605CURBING

605.01Description

This work shall consist of the construction of curb or curb turnouts, combination curb and gutter, combined curb and gutter turnouts, or resetting curb in accordance with 105.03.

605.02Materials

Materials shall be in acco rdance with the following: 605.01

Coarse Aggregate, Class D or Higher, Size No. 53 ..... 904.03 Joint Mortar ................................................................. 907.12 Precast Concrete Curbing ............................................ 905.04 Reinforcing Bars .......................................................... 910.01

605.03Precast Cement Concrete Curbing

Excavation shall be made to the required depth and the base upon which the curb is to be set shall be compacted to a firm even surface. All soft and unsuitable material shall be removed and replaced with suitable material which shall be thoroughly compacted.

The curb shall be set in accordance with the line and grade required. The face and top of the curb shall be checked with a 10 ft straightedge. Portions showing irregularities of 1/4 in. or more shall be removed and replaced with no additional payment. All spaces under the curbing sh all be filled with thoroughly tamped bed 30 course material. The bed course material shall be coarse aggregate No. 53.

Curbing shall be placed with joints as shown on the plans. These joints shall be filled with mortar as specified. Where a port land cement concrete pavement is to be constructed contiguous to a curbing, joints shall be constructed in the curbing directly in line with pavement expansion joints. The joint in the curbing shall be the same width as the pavement joint and shall be filled with an expansion joint filler of the nominal thickness as the pavement joint. Any voids between the joint filler and the curb shall be filled with mortar. 40

After the curb has set, any remaining excavated areas shall be filled with approved material. This material shall be placed and thoroughly tamped in layers not to exceed 6 in. in depth.

605.04Cast in Place Cement Concrete Curbing

Excavation and bedding shall be in accordance with 605.03(a). 50

Forms shall be of wood or metal, straight, free from warp, and of such construction that there will be no interference to the inspection of grade or alignment. All forms shall extend for the entire depth of the curb and shall be braced and secured 605.04

sufficiently so no deflection from alignment or grade occurs during the placing of the concrete.

Concrete shall be proportioned, mixed, and placed in accordance with 502, except 60 utilization of the Department provided spreadsheet is not required for the CMDS. Where integral curb and gutter is specified, that portion of the curb below the upper surface elevation of the adjoining pavement shall be constructed by extending the pavement to the outer vertical plane of th e curb at the time the pavement is placed. The concrete used in this extension shall be the same composition as that of the pavement.

As an option, an integral curb and gutter may be placed at the same time as the PCCP pavement by the slip form method. The slip form machine shall have an attachment to place, consolidate, and shape the concrete to the required profile and 70 dimensions. The reinforcing tie bars or stirrups between the pavement and the curb shall be omitted.

After the concrete for the upper portion is placed in the forms, it shall be tamped and spaded or vibrated until mortar entirely covers the surface. The top shall be floated smooth and the outer upper corner rounded to a 1/4 in. radius.

The face and top of the curb, integral curb , and gutter shall be checked with a 10 ft straightedge. Portions showing irregularities of 1/4 in. or more shall be removed and replaced. 80

Consolidation of concrete placed in the forms shall be by vibration or other acceptable methods. Forms shall be left in place for 24 h or until the concrete has set sufficiently so that they can be removed without injury to the curbing. Upon removal of the forms, the exposed curbing face sh all be rubbed immediately to a uniform surface. Rubbing shall be accomplished by the use of water and a carborundum brick. For the purpose of matching adjacent concrete finishes or for other reasons, other methods of finishing may be allowed. No plastering will be allowed.

Turnouts will be required with specified inlets or with concrete gutter and paved side ditch in accordance with 607 and as shown on the plans. Concrete gutter and paved side ditch shall be constructed monolithically with the curb turnout.

Joints in integral curbs shall be located at joints in adjoining PCCP. The joints shall be saw cut or formed with 1/4 in. thick preformed joint material. Joint sealant is not required for joints in integral curbs.

Curbing not constructed integral with ad jacent pavement shall be constructed with 100 intermediate joints located at 10 ft intervals. These joints may be sawed or formed with 605.04

metal separator plates, and the depth and width shall be in accordance with the plans.

Preformed expansion joints, 1/4 in. thick, shall be placed at the beginning and end of all curb returns and also at castings.

Immediately upon completion of the rubbing, the curbing shall be moistened and kept moist for three days, or cured by using membrane forming material. The method and details of curing shall be subject to approval. 110

After the concrete has set sufficiently, the spaces in front and back of the curb shall be refilled with suitable material to the required elevations in layers of not more than 6 in. and be tamped thoroughly.

Curb machines may be used to construct curb provided the curb can be constructed to the requirements of the specifications.

605.05Reflecting Ceme nt Concrete Curbing

Construction methods for this item shall be in accordance with 605.03 and the following requirements.

The reflecting surface of the curbing shall be a mortar mix consisting of 1 part white portland cement to 1 3/4 parts of light colored, washed, mortar sand. This mortar mix shall have a thickness of approximately 1 in. Alternately, the entire curbing may be constructed of concrete made with white portland cement.

Washed mortar sand shall meet all the requirements for mortar sand and shall be 130 of a satisfactory light color. The reflecting surface mortar shall be placed immediately after the placing of the base concrete. No more than 20 minutes shall elapse between the placing of the base concrete and the placing of the reflecting surface.

Scoring or surface deformation and finish of the reflecting surface shall be in accordance with the details shown on the plans.

605.06Concrete Center Curbing

The subgrade shall be prepared the same as for the adjoining pavement. If subbase is provided for the adjoining pavement, it shall be carried through for the full width of 140 the curb and at the same thickness as that for the pavement.

The temperature limitations of 502.11 shall apply to placing the concrete. The surface shall be troweled smooth with a me tal trowel. Curing shall be in accordance with 504.04.

Forms shall be removed within 24 h af ter the concrete has been placed. Plane 605.06

surfaces and exposed sides of the curb shall be checked with a 10 ft straightedge. Portions showing irregularities of 1/4 in. or more shall be removed and replaced in compliance with these specifications. 150

Joints in center curbs adj acent to PCCP shall be aligne d with joints in adjoining PCCP. Joints in center curbs adjacent to asphalt shall be spaced at 18 ft maximum. The joints shall be saw cut or formed with 1/4 in. thick preformed joint material. Joint sealant is not required for joints in center curbs.

Where an expansion joint is constructed in PCCP adjacent to concrete center curb, the expansion joint shall be carried through the center curb in accordance with applicable requirements of 503.03(f).

605.07HMA Curbing

Excavation shall be in accordance with 605.03(a).

When curbing is to be constructed on a fresh laid HMA surface, the curb may be laid only after the surface has been cleaned.

When curbing is to be constructed on a cured or aged portland cement concrete 170 base, asphalt pavement, or asphalt treated base, the bed shall be thoroughly swept and cleaned with compressed air. The surface shall be thoroughly dried and, immediately prior to placing of the HMA mixture, shall receive a tack coat in accordance with 406. During application, the spread of this tack coat to areas outside of the area to be occupied by the curb shall be prevented.

The mixture shall be in accordance with 402.07(d).

A Type D certification in accordance with 916 shall be provided for the HMA 180 curbing mixture. The test results shown on the certification shall be the quality control tests representing the material supplied and include gradation and binder content. The gradation tolerances shall be ±2.5% on the No. 200 (75 μm) sieve, ±4.0% on the No 4 (4.75 mm) sieve, and binder content tolerance shall be ±0.5% from DMF.

HMA curbing shall be constructed by use of a self-propelled automatic curber, curb machine or paver with curbing attachments. The curbing shall be in accordance with the section shown on the plans. The au tomatic curber or machine shall meet the following requirements and is subject to approval prior to use. 190

compaction is obtained without the machine riding above the bed on which curbing is being constructed. 605.07

shape, and density.

The construction of curbing by means other than the automatic curber or machine may be allowed when short sections or sections with short radii are required, or for 200 such other reasons as may seem warranted. The resulting curbing shall conform in all respects to the curbing produced by the us e of the machine. The face and top of the HMA curb shall be checked with a 10 ft straightedge. Portions showing irregularities of 1/4 in. or more shall be removed and replaced.

Weather limitations shall be in accordance with 402.12.

When sealing or painting is required, it shall be performed only on a curbing which is clean and dry, and which has reached the ambient temperature. 210

605.08Resetting Curbing

Curbing specified for resetting shall be cleaned, removed, and stored. Any existing curbing that is to be reset which is lost, damaged, or destroyed as a result of operations or because of failure to store and protect it in a manner that would eliminate its loss or damage, shall be replaced.

Curbing, which is unsuitable for resetting and which has not been damaged due to negligence, shall be removed and disposed of as directed.

Excavation and bedding shall be in accordance with 605.03(a).

The curb shall be set on a firm bed in accordance with the required line and grade. All sections of curbing shall be set so that the maximum opening between adjacent sections is 3/4 in. wide for the entire exposed top and face. Any dressing of the ends 230 of the curbing necessary to meet this requirement shall be performed as needed.

Cutting or fitting may be necessary in order to install the curbing at the locations as

directed.

After the curb has been set, the joints shall be completely filled with mortar as

specified.

The spaces in front and back of the curb shall be refilled to the required elevation

with suitable material. This material shall be tamped thoroughly in layers not to exceed240

6 in. in depth.

605.08

514

605.09Method of Measurement

Curbing, both new and reset, and curb removal will be measured by the linear foot

along the front face of the section at the finished grade elevation. Combined curb and

gutter will be measured along the face of the curb. Curb turnout will be measured

longitudinally by the linear foot as curb of the type specified, from the ends of the radii

which touch the front face of the longitudinal curb portion. Combined curb and gutter

turnout will be measured longitudinally by the linear foot as curb and gutter of the type

specified, from the ends of the radii which touch the front face of the longitudinal curb250

portion. No deduction in length will be made for drainage structures installed in the

curbing such as catch basins or drop inlets. Concrete center curb will be measured by

the linear foot, unless it is of variable width, in which case measurement will be by the

square yard.

Bed course material will be measured by the ton.

605.10Basis of Payment

The accepted quantities of curb work will be paid for at the contract unit price per

linear foot for curb; curb and gutter; curb, reset; or center curb, of the type specified.260

Variable width center curb will be paid for at the contract unit price per square yard

for center curb, of the width specified. Bed course material will be paid for at the

contract unit price per ton, complete in place.

Curb turnout will be paid for at the contract unit price per linear foot of the type

of curb specified. Combined curb and gutter will be paid for at the contract unit price

per linear foot for curb and gutter of the type specified.

Payment will be made under:

270

Pay Item Pay Unit Symbol

Bed Course Material .................................................................. TON

Center Curb, _____ ................................................................... SYS

type LFT

Curb and Gutter, _____ ............................................................. LFT

type

Curb, _____ ............................................................................... LFT

type

Curb, Remove............................................................................ LFT280

Curb, Reset, _____ .................................................................... LFT

type

The cost of tack coat, reinforcing bars or welded wire reinforcement for curb, curb

and gutter, or center curb shall be included in the cost of the pay items. The cost of

replacement curb portions for those which show irregularities or 1/4 in. or more shall

be included in the cost of curb.

605.09