Construction Manual  

 

846-3 CONSTRUCTION METHODS

(A) GENERAL

Prior to the placement of forms for curb and gutter, etc., the base or subgrade shall have been compacted to the degree required by the applicable section of the Specifications. As this item of work is one of the most visual of any item on a highway construction project, the Engineer and Technician should ensure that it is built to the proper line and grade and finished according to the Specifications. Poor curb and gutter construction will detract from the appearance of the entire roadway. The Contractor may elect to “slip form” the curb and gutter. If the Contractor chooses this option, he will have to submit a special non-vibrated concrete mix design.

 

The surface of the concrete should be given a light broom finish parallel to the curb or gutter line. As the appearance of curb and gutter is crucial to the appearance of the entire project, the Technician should constantly observe the finishing operations to ensure that good workmanship is being received.

 

Cure concrete in accordance with Subarticle 700-9(B).

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(B) FORMS

The Technician shall check and approve the form alignment and grade before the placement of any concrete. Flexible forms are typically utilized by the Contractor for sharp radii, and these are considered acceptable provided they will adequately support the typical section required. A string line or 10-foot straightedge shall be used to check the forms for straightness requirements. After forms are set, they shall be checked for alignment and grade according to the stakes previously established for this work. The Technician shall then check the entire form length for any visual irregularities in line or grade. If any major irregularities or discrepancies are noticed, the Technician shall consult with the Survey Party to determine if the grade stakes are correct. The Technician should also check the forms or slip-form machine to ensure that the thickness and shape of curb or curb and gutter conforms to the Standard Drawing. Do not take for granted that the forms or machine are set correctly.

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(C) JOINTS

No joint spacing shall be less than five feet. If there is a crack closer than five feet to a joint, then at least a 5-foot section must be removed and replaced. Curb and gutter placed adjacent to concrete pavement shall have the joints in the curb and gutter located to line up with joints in the concrete pavement. The Engineer does have the authority to alter joint spacing in order to prevent uncontrolled cracking. The Technician should periodically check the joints in the concrete curb and gutter to ensure that depth and width requirements of the joints are being met. Where curb and gutter is placed adjacent to any rigid object, expansion joints must be utilized. In curb and gutter sections, joint sealer shall not be poured above the top surface of the gutter. Joints in curb and gutter shall be sealed prior to backfilling or performing other adjacent operations. The Technician should check the joint operation and sealing operations at their initiations to determine if the requirements of the Specifications are being met. If a section is damaged prior to final acceptance, the minimum removal size will be five feet.

 

Form grooved contraction joints as required by Article 825-10(B).

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(D) SURFACE TOLERANCES

The finished surface shall not vary from a straight line by more than 1/4 inch when checked longitudinally with a 10-foot straightedge. The Technician should check this tolerance constantly to ensure that this requirement is being met. Specific attention should be given to this requirement to have a clear understanding with the Contractor of the tolerances that are expected. The Contractor should be immediately advised of any discrepancies noted, and if he proposes any corrective action other than removal and replacement of the curb and gutter at his expense, it must be approved by the Engineer. The finished gutter shall be checked by the Technician to ensure there is no standing water. This can be accomplished by the use of a straightedge, string line, or water after initial set of the curb and gutter. Prior to the final acceptance, the Contractor shall clean the curbs that are stained due to his operations. This would include earth material stains, asphalt stains, and tack material on curb. Tire marks due to the Contractor's operations shall also be removed. The Contractor is responsible for any defacing of the curb and gutter due to vandalism or weather.

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(E) BACKFILLING

Any honeycombing, etc., that is necessary to be patched prior to backfilling shall be pointed out to the Contractor as soon as forms are removed and prior to curing compound being applied. The backfill material shall be compacted to the same degree as adjacent undisturbed material. Backfilling should be accomplished within 4 calendar days after the specified three day curing period to prevent possible undermining and washing of base material under the curb and gutter. The joints should be sealed in the gutter prior to being backfilled to prevent contaminating the joints with earth material, which would prevent adherence of the joint sealer.

 

Until backfill is placed, it is crucial that proper drainage be provided behind the curb to assure that water does not stand against the curb and undermine any sections of the gutter. Any damage to the curb and gutter or base material under the gutter as a result of improper drainage shall be repaired at no cost to the Department.

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(F) OPENING TO TRAFFIC

Prior to placing traffic through a curb and gutter section, the Engineer should ensure that all corrective actions have been performed and the concrete has reached strength.

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846-4 MEASUREMENT AND PAYMENT

The Technician should remember when completing the pay record book for the items covered by this section of the Specifications to clearly delineate the size and type of the curb and gutter.

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ADDITIONAL RESOURCES