771 SECTION 690 SURFACE PREPARATION AND POWDER COATING OF NEW GALVANIZED STEEL FOR HIGHWAY SIGNING AND LIGHTING STRUCTURES
690.1 -GENERAL : 690.1.1 -Purpose and Scope: This Specification provides the material and workmanship requirements for the surface preparation and powder coating of new galvanized steel surfaces. The work consists of surface preparation and application of the powder coating system.
690.1.2 -Reference Standards: The latest edition of the following standards and regulations form a part of this specification.
Coatings on Iron and Steel Products
and Steel Hardware
Cadmium Surfaces
Air
Gages
or Eddy -Current (Electromagnetic) Test Methods
Thickness.
Painting Structural Steel.
690.2 -PRODUCTS : 690.2.1 -Hot-Dip Galvanized Materials: Material to be powder coated is required to be Hot-Dip galvanized as described in ASTM A123 and A153.
690.2.2 -Hot-Dip Galvanizing Requirements: Water quenching or chromate conversion coating shall be avoided as these processes interfere with paint adhesion and surface preparation. Testing for the presence of chromate coatings in accordance with ASTM B201 can be conducted if necessary.
772 690.3 -SURFACE PREPARATION AND POWDER COATING : Cleaning and powder coating shall be done in accordance with WVDOH Standards and Specifications, Section 688. Preparation of the galvanized surface, prior to powder coating shall conform to written recommendations from the powder coating manufacturer, or at a minimum, in accordance with subsection 690.3.B. This recommendation will then become part of the Paint Quality Control Plan (QC Plan).
burrs smooth, and shall round sharp edges such as those created by flame cutting and shearing.
rounding unless specifically directed by the Engineer.
by SSPC -SP1, Solvent Cleaning.
remains on the surface of the galv anized steel can potentially retain air or moisture. This may cause the powder coating to blister or create voids. Likewise, the galvanized coat may also release gas.
Cleanin g. This process will also promote good adhesion between galvanized surface of steel and powder coating.
process known as pre -baking. This is done in a drying oven operated at higher temperatures than the curing temperature. This temperature is typically 55º F higher than the recommended curing temperature. In no instance the temperature should exceed 535º F.
immediately after the preparation.
* Chemical cleaning leaves a film in the material surface that may create the effect of bond breaker between the base material and the powder coating.
690.4 -ENVIRONMENTAL CONDITIONS :
and/or relative humidity ranges required by the powder coating manufacturer.
humidity between 40 to 60%.
773 690.5 -POWDER COATING : Except as otherwise specified, powder coating materials shall meet the following requirements :
60 - 80 Semi -Gloss 70- 100 High Gloss ii. Adhesion ASTM D3359 100% (5B) iii. Hardness ASTM D3363 H-2H Pencil iv. Conical Mandrel ASTM D522 ⅛" Mandrel
No Cracking vi. Salt Spray ASTM B117 1,000 Hrs. <⅛" Scribe Creep –No Blisters vii. Humidity ASTM D1735 1,000 Hrs. <1/16 " Scribe Creep No Blister viii. All powder products shall be ready mixes from the manufacturer. No mixing is to be done in the applicator shop.
690.6 -POWDER COATING APPLICATION : Prior to any powder coating application, any area that is not to be coated (threads, tight fit holes, friction bolted connections, etc.) will be masked. All powder coatings shall be applied at a minimum of three (3) mils dry film thickness. Prior to application of powder coating, determine the average thickness of the bare Galvanized layer. Subtract the average galvanized thickness from total measured dry film thickness in order to determine the actual powder coating film thickness. Verify that the coating thickness of each coat is in accordance to the coating manufacturer ’s requirement or plan’s notes.
690.7 -REPAIR OF DAMAGED COATING : All shop and field repairs to the powder coating shall be made in accordance with WVDOH Standards and Specifications 688.3.6 and the powder coating manufacturer’s recommendations. In addition, the powder coating applicators shall include touch up paint with the Shipment of finished products to the job site.
690.8 -INSPECTION :
the requirements of this Specification. The Contractor sha ll facilitate this inspection as required, including allowing ample time for the inspections and access to the work. Inspections may include, but are not limited to, surface preparation, pre -painting cleanliness, paint application, dry film thickness, fil m appearance, and adhesion.
responsibility to comply with all provisions of this Specification and to provide adequate inspections of its own.
instrumentation needed to inspect all phases of the work.
690.9 -BASIS OF PAYMENT : The basis of payment for the “Surface Preparation and Powder Coating” shall be incidental to highway signing, signal, and lighting structures required to be powder coated.
774
MATERIALS DETAILS
775 SECTION 701 HYDRAULIC CEMENT
The Contractor shall provide suitable means for storing and protecting the cement against dampness. Cement which for any reason has become partially set or which contains lumps of caked cement will be rejected. Cement salvaged from discarded or used bags shall not be used.
701.1 -PORTLAND CEMENT : Portland cement shall conform to the requirements of ASTM C150, Type I.
701.2 : Blank
701.3 -BLENDED HYDRAULIC CEMENTS : Blended hydraulic cement shall conform to the requirements of ASTM C595 for Portland blast -furnace slag cement, Type IS, or Portland -pozzolan cement, Type IP, or Portland -limestone cement, Type IL.
701.4 -MASONRY CEMENT : Masonry Cement shall conform to the requirements of ASTM C91.