548Coating of Concrete

548.1 Description

This Work consists of applying Class 4, Special Surface Finish to concrete. Reference

511.3 9, “Finishing” for additional required surface treatment. This section includes

Specifications for colored conc rete stain/sealer, thin film liq uid applied coatings (referred to as paint), and textured coating. For Penetrating Water Repellent Treatment, see Section 532, “P enetrating Water Repellent Treatment.” For Permanent Anti-Graffiti Protective C oating, see Section 531, “Permanent Anti-Graffiti Protective Coating.”

548.2 Materials

The following coating systems are included in this Specificatio n: 1. Coating System 548-1: col ored concrete stain/sealer; 2. Coating System 548-2: paint; and 3. Coating System 548-3: textured coating. When the Contract require a Class 4 Special Surface Finish, the Contractor shall provide Coating System 1: colored concrete stain/sealer, unless anothe r method is specifically required in the Contract. For new construction with no drainage systems, Coating Systems 1, 2, and 3 require the application of waterproofing Materials on the backside of below grade walls such as retaining walls and planter boxes. Waterpr oofing shall be per Section 51 1, “Concrete Structures.” Unless noted in the Contract, the color shall be selected by th e Project Manager from the Federal Standard 595C color char t for Coating Systems 1, 2, and 3. The Contractor shall select a coating system from the Departmen t’s Approved Products List for Coating Concrete.

548.2.1 Coating System 548-1: Colored Concrete Stain/Sealer

The Contractor shall provide an acrylic polymer penetrating co ncrete stain. Compositions including acrylic, silicone, silane and / or siloxane are Accep table. Solid, opaque, and semi- transparent products are Acceptable. The stain shall contain a minimum of 40.3% solids by mass and meet the requirements described in Table 548.2.1:1, “C olored Concrete Stain/Sealer Requirements.” Table 548.2.1:1 Colored Concrete Stain/Sealer Requirements Test Description Test Criteria Water Vapor Transmission ASTM D1653 0.4-0.8 grains/ sq.ft. / hr Adhesion to Concrete ASTM D7234 500 psi Colored Concrete Stain/Sealer Requirements Test Description Test Criteria Wind Driven Rain Resistance ASTM D6904 or TT-C-555B 48 hr duration no visible leaks, no weight gain Accelerated Weathering ASTM D4587 - 11 cycle, 1,000 hour duration pass The Contractor shall apply two (2) coats. The manufacturer sh all determine the composition of the two (2) coats: i.e. one (1) coat of stain a nd one (1) coat of sealer, or two

548.2.2 Coating System 548-2: Paint

The Contractor shall provide paint products from the Master Pa inters Institute’s Approved Product List – MPI #108. The pr oduct shall possess the followi ng properties: 1. Does not show excessive settling in a freshly opened full co ntainer; 2. Easily re-disperses with a paddle to a smooth, homogeneous s tate free of curdling, slivering, caking, color s eparation, lumps and skins; 3. Brushes on easily; 4. Shows no running or sagging tendencies when applied to smoot h vertical surfaces; and 5. Dries to a uniform finish. The final condition of the conc rete must have penetrating wate r repellent properties consistent with ASTM D6532; water absorption shall perform a mi nimum of 80% better than untreated Material. A combination of products may be required to meet this requirement (paint, sealer, penetrating water repellent, etc.). For coatin g system 548-2, the Contractor shall provide a letter from the manufacturer recommending the o rder of application of products that will meet their product requirements and water repellent c apability. This letter shall confirm the compatibility of a ll products in the system.

548.2.3 Coating System 548-3: Textured Coating

The Contractor shall provide a textured coating product from t he Master Painters Institute’s Approved Product List MPI #42. A light sand texture shall be provided unless otherwise specif ied in the Contract (note: textured coatings can be specified as smooth). The final condition of the conc rete must have penetrating wate r repellent properties consistent with ASTM D6532; water absorption shall perform a mi nimum of 80% better than untreated Material. A combination of products may be required to meet this requirement (textured coating, sealer, penetrating water repellent, etc.). For coating system 548-3, the Contractor shall provide a letter from the manufacturer recomme nding the order of application of products that will meet their product requirements and water repellent capability. This letter shall confirm the compatibility of all products in the system. The Contractor shall submit manufacturer’s product data sheets, application instruct ions, paint certifications and an applic ation Plan 30 Days prior to a pplication of coatings. The Contractor shall provide a coating Application Plan accord ing to the manufacturer’s written recommendations. The Plan shall include: 1. Proposed surface preparation; 2. Mixing and thinning directions; 3. Rate of application; 4. Recommended spray nozzles and pressures; 5. Number of necessary coats; 6. Allowable ambient air temperature range; 7. Allowable ambient surface temperature range; and 8. Safety and damage protection Plan. If the color varies from the specified color, the Contractor s hall submit color samples on boards at least eight (8) inches b y ten (10) inches for review and approval.

548.3 Construction Requirements

548.3.1 General

Prior to application of a Class 4, Special Surface Finish (ref erence Section 511.3.9.5, “Class 4, Special Surface Finish”), the Contractor shall ensure that the surface meets the requirements of a Class 2, Rubbed Surface Finish (reference Sec tion 511.3.9.3, “Class 2, Rubbed Surface Finish”). The Class 2 Rubbed Surface Finish, including any patch Materia l, must be allowed 28 Days to cure prior to the application of coating systems unless otherwise recommended by the manufacturer and approved by the Department.

548.3.2 Surface Preparation

The Contractor shall prepare the surface in conformance with t he manufacturer’s recommendations and shall, at a minimum, include power spraying with a minimum 4000 PSI sprayer with a zero degree (0°) rotary nozzle at a six (6) inch stand-off distance. The Contractor may also find it necessary to employ detergents or a brasives. Unless otherwise directed by the manufacturer, the prepared surface shall be in conformance with SSPC-SP 13 / NACE No. 6 ‘Surface Preparati on of Concrete.’ The concrete s urface must be free of contaminants, curing compounds, form release agents, effloresce nce, and existing incompatible coatings, laitance, loosely adhered concrete, and dust and shall provide a sound, uniform substrate. Alkalinity testing by the Contractor and associated follow-up action shall be required if recommended by the manufacturer.

548.3.3 Temperature and Weather Limitations

The Contractor shall apply coatings on concrete surfaces that h ave cured for a minimum of 28 Days and only when the atmospheric temperature is in the range from 50 degrees F to 100 degrees F, and when the relative humidity is at or below 85 percent. Coatings shall only Section 548: Coating of Concrete Page 559 be applied to a surface which is at least five (5) degrees F ab ove the dew point. The surface temperature should remain above the minimum temperature specifi ed above until the coating is thoroughly dry. Coatings shall not be applied when weather conditions exist which might damage the Work such as windborne dust. With the approval of t he Project Manager, temperature and weather limitations may be adjusted to those co nditions recommended by the manufacturer.

548.3.4 Precoating Requirements

The Contractor shall allow the surface to visually dry complet ely before application of coatings. All concrete surfaces shall be inspected by the Project Manage r prior to application of coatings. The Contractor shall not apply penetrating water repellent tre atment to the concrete surface before coating the conc rete, unless otherwise recommend ed by the manufacturer.

548.3.5 Coating Application

Coating shall be applied in accordance with SSPC-PA 14. No coating shall be applied unt il the preceding coat has dried /cured to the extent specified by the manufacturer. All coatings shall be applied so that the cured film is contin uous and consistent.

548.3.5 1 Thinning the Coatings

The Contractor shall not thin the coating Material without Manu facturer and Department approval.

548.3.5 2 Application Equipment Requirements

Spray application Equipment shall be employed to apply the coa tings unless otherwise recommended by the manufacturer. The Contractor shall employ a pplication Equipment that meets the requirements of the manufacturer. Brushes and roller s may be used for touch-up paint and on areas less than 20 square feet. 548.3.5.3 Dry Film Thickness The Contractor shall apply the coatings at the dry film thickn ess recommended by the manufacturer. Dry film thickness shall be measured by the Cont ractor in accordance with ASTM D6132 using an ultrasonic film thickness gage that shall b e provided and retained by the Contractor. Dry film thickness readings shall be taken and recorded every 1,000 square feet or at a minimum of once per workshift.

548.3.6 Inspection and Reporting

The Contractor shall maintain daily field report s that include : 1. Weather and temperature data; 2. Surface preparation obser vations including photographs; 3. Product tracking information including lot and batch numbers of the products applied; Section 548: Coating of Concrete Page 560 4. Description of Equipment used and names of applicators; and 5. Records of dry film thickness (reference Section 548.3.5.3, “Dry Film Thickness”). The Contractor shall submit the inspection reports to the Proj ect Manager on a weekly basis.

548.3.7 Project Test Area

For areas greater than 500 square feet, a Project test area sh all be prepared and tested by the Contractor. The test area can be either on the Structur e itself or on a sample that is representative of the substrate to be coated. The test panel s hall be no smaller than three (3) square feet in size. The test panel shall be of the same Mater ial and application process as the final product. Following cure, adhesion testing shall be performed by the Con tractor on the test panel in accordance with ASTM D7234. The location of the disbondment fo r each of the three (3) pulls shall be within the concrete substrate (i.e. cohesive failure o f the concrete). Testing shall be observed by the Project Manager. Results of the test shall be submitted in writing to the Project Manager.

548.4 Method of Measurement

Coating of the Concrete surface s will be measured by the squar e foot.

548.5 Basis of Payment

Pay Item Pay Unit Coating of Concrete – Stain Square Foot Coating of Concrete – Paint Square Foot Coating of Concrete – Textured Coating Square Foot

548.5.1 Work Included in Payment

The Department will consider as included in the payment for th e pay item(s) listed in this section and will not measure or pay separately for the followin g Work: 1. Preparation of the concrete surfaces to be painted; 2. Protection of pedestrian, vehicular or other traffic near or under the Work from paint spatter and disfigurement; and 3. Inspection and testing as requi red by this Specification and the Contract. Section 550: Treated Timber Page 561