) Application of Coating:

The coating shall be applied as an electrostatically charged dry powder sprayed into the grounded steel bar using an electrostatic spray gun. The powder may be applied to either a hot or cold bar. The coated bar shall be given a thermal treatment as specified by the manufacturer of the epoxy resin which will provide a fully cured and bonded finish coating. Temperature shall be controlled as recommended by the manufacturer of the coating material to ensure a workmanlike finish without blistering or other defects. All bars, including bar ends, shall be completely coated with epoxy resin powder to the minimum thickness specified in Section 1070­8(G).

The production line shall be run at such a speed as to provide proper cure time prior to quench by air or water.

(G) Quality Control Requirements:

For acceptance purposes, each recorded film thickness measurement shall be in the range of 7 to 12 mils after cure. No area of a bar shall indicate a coating thickness of less than 7 mils.

A single recorded coated reinforcing bar thickness measurement is the average of three individual readings obtained from three adjacent areas on the body of the bar (that is, three adjacent areas between deformations). A minimum of five recorded measurements shall be obtained approximately evenly spaced along each side of the test bar (that is, a minimum of ten recorded measurements per bar).

Each coated bar shall be visually inspected by the coating applier after cure for continuity of coating and the coating shall be free of holes, voids, contamination, cracks, and damaged areas discernible to the unaided eye. In addition, there shall be no more than an average of two holidays per linear foot of bar providing the total quantity of holidays does not exceed five in any linear foot. Bars that contain no more than five holidays in any linear foot of bar will be acceptable providing any holidays in excess of two per linear foot are coated with 6 mils of patching material specified in Section 1070­8(C). The coater shall retest the bars after patching to confirm that no more than two (2) holidays exist in any linear foot of bar.

The adhesion of the coating shall be evaluated by the coating applier on a representative number of bars selected by the Engineer or his representative from each proposed shipment as specified in Section 1070­8(L). No visible cracks or disbonding of the coating shall be allowed when tested in accordance with Section 1070­8(H).

(H) Test Methods Required of the Coater:

The thickness of the coating shall be measured on the body of the bar between the deformations or ribs. Non-destructive coating thickness measurements using magnetic gages shall be made in accordance with ASTM G12, with the following additions applicable to commercially available pull-off gages, and to fixed probe gages with a magnetic field of vision not exceeding 0.015 in. (0.4 mm) of steel depth (0.015 in. is the minimum thickness of smooth steel to which adding more material will not change the zero reading).

Gage calibration with shims shall be performed on a smooth, clean low-carbon steel plate (with minimum dimensions of 3 by 3 1/2 in)., rather than on a cleaned reinforcing bar.

A correction factor defining the effect of the bar preparation process shall be obtained as the difference between (a) the average of ten gage readings on a cleaned, but uncoated reinforcing bar of the size and lot being coated, and (b) the average of five gage readings on a smooth mild steel plate. This correction factor shall then be subtracted from all subsequent gage readings on coated bars.

Fixed probe gages shall be checked to ensure that the force generated by the springloaded probe housing is sufficient to ensure intimate contact between the probe tip and the coatings of the curved bar surface. If intimate contact does not result, it will be necessary to remove the probe housing and utilize hand pressure to obtain valid indicated thickness readings.

Thumbwheel pulloff gages may be used to provide valid thickness measurements on coated reinforcing bars with a deformation spacing which is less than the maximum outer dimensions of the probe housing. The base of the probe housing shall be positioned against the top of two adjacent deformations and the probe shall be extended through the air gap to the body of the bar. The gage shall be held very steady and continuous light downward pressure shall be applied to the housing during the measurement.

A 67.5V holiday detector equipped with a holiday marker shall be used in accordance with the detector manufacturer's instructions. The detector shall be maintained in perfect working condition at all times during the bar coating process. Immediately after coating, each bar shall be routed through the detector for holiday detection. Bars containing more than five holidays in a linear foot of bar or averaging more than two holidays per foot of bar shall either be rejected or cleaned, recoated, and retested for holidays. A coating holiday for the purpose of this specification is defined as a discontinuity in the applied coating that occurs during the coating process that may be detected either visually or electromechanically.

The adhesion of the coating shall be evaluated by bending production coated bars 120 degrees (after rebound) around a mandrel of specified size as prescribed in Table 1070­8(1). The bend test shall be made at a uniform rate and may take up to 90 seconds to complete. The two longitudinal deformations shall be placed in a plane perpendicular to the mandrel radius, and the test specimen shall be at thermal equilibrium between 68° and 85°F. If the specimen for the adhesion of coating shows evidence of cracking or disbonding of the coating, two retests shall be conducted on random samples. If the results of both retests meet the specified requirements, the coated bars represented by the samples shall be accepted.

The fracture or partial failure of the steel-reinforcing bar in the bend test for adhesion of coating shall not be considered as an adhesion failure of the coating. If failure of the bar occurs, two check samples are to be tested without bar failure.

Test bars shall be conditioned at a temperature range of 68°F to 85°F. In cases of dispute, tests shall be conducted at 73°F and 50% relative humidity in accordance with Recommended Practices ASTM D-3451.

(I) Handling and Identification:

All systems for handling coated bars at the coating plant, fabricator, and project shall have padded contact areas. All bundling bands shall be padded or suitable banding shall be used to prevent damage to the coating. All bundles of coated bars shall be lifted with a strong back, spreader bar, multiple supports or a platform bridge to prevent bar-to-bar abrasion from sag in the bundles of coated bars.

(J) Fabrication of Steel-Reinforcing Bars After Coating:

Drive rolls and automatic kick-off levers on shear beds, and drive pins, center pins, and back-up barrels on benders shall be protected with a suitable covering to minimize damage during the fabrication process. The fabricator should note that these specifications permit a maximum of 5 percent of the surface area of a bar to contain patching material. This includes patching due to damage to the coating by the coater, fabricator, and contractor.

Coated bars shall be stored as required by Section 1070­8(M).

The fabricator shall maintain the identification of the coated bars, and shall assure that the coated, fabricated bars are identified with proper tags for final shipment to the job site.

Coating repairs are to be performed as described in Section 1070­8(K) with material specified in Section 1070­8(C).

Flame cutting of coated bars to the required dimensions will not be permitted. Any mechanical device used for cutting the coated bars to required length must be maintained in good working order to minimize damaging the coating in the vicinity of the cut ends. Coating damage in these areas is to be repaired as described in Section 1090­8(K) with material specified in Section 1070­8(C).

(K) Procedures for Repair of Coating:

Repair will be required of all coating damage of the reinforcing bars with material described in Section 1070­8(C) when coating bond loss and damage exist, including crushed coating and hairline cracking if bare metal is evident. When repair is required, all damage shall be cleaned and repaired. The cleaning shall remove crushed coating and loose or deleterious material. In areas where rust is present, it shall be removed by wire brushing with a power tool to the cleanness specified in Section 1070­8(E) prior to repair.

A maximum of 5 percent of the surface area of a bar shall contain patching material. This includes patching due to damage to the coating by the coater, fabricator, transporter, and contractor.

(L) Inspection by the Department:

Coated bars shall be inspected by the Engineer or his representative at both the coating and fabrication shops unless otherwise approved. The coater and/or fabricator is required to furnish mill test reports attached to a completed Department of Transportation Reinforcing Steel Certification Form Number 913 to the Engineer for all reinforcing bars to be coated. These certification forms can be obtained from the State materials Engineer. No epoxy coated reinforcing steel may be coated, fabricated or shipped to the project site without the approval of the Engineer.

The Engineer or his representative shall have free entry to the plant and facilities of the coater and/or fabricator for the inspection of all manufacturing processes including but not limited to the cleaning, coating and fabrication of the bars ordered.

On a random basis, lengths of coated bars or fabricated bars will be taken by the Engineer from the production run at the point of coating application, for test, evaluation, and check purposes.

All bar tests will be made at the coating applicator's and/or fabricator's plant, prior to shipment, unless otherwise approved by the Engineer. The coating applier and/or fabricator shall notify the State Materials Engineer or his representative, five working days prior to the time the material will be coated or fabricated. Bars shall not be shipped until they have been inspected and tagged by the Department or its representative.

The Engineer or his representative will randomly select three coated bars of each size from each proposed shipment to test for holidays, damage and coating thickness. If any bar fails to conform to these specification requirements, six (6) samples will be selected and tested. If these tests reveal that the coating conforms to specification requirements the shipment will be acceptable. If any of the second set of samples fail to conform to these specifications the coater will be required to test all bars of that size that will be included in the shipment and re-submit the shipment to the Department for inspection. The Engineer or his representative will select from each proposed shipment two (2) samples of each size bar for bend tests by the coater for determining that the adhesion and flexibility of the coating conforms to Sections 1078­8(H).

(M) Repairs to Coating Due to Loading, Transporting, and Handling:

The bundled bars shall be transported from the coater or fabricator to the project site with padding, such as carpet padding or used carpet, placed over each bundle of steel upon which another bundle of steel will be placed unless wooden spacers are placed between each bundle to prevent contact.

All bundles of bars shall be loaded horizontally for transporting. The bars shall be transported on a flat-bed trailer. The length of bars extending beyond the trailer bed shall not exceed 8 feet.

Repairs to coating due to handling and transporting damage or other causes shall be repaired with material specified in Section 1070­8(C). All coating damage shall be repaired as specified in Section 1070­8(K).

(N) Rejection:

Coated bars which do not meet the requirements of this specification shall be rejected. At the Contractor's option, coated bars containing defects beyond the limits of these specifications shall be replaced or alternatively, stripped of coating, recleaned, and recoated in accordance with the requirements of this specification.