609Concrete Gutter, Curb, and Combination Curb and Gutter

609.01 Description. This work consists of constructing curb, gutter, and combination

curb and gutter in accordance with these specifications and in reasonably close conformity with the lines, grades, dimensions, and cross sections shown on the plans or as established.

609.02 Materials. Concrete for detached curb, gutter, and combination curb and gutter

shall meet the requirements of Section 601. Concrete for curbs integral with concrete pavement shall meet the requirements of Section 501. Mixtures for bituminous curb shall be in accordance with Sections 401 and 403 and, unless otherwise specified or approved, shall be a Type ST, 12.5 mm mixture.

609.03 Construction Requirements.

609.03.1 Excavation and In-Grade Preparation. Excavation and in-grade preparation

for gutter, curb, and combination curb and gutter shall be performed in accordance with the applicable provisions of Section 321.

609.03.2 Cast-in-Place Hydraulic Cement Concrete.

609.03.2 1--Forms. Forms, except for divider plates and templates, may be wood or metal.

All forms shall be full depth, straight, and free of warp and shall be securely staked, braced, and sufficiently tight to prevent leakage of mortar. All forms shall be cleaned thoroughly and oiled before placing concrete against them. Lumber for wood forms shall be sound, free of bulges, loose knots, and warps, and of uniform width. All lumber shall be dressed commercial lumber at least two inches thick, except the Engineer may permit the use of flexible material on short radii. Metal forms shall be of approved sections and shall have a flat surface on top. They shall present a smooth surface and be of sufficient strength when braced to withstand the weight of the concrete without bulging or displacement. Special car e shall be exercised to keep metal forms free from rust, grease, or other foreign matter that would discolor the concrete. Metal templates or dividing plates shall be of sufficient thickness and of such design as to hold the forms rigidly in place and to produce a smooth vertical joint after the plates are removed. They shall be of the full dimensions shown on the plans for curb, gutter, or combination curb or gutter.

609.03.2 2--Proportioning, Mixing, and Placing Concrete. Unless otherwise specified,

concrete used for detached curb, gutters, and combination curb and gutter shall be Class "B" proportioned, mixed, and placed in accordance with the provisions of Section 601. Concrete used for curb integral with concrete pavement shall be proportioned, mixed, and placed in accordance with the provisions of Section 501. The concrete shall be placed on a moist grade and consolidated by vibration or other acceptable methods. Weep holes shall be pl aced through cu rbs where indicated on the plans or as directed.

609.03.2 3--Extruded Construction. Concrete curb and curb and gutter may be

constructed by the use of a curb forming mach ine. Such a machine shall conform to (a), (b), and (e) of Subsection 609.03.3.2, and in addition, its continued use shall be contingent upon it producing curb with the specified sec tion, line, and grade. If these conditions cannot be met, construction shall be by conventional methods. In the event a curb forming machine is used , minor modifications in the concrete mix design may have to be made to improve placement, subject to approval of the State Materials Engineer.

609.03.2 4--Sections and Joints . Concrete curb, gutter, or combination curb and gutter

shall be constructed in uniform sections of the length specified on the plans. These lengths may be reduced where necessary for closure but no section less than six feet will be permitted. The templates shall be accurately set before placing the concrete and, to the extent possible, allowed to remain in place until the concrete has set sufficiently to hold its shape. The templates shall be removed while the forms are still in place. Expansion joints shall be formed of premolded joint filler of the specified thickness, and shall be placed in line with expansion joints in the adjoining pavement or structure and at other locations designated on the plans. All joint fillers shall be cut to full cross section and shall extend for full depth, width, and length. All expansion joint material protruding after the concrete is finished shall be trimme d as directed. Immedi ately after removal of forms, the outer edges of filled joints shall be carefully exposed.

609.03.2 5--Finishing. The concrete shall be finished smooth and even by an approved

float. Forms on the face of curbs shall be re moved as soon as the concrete will hold its shape, and the surface shall be finished with a float to a smooth even texture. Plastering will not be permitted. Strike-off templates of the form and shape of the gutter shall be used to shape the top surface of gutters. Before fi nal finishing the surface of gutters shall be checked with a 10-foot straightedge, and all irregularities of more than 1/8 inch in 10 feet shall be corrected. Edges on the faces of curbs shall be rounded with finishing tools having the radii shown on the plans. Edges where templates have been removed or expansion joint material has been placed shall be finished with an edging tool having a radius of 1/4 inch. All exposed surfaces against which some rigid type of cons truction is to be made shall be left smooth and uniform so as to permit free movement of the curb, gutter, or combination curb and gutter. All tool marks shall be removed with a wetted brush or wood float. The finished surface shall be a uniform color free from discolorations.

609.03.2 6--Protection and Curing. Concrete shall be cured for at least 72 hours. Curing

shall be by moist cotton or burlap mats, waterproof paper, white polyethylene sheeting, straw curing as set out in Subsection 501.03.20, or by other approved methods. The Contractor shall have materials available at all times for the protection of unhardened concrete against rain. During the curing period all traffic, both pedestrian and vehicular, shall be kept off the concrete. Vehicular traffic shall be kept off for such additional time as the Engineer may direct. The Contractor shall protect the work from damage until release of maintenance. All sections dama ged before release of maintenance shall be removed and reconstructed by the Contractor without extra compensation.

609.03.3 Bituminous Curbing.

609.03.3 1--Preparation of Bed. When curbing is to be constructed on a newly placed

bituminous surface, the curb may be laid if the surface is clean. When curbing is to be constructed on concrete or bituminous pavement that is not newly placed, the bed shall be thoroughly swept and cleaned by compressed air. The surface shall be dry, and immediately prior to placement of the curb shall be tacked with bituminous material of the type and grade approved by the Engineer. The rate of application of the tack coat material shall be between 0.05 to 0.15 gallons per square yard of surface. The Contractor shall prevent the tack coat material from spreading to areas outside that to be occupied by the curb.

609.03.3 2--Placing. Bituminous curbing shall be constructed with a self-propelled

curbing machine or paver with curbing attach ments designed to extrude and compact the material in accordance with the typical section on straight and curved alignments. The automatic curb machine shall meet the following requirements and shall be tentatively approved prior to its use. Its continued use shall be contingent upon its production of curbing meeting the specified requirements.

609.03.3 3--Painting. When painting is required, it shall consist of two coats of the

specified traffic paint meeting requirements of Section 625. Glass beads shall also conform to the requirements of Section 625 and shall be applied onto the top coat of paint in a manner that will embed the beads sufficiently to adhere to the painted surface.

609.03.4 Backfilling and Cleaning Up . After the concrete has set sufficiently or the

bituminous curb has cooled, the areas on the sides of the curb, gutter, and combination curb and gutter shall be filled to the required elevation with the specified materials and compacted as specified or directed. All surplus material shall be disposed of as directed, and the entire area shall be left in a neat and satisfactory condition.

609.04 Method of Measurement . Concrete gutter, curb, combination curb and gutter,

and bituminous curb will be measured by the linear foot along the face of the curb or flow line of the gutter. Deduction will be made for driveway openings. Concrete integral curb, complete in place, w ill be measured by the linear foot along the face of the curb including the full length of curb returns for driveways. No deduction in length will be made for drainage structures such as catch basins and inlets installed in the curbing.