CONCRETE GUTTER, CURB ELEMENTS, AND TRAFFIC SEPARATOR
520-1 Description.
Construct portland cement concrete curb. Curb will include concrete curb and gutter, concrete traffic separator, valley gutter, special concrete gutter, curb for sidewalk curb ramps and driveways, and any other types of concrete curb not specified in other Sections.
520-2 Materials.
520-2.1 Concrete: Use concrete meeting the requirements of Section 347.
520-2.2 Reinforcement: For all steel reinfo rcement required by the Plans, meet the
requirements of Section 415.
520-2.3 Joint Materials: Meet the requirements of Section 932.
520-2.4 Toll Header Curb Concrete: Use concrete meeting the requirements of
Section 346, Class II.
520-3 Forms.
520-3.1 Form Materials: Construct forms for this work of either wood or metal. Provide
forms that are straight, free from warp or bends, and of sufficient strength, when staked, to resist the pressure of the concrete without deviation from line and grade. For all i tems constructed on a radius, use flexible forms.
520-3.2 Depth of Forms: Ensure that forms have a depth equal to the plan dimensions
for the depth of concrete being deposited against them.
520-3.3 Machine Placement: The Contractor may place these items by machine methods
with the approval of the Engineer provided that the Contractor consistently produces an acceptable finished product, true to line, grade, and cross section.
520-4 Excavation.
Excavate to the required depth, and compact the foundation ma terial upon which these items are to be placed as specified in 120 -9.
520-5 Placing Concrete.
Place the concrete in the forms, and tamp and spade it to prevent honeycombing, and until the top of the structure can be floated smooth and the edges rounded to the radius shown in the Plans.
520-6 Joints.
520-6.1 Contraction Joints: Except for machine p laced items, the Contractor may form
joints by using dummy joints (either formed or sawed) or by using sheet metal templates. If using sheet metal templates, ensure that they are of the dimensions, and are set to the lines, shown in the Plans. Hold templat es firmly while placing the concrete. Leave templates in place until the concrete has set sufficiently to hold its shape, but remove them while the forms are still in place. Saw contraction joints, for machine placed items, unless the Engineer approves a n alternate method. Saw the joints as soon as the concrete has hardened to the degree that excessive raveling will not occur and before uncontrolled shrinkage cracking begins. FY 2023-24 Return to Table of Contents Space contraction joints at intervals of 10 feet except where closure requires a lesser interval, but do not allow any section to be less than 4 feet in length.
520-6.2 Expansion Joints: Construct expansion joints at all inlets, at all radius points,
and at other locations indicated in the Plans. Locate them at intervals of 500 feet between other expansion joints or ends of a run. Ensure that the joint is 1/2 inch in width.
520-7 Finishing.
520-7.1 Repair of Minor Defects: Remove the forms within 24 hours after placing the
concrete, and then fill minor defects with mortar composed of one part portland cement and two parts fine aggregate. The Engineer will not allow plastering on the face of the curb. Remove and replace any rejected curb, curb and gutter, or valley gutter without additional compensation.
520-7.2 Final Finish: Finish all exposed surfaces while the concrete is still green. In
general, the Engineer will only require a brush finish. For any surface areas, however, which are too rough or where other surface defects make additional finishing necessary, the Engineer may require the Contractor to rub the curb to a smooth surface with a soft brick or wood block, using water liberally. Also, if necessary to provide a suitable surface, the Engineer may require the Contractor to rub further, using thin grout or mortar.
520-7.3 Imprinted Concrete: Install imprinted concrete as shown in the Plans.
520-8 Curing.
520-8.1 General: Continuously cure the concrete for a period of at least 72 hours.
Commence curing after completely finishing and as soon as the concrete has hardened sufficiently to permit application of the curing material without marring the surface. Immediately replace any curing material removed or damaged during the 72 hour period. After removing the forms, cure the surfaces exposed by placing a berm of moist earth against them or by any of the methods described below, for the remainder of the 72 hour curing period.
520-8.2 Wet Burlap Method: Place burlap, as specified in 925 -1, over the entire
exposed surface of the concrete, with sufficient extension beyond each si de to ensure complete coverage. Overlap adjacent strips a minimum of 6 inches. Hold the burlap securely in place such that it will be in continuous contact with the concrete at all times, and do not allow any earth between the burlap surfaces at laps or be tween the burlap and the concrete. Saturate the burlap with water before placing it, and keep it thoroughly wet throughout the curing period.
520-8.3 Membrane Curing Compound Method: Apply clear membrane curing
compound or white pigmented curing compound, as specified in 925 -2, by a hand sprayer meeting the requirements of 350 -3.10, in a single coat continuous film at a uniform coverage of at least one gallon per 200 square feet. Immediately recoat any cracks, checks, or other defects appearing in the coating. Thoroughly agitate the curing compound in the drum prior to application, and during application as necessary to prevent settlement of the pigment.
520-8.4 Polyethylene Sheeting Method: Place polyethylene sheeting, as specified in
925-3, over the entire exposed surface of the concrete, with sufficient extension beyond each side to ensure complete coverage. Overlap adjacent strips a minimum of 6 inches. Hold the sheeting securely in place and in continuous contact with the concrete at all times . FY 2023-24 Return to Table of Contents
520-9 Backfilling and Compaction.
After the concrete has set sufficiently, but not later than three days after pouring, refill the spaces in front and back of the curb to the required elevation with suitable material. Place and thoroughly compact the ma terial in layers not thicker than 6 inches.
520-10 Surface Requirements.
520-10.1 Straightedge: Test the gutter section of curb and gutter with a 10 foot
straightedge laid parallel to the centerline of the roadway and while the concrete is still plastic. Perform straightedging along the edge of the gutter adjacent to the pavement or along other lines on the gutter cross -section, as directed by the Engineer. Immediately correct irregularities in excess of 1/4 inch.
520-10.2 Elevation and Cross Slope: Place curb and gutter s o the calculated actual
roadway or shoulder cross slope to be placed within the curb and gutter is within +/ - 0.2% of the calculated design cross slope for that location. Once per 500 feet, check the elevation of lip of curb and gutter an d calculate actual cross slope between curb and gutter on each side of a lane or set of adjacent lanes. Perform these checks prior to placement of the curb and gutter and adjust to ensure cross slope tolerance is met. After placement and curing of curb and gutter, perform the above check s again. Correct any curb and gutter found to be outside the cross slope tolerance described above.
520-11 Method of Measurement.
For curb or curb and gutter, the quantity to be paid will be the plan quantity, in feet, measured along the face of the completed and accepted curb or curb and gutter. Curb for sidewalk curb ramps or driveways will be paid at the Contract unit price for the adjacent curb type. For valley gutter or shoulder gutter, the quantity to be paid will be the plan quantity, in feet, measured along the gutter line of the completed and accepted valley gutter or shoulder gutter. For concrete traffic separator of constant width, meeting the requirements of Standard Plans, Index 520-020, the quantity to be paid will be the plan quantity, in feet, measured along the center of its width, completed and accepted, including the length of the nose. For concrete traffic separator of nonstandard or varying width, the quantity to be paid will be the plan quantity, in square yards, completed and accepted. For curb of any type next to concrete pavement, the curb -pavement joint quantity to be paid will be the plan quantity, in feet, measured along the face of the completed and accepted curb.
520-12 Basis of Payment.
520-12.1 Concrete Gutter, Curb Elements, and Traffic Separator: Price and payment
will be full compensation for all work specified in this Section, including reinforcement steel, dowels, asphalt pavement and base under traffic separator, joint ma terials and asphalt curb pad.
520-12.2 Excavation: Excavation for new installations will be paid for as roadway
excavation in accordance with 120 -13.2.
520-12.3 Payment Items: Payment will be made under:
Item No. 520 - 1- Concrete Curb and Gutter - per foot. Item No. 520 - 2- Concrete Curb - per foot. Item No. 520 - 3- Concrete Valley Gutter - per foot. FY 2023-24 Return to Table of Contents Item No. 520 - 4- Curb-Concrete Pavement Joint - per foot. Item No. 520 - 5- Concrete Traffic Separator - per foot. Item No. 520 - 6- Concrete Should er Gutter - per foot. Item No. 520 - 70- Concrete Traffic Separator - per square yard. FY 2023-24 Return to Table of Contents SECTION 521 CONCRETE BARRIERS, TRAFFIC RAILING S, AND PARAPETS
521-1 Description.
Construct precast or cast in place concrete barriers, traffic railings, opaque visual barriers, and parapets, herein referred to as rigid barrier, in accordance with the Standard Plans and the details shown in the Plans. Use stationary removable forms or sliding forms to construct the rigid barrier. Do not use permanent precast concrete rigid barrier on bridge or box culvert structures. Submit written certification from t he manufacturer of the precast rigid barrier that the barrier meets the requirements of this Section. Rigid barrier is produced using certification acceptance; therefore, assume responsibility for performance of quality control testing and inspections requ ired by Sections 346 and 400. Perform all Quality Control Testing and inspections using CTQP qualified testing personnel. Perform compressive strength testing in a laboratory inspected by CCRL or CMEC. Ensure that each shipment of products to the job site includes a list of products shipped and the required written certification statement for each product. Submit this list and certifications to the Engineer.
521-2 Materials.
Meet the following requirements: Flowable Fill ................................ ....................... Section 121 Concrete ................................ .............. Sections 346 and 347 Reinforcing Steel ................................ ................ Section 415 Joint Materials ................................ ........................... 932-1.1 Joint Materials* ................................ ..... 932-1.2 and 932 -1.3 Barrier Delineators * ................................ ......... Sections 705 *Use products listed on the Department’s Approved Product List (APL).
521-3 Precast Temporary Concrete Barrier.
Meet the requirements of 102 -9.5.
521-4 Construction.
521-4.1 General: The Contractor may use stationary removable forms or slip form
construction methods provided a completed rigid barrier with acceptable alignment and finish is obtained. Do not use forms which a re damaged or are not in alignment. At no expense to the Department, remove and replace sections of rigid barrier having unconsolidated concrete, surface blemishes, deviations in alignment or profile which exceed tolerances, or other defects which cannot be repaired to the satisfaction of the Engineer.
521-4.2 Stationary Form Construction: Provide precast or cast in place concrete rigid
barrier constructed using stationary forms in accordance with Section 400 and provid e a general surface finish. Align and erect the stationary form so that all plane surfaces of the finished barrier will have no deviation greater than 3/8 inch measured as an ordinate between the concrete and a 10 foot straightedge. Correct all alignment deviations greater than 3/8 inch. Stra ightedge by half lapping the straightedge for the full length of all plane surfaces.
521-4.3 Slip Form Construction: When electing to use the slip form method in lieu of
the stationary forming method, place the concrete with a slip form machine approved b y the FY 2023-24 Return to Table of Contents