610Curbs, Combination Curbs and Gutters, and Medians

610.1-DESCRIPTION: This work shall consist of the construction or resetting of curbs, combination curbs and gutters, and medians in accordance with these Specifications and in reasonably close conf ormity with the lines , grades, dimensions, and locations shown on the Plans or established by the Engineer. The types of curbing, combination curbs and gutters, or medians are as follows:

610.2-MATERIALS: Except as provided below, materials shall meet the requirements of the following Subsections of Division 700: MATERIAL SUBSECTION Asphalt Emulsion for Paint Coat 705.4 or 705.11 Asphalt for Tack Coat 705.4 or 705.11 Expansion Joint Filler Preformed 708.1 Joint Sealing Material 708.3 or 708.4 Joint Tie Bolt Assembly 709.7 PG Binder for Asphalt Curb 705.5* Reinforcing Steel 709.1, 709.4 * Standard grade specified for local area unless indicated otherwise on the Plans. Concrete shall meet the requirements of Section 601, Class B, or 501. Concrete, asphalt mixes, and manufactured curbing materials will be subject to inspection and tests at the plants for compliance with quality requirements. All materials will be subject to inspection for acceptance as to condition at the latest practicable time the Engineer has the opportunity to check for compliance prior to or during incorporation of materials in the work. Asphalt curbing component materials shall meet the applicable requirements of Section 401 and the composition of the mix shall meet the following Table 610.2: 426 TABLE 610.2 (MASTER RANGE CRITERIA) ½ inch (12.5 mm) 100 3/8 inch (9.5 mm) 80 – 100 # 4 (75 mm) 50 – 80 # 8 (2.36 mm) 30 – 60 # 16 (1.18 mm) 20 – 50 # 30 (600 mm) 12 - 36 # 50 (300 mm) 5- 25 # 200 (75 mm) 3- 9 % Asphalt 4 – 10 No mix design approval will be required for asphalt curbing, however, the Contractor shall establish a Plant Mix Formula (PMF) for asphalt content and gradation which meets the above requirements and submit it to the District for approval. The District shall review the design and submit a completed T-400 form to the Materials Control, Soil, and Test Division. The Materials Division will assign a laboratory number to the design. This PMF shall also include the percentage of any additive that may be used as a stiffener for the curbing mix. If lime or other similar granular additive is used, then this material should be included in the PMF gradation. The mix shall be produced within the allowable tolerances of the following table. Plant Mix Formula Plant Mix Tolerance Range Percentage Passing Sieve Sizes 3/8 inch (9.5 mm), # 4 (4.75 mm) ± 7 Percentage Points Percentage Passing Sieve # 8 (2.36 mm) ± 6 Percentage Points Percentage Passing Sieve Sizes # 16 (1.18 mm), # 30(600μm) ± 5 Percentage Points Percentage Passing Sieve Size # 50 (300μm) ± 4 Percentage Points Percentage Passing Sieve Size # 200 (75μm) ± 3 Percentage Points Percentage of Asphalt ± 0.5 Percentage Points The Contractor shall perform quality control sampling and testing of the asphalt curbing mix by taking a random sample once per day of production and testing for asphalt content and gradation to verify the materials composition. If testing indicates that the plant mix formula tolerances are not being met, then production shall halt until the reason for any deficiencies are determined and adjustments are made to correct these deficiencies and documented in the plant diary. 427 CONSTRUCTION METHODS 610.3-PLAIN CONCRETE CURBING, INTEGRAL CONCRETE CURBING, AND COMBINATION CONCRETE CURB AND GUTTER: 610.3.1-Excavation: Excavation shall be made to the required depth, and the base upon material shall be removed and replaced with suitable material which shall be thoroughly compacted. When called for on the Plans, the base upon which the curb is to be set shall be constructed of bed course material in accordance with Section 609. 610.3.2-Form: Forms shall be of wood or metal, straight, free from warp, and of such construction that there will be no interference with the inspection of grade or alignment. All form shall extend for the entire depth of the curb and shall be braced and secured sufficiently so that no deflection from alignment or grade will occur during the placing of the concrete. Forms shall be cleaned and oiled just prior to placing the concrete. 610.3.3-Mixing, Placing, and Finishing: Concrete shall be proportioned, mixed, and placed in accordance with the requirements for the class of concrete specified. Concrete shall not be transported in nonagitating trucks. Compaction of concrete placed in forms shall be by vibration or other acceptable methods. Drainage openings shall be made through the curb, where indicated, or as directed by the Engineer, at the elevation and of the size required. Forms shall be left in place for 24 hours unless the concre te has set sufficiently prior to that time to permit their removal without injury to the curbing. Upon removal of the forms, the exposed curbing face shall be immediately rubbed to a uniform surface. Rubbing shall be accomplished by the use of water and a wood block or carborundum brick. For the purpose of matching adjacent concrete finishes or for other reasons, the Engineer may permit other methods of finishing. No plastering will be permitted. All damaged and rejected curb shall be removed and replaced. 610.3.4-Sections: All concrete curbing shall be constructed in sections having an approximate length of ten (10) feet unless otherwise indicated on the Plans or directed. In the construction of integral concrete curb or combination concrete curb and gutter abutting concrete pavement, the sections shall be such that the contraction and expansion joints are located opposite the contraction and expansion joints respectively in the pavement. Sections shall be separated by joints ⅛ inch wide except at expansion joints. All joints shall be filled with joint sealing material conforming to the requirements of subsection 708.3. 610.3.5-Expansion Joints: Expansion joints shall be formed at the intervals shown on the Plans using a preformed expansion joint filler having a thickness of ¾ inch. When the curb is constructed adjacent to or on concrete pavement, expansion joints shall be located opposite or at expansion joint in the pavement. 610.3.6-Curing: Immediately upon completion of the rubbing, th e curbing shall be moistened and kept moist for three days, or the curbing shall be cured by the use of membrane forming material. The methods and details of curing will be subject to the approval of the Engineer. 610.3.7-Backfilling: After the concrete has set sufficiently, the spaces in front and back of the curb shall be refilled to the required elevation with suitable materials, which shall be thoroughly tamped in loose layers of not more than six (6) inches. 428 610.3.8-Curb Machine: Where a concrete curb or curb and gutter is not required to be constructed integral with or tied to a concrete base and pavement it may be placed with a self- propelled machine consisting of a hopper and having a power driven screw or screws. The proper density and cro ss section shall be obtained by forcing the concrete through a mold of the specified cross section. Where a track is used, the track on which the machine operates shall be set and held to the line and grade given by the Engineer. The concrete shall be of such consistency that it can be molded into the desired shape and will remain as placed without slumping of the vertical or sloping faces. The consistency test may be omitted, and the yield determined from the volume required, adjusted for waste. 610.4: Blank 610.5-ASPHALT CURBING: 610.5.1-Equipment & Tools: All equipment, tools, and plant machinery to be used for executing the work prescribed will be subject to the approval of the Engineer. Asphalt curbing shall be constructed by the use of self-propelled automatic curber or curb machine or a paver with c urbing attachments. This automatic curber or machine shall meet the following requirements:

the machine riding above the bed of which curbing is constructed. ii. The machine shall form curbing that is uniform in texture, shape, and density. 610.5.2-Excavation: Excavation, when required, shall conform to the requirements of subsection 610.3.1. 610.5.3-Preparation of Bed: When curbing is to be constructed on a fresh laid asphalt surface, the curb shall be laid only after the surface has been cleaned. When curbing is to be constructed on a cured or aged Portland cement concrete base, asphalt pavement, or asphalt treated base, the bed shall be thoroughly swept and cleaned by compressed air. The surface shall be thoroughly dried and, immediately prior to placing of the asphalt mixture, shall receive a tack coat of asphalt material. The rate of application of tack coat material shall be between 0.05 to 0.15 gallons per square yard of surface. The Contractor shall prevent the spread of this tack coat to areas outside of the area to be occupied by the curb. 610.5.4-Mixing and Placing: The asphalt mixture specified in subsection 610.2 shall be homogeneously mixed and shall be delivered to the hopper of the curb laying machine at a temperature of not less than 200 °F nor more than 300°F. Each hopper load of asphalt plant mix shall be run through the curb laying machine which has been adjusted to form and properly compact the asphalt curb. The Engineer may permit the construction of curbing by means other than the automatic curber or machine when short sections or sections with short radii are required or for such other reasons as may seem to warrant it. The resulting curbing shall conform in all respects to the curbing produced by the use of the machine. 429 610.5.5-Joints: Unless conditions warrant, asphalt curb construction at the specified temperature shall be a continuous operation in one direction to eliminate curb joints. However, where conditions are such that this is not possible, the joints between successive days' work shall be carefully made in such a manner as to insure a continuous bond between the old and new sections of the curb. All contact surface of previously constructed curb shall be given a thin, uniform coat of hot asphalt material just prior to placing the fresh asphalt curb material. 610.5.6-Curing: The newly laid curb shall be protected from traffic by barricades or other suitable methods until the heat of the asphalt mixture has dissipated and the mixture has obtained its proper degree of hardness. 610.5.7-Painting Curb: The completed curb sha ll be painted with a diluted emulsified asphalt paint coat or emulsified asphalt slurry to prevent moisture absorption. The paint coat shall be prepared with a 50-50 blend of water and emulsified asphalt, grade SS-1. 610.5.8-Seasonal Limitations: No asphalt material shall be laid when the temperature of the air is 50°F or less, or during other unfavorable weather conditions. 610.6-MEDIAN BARRIER: Median Barrier shall be constructed in accordance with the Standard Details Book, Volume I, and to the details shown on the Plans. Construction methods shall conform to the applicable requirements in subsection 610.3. 610.7-RAISED CONCRETE TRAFFIC ISLAND: Raised Concrete Traffic Islands are curb-enclosed areas with standard concrete curbing enclosing an area of raised concrete island cover for the channelization of vehicular traffic and the safety of pedestrian, which shall be constructed at the locations and to the outlines and dimensions shown in the plans. Construction methods for this item shall conform to the requirements of Section 609. The curb will be paid for separately and shall conform to the requirements of subsection 610.3. The curb and adjacent raised concrete traffic island may be constructed monolithically, with the approval of the Engineer. 610.8-METHOD OF MEASUREMENT: Curbing will be measured by the linear foot along the front face of the section at the finished grade elevation. Combination Curb and Gutter will be measured by the linear foot along the face of the curb. No deduction in length will be made for drainage structures installed in the curbing. The quantity of Median Barrier to be paid will be measured in linear feet, complete in place and accepted, on the surface and along the centerline of the median. Raised Concrete Traffic Island will be measured by square yards. The quantity will be determined by the plan quantity as provided in the proposal unless otherwise directed by the Engineer. Bed course material will be measured by the cubic yard. 430 610.9-BASIS OF PAYMENT: The quantities, determined as provided above, will be paid for at the contract unit prices bid for the items listed below, which prices and payments shall be full compensation for furnishing all the materials and doing all the work prescribed in a workmanlike and acceptable manner, including all labor, tools, equipment, supplies, and incidentals necessary to complete the work.

610.10PAY ITEMS:

ITEM DESCRIPTION UNIT 610001-* Plain Concrete Curbing, Type “type” Linear Foot 610002-* Integral Concrete Curbing, Type “type” Linear Foot 610003-* Combination Concrete Curb and Gutter, Type “type” Linear Foot 610005-* Asphalt Curb, Type “type” Linear Foot 610006-* Median Barrier, Type “type” Linear Foot 610007-* Raised Concrete Traffic Island, “thickness” Square Yard 610008-* Bed Course Material Cubic Yard * Sequence number “type” Type of concrete curb (I, II, III, or IV) or median barrier (X) per Standard Detail “thickness" in inches 431