SECTION 609: CURB AND GUTTER
609.1 Description
This Work consists of construc ting asphalt or concrete curb, co ncrete gutter, and concrete curb-and-gutter combinations.
609.2 Materials
609.2.1 Concrete
The Contractor shall construct PCC curb and gutter with Class A or Class F concrete in accordance with Section 510, “Portland Cement Concrete.” The C ontractor shall provide Class A concrete if the concrete is being cast directly into fo rms and Class F if the concrete is being slip-formed.
609.2.2 Joint Fillers
The Contractor shall provide pref ormed expansion joint filler i n accordance with AASHTO M 33 or AASHTO M 153.
609.2.2 1 Silicone Joint Sealant and Backer Rod
The Contractor shall provide silicone joint sealant and backer rod (bondbreaker) in accordance with Section 452, “Sea ling and Resealing Concrete Pa vement Joints.”
609.2.3 Bed Course Material
The Contractor shall provide bed course Material that consists of cinders, sand, gravel, crushed stone, or other granular aggregate, with 100% passing a 1/2 inch sieve and not more than 12% passing the No. 200 sieve. Alternatively, Base Course as per Section 303, “Base Course” may be used.
609.2.4 Asphalt Material
The Contractor shall provide asphalt Material for curbing in ac cordance with Section 423, “Hot-Mix Asphalt (HMA) (Major Paving),” and as approved by the Project Manager.
609.3 Construction Requirements
609.3.1 Foundation
The Contractor shall place concrete curb and gutter on an appro ved foundation in accordance with Section 203, “Excavation, Borrow, and Embankmen t;” Section 207, “Subgrade Preparation;” and Section 303, “Base Course.” The Co ntractor shall prepare the foundation by excavating or cons tructing Embankment to the spec ified Subgrade.
609.3.1 1 Excavation
If required, the Contractor shall excavate to the specified dep th and compact the base for the curb and gutter in accordance with Section 207, “Subgrade P reparation.” The Contractor shall remove soft and unacceptable Material to t wo (2) ft below the specified Subgrade and replace wi th Material having at least th e minimum specified design R- value in accordance with Section 203, “Excavation, Borrow, and Embankment,” and Section
609.3.1 2 Bed Course Placement
For existing ground under bed course, the Contractor shall comp act the thickness shown in the Contract to 95% of maximum density in accordance with Se ction 203.3.7, “Moisture and Density Control.” The Contractor shall compact bed course Material to a density o f at least 96% of maximum density in accordance wi th Section 303.3.2, “Mixing and Placing.”
609.3.2 Cast-in-Place Concrete Curb and Gutter
609.3.2 1 Forms
The Contractor shall use wood or metal forms that are straight and free of warps, and constructed to permit the ins pection of grade or alignment. The Contractor shall ensure forms extend the entire depth of th e curb and gutter. The Contractor shall brace and secure the forms sufficiently to pre vent deflections during concrete placement. The Contractor shall use flexible forms in curved sections so t hat the top surface of the forms will produce a smooth, continuous arc. The Contractor shall treat forms with form release oil to preve nt damage to the concrete during form removal. The Contractor shall form the slope of th e gutter to match the Roadway cross slope.
609.3.2 2 Mixing and Placing
The Contractor shall thoroughly moisten the bed course immediat ely before placing the concrete. The Contractor shall not allow standing water on the bed course. The Contractor shall proportion, mix, and place concrete in acc ordance with Section 451, “Portland Cement Concrete Pavement,” Section 510, “Portland Cem ent Concrete,” and Section 511, “Concrete Structures, ” for the specified class of concrete. The Contractor shall consolidate the placed concrete in the for ms using vibration or other Acceptable methods. The Contractor shall finish the surface with a float. The Cont ractor shall not plaster or re- temper the surface with water. Unless otherwise specified, the Contractor shall give the top surfaces of the concrete a tran sverse broomed finish after floa ting. The Contractor shall use an edging tool with a 1/4 inch radius on the outside edges of the curb and gutter and joints. The Contractor shall leave forms in place until the concrete ha s set sufficiently to allow removal without damaging the curb and gutter.
609.3.3 Slip-Formed Concrete Curb and Gutter
The Contractor may place curb and gutter using a slip-form mach ine (except on Structures) if the finished curb and gutter is true to line and grade, and the concrete is dense Section 609: Curb and Gutter Page 668 and of the specified surface texture. The Contractor shall construct curb and gutter using a slip-for m machine in accordance with Section 451, “Portland Cement Concrete Pavement.” The Contractor shall ensure that the top and face of the finish ed curb and gutter are true and straight, and the top surface is of uniform width and free from humps, sags, and other irregularities. The Contractor shall use concre te of a consistency that will ma intain the shape of the curb and gutter section without support after slip forming. The Contractor shall ensure that the forming portion of the sli p-form machine is readily adjustable vertically during the forward motion of the machine, to provide a variable height of curb and gutter grade, if necessary. The Contractor shall attach a grade line gauge or pointer to th e slip-form machine so that the Contractor can make a continual comparison between the curb and gutter grades indicated by the gauge or pointer and the offset guidelines. The Contractor shall feed concrete to the slip-form machine at a uniform rate. The Contractor shall operate the slip-form machine under sufficient uniform restraint from forward motion to produce a well-compacted mass of concrete that is fre e of surface pits with diameters larger than 0.19 inch, and that requires no further f inishing, other than light brushing with a wet brush. The Contractor shall not finish with a brush application of grout.
609.3.4 Joints
The Contractor shall construct curb and gutter in sections with uniform lengths of 30 feet. The Contractor shall separate sections by open joints, 1/8 inch wide, except at expansion joints. The Contractor shall c onstruct contraction joints at i ntervals of five (5) feet. The Contractor shall form expansion joints at the intervals in accordance with the Contract, using the preformed expansion joint filler with a thi ckness of 3/4 inch. The Contractor shall construct transverse weakened plane and ex pansion joints at right angles to the line of the concrete curb and gutter. The Contractor may construct expansion joints by sawing through the concrete curb and gutter section to its full depth. The Contractor shall ensure that the width of the cut Accepts the joint filler with a snug fit. The Contractor shall complete the operations of sawing and inse rting the joint filler before curing the concrete. At the c onclusion of the curing period, t he Contractor shall check the filler in each joint for tightness. The Contractor shall mortar in pl ace and cure loose filler in joints. If constructing the curb and gutte r adjacent to or on concrete pavement, the Contractor shall locate expansion joints opposite to or at expansion joint s in the pavement.
609.3.5 Curing
The Contractor shall cure concrete in accordance with Section 5 11.3.9, “Curing.”
609.3.6 Backfilling
Section 609: Curb and Gutter Page 669 After the concrete attains a compressive strength of 2,500 psi, the Contractor shall fill the spaces in back of the curb to the specified elevation with Emba nkment Material, and compact in accordance with Section 203.3.7, “Moisture and Density Contr ol,” unless otherwise specified in the Contract.
609.3.7 Asphalt Curbing
If constructing asphalt curbing on an asphalt surface, the Cont ractor shall place the curb after cleaning the surface and applying a tack coat of asphalt Material. The Project Manager will determine the tack coat application ra te. The Contractor shall construct asphalt curbi ng using a paver with curbing attachment s.
609.4 Method of Measurement
The Department will measure curb along the front face of the se ction. The Department will measure gutte r and curb-and-gutter combinat ions along the flowline of the gutter.
609.5 Basis of Payment
Pay Item Pay Unit Concrete Curb ___inch Linear Foot Bituminous Curb Linear Foot Header Curb Linear Foot Concrete Sloped Curb and Gutter ___inch × ___ inch Linear Foot Concrete Vertical Curb and Gutter Type___, ___inch × ___ inch Linear Foot Standard Curb and Gutter Linear Foot Concrete Valley Gutter ___inch × ___ inch Linear Foot Concrete Laydown Curb ___ inch Linear Foot
609.5.1 Work Included in Payment
The following Work Included in payment will be considered as in cluded in the payment for the main item(s) and will not be measured or paid for separatel y: 1. Excavation, borrow, bed c ourse, compaction and Embankment; 2. For foundation of curb and gutter, expansion joint Material (including silicone joint sealant and backer rod), colori ng, and other related items and appurtenances; and 3. Backfilling behind curb and reflectorized yellow paint for M edian curb and gutter from radius point to radius poi nt on the bull nose portion. Section 610: Cattle Guards Page 670