atch 1 2576 Hydraulic Cement Repair.pdf

Hydraulic Cement Repair of Concrete Pavements FA5000-12-R-0001 Attachment 1

2576- 1

1. SCOPE:

1.1 This section covers the repair of spalled Portland cement concrete (PCC) areas using hydraulic cement.

2. APPLICABLE STANDARDS:

2.1 American Society for Testing and Material (ASTM)

ASTM C-109 Compressive Strength of Hydraulic Cement Mortars

ASTM C-157 Length Change of Hydraulic Cement Mortars and Concrete

ASTM C-882 Bond Strength

ASTM C-136 Sieve or Screen Analysis of Fine and Course Aggregates

3. MATERIALS:

3.1 Rapid setting cement mortars shall be a one compound system that requires only the addition of water and gravel. They shall meet the following minimum performance requirements:

3.2 Aggregate: Aggregate shall consist of 1/4" - 3/8" clean, washed and dried gravel or crushed stone of reasonably uniform quality throughout.

4. MATERIAL SUBMITTALS / CONTRACTOR’S QUALITY CONTROL:

4.1 Material Submittals:

Bond Strength:

(ASTM C-882)

1 day

7 days

1500 psi

2500 psi

Length Change:

(ASTM C-157)

28 days

28 days dry - 0.05% wet + 0.05%

Compressive Strength:

(ASTM C-109)

1 hour

1 day

7 days

2000 psi

6000 psi

7000 psi

Pavements - REQ

FXSB 11-2102

Section 2576

Hydraulic Cement Repair of Concrete Pavements

2576- 2

4.1.1 Certified copies of manufacturer's test reports demonstrating conformance to applicable material specifications shall be approved by the Contracting Officer prior to use of the following materials on the project:

4.1.1.1 Hydraulic Cement Mortar: ASTM C-882, ASTM C-109, ASTM C-157

4.1.1.2 Aggregates: ASTM C-136

4.1.2 Submit manufacturer's details, directions, recommendations and procedures in writing. On Contracting Officer's approval, they shall form a part of the specifications.

4.2 Contractor’s Quality Controller shall establish and maintain quality control of the work in this section, including but not limited to:

4.2.1 Laboratory trial batches shall be made by the Contractor prior to field placement of any mixtures. Preparation of the trial batches by the Contractor shall be observed by the project engineer / project inspector and approved by the Contracting Officer and the proportions finally selected by the Contractor shall be approved by the Contracting Officer.

4.2.2 Hydraulic cement material shall be delivered to the site in such manner as to avoid damage or loss. Storage areas shall be in a windowless and weather-proof, but ventilated, insulated noncombustible building, with provision nearby for conditioning the material to 70 F to 85 F for a period of 48 hours prior to use. The ambient temperature in the storage area of the epoxy materials shall at no time be higher than 100 F.

4.2.3 All repair materials shall be premixed, prepackaged materials requiring only the addition of water and gravel. They must be packaged in original unopened package, clearly labeled with the manufacturer's identification and printed instructions. All material shall be stored and handled in accordance with recommendations of the manufacturer and the American Concrete Institute for Concrete and Concrete Products.

5. EXECUTION:

5.1 Preparation of Existing Surfaces: In the area to be patched, the surface of the existing concrete shall be removed to a minimum depth of 2 inches

(or per manufacturer’s requirements) and to such additional depth (unless otherwise indicated on the plans) where necessary to expose a surface of sound, un-weathered concrete that is uncontaminated by oils, greases or deicing salts or solutions.

Vertical saw cut at least two inches deep (or per manufacturer’s requirements) shall be made a minimum of six inches outside of the area to be repaired. The surface shall be thoroughly cleaned by sweeping and blowing with compressed air. Prior to applying the hydraulic cement material, areas showing traces of oils or grease shall be cleaned by sandblasting.

5.1.1 Preparation of Joints: Joint-sealing and expansion-joint materials shall be removed flush with the prepared surface, and, if on the pavement surface to be patched, shall be removed by sandblasting. The use of solvents will not be permitted. Care shall be used to prevent bonding of the adjacent concrete slabs at the location of the existing joints. The prepared surfaces shall be washed with a high pressure water jet followed by an air jet to remove free water. Maintenance of these existing joints shall be accomplished by the use of fiber- board or other approved inserts of appropriate dimensions. Place a thin strip of wood or metal coated with bond-breaking material or lined with plastic in the joint groove, and tamp the mix onto the old surface and against this form.

Care will be taken in placing this filler board or joint cap so that it is aligned with the existing joint.

2576- 3

5.1.2 Hydraulic cement material shall be placed in one application. Tamp or vibrate the mixture to ensure consolidation and positive bonding with the existing concrete. Discard any prepared repair mixture not placed within 60 minutes and prepare a new batch. When the finishing and edging have been completed, the patch will be finished to a texture matching the adjacent areas. When patch mixture has attained its initial set, the filler board will be removed and the joint cleaned with a hook or similar device. This procedure is necessary to ensure that no damage to the patched area will result from excessive stresses during expansion movement of the mix. All patched areas will be cured. The open joints will be filled with joint material prior to permitting use by traffic.

5.2 Field Mixing and Batch Size: The maximum individual batch size for field repairs shall be limited to that required for the specific area or areas to be sealed immediately and shall be subject to acceptance of the Project engineer / project inspector.

5.2.1 Carefully read and understand the manufacturer's instructions as printed on the unit.

5.2.2 Mixing: The mixing operation should be located close to the repair area. A mortar mixer is recommended for large jobs. For smaller quantities, an electric drill and paddle mixer is recommended. The mixing order for mortar type mixer shall be as follows:

5.2.2.1 Clean water shall be placed in the mixer at the rate specified on the bagged instructions.

Water content is critical; do not deviate from the rate specified.

5.2.2.2 When temperatures exceed 90 F, a pre-packaged set retarder shall be used as recommended by the manufacturer. Add retarder to mixing water maximizing dispersion in the mix.

5.2.2.3 For large pours, 3/8-inch clean washed pea gravel should be added to the mix at a rate not to exceed 30 lbs per 50-lb bag.

5.2.2.4 Add the patching material. This sequence is important in order to produce a consistent mix and to reduce mixing time. Allow approximately 3 minutes mixing time.

5.2.2.5 When pouring large volumes of material, special consideration should be given to maintaining a continuous flow of material producing a wet leading edge. More than one mixer may be necessary to deliver enough material to ensure no cold joints.

5.3 Placing Hydraulic Cement Material:

5.3.1 Placing: Place the mixed material into the prepared area, starting from one side of the repair and working to the other side. Do not place the patch material in lifts. Work the material firmly into the bottom and sides of the patch. Screed the material to the desired level. Close up edges of the patch with a trowel. Finish the material to the desired texture. Do not re-temper the material.

Clean the mixer and tools periodically with water to prevent build-up, especially in hot temperatures.

5.3.2 Curing: The hydraulic cement material shall be allowed to cure in accordance with the manufacturer's recommendations. Provide curing compound to meet ASTM C 309 as a minimum.

5.4 Pavement Protection: The Contractor shall protect the patched areas against damage prior to final acceptance of the work by the Government. Traffic shall be excluded from the patched areas by erecting and maintaining barricades and signs until the completion of the curing period.

2576- 4

5.5 Plane Grade: The finished surfaces of patched areas shall meet the grade of adjoining pavements and shall not deviate more than 1/8-inch from a true place surface within the patched area.

5.6 Field Test Specimens: Samples of the hydraulic cement will be taken in the field from mixtures used in the patches to determine the adequacy of control of materials and proportioning, consistency, mixing, compressive strength and air contents of the material. Tests shall be performed by the Contractor at the rate of l set of tests per day of placing of hydraulic cement.

Follow testing requirements shown in SECTION: SPALL REPAIR OF RIGID PAVEMENTS.

Contractor will submit test results to the project engineer / project inspector and patch the test area per above specifications.

6. WEATHER LIMITATIONS:

6.1 Concrete repairs using hydraulic cement grout, as described herein, shall be accomplished when the atmospheric and concrete temperatures are above 50 F and less than 100 F and expected to remain in this range for a period of at least 24 hours after the repairs are made unless the hydraulic cement manufacturer approves a lower application temperature in writing.

6.2 When concrete repairs are required to be made at temperatures other than in the above range or work progress requires, an artificial environment shall be provided as required to maintain the specified temperature range.

6.3 Hydraulic cement material shall not be placed when water is present on the contact surface of the area to be repaired. All repairs shall be protected for at least 12 hours after placement. Type of protection shall be accepted by the Project engineer / project inspector.

7. HEALTH AND SAFETY PRECAUTIONS:

7.1 Protective creams of a suitable nature for the operation shall be applied.

7.2 Portable eye-washing facilities shall be maintained at mixing and placing operations.

7.3 Adequate fire protection shall be maintained at all mixing and placing operations.

7.4 Smoking or the use of spark or flame producing devices shall be prohibited within 50 feet of mixing and placing operations.

7.5 The mixing, placing or storage of epoxy resin grout, binder or solvent shall be prohibited within 50 feet of any vehicle, equipment or machinery which could be damaged from fire or could ignite vapors from the materials.

7.6 Full face shields shall be provided for all cutting, resurfacing, routing, sandblasting, mixing and blending operations and for placing operations as required.

7.7 Protective coveralls and neoprene-coated gloves shall be provided to all workmen engaged in the operations.

8. UNIT OF MEASUREMENT AND PAYMENT: Per the Bid Schedule and Section 1020.

End of Section