349 SECTION 748
748.01 Description
This work consists of constructing curb, gutter, or combination curb and gutter.
748.02 Equipment
Equipment Section Concrete Equipment 155
748.03 Materials
Item Section Concrete Class AE 802 Impervious Membrane Cure 810.01 B .1 or 810.02 B.2 Joint Materials 826 Expansion Joint Material 826.02 C or F Reinforcing Steel, Dowel Bars, and Tie Bars 836
748.04 Construction Requirements
A.General. Construct curb and gutter using a slip-form machine or full depth fixed forms. Do not allow traffic or equipment on newly placed concrete until it has attained a flexural strength of 450 psi or a compressive strength of 3,000 psi .
B.Excavation. Eliminate deviations greater than 1/2 inch when measured with a 10 foot straightedge. Compact the subgrade as specified in Section 203.04 G .4, “Compaction Control, Type C” . Remove all soft and yielding materials and replace the volume with aggregate base.
C.Mixing, Placing, and Finishing. Place curb and gutter concrete on a damp base. Consolidate the concrete by vibration. Check the top and face of curbs with a 10 foot straightedge and correct all variations gr eater than 1/4 inch in 10 feet before the final finish. Finish the exposed surfaces with a moistened wood float and a stiff bristled broom. Do not place concrete on or against frozen ground. If honeycombed areas are exposed when the forms are removed, the Engineer will determine if replacement is required. If replacement is not required, repair the honeycombed areas. When repairing the honeycombed areas, use mortar composed of one part cement and two parts sand, mixed with water. Do not use water to facilitate finishing. 350 D. Curing. Apply the final cure within 30 minutes of placing the concrete. Cover the entire concrete surface wi th an impervious membrane cure. Immediately cover the exposed sides of the concrete pavement with curing compound if removing forms exposes curing concrete before the expiration of the curing period. Allow concrete to cure for a period of at least 72 hours before performing work adjacent to the concrete. If weather conditions cause rapid drying of the curb and gutter surface, apply a fine mist or fog spray to the surface. Do not apply water with brushes. If the ambient temperature falls below 40°F, maintain the concrete surface temperature between 40°F and 90°F for the duration of the curing period. If Class ASE concrete is used, maintain the surface temperature between 50°F and 90°F. Conduct heating operations to avoid sudden temperature changes in the concrete. Before removing any enclosures, reduce the heat in a manner that will allow the concrete’s surfac e temperature to decrease to the air temperature at a rate not to exceed 15°F per hour. The Engineer will suspend the paving operations if the cure is not properly applied. Maintain the surface temperature of newly placed concrete above 40°F for 5 days. Submit a detailed temperature maintenance plan before placing concrete, if the ambient temperature is expected to drop below 40°F.
748.05 Method of Measurement
The Engineer will measure completed and in place as specified in Section 109.01, “Measurement of Quantities” and as follows: The Engineer will measure the flow line of curb and gutter and continuously through drainage structures and areas of dropped curb for driveways.
748.06 Basis of Payment
Pay Item Pay Unit Curb and Gutter Type __ Linear Foot Curb Type __ Linear Foot Valley Gutter Linear Foot or Square Yard Such payment is full compensation for furnishing all materials, equipment, labor, and incidentals to complete the work as specified. Section 750 351 SECTION 750 DETECTABLE WARNING PANELS, SIDEWALKS, DRIVEWAYS, AND MEDIANS
750.01 Description
This work consists of constructing detectable warning panels, sidewalks, driveways, and medians.
750.02 Equipment
Equipment Section Concrete Equipment 155
750.03 Materials
Item Section Concrete Class AE 802 Impervious Membrane Cure 810.01 B Preformed Expansion Joint Material for Structural Construction 826.02 C or F Reinforcing Steel, Dowel Bars, and Tie Bars 836 Detectable Warning Panels 885 For imprinted concrete use any size coarse aggregate specified in Section 802.01 C.2, “Coarse Aggregate” . Produce a mix that consists of 60 percent fine aggregate and 40 percent coarse aggregate.
750.04 Construction Requirements
A.Forms. Use fixed forms or slip forms. If using fixed forms, construct straight forms so that the top face and the contact surface do not vary from true by more than 1/4 inch when measured using a 10 foot straightedge. On curves, install forms to within 1/2 inch of the specified radius.
B.Excavation. Eliminate deviations greater than 1/2 inch when measured with a 10 foot straightedge. Compact the subgrade as specified in Section 203.04 G .4, “Compaction Control, Type C” . Remove all soft and yielding materials and replace the volume with aggregate base.
C.Mixing Pigmented Concrete. While the mixer is operating at mixing speed, add pigment to the concrete at a ratio recommended by the manufacturer. Uniformly blend the pigment into the concrete.
D.Placing Concrete. Place concrete on a damp surface. Uniformly consolidate concrete by vibration. Repair or replace concrete if honeycombed areas are exposed when the forms are removed. The Engineer will determine if replacement is required. When repairing honeycombed areas,
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 384–385 of 550.