Section 03740 CONCRETE STRUCTURE REPAIR

Section 03740

_{CONCRETE STRUCTURE REPAIR}

PART 1 - GENERAL

1.1 SUMMARY

A. Section Includes:

1. Concrete finishing and repair of surface defects.

B. Related Specification sections include but are not necessarily limited to:

1. Division 01, Additional General Requirements

2. Section 03100, Concrete Formwork

3. Section 03300, Cast-in-Place Concrete

4. Section 03360, Concrete Curing, Finishing, and Dampproofing

1.2 QUALITY ASSURANCE

A. Referenced Standards:

1. American Concrete Institute (ACI):

116R Cement and Concrete Terminology

2. ASTM International (ASTM):

C150 Standard Specification for Portland Cement

C309 Standard Specification for Liquid Membrane-Forming

Compounds for Curing Concrete

C1315 Standard Specification for Liquid Membrane-Forming Compounds Having Special Properties for Curing and Sealing Concrete

D4258 Standard Practice for Surface Cleaning Concrete for Coating

D4259 Standard Practice for Abrading Concrete

3. Society for Protective Coatings/NACE International (SSPC/NACE): SP 13/NACE No. 6, Surface Preparation of Concrete.

B. Qualifications:

1. Applicator of metallic aggregate topping, acrylic, epoxy, surfacer/filler, shall be approved, in writing, by manufacturer.

2. Manufacturer of metallic aggregate topping, acrylic, epoxy, surfacer/filler, shall have minimum of five (5) years experience in manufacturing of same with documented performance history for similar installations.

3. Installer/applicator of metallic aggregate topping, acrylic, epoxy, surfacer/filler shall have minimum of three (3) years experience installing similar coatings and shall be licensed or approved in writing by manufacturer to install/apply this product.

4. Applicator of concrete sealer, hardener, densifier shall be factory trained and approved, in writing, by the manufacturer to apply the product.

a. Applicator shall have a minimum of five (5) years experience successfully applying materials specified.

1.3 DEFINITIONS

A. Vertical Surface Defects:

1. Any void in the face of the concrete deeper than 1/8 inch, such as:

a. Tie holes.

b. Air pockets (bug holes). c. Honeycombs.

d. Rock holes.

2. Scabbing:

a. Scabbing is defect in which parts of the form face, including release agent, adhere to concrete.

3. Foreign material embedded in face of concrete.

4. Fins 1/16 inch or more in height. B. Installer or Applicator:

1. Installer or applicator is the person actually installing or applying the product in the field at the Project site.

2. Installer and applicator are synonymous.

C. Other words and terms used in this Specification section are defined in ACI 116R.

1.4 SUBMITTALS

A. Shop Drawings:

1. Submittals shall be made in accordance with the General Requirements, Additional General Requirements and as specified herein.

2. Product technical data including:

a. Acknowledgement that products submitted meet requirements of standards referenced.

b. Manufacturer's installation instructions.

3. Certifications:

a. Certification of aggregate gradation.

b. Certification that products being used will not interfere with bonding of future floor or wall finishes.

B. Miscellaneous Submittals:

1. Submittals shall be made in accordance with the General Requirements, Additional General Requirements and as specified herein.

1.5 DELIVERY, STORAGE, AND HANDLING

A. Comply with manufacturer's recommendations and requirements for materials used.

1.6 WARRANTY

A. Provide warranty equal to specified manufacturer's standard warranty for all products used.

PART 2 - PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Subject to compliance with the Contract Documents, the following manufacturers are acceptable:

1. Chemical floor sealer (CS-1) (CS-3):

a. L&M Construction Chemicals, Inc. b. Euclid Chemical Co.

c. Dayton Superior. d. Or Equal.

2. Bonding agents:

a. Euclid Chemical Co.

b. BASF Admixtures, Inc.

c. L&M Construction Chemicals, Inc. d. Or Equal.

2.2 MATERIALS

A. Chemical Floor Sealer CS-1:

1. Colorless low VOC water-based solution containing acrylic copolymers. a. ASTM C1315, Class B, minimum 30 percent solids.

b. ASTM C309, Type 1.

c. Non-yellowing UV resistant.

d. Capable of being painted after cured.

2. L&M Construction Chemicals, Inc. Dress and Seal WB 30, Euclid Chemicals

Super Floor Coat, Or Equal. B. Bonding Agent:

1. For use only on concrete surfaces not receiving liquid water repellent coating:

a. High solids acrylic latex base liquid for interior or exterior application as a bonding agent to improve adhesion and mechanical properties of concrete patching mortars.

b. Euclid Chemical Co. "Flex-Con."

c. BASF Admixtures, Inc. "Acryl-Set."

d. L&M Construction Chemicals, Inc. "Everbond." e. Thoro System Products "Acryl 60."

f. Or Equal

2. For use only on concrete surface receiving liquid water repellent:

a. Non-acrylic base liquid for interior or exterior application as a bonding agent to improve adhesion and mechanical properties of concrete patching mortars.

C. Cement:

1. ASTM C150, Type II or V Portland for all concrete.

D. Aggregate:

1. Sand: Maximum size #30 mesh sieve.

_{2. For exposed aggregate finish surfaces: Same as surrounding wall.}

E. Water: Potable.

F. Non-Shrink Grout: See Specification section 03600, Grouts, and Specification section 03300, Cast-in-Place Concrete.

2.3 MIXES

A. Bonding Grout: One (1) part cement to one (1) part aggregate. B. Patching Mortar:

1. One (1) part cement to two and one-half (2-1/2) parts aggregate by damp loose volume.

a. Substitute white Portland cement for a part of gray Portland cement to produce color matching surrounding concrete.

PART 3 - EXECUTION

3.1 PREPARATION

A. For methods of curing, see Specification section 03360, Concrete Curing, Finishing and Dampproofing.

B. Preparation of Bonding Grout Mixture:

1. Mix cement and aggregate.

2. Mix bonding agent and water together in separate container in accordance with manufacturer's instructions.

3. Add bonding agent/water mixture to cement/aggregate mixture.

4. Mix to consistency of thick cream.

5. Bonding agent itself may be used as bonding grout if approved by manufacturer and ENGINEER.

C. Preparation of Patching Mortar Mixture:

1. Mix cement and aggregate.

2. Mix bonding agent and water together in separate container in accordance with manufacturer's instructions.

3. Add only enough bonding agent/water mixture to cement/aggregate mixture to allow handling and placing.

4. Let stand with frequent manipulation with a trowel, until mix has reached stiffest consistency to allow placement.

D. Clean surfaces in accordance with ASTM D4258 to remove dust, dirt, form oil, grease, or other contaminants prior to abrasive blasting, chipping, grinding or wire brushing.

1. Abrasive blast surfaces in accordance with ASTM D4259 and SSPC SP13/NACE No. 6 to completely open defects down to sound concrete and remove laitance.

a. If additional chipping or wire brushing is necessary, make edges perpendicular to surface or slightly undercut.

b. No featheredges will be permitted.

2. Rinse surface with clean water and allow surface water to evaporate prior to repairing surface defects.

E. Repairing Surface Defects:

1. This method of repairing surface defects is to be used only on vertical concrete surfaces, in tanks containing water, surfaces to receive liquid water repellent and exterior surfaces.

2. Fill and repair using patching mortar mix specified in Article 2.3.

a. Use non-shrink grout to fill tieholes as outlined in this Specification section.

3. If required by bonding agent manufacturer, etch surfaces with a muriatic acid solution followed by a thorough rinse with clean water.

a. Test concrete to determine pH level and continue flushing with clean water until surface pH is within acceptable limits.

4. Dampen area to be patched and an area at least 6 inches wide surrounding it prior to application of bonding grout.

5. Brush bonding grout into the surface after the surface water has evaporated.

6. Allow bonding grout to set for period of time required by bonding agent manufacturer before applying premixed patching mortar.

7. Fill tie holes with non-shrink non-metallic grout.

a. Where exposed to view and scheduled to receive concrete Finish #2 or #5, hold grout below surface of concrete and fill with patching mortar to match surrounding concrete.

8. Fill all other defects with patching mortar. a. Match color of surrounding wall.

b. Do not use acrylic bonding agent in patching mortar for filling defects in surfaces to be treated with liquid water repellent.

9. Consolidate grout or mortar into place and strike off so as to leave patch slightly higher than surrounding surface.

10. Leave undisturbed for at least 60 minutes before finishing level with surrounding surface.

a. Do not use metal tools in finishing a patch in a formed wall which will be exposed or coated with other materials.

11. Keep areas damp in accordance with grout manufacturer or bonding agent manufacturer's directions.

3.2 INSTALLATION AND APPLICATION

A. Do not repair surface defects or apply wall or floor finishes when temperature is or is expected to be below 50 degrees F.

1. If necessary, enclose and heat area to between 50 and 70 degrees F during repair of surface defects and curing of patching material.

a. Use only clean fuel, indirect fired heating apparatus. B. Chemical Floor Sealer Application:

1. Apply to floor areas indicated on the Drawings in accordance with manufacturer's recommendations.

2. Apply at rate recommended by manufacturer.

3. After final coat of material is applied, remove surplus in accordance with manufacturer's recommendations.

4. Do not apply sealer to floors scheduled to receive epoxy floor finish. C. Concrete Finishes for Vertical Wall Surfaces:

1. General: Give concrete surfaces finish as specified below after removal of formwork and repair of surface defects.

2. Finish #1 - As cast rough form finish:

a. Selected forming materials are not required.

b. Prepare surface in accordance with Article 3.1 and repair the following surface defects:

1) Tie holes.

2) Honeycombs deeper than 1/4 inch.

3) Air pockets deeper than 1/4 inch.

4) Rock holes deeper than 1/4 inch.

c. Chip or rub off fins exceeding 1/4 inch in height.

d. Use at unexposed surfaces such as foundations and backfilled surfaces of walls not to be waterproofed.

3. Finish #2 - As cast form finish:

a. Form facing material shall produce a smooth, hard, uniform texture.

1) Use forms specified for surfaces exposed to view in accordance with

Specification section 03100, Concrete Formwork.

b. Prepare surface in accordance with Article 3.1 and repair the following surface defects:

1) Tie holes.

2) Honeycombs deeper than 1/4 inch or larger than 1/4 inch in diameter.

3) Air pockets deeper than 1/4 inch or larger than 1/4 inch in diameter.

4) Rock holes deeper than 1/4 inch or larger than 1/4 inch in diameter.

5) Scabbing.

c. Chip or rub off fins exceeding 1/8 inch in height.

1) Finish shall provide uniform color and texture. d. Provide this finish for:

1) Inside walls of wet wells, basins, tanks, and manholes, refuse pit walls pipe trenches.

2) Walls being waterproofed or coated with some other material.

3) Exposed surfaces not specified to receive another finish.

4. Finish #5 - Smooth form finish:

a. Form facing material shall produce a smooth, hard, uniform texture.

1) Use forms specified for surfaces exposed to view in accordance with

Specification section 03100, Concrete Formwork.

b. Prepare surface in accordance with Article 3.1 and repair the following surface defects:

1) Tie holes.

2) Honeycombs, air pockets, rock holes and other holes deeper than 1/16 inch or larger than 1/16 inch in diameter.

3) Scabbing.

c. Chip or rub off fins exceeding 1/16 inch in height.

d. Provide this finish for:

1) All surfaces which are to be painted, are to receive tank linings or are to remain exposed to view.

D. Related Unformed Surfaces Except Slabs:

1. Strike smooth and level tops of walls or buttresses, horizontal offsets, and similar unformed surfaces occurring adjacent to formed surfaces after concrete is placed.

2. Float surface to a texture consistent with that of formed surfaces.

a. If more than one (1) finish occurs immediately adjacent to unformed surface, provide surface with most stringent formed surface requirement.

3. Continue treatment uniformly across unformed surfaces. E. Concrete Finishes for Horizontal Slab Surfaces:

1. General:

a. Tamp concrete to force coarse aggregate down from surface.

b. Screed with straightedge, eliminate high and low places, bring surface to required finish elevations; slope uniformly to drains.

c. Dusting of surface with dry cement or sand during finishing processes not permitted.

2. Unspecified slab finish:

a. When type of finish is not indicated, use following finishes as applicable:

1) Surfaces intended to receive bonded applied cementitious applications: Scratched finish.

2) Surfaces intended to receive roofing, or waterproofing membranes: Floated finish.

3) Floors: Troweled finish.

_{4) Garage floors and ramps: Broom or belt finish.}

5) Exterior slabs, sidewalks, platforms, steps and landings, and ramps, not covered by other finish materials: Broom or belt finish.

6) All slabs to receive a floated finish before final finishing.

3. Scratched Slab Finish: After concrete has been placed, consolidated, struck off, and leveled to a Class B tolerance, roughen surface with stiff brushes or rakes before final set.

4. Floated finish:

a. After concrete has been placed, consolidated, struck off, and leveled, do no further work until ready for floating.

b. Begin floating when water sheen has disappeared and surface has stiffened sufficiently to permit operations.

1) Use wood or cork float.

c. During or after first floating, check planeness of entire surface with a 10-foot straightedge applied at not less than two (2) different angles.

d. Cut down all high spots and fill all low spots to produce a surface with Class

B tolerance throughout.

e. Refloat slab immediately to a uniform texture.

5. Troweled finish:

a. Float finish surface to true, even plane. b. Power trowel, and finally hand trowel.

c. First troweling after power troweling shall produce a smooth surface which is relatively free of defects, but which may still show some trowel marks.

d. Perform additional trowelings by hand after surface has hardened sufficiently. e. Final trowel when a ringing sound is produced as trowel is moved over

^surface.

f. Thoroughly consolidate surface by hand troweling.

g. Leave finished surface essentially free of trowel marks, uniform in texture and appearance and plane to a Class A tolerance.

h. On surfaces intended to support floor coverings, remove any defects that would show through floor covering by grinding.

6. Broom or belt finish: Immediately after concrete has received a float finish as specified, give it a transverse scored texture by drawing a broom or burlap belt across surface.

7. Underside of concrete slab finish:

a. Match finish as specified for adjacent vertical surfaces.

b. If more than one (1) finish occurs immediately adjacent to underside of slab surface, provide surface with most stringent formed surface requirement.

3.3 FIELD QUALITY CONTROL

A. Horizontal slab finishes will be accepted provided:

1. Applicable specification requirements are satisfied.

2. Water does not pond in areas sloped to drain.

3. Gap between a 10-foot straightedge placed anywhere and the finished surface does not exceed:

a. Class A tolerance: 1/8 inch. b. Class B tolerance: 1/4 inch.

c. Class C tolerance: 1/2 inch.

4. Accumulated deviation from intended true plane of finished surface does not exceed 1/2 inch.

5. Accuracy of floor finish does not adversely affect installation and operation of movable equipment, floor supported items, or items fitted to floor (doors, tracks, etc.).

B. Unacceptable finishes shall be replaced or, if accepted in writing by ENGINEER, may be corrected provided strength and appearance are not adversely affected.

1. High spots to be removed by grinding and/or low spots filled with a patching compound or other remedial measures to match adjacent surfaces.

3.4 PROTECTION

A. All horizontal slab surfaces receiving chemical floor sealer shall be kept free of traffic and loads for minimum of 72 hours following installation of sealer.