Section 609 — Curb and Gutter

Description

609.01This work consists of constructing or resetting curb, gutter, combination curb and gutter, and wheelstops.

Material

609.02Conform to the following Subsections: General mortar 701.05(a) Reinforcing steel 709.01 Rock for masonry structures (stone curbing) 705.03 Sealants, fillers, and seals 712.01 Soil and soil- aggregate materials 704.01

Construction Requirements

609.03General. Excavate and backfill according to Section 209. Place and compact the bedding material. Compact the bedding material with at least three passes of a lightweight mechanical tamper, roller, or vibratory system. Construct minor concrete according to Section 601.

609.04Stone Curb. Do not use stone with visible drill marks on the exposed faces. Conform to the dimensions of stone curb specified and the following:

(a)Type 1. Saw or point the top surface of vertical stone curb to an approximate true plane with no depression or projection on that surface of over ¼ inch. Pitch the front and back arris lines straight and true. Limit projections or depressions on the back surface to not exceed a batter of 1 inch horizontal to 3 inches vertical. Saw, point, or smooth quarry split the front exposed face of the vertical stone curb and form to an approximately true plane. Limit projections or depressions on the remaining face distance to 1 inch or less from the plane of the exposed face. Square the ends of vertical stone curb so when the sections are placed end to end, no space more than ½ inch shows for the full width of the top surface and for the entire exposed front face. The remainder of the end may break back no more than 4 inches from the plane of the joint. Cut the joints of circular or curved stone curb on radial lines. Make stone curb segments at least 48 inches long, but the length may vary where a depressed or modified section of curb is required for driveways, crossings, or closures.

(b)Type 2 (sloped stone curb). Conform to the requirements of Type 1 stone curb, except as follows: The maximum allowable projection or depression on a horizontal top surface is limited to ½ inch. On other exposed faces, the maximum allowable projection or depression is limited to 1 inch. For unexposed surfaces, the maximum allowable projection or depression from a true plane on a 24-inch length is 3 inches. The maximum allowable space showing on expo sed faces between adjacent segments of slope stone curb is ¾ inch. Make slope stone curb segments at least 24 inches long. Clean the curb material thoroughly and wet it immediately before setting. Set the curb in bedding material so the face and top lines are to line and grade. Make the joints ½ to 1 inch wide and fill the joints with mortar. Complete the first 25 feet of curb to demonstrate the ability to build a curb conforming to these requirements. Do not continue construction until the 25- foot test sec tion is approved. Where a concrete pavement is constructed contiguous to the curb, construct the joints in the curb directly in line with the pavement expansion joints. Make the curb joint ¾ inch wide and fill it with expansion joint filler of the same nominal thickness as the pavement joint. Fill voids between the joint filler and the curb with mortar.

609.05Concrete Curb or Curb and Gutter. The curb or curb and gutter may be cast -in-place or slip - formed.

(a)Cast -in-place. Use forms that extend for the full depth of the concrete. Use curved forms for curb with a radius of 300 feet or less.

(1)Contraction joints. Construct at intervals no more than 10 feet. Use metal divider plates or form joints with a jointing tool or saw joints to a depth of ¼ to ⅓ the thickness of the concrete and about ⅛ inch wide. If the curb is constructed adjacent to or on concrete pavement, match the contraction joints in the pavement.

(2)Expansion joints. Form expansion joints at intervals of 60 feet using a ¾- inch thick preformed expansion joint filler. Where the curb is constructed adjacent to or on rigid pavement, match the expansion joints in the pavement. Finish the concrete smooth and even with a wood float. Broom finish parallel to the curb line according to Subsection 552.12(c)(2) . If an exposed aggregate finish is required, finish according to Subsection 552.12(c)(4) . Leave forms in place for 24 hours or until the concrete has set sufficiently so the forms can be removed without harming the curb.

(b)Slip-formed. Use a self -propelled automatic curb machine or a paver with curb attachments. Use a machine that is heavy enough to obtain consolidation without the machine riding above the foundation. Adjust the concrete aggregate gradation, if necessary, to produce a curb or curb and gutter that has well defined web marks of water on the surface. Remove and replace sections with craters larger than 3⁄16 -inch or other sections determined to be damaged or defective. Repairing surface craters and other defective sections by plastering is not allowed. After the concrete has hardened sufficiently to allow sawing without damage, saw contraction joints according to Subsection 609.05(a)(1). Construct expansion joints according to Subsection 609.05(a)(2) .

609.06Asphalt Concrete Curb or Gutter. Where curb is constructed on a pavement, apply a n asphalt tack coat according to Section 412 on the area under the curb. Construct asphalt concrete curb according to Section 403, Type II. Use a self -propelled automatic curb machine or a paver with curb attachments that is heavy enough to compact a cu rb without riding above the foundation. Make the curb uniform in texture, shape, and density. Curb may be constructed by other means only in short sections or sections with short radii. Construct gutters according to Sectio n 403, Type II.

609.07Bonding Concrete Curb to Surface. If bonding curb to asphalt pavement, thoroughly clean the pavement surface before placing the curb. Remove dust and loose material on the asphalt pavement. Bond the extruded curb to the asphalt pavement using an approved adhesive or a two- component epoxy designed to bond curb to the pavement. 609.08 Resetting Stone Curb. Salvage the stone curb according to Subsection 203.04. Cut or fit the curb as necessary for installation. Replace lost, damaged, or destroyed curb. Reset the curb according to Subsection 609.04.

609.09Wheelstops. Pin the wheelstops in place with two 36- inch sections of No. 6 reinforcing steel or ¾-inch steel rods. Reset wheelstops in the same manner.

609.10Acceptance. See Table 609-1 for sampling, testing, and acceptance requirements. Bedding material will be evaluated under Subsections 106.02 and 106.04. Material for mortar will be evaluated under Subsections 106.02 and 106.03. Mortar will be evaluated under Subsections 106.02 and 106.04. Precast units (wheelstops) will be evaluated under Subsections 106.02 and 106.03. Stone for stone curbing will be evaluated under Subsections 106.02 and 106.04. Construction of curb, curb and gutter, gutter , and wheelstops will be evaluated under Subsections 106.02 and 106.04. Asphalt concrete will be evaluated under Section 403. Asphalt tack coat will be evalua ted under Section 412. Excavation and backfill will be evaluated under Section 209. Minor concrete will be evaluated under Section 601.

Measurement

609.11Measure the Section 609 pay items listed in the bid schedule according to Subsection 109.02 and the following as applicable: When measuring curb or curb and gutter by the linear foot, do not deduct the length for drainage structures installed in the curb section or for driveway and accessibility ramp openings where the gutter is continuous across the opening.

Payment

609.12The accepted quantities will be paid at the cont ract price per unit of measurement for the Section 609 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 . Table 609-1 Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Source

Bedding

material (704.01 ) Measured & tested for conformance (106.04 & 105) Gradation − Subsection

704.011 per soil type & source of material Source of material Yes Before using in work Not required if using

Governmen t-

furnished source Liquid limit − AASHTO R 58 & T 89, Method A " " " " "

Production

Bedding

material (704.01 ) Measured & tested for conformance (106.04 ) Gradation − AASHTO T 27 & T 11 1 per 600 yd3 Production output or stockpile Yes 4 hours − Liquid limit − AASHTO R 58 & T 89, Method A " " " " −