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Section 30 – Concrete Structures

(40°) F for an additional four (4) days. When required by the Agency, the Contractor shall

submit a written outline of the proposed methods for protecting the concrete.

30-15 SURFACE FINISH

All exposed surfaces of structures shall have a smooth form finish as specified in the ACI

Manual of Concrete Practice 301.5.3.3, ”Finishing Formed Surfaces”, unless otherwise shown

or specified in the Contract. All other surfaces shall have an ordinary surface finish unless

otherwise shown or specified in the Contract.

Immediately after forms have been removed, all form bolts shall be cut off one inch (1”)

below the finished surface of the structure and the holes remaining shall be filled with cement

mortar using one (1) part cement to two (2) parts sand. Add white cement as needed to match

surrounding concrete on all exposed surfaces.

Any defects in the concrete surface caused by poor material in the forms, poor form

construction, or by voids or pockets in the concrete, shall be repaired and finished to make the

surface finish uniform. The Agency may direct the Contractor to correct such defects at the

Contractor’s expense.

30-15.02 Smooth Form Finish (Sacking)

A smooth form surface for exposed surfaces or preparation for coating shall consist of

finishing the surfaces of the structure as necessary to produce smooth, even surfaces of

uniform texture and appearance, free of unsightly bulges, depressions and other imperfections.

The degree of care in building forms and character of materials used in form work will be a

contributing factor in the amount of additional finishing required to produce smooth, even

surfaces of uniform texture and appearance, free of unsightly bulges, depressions and other

imperfections, and the Agency shall be the sole judge in this respect. The use of power

carborundum stones or disks may be required to remove bulges and other imperfections. The

grout-cleaned finish (sacking) requires a sound, clean, dry substrate. Grind surfaces, including

seams, bumps, and imperfections smooth and flat. Remove form release agent, laitance, and

cure, if present. If coating is required, provide a profile for coating adherence by whip-blasting

or acid-etching. Wet a small area of concrete to be sacked and rub a slurry of gray concrete,

white concrete (to match existing color), and fine sand into the surface with a sponge float, filling

all holes. Non-epoxy acrylic bonding compound may be used in the slurry or in the water.

Scrape off excess slurry and rub area lightly with a burlap sack until uniform in appearance. If

approved by the Agency, a cementitious mortar may be troweled on the concrete surface after

achieving a smooth and flat surface by grinding, including seams, bumps, and imperfections.

30-15.03 Ordinary Surface Finish

The ordinary surface finish required on non-exposed concrete structures shall be minimized

by careful forming, use of quality materials, and proper concrete placement procedures.

Ordinary surface finish shall consist of removing snap ties and bolts to a minimum depth of one

inch (1") and filling the holes. Holes or depressions three-eighths inch (3/8”) or larger shall be

filled, all rock pockets shall be repaired, and all fins shall be removed.

30-15.04 Tolerance on Concrete Paving

All concrete structures having a roadway deck shall have a smooth riding surface. The

finished surface shall be tested with a twelve-foot (12’) straight edge. The surface shall not vary

more than 0.01 foot from a plane defined by the lower edge of the straight edge. All areas

higher than 0.01 foot above the test plane shall be removed by abrasive means. All areas lower

than 0.01 foot below the test plane shall be cut out to a depth of one inch (1”) below the test

plane and patched with epoxy concrete.