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This section consists of the general requirements for the construction of all incidental concrete construction. The provisions of Sections 838, 840, 842, 844, 846, 848, 850, 852, 853, 854, 855, 857, and 858 will prevail over any conflicting provisions of this section.
Concrete shall meet the applicable provisions of Section 1024.
Where the concrete is to be precast and then transported to the required location, the applicable provisions of Section 1077 shall be followed and will prevail over any conflicting provisions of this section.
(A) General:
Forms shall be maintained true to the required lines, grades and dimensions. Forms shall be constructed with material of such strength and with sufficient rigidity to prevent any appreciable deflection between supports. Forms shall be mortar-tight, and shall be filleted at sharp corners when indicated on the plans.
Clamps, pins, and metal spacers, anchorages, and other connecting devices shall be designed to hold the forms rigidly together. Any metal spacers or anchorages which are required within the forms shall be so constructed or installed that the metal work can be removed to a depth of at least 1 inch from the exposed surface of the concrete without injury to the surface. The recess thus formed in the concrete shall have a diameter not greater than 1 1/2 times depth.
The shape, strength, rigidity, and surface smoothness of forms that are to be re-used shall be maintained at all times. Forms shall be thoroughly cleaned of all dirt, mortar, and foreign material before being used.
Before concrete is placed, all inside form surfaces shall be thoroughly coated with commercial quality form oil or other equivalent coating.
(B) Wood Forms:
The forms shall have a smooth and uniform texture. Joints between forms shall be tight and even so that no appreciable form marks remain after the forms are removed.
Plywood sheets showing torn grain, worn edges, patches, or other defects which impair the texture of concrete surfaces shall not be used on surfaces which will be exposed to view.
(C) Metal Forms:
Metal forms shall be of such thickness and rigidity that the forms will remain true to shape. Bolt and rivet heads shall be counter-sunk. Metal forms which do not present a smooth surface or line up properly shall not be used. Care shall be exercised to keep metal forms free from all foreign matter which will discolor the concrete.
Reinforcement shall be furnished and placed as shown on the plans and in accordance with the provisions of Section 425.
No concrete shall be placed until the foundation, the adequacy of the forms, and the placing of reinforcement and other embedded items have been inspected and approved by the Engineer.
Concrete shall be placed in daylight unless an adequate lighting system meeting the approval of the Engineer is provided.
In preparation for placing concrete all debris shall be removed from the interior of forms. Earth or base course surfaces on which concrete is to be placed shall be in a moist condition immediately before placing concrete. No concrete shall be placed on excessively wet or frozen surfaces.
No concrete shall be used which does not reach its final position in the forms within the time stipulated in Subarticle 10004(E).
Concrete shall be placed as to avoid segregation of the materials and the displacement of the reinforcement. The concrete shall be thoroughly worked during the placing. The working shall be such as to bring mortar against the forms to produce a smooth finish, substantially free from water and air pockets or honeycombs.
No concrete shall be placed when the air temperature, measured at the location of the concrete operation in the shade away from artificial heat, is below 35°F without permission of the Engineer. When such permission is granted, the aggregates and water shall be uniformly heated to a temperature of not higher than 150°F. The temperature of the heated concrete shall not be less than 55°F and not more than 80°F at the time it is placed in the forms.
The provisions of Article 4207 will be applicable to testing the slump of the concrete.
(A) General:
The type of finish to be used shall be that required by the section of the specifications directly applicable to the work being constructed.
(B) Ordinary Surface Finish:
All form ties or metal spacers shall be removed to a depth of at least 1 inch below the surface of the concrete and the resulting holes or depressions cleaned and filled with grout. Metal devices with exposed cross-sectional area not exceeding approximately 0.05 square inches on surfaces permanently in contact with earth fill may be broken off flush with the surface of the concrete.
All fins caused by form joints and other projections shall be removed. Stains and discoloration shall be removed. All pockets shall be cleaned and filled with grout as directed by the Engineer. Grout shall consist of 1 part cement and 2 parts sand. Grout shall be cured for not less than 3 days. After the grout has thoroughly hardened, the patch shall be rubbed with a carborundum stone as required to match the texture and color of the adjacent concrete.
The surface of all concrete to be repaired with grout shall be thoroughly soaked with water prior to application of the grout.
On surfaces which are to be backfilled or surfaces which are enclosed, the removal of form marks, fins, and pockets; the rubbing of grouted areas to uniform color; and the removal of stains and discoloration will not be required.
(C) Sidewalk Finish:
Fresh concrete shall be struck off and compacted until a layer of mortar has been brought to the surface. The surface shall be finished to grade and cross section with a float, troweled smooth, and finished with a broom.
(D) Rubbed Finish:
After the ordinary surface finish has been completed, the entire surface shall be thoroughly wetted and rubbed with a coarse carborundum stone or other equally good abrasive to bring the surface to a smooth texture and remove all form marks. The paste formed by the rubbing as above described shall be finished carefully stroking with a clean brush, or it shall be spread uniformly over the surface and allowed to take a "reset," after which it shall be finished by floating with a canvas, carpet-faced, or cork float; or rubbed down with dry burlap.
(E) Float Finish:
The surface shall be finished with a rough carpet float or other suitable device leaving the surface even, but distinctly sandy or pebbled in texture.
Forms shall not be removed from freshly placed concrete until it has hardened sufficiently to resist spalling, cracking, or any other damage.
825-8 PROTECTION FROM COLD WEATHER.
Concrete that has been placed when the atmosphere temperature is below 35°F, and concrete that has not yet attained an age of 3 days before the atmospheric temperature falls below 35°F, shall be immediately protected from freezing until at least 3 curing days have elapsed. A curing day shall be as defined in Article 8259. If the concrete contains fly ash or ground granulated blast furnace slag, it shall be protected from freezing until a minimum of 7 curings days have elapsed.
Immediately after finishing operations have been completed and surface water has disappeared, the concrete shall be cured with membrane curing compound in accordance with the provisions of Subarticle 7009(B). Where forms are removed before the expiration of the required curing period, the curing compound shall be applied immediately after the forms have been removed.
The required curing period shall be 7 curing days.
A curing day will be considered as any consecutive 24 hour period, beginning with the manipulation of each separate mass has been completed, during when the air temperature adjacent to the mass does not fall below 40°F.
(A) General:
All joints shall be constructed in accordance with the requirements of these specifications and the details shown on the plans.
Joints shall be constructed at right angles to the surface of the concrete. Joints shall be located at right angles to the longitudinal centerline of curb, curb and gutter, gutter, islands, median, median barrier, and all paved areas, except where different joint locations are called for on the plans.
Where concrete is to be placed adjacent to any existing slab or pavement which has a broken or irregular edge, a reasonably vertical edge shall be provided on the existing slab or pavement by sawing.
(B) Grooved Contraction Joints:
Grooved contraction joints shall be formed by a tool specifically constructed for this purpose, or by sawing with an approved concrete saw, or by other methods acceptable to the Engineer.
Grooved contraction joints shall be of the depth shown on the plans and between 1/4 inch and 1/2 inch wide unless otherwise shown on the plans. If formed by a tool, they shall have a radius of 1/8 inch at the corners of the adjacent concrete.
(C) Expansion Joints:
Construction joints shall be constructed with an expansion joint filler. The filler shall be cut into the shape necessary to fill the joint. The filler shall be 1/2 inch thick unless otherwise indicated on the plans. After the concrete has hardened the filler shall be cut away to a depth of 1/2 inch to provide space for the joint sealer.
An expansion joint shall be constructed adjacent to any existing slab, pavement, or structure against which new concrete is to be placed and at other locations where required by the plans.
(D) Construction Joints:
Construction joints shall be constructed as shown on the plans, or where permitted in writing by the Engineer.
(E) Sawing Joints:
Sawing shall be done as soon as practical after the concrete has hardened sufficiently to be sawed without spalling and raveling but not more than 24 hours after the concrete has been placed.
(F) Sealing Joints:
All contraction and expansion joints shall be sealed except as otherwise specified in that section of the specifications directly applicable to the work being constructed. Sealing shall be done before the backfill is placed.
Before the joint is sealed, the joint shall be thoroughly cleaned to remove all foreign matter and dust. Joints shall be thoroughly dry before sealing.
Joints shall be filled to within 1/8 inch to 1/4 inch of the surface of the concrete with joint sealer. Care shall be taken in handling the nozzle of the application equipment so that the joint will be filled from the bottom up. Any sealer spilled on the surface of the concrete shall be removed immediately.
Equipment used to place joint sealer shall meet the specifications of the manufacturer of the sealer material.
There will be no direct payment for the work covered by this section.
Payment at the contract prices for the various items covered
by those sections of the specifications directly applicable to
the work being constructed will be full compensation for all work
covered by this section.