8-4 Section 802. Concrete Curb, Gutter, and Dividers
802.01 Description
This work consists of constructing the following items on the prepared base, with or without reinforcement, as required by the contract:
A.Concrete curb, combination curb and gutter, and curb nose;
B.Valley gutter and shoulder gutter;
C.Downspout headers and spillways ; and
D.Dividers.
802.02 Materials
Provide materials in accordance with the following sections : Curing Compound ................................................................................. 903 Asphaltic Materials ................................................................................ 904 Steel Reinforcement ............................................................................. 905 Geot extile Liner ..................................................................................... 910 Lane Ties .............................................................................................. 914 Joint Fillers ............................................................................................ 914 Concrete, Grade 3500 ........................................................................ 1004 Mortar, Type R -2 ................................................................................. 1005
802.03 Construction
A.Preparation of Base. Prepare the base in accordance with subsection
602.03 B . Construct a uniform base. Compact the base material to 95% of
the maximum unit weight . Prepare the base and geotextile liner for concrete spillways in accordance with subsection 814.03.A.
B.Placing Forms . Place fixed forms in accordance with subsection
602.03 C . Use face forms , if necessary, to construct straight curbs .
If using slip-forming methods, match the dimensions of the form to the dimensions of the curb shown on the plans.
C.Placing Steel Reinforcement . Place steel reinforcement and lane ties in the correct position during concrete placement , as required. Splice st eel reinforcement bars by lapping them at least 10 inches . Tie bar laps with wire ties within 2 inches of each end of the lap.
D.Placing Concrete. Obtain the Engineer’s approval of the base before placing concrete. Wet the base before placing concrete. For c oncrete curbing constructed as an integral part of the concrete pavements, except at night headers, place concrete curbing within MDOT Standard Specifications for Construction Section 802 8-5 30 minutes of placing the concrete for the pavement . At night headers, use ties and methods approved by the Engineer. Construc t transitions between concrete valley gutter and concrete curb and gutter in accordance with section 602. Place concrete to the required depth and spade or vibrate to ensure consolidation. Apply membrane-curing compound as soon as concrete has been placed and in areas requiring repairs after the repairs have been made. Repair honeycombed areas or voids with Type R -2 mortar .
E.Joints . Construct joints perpendicular to the surfaces of the curb, gutter , or dividers in accordance with the MDOT Standard Plan R -30 or R-33 series . Seal joints in accordance with subsection 602.03.S.
1.Contraction Joints and Plane -of-Weakness Joints. Construct joints, in accordance with p lans, to ensure a plane-of -weakness at least one-fourth the depth of the section.
2.Expansion Joints . Place expansion joint fil ler to the full depth of the joint. Recess the top of the joint filler ¼ to ½ inch below the finished surface of the structure.
F.Finishing . Round the exposed edges to a ¼ -inch radius, including transverse joints . Shape the face of the curb to produce the radii shown on the plans . Fill low spots with the same concrete mixture used in the work. Finish exposed surfaces smooth and even, and lightly brush using a broom or brush . Finish the gutter and top of curb to within 3⁄16 inch of the plan dimensions when c hecked with a 10-foot straightedge. Finish other exposed surfaces to within ⅜ inch of the plan dimensions. Do not add water to the concrete surface to aid finishing.
G.Stenciling . Stencil survey station numbers, in accordance with subsection 602.03.L, into t he exposed surface of continuous runs of concrete curb, gutter, curb and gutter, and driveway opening, or shoulder that directly adjoins the traveled way . Stenciling curb and gutter is not required if concrete barrier is present and is stenciled in accorda nce with subsection 602.03.L. Place stencil numbers as follows:
1.To be read from the traveled way;
2.On one side of one- way roadways (preferably the right side); MDOT Standard Specifications for Construction Section 802 8-6 3. On both sides of the traveled way of two-way roadways; and
4.Midway up on the face of a curb or 2 inches from the back of a gutter or driveway opening. Do not stamp, stencil, or in any way mark concrete with a company name, logo, or other such information.
H.Curing . Cure concrete curb, gutter, and dividers in accordance with subsection 602.03.M.
I.Weather and Temperature Limitations. Protect concrete curb, gutter, and dividers in accordance with subsection 602.03.T.
J.Backfilling. Place and compact backfill after the concrete gains the needed strength to support placing and compacting. Grade the remaining excavated areas.
802.04 Measurement and Payment
Pay Item Pay Unit Curb, Conc, Det __ .................................................................................... Foot Curb and Gutter, Conc, Det __ .................................................................. Foot Valley Gutter, Conc .................................................................................... Foot Curb and Gutter, Bridge Approach, Det__ ................................................. Foot Shld Gutter, Conc, Det __ ......................................................................... Each Curb Nose ................................................................................................ Each Downspout Header, Conc ......................................................................... Each Driveway Opening, Conc, Det M ................................................................ Foot Spillway, Conc ........................................................................................... Foot Divider, Conc, Type __ ................................................................... Square Foot
A.Concrete Acceptance. Conduct concrete QC as specified in section 1002. The Engineer will conduct QA as specified in section 1003. The Department will apply adjustments to this work based on the QA results .
B.Curb , Concrete; Curb and Gutter, Concrete; Valley Gutter, Concrete; and Curb and Gutter, Bridge Approach , Det__. The Engineer will measure Curb and Gutter, Conc, Det __, Valley Gutter, Conc, and Curb and Gutter, Bridge Approach , Det__ in place along the joint of the curbing with the pavement . The Engineer will not make deductions in the pay item measured length for catch basins, inlet castings, or Detail L driveway openings . The Engineer will divide transition areas between Valley Gutt er, Conc and Curb and Gutter, Conc in half and will measure each half in the units of the adjacent item.
C.Integral Curb and Pavement Construction . If the Contractor chooses to construct curb as an integral part of the pavement, the Engineer will MDOT Standard Specifications for Construction Section 802 8-7 measure the curb separately . The Department will not consider payment for extras or increases in pay quantities due to the Contractor’s choice to cast curbing integral with the pavement.
D.Shoulder Gutter, Concrete . The unit price for Shld Gutter, Conc , Det __ includes the cost of providing and placing a geotextile liner . The plans will show the pay limits for Shld Gutter, Conc , Det __.
E.Driveway Opening, Conc, Det M . The Engineer will measure Driveway Opening, Conc, Det M from springline t o springline.
F.Spillway, Concrete . The unit price for Spillway, Conc includes the cost of providing and placing a geotextile liner.
G.Divider, Concrete, Type __. The unit prices for concrete divider include the cost of steel reinforcement, if required.
H.Excavation and Backfill . Unless the contract includes separate pay items for excavation and backfill, the unit price for other items of work will include the cost of excavation and backfilling .
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 565–568 of 1,146.