Rev. 9-1-95

MASONRY COATING

728-B-039

 

The Standard Specifications are revised as follows:

 

SECTION 728, BEGIN LINE 1, INSERT AS FOLLOWS:

SECTION 728 -- MASONRY COATING

728.01 Description. This work shall consist of the preparation of the concrete surfaces, cleaning such surfaces by means of sandblasting, and furnishing and applying masonry coating as described herein. The masonry coating shall be applied to all concrete surfaces shown on the plans or as directed.

MATERIALS

728.02 Materials. Materials shall be in accordance with 909.13.

CONSTRUCTION REQUIREMENTS

728.03 Surface Preparation. The surfaces to be masonry coated shall be given a class 1 finish in accordance with 702.21(a). Such surfaces shall then be sealed with a concrete sealer in accordance with 709. Air pockets of up to 6 mm (1/4 in.) in width and depth will not require grouting prior to application of the masonry coating. Air pockets larger than 6 mm (1/4 in.) in width and depth shall be filled with a grout mix composed of one part portland cement, two parts screened and washed sand graded to pass the 1.18 mm (No. 16) sieve with not more than 5 percent retained on the 600 :m (No. 30) sieve, and sufficient water to produce a thick liquid mix. The grout shall be applied to fill the air pockets and voids by using burlap pads, float sponges or other acceptable methods. As soon as the grout has taken its initial set, the surface shall be brushed to remove all loose grout, leaving the surface smooth and free of air pockets and voids. Prior to the application of the masonry coating, regardless of whether the concrete surface has been previously sealed, the surface to be coated shall be lightly sandblasted to remove flaking coatings, dirt, oil and other substances deleterious to the applied finish coating. Overblasting, exposing additional air pockets, or disfiguring the surface shall be prevented. Final cleaning shall be done with compressed air. The air compressor shall be equipped with suitable separators, traps, or filters which shall remove water, oil, grease, or other substances from the air line.

Prior to application of the finish coating, the surfaces shall have been prepared in accordance with the manufacturer's recommendations and shall be in a condition consistent with the manufacturer's requirements.

728.04 Application. The application, including equipment used, shall be in accordance with the manufacturer's recommendations. The material shall be applied by qualified personnel experienced in the work.

The material shall be thoroughly mixed in its original container. If skins have formed, the material will be rejected. The material shall not be thinned. The masonry coating may be applied over a damp, but not wet, surface. It shall be applied at a uniform film thickness at a rate of 1.1 " 0.1 m5/L (45 " 5 sft/gal.) or as recommended by the manufacturer and approved by the Engineer. In either case, the application rate shall be sufficient to produce a uniform color and texture. The material shall be applied only when the ambient temperature is between 7EC (45EF) and rising, and 38EC (100EF). It shall not be applied onto frozen surfaces or if rain is imminent. If rain occurs on a freshly applied surface, recoating may be required based on the extent of rain damage.

The material shall not be applied if dusty conditions exist in the vicinity of the surfaces to be coated. When dust conditions are beyond the control of the contractor, or are generated off-site, application shall not take place until more favorable conditions exist. The application of the masonry coating shall be scheduled as one of the final finishing operations to minimize construction generated dust. A wet edge shall be maintained at all times to prevent lap marks. Stopping and starting in the middle of a section of concrete will not be permitted. If applying the coating with a roller, the material shall initially be applied in vertical strokes, cross rolled for even film and appearance, then finished with vertical strokes.

After application, the coating shall be dry to the touch within 48 hours. The coating shall achieve a final cure within two to three weeks under ideal conditions.

728.05 Finishing. The coating material in the finished state shall be capable of accommodating the thermal and elastic expansion ranges of the substrate without cracking.

The texture of the completed finish coat shall be generally similar to that of rubbed concrete. The completed finish coat shall be tightly bonded to the structure to present a uniform appearance and texture. If necessary, additional coats shall be applied to produce the desired surface texture and uniformity.

Coatings shall be entirely removed from the structure upon their failure to positively adhere without chipping, flaking or peeling, or attaining the desired surface appearance. The finish coat shall be reapplied after proper surface preparation until the desired finished product is achieved. The average thickness of the completed finish coat shall not exceed 3 mm (1/8 in.).

The manufacturer shall submit, for each batch of material used, the product analysis data as follows:

(a) Mass per liter (Weight per gallon).

(b) Viscosity in Kreb units.

(c) Mass percent pigment.

(d) Mass percent vehicle solids.

(e) Infrared spectra of vehicle solution.

 

728.06 Method of Measurement. Only those measurements necessary to verify application rates will be made.

728.07 Basis of Payment. Masonry coating used on concrete bridge railing or bridge concrete median barrier will be paid for at the contract lump sum price for masonry coating. Concrete sealer will be paid for in accordance with 709.08.

Payment will be made under:

Pay Item ------------------------------------------------Pay Unit Symbol

Masonry Coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .LS

Surface Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LS

The cost of masonry coating used on roadway concrete median barrier shall be included in the cost of such median barrier. The cost of surface preparation, furnishing and applying the material, labor, equipment, and necessary incidentals shall be included in the cost of this work.

SECTION 909, AFTER LINE 692, INSERT AS FOLLOWS:

909.13 Masonry Coating Material. Masonry coating material shall be a commercial product designed specifically for coating concrete. The material shall be suitable for application on damp concrete, or concrete which is not fully cured. Only one coating material shall be used on an individual structure. It shall be delivered to the project site in sealed containers bearing the manufacturer's original labels. The brand, color, and type shall be clearly marked on each container. All material shall be from the same lot or batch unless otherwise authorized. A copy of the manufacturer's printed instructions shall be made available.

The coating material shall be stored in airtight, upright containers. The containers shall be stored in a dry enclosure where the temperature is above 7EC (45EF) and less than 38EC (100EF). Material which has been subjected to freezing will be rejected.

The masonry coating shall have a shelf life of not less than 12 months.

The color of the applied masonry coating shall be in accordance with Federal Color Standard No. 595a. Such color shall match the color identification number shown on the plans.

(a) Material Testing. All testing shall be performed by a qualified commercial testing laboratory acceptable to the Division of Materials and Tests.

The applied finish coating shall be subjected to and shall satisfy the requirements of the tests listed below, prior to use on a structure. The masonry coating manufacturer shall certify that the coating is compatible with the sealer used on the concrete surface,

1. Freeze-Thaw Tests. The applied finish coating shall be subjected to freeze-thaw cycle tests as follows:

a. Three concrete specimens, not less than 100 mm by 150 mm by 150 mm (4 in. by 6 in. by 6 in.), of the mix design for the structure shall be cast and cured. Fourteen days moist curing with a drying period at room temperature, 16EC to 27EC (60EF to 80EF), for 24 hours will be required before the specimens are coated with the applied finish. There shall be noexcessive oil on specimen forms.

The finish coating shall be applied to the sides of specimens at a spreading of 1.2 " 0.2 m5/l (50 " 10 sft/gal). Brush application will be permitted. Cementitious coatings shall be cured at room temperature and 50 percent relative humidity for 24 hours, at room temperature and 90 percent relative humidity for 48 hours, at room temperature and 50 percent relative humidity for four days for a total curing time of seven days. Other coatings shall be cured at room temperature for 48 hours after the completing of curing.

b. The specimens shall be immersed in water at room temperature for three hours, then removed.

c. The specimens shall be placed in cold storage at -26EC (-15EF) for one hour, then removed.

d. The specimens shall be thawed at room temperature for one hour.

e. Steps c. and d. above shall be repeated for a total of 50 cycles. At the end of 50 cycles, the specimens shall show no visible defects.

2. Accelerated Weathering. The applied finish coating shall be subjected to a 5,000 hour exposure test in a Twin-Carbon-Arc-Weatherometer, ASTM G 23, Type D, at an operating temperature of 63EC (145EF). The test shall be made at 20 minute cycles consisting of 17 minutes of light and 3 minutes of water spray plus light. At the end of the exposure test, the exposed samples shall show no chipping, flaking, or peeling. The panels for this test shall be prepared by means of applying the coating at a spreading rate of 1.2 " 0.2 m5/l (50 " 10 sft/gal.) to both sides and edges. Panels shall be cut from asbestos cement shingles in accordance with Federal Specification SS-S-346, Type I. Curing time shall be in accordance with 908.12(b)1.

3. Fungus Growth Resistance. The applied finish coating shall pass a fungus resistance test in accordance with Federal Specification TT-P-29g. Fungus growth shall not be indicated after a minimum incubation period of 21 days.

4. Abrasion Resistance. The applied finish coating shall pass the 3,000 liter sand abrasion test in accordance with Method 6191 Abrasion Resistance - Falling Sand, Federal Test Method Standard 141a. The specimens for this test shall be prepared by means of applying the coating to a cleaned steel panel at a spreading rate of 1.2 " 0.2 m5/l (50 " 10 sft/gal.). The specimens shall be cured at room temperature for 21 days.

5. Impact Resistance. The coating shall be applied to a concrete panel prepared in accordance with Federal Test Method Standard 141a, Method 2051, at a spreading rate of 1.2 " 0.2 m5/l (50 " 10 sft/gal.), and permitted to cure for 21 days a room temperature. The test shall then be run using the Gardner Mandrel Impact Tester in accordance with ASTM D 2794 using a 13 mm (2 in.) indenter with an impact load of 2.7 joules (24 in.Albs). The coating shall shown no chipping under this impact load.

6. Salt-Spray Resistance Test. A concrete specimen shall be coated at the rate of 1.2 " 0.2 m5/l (50 " 10 sft) and cured for 21 days at room temperature. The coated specimen shall be exposed to a 5 percent salt solution in accordance with ASTM B 117 for 300 hours where the atmospheric temperature is maintained at 32EC " 1EC (90EF " 2EF). At the end of 300 hours of exposure, the coating shall shown no ill effects, loss of adhesion, or deterioration.

7. Flexibility Test. A sheet metal specimen shall be coated with the applied finish coating at a rate of 1.1 " 0.2 m5/l (45 " 10 sft/gal.) and permitted to cure for 48 hours at room temperature. The coated specimen shall be bent 180 degrees over a 25 mm (1 in.) diameter mandrel. After bending, the coating shall show no breaking.

(b) Certification. Before material is applied, a type B certification in accordance with 916 shall be furnished attesting that the commercial product furnished is in accordance with the same formula as that previously subject to the tests specified below and approved. Copies of the test reports shall be attached to the certification. Reports for tests made more than four years prior to shipment to the contract will not be accepted.

A service record shall be supplied which shows that the finish coating material has a satisfactory service record on sealed concrete surfaces for a period of not less than five years prior to the date of submission of the service record. The finish coating shall also have shown satisfactory service characteristics without peeling, chipping, flaking, or nonuniform change in texture or color. A specific structure for the specific product shall be named for the service record.

SECTION 916, AFTER LINE 65, INSERT AS FOLLOWS:

Masonry Coating Material 909.13