Section 2301. Portland Cement Concrete Pavement.
Concrete pavement shall consist of a single course of PCC of the type and class specified in the contract. If the class of concrete is not specified, Class C concrete shall be used.
TYPE OF PAVEMENT.
Concrete pavement shall be one of two types, Standard or Slip Form.
A. Standard Concrete Pavement.
Standard concrete pavement may be reinforced or non-reinforced, and shall consist of concrete of the class specified in the contract documents, reinforced as shown in the contract documents, placed within fixed forms, and consolidated and finished by equipment operating on forms.
B. Slip Form Pavement.
Slip form pavement may be reinforced or non-reinforced, and shall consist of concrete of the class specified in the contract documents, reinforced as shown in the contract documents, placed, consolidated, and finished without the use of fixed forms.
Irregularly shaped areas of either type of pavement may be formed and finished by hand methods.
When the contract allows standard or slip form pavement, the type is an option of the Contractor. When the contract allows only one type, the type specified shall be used. When the slip form type is specified, small or irregular areas may be constructed with fixed forms.
Reinforced bridge approach sections shall be placed in accordance with the details and limits shown in the contract documents.
All materials shall meet requirements for the respective items in Division 41. Unless otherwise specified, coarse aggregate shall be of the durability class required by Article 4115.04.
Compatibility of all material combinations shall be the responsibility of the Contractor. If the concrete materials are not producing a workable concrete mixture, a change in the material may be required. Any changes will be at no additional cost to the Contracting Authority.
2301.04 PORTLAND CEMENT CONCRETE PAVEMENT.
Materials for pavement concrete shall be proportioned in any one of the mixtures identified in the current Materials I.M. 529 for the class of concrete specified in the contract documents. Any of the mixtures may be used, at the Contractor's option, provided the gradation of the separate aggregates complies with the gradation required for that mixture. C-5 and C-6 concrete mix proportions will not be used for pavements on Interstate and Primary highways.
After October 31, all items of concrete pavement specified to be constructed with Class B concrete shall be constructed with Class A concrete. The Engineer either will require completion by continuing placement operations past October 31 or will allow the Contractor the option of a winter shutdown. When completion is required, the Contracting Authority will pay the net increase in cost of materials resulting from the change in proportions for any pavement placed within the contract period or authorized extensions thereof, and other increases in cost shall be at the Contractor's expense.
A. Combined Fine and Coarse Aggregate.
If use of combined fine and coarse aggregate is approved, the proportions will be fixed on the basis of the relative amounts of fine and coarse aggregate contained, so as to be equivalent to one of the appropriate mixes specified for screened aggregates.
The foregoing proportions are based on a specific gravity of 2.62 for Class V aggregate and 2.65 for other aggregates. If the material furnished shows an average specific gravity other than these values, the proportions will be adjusted by the ratio which the actual average specific gravity bears to the foregoing values.
B. Water, Consistency, and Batch Yield.
The amount of mixing water used shall be that which will produce workable concrete of uniform consistency. Except as specifically modified by the Engineer, the slump, measured in accordance with Materials I.M. 317, shall not be less than 1/2 inch (15 mm) or more than 2-1/2 inches (65 mm) for machine finished, or fixed form; or 4 inches (100 mm) for hand finished pavement.
If it is found impossible to produce concrete having the required consistency without exceeding the maximum allowable water cement ratio specified, the cement content may be increased or water reducing admixture may be added as approved by the Engineer so that the maximum water cement ratio will not be exceeded. Any additional cement or water reducer will be considered incidental, and no additional payment will be allowed.
The basic absolute volume of water per unit volume of concrete is based on average conditions. If characteristics of the material are such that the total quantity of water used to secure the required consistency is such that the batch yield, computed on the basis of absolute volumes of the batch quantities used, is deficient by more than 2.0%, the proportions may be adjusted by the Engineer to correct the yield. Adjustment described in this paragraph will not be a basis for adjustment of the contract unit price.
C. Entrained Air Content.
Air entrainment shall be accomplished by addition of an approved air entraining agent. Air content as determined by Materials I.M. 318, shall be determined on each day of production as early and as frequently as necessary until the air content is consistently acceptable. The intended air content of finished concrete is 6.0% and the target air content shall be determined to account for air loss during consolidation of concrete during slip form paving. The difference between before and after the paver air contents for a given location shall be considered the air loss.
On the first day of paving,
air content shall be tested as follows
the first load shall be tested at the plant.
For central batch plant, the first load shall be tested at the plant and
Tthe air content
shall be between 8.0% and 12.0%. The next ten loads will be accepted on the basis of
this complying air test. Starting with the twelfth load all samples shall be taken at the
point of acceptance and the air content before the paver shall be 7.5% plus 1.5% or
minus 1.0%. For ready mixed
concrete the air content before the paver shall be 7.5% plus 1.5% or minus 1.0%.
For ready mixed concrete the air content before the paver shall be 7.5% plus 1.5% or minus 1.0%
5000 7500 square
yards ( 4000 6000 m2),
Tthe air loss shall be determined at a minimum of two locations. The air loss
from both locations shall be averaged and added to 6.0% to establish the target air content,
rounded to the next higher 0.5%. After the air loss has been established, the air content
before the paver shall be target air content plus 1.5% or minus 1.0%
After the first day of paving, the air content before the paver shall be the target air content plus 1.5% or minus 1.0%. A new target air content shall be established if the average air loss from two consecutive tests deviates by more than 0.5% from the air loss. The air loss shall be determined at one location per half day. At the option of the Engineer, air loss determination may be reduced if the air loss is consistent.
For projects less than
5000 7500 square yards ( 4000
6000 m2) the air content
before the paver shall be 7.5% plus 1.5% or minus 1.0%. At the option of the
Contractor, the target air content may be established using the air loss.
The air content for non slip form paving shall be 7.0% plus 1.5% or minus 1.0%.
When authorized by the Engineer, approved admixtures complying with Section 4103 may be used.
E. Use of Fly Ash.
F. Use of Ground Granulated Blast Furnace Slag
1. Type IS and Type I(SM) may be furnished according to Section 4101 and Section 4108. Fly Ash substitution rate shall be according to Article 2301.04, E. The total mineral admixture substitution rate shall not exceed 40%.
2. GGBFS may be substituted for Portland cement in concrete mixtures which do not contain blended hydraulic cement. The GGBFS substitution rate shall be not more than 35% by weight (mass). When GGBFS is substituted as a mineral admixture, fly ash will be permitted in ready mix concrete mixtures only, with a maximum total mineral admixture substitution rate of 40%. The mixing equipment shall meet the requirements of Article 2001.21, B.
3. GGBFS substitution will be allowed from October 16 through March 15 only when maturity method is used to determine time of opening.
The Contractor shall provide sufficient equipment to perform all operations necessary to complete the work. Equipment shall meet the appropriate requirements of Section 2001 and the following provisions.
2301.06 PROPORTIONING AND MIXING EQUIPMENT.
Equipment used for proportioning and mixing concrete materials shall comply with the following:
A. Weighing and Proportioning Equipment.
Article 2001.20 shall apply.
B. Mixing Equipment.
Article 2001.21 shall apply.
Article 2001.06 shall apply.
2301.07 CONSTRUCTION EQUIPMENT FOR PORTLAND CEMENT CONCRETE PAVEMENT.
Equipment necessary for construction of concrete pavement shall comply with the following requirements:
A. Equipment for Standard Concrete Pavement.
1. Side Forms.
Side forms shall have a height, without horizontal joint, at least equal to the designed thickness of the pavement at its edge, except the additional height represented by integral curb may be secured by bolting extra forms upon the top of the main form.
The top face of a form shall not vary from a true plane by more than 1/8 inch in 10 feet (3 mm in 3 m), and the vertical face shall not vary from a true plane by more than 1/4 inch in 10 feet (6 mm in 3 m).
Flexible or curved forms shall be used for curves having radii of 100 feet (30 m) or less.
a. Forms Required to Support Heavy Equipment.
Forms required to support heavy equipment shall be made of steel not thinner than U.S. standard 5 gauge (approximately 7/32 inch (5 mm)). They shall be equipped with a device for holding abutting sections firmly in alignment. This device shall permit adjustment for horizontal and vertical curves. Forms having a height of 8 inches (200 mm) or more shall have a base not less than 8 inches (200 mm) wide. Forms having a height less than 8 inches (200 mm) shall have a base width not less than their height. They shall be equipped with not less than three staking points per each 10 feet (3 m) of length with means for securely locking the form to each stake. Flange braces and staking pockets shall extend outward on the base not less than 65% of the height of the form.
b. Forms Not Required to Support Heavy Equipment.
Forms not required to support heavy equipment may be made of wood or steel. They shall have sufficient stiffness and shall be staked to remain vertical and substantially true to line and grade during placing and finishing of concrete. Straight wood forms shall be of nominal 2 inch (50 mm) stock. All wood forms shall be finished on the side supporting the concrete and on their upper edge.
2. Integral Curb Forms.
Forms used to form the back of all integral curbs shall be metal except where returns of small radius or other special sections make use of metal forms impractical.
Back forms for curb shall be rigidly attached to the side forms for the pavement slab, using all fastenings provided by the manufacturer of the forms. A sufficient length of curb forms and number of fastenings shall be supplied to make it possible to leave the forms and fastenings in place for at least 6 hours after the curb is placed. At the time the curb form is placed, the top of the pavement form shall be free of any substance which might prevent the rigid fastening or accurate alignment of the curb form. The curb form shall extend the plane of the pavement form without a variation of more than 1/8 inch (3 mm). The top of the curb form shall be set at the elevation of top of curb being built, except at curb runouts.
Sloping faced curb not more than 4 inches (100 mm) in height may be shaped to the desired cross section with a curb mule without the use of face forms.
For straight sections of integral curb more than 4 inches (15 mm) in height, the Contractor may use face forms or a slip form curb mule. If face forms are used, not less than 100 feet (30 m) shall be provided for each curb being constructed. These face forms shall be of metal and shall be sufficiently rigid and properly secured to maintain their shape and position during use. The face forms shall produce a curb of the cross section shown in the contract documents, except that approved hand shaping tools and methods may be used to supplement the forms in shaping the top roll and on returns and other special sections. Unless mounted on a machine, the slip form for shaping the curb shall be not less than 6 feet (1.8 m) long, and subject to approval by the Engineer. Both back and face forms will be required when constructing barrier curbs or any curb having a top width of 8 inches (200 mm) or more.
3. Supplementary Rails.
The Contractor shall provide suitable metal rails capable of being securely attached to the top of the side forms to provide a track upon which spreading, finishing, and curing equipment can be backed over the end of the previous day's run. The length of rails provided shall be sufficient to accommodate all equipment which must be backed out of the way.
The rails shall be of such height that all wheels and flanges of wheels will clear the previously placed concrete by at least 1/2 inch (15 mm).
4. Form Line Excavating Machine.
The form line for all forms supporting mechanical finishing equipment shall be excavated substantially to line and grade by a machine designed for this purpose and approved by the Engineer, or by an approved machine which concurrently trims the subgrade or subbase to grade.
5. Subgrade Preparation.
The subgrade or subbase shall be trimmed to grade with a machine having electronic elevation controls. Other methods for trimming must be approved by the Engineer.
6. Consolidating and Finishing Equipment.
For placing and finishing standard type pavement, the following equipment will be required:
1) The full width and depth of concrete requiring a finishing machine shall be consolidated by a single pass of an approved internal or surface vibrator. Internal vibrators shall be operated within a frequency range of 4000 to 8000 vibrations per minute. The Engineer may authorize the minimum vibration frequency be lowered to 3500 vibrations per minute for particular sections of paving such as superelevations. Surface vibrators shall be operated within a frequency range of 3500 to 6000 vibrations per minute. Vibrators shall not be operated in a manner to cause a separation of the mix ingredients; either a downward displacement of large aggregate particles or an accumulation of laitance on the surface of the concrete. Avoidance of separation of the mix may require a reduction in vibrator frequency when forward motion of the paver is reduced.
If a vibrator fails to operate within the specifications, the Contractor shall repair or change the vibrator before the paving begins the following day or begins the same day if the continuous paving that day is stopped at a header or at the end of a session.
If two adjacent vibrators fail to operate within specifications, the paving operation shall stop and repairs made or vibrators replaced.
Vibrators shall be stopped whenever forward motion of the paver is stopped.
2) An electronic vibrator monitoring device displaying the operating frequency of each individual internal vibrator shall be required for all Interstate and Primary contracts with PCC paving quantities of mainline paving over 50,000 square yards (40,000 m2); and shall apply to other contracts only when specified in the contract documents. When required on a contract they will only be required in areas where mainline pavement exceeds 600 feet (175 m) in length. When project staging necessitates small mainline sections be paved separately from the majority of mainline paving, the Engineer may waive this requirement for those small sections.
The monitoring device shall have a readout display near the operator's controls visible to the paver operator and the Engineer. It shall operate continuously while paving, and shall display all vibrator frequencies with manual or automatic sequencing among all individual vibrators. The monitoring system shall also record, at minimum, the clock time, station location, paver track speed, and operating frequency of individual vibrators. Recordings shall be made after each 25 feet (8 m) of paving or after each 5 minutes of time. An electronic record of the data shall be provided to the Engineer daily for the first 3 days of paving and weekly thereafter. The Engineer may determine that more frequent submission is necessary, particularly if equipment malfunctions occur.
If the electronic monitoring device fails to operate properly, the vibrators shall immediately be checked manually. If the vibrators are functioning properly, paving may continue but the Contractor shall make all efforts to correct the malfunction in a reasonable amount of time. If the recording device fails to operate, paving may continue but the Contractor shall correct the malfunction within 3 paving days. The Engineer may allow additional time if circumstances are beyond the Contractor's control.
3) The depth of penetration into the concrete pavement slab of internal vibrators shall be set to mid slab or as deep as possible while passing above any reinforcing steel. An operating position locking device shall be provided so that no part of the vibrating unit can be lowered to the extent that it will come in contact with reinforcing steel or tie bars while paving.
4) Horizontal spacing of vibrators shall not exceed the manufacturer's recommendations, but in no case exceed 16 inches (410 mm) from center to center.
5) The longitudinal axis of the vibrator body shall be mounted approximately parallel to the direction of paving with the exception that the trailing end of each vibrator shall be tilted downward to an approximate slope of 15 degrees below horizontal.
6) Vibrators shall meet or exceed the following specifications at manufacturer's design frequency of 10,000 vpm:
a) amplitude (peak to peak) 0.070 inches (1.75 mm)
b) centrifugal force 1200 pounds (5500 N)
b. Finishing Machine.
Where side clearance is provided, a finishing machine designed for concrete paving and subject to approval of the Engineer will be required on all uniform width slabs 8 1/2 feet (2.6 m) or more in width upon which a continuous line of forms more than 600 feet (180 m) in length may be set. Utility access, intakes, and other small fixtures will not be considered as an obstruction to the continuity of the form line. Railroad tracks, bridges, and existing paved intersections will be considered as obstructions in the continuity of the form line.
The finishing machine shall leave the top of the concrete slab smooth with the desired crown and at the proper elevation. When the contract documents require the pavement to be laid partly with crown and partly without crown, the screed shall be equipped so that it can be adjusted to the change in shape at the required rate of change.
If in the operation of subgrade or finishing equipment it is necessary to operate one or both sets of wheels or tracks on previously placed concrete, wheels or tracks shall be adjusted or altered so that the bearing on the concrete will not be closer than 3 inches (75 mm) from the pavement edge. When operating with one side of the machine on pavement and the other side on forms, the wheels operating on the forms may be double flanged. Wheels operating on the pavement shall be flangeless and rubber faced. The ends of the finishing machine screeds operating over the edge of concrete less than 2 months old shall be supported by an approved device to provide from 1/16 inch to 1/8 inch (2 mm to 3 mm) clearance between the screed and previously placed pavement.
Suspension resulting in a pendulum effect will not be approved.
Sections of pavement not required to be finished with a finishing machine may be finished by hand equipment as provided in Article 2301.07, D.
B. Equipment for Slip Form Concrete Pavement.
1. Form Line Excavating Machine.
The path over which the pavement laying machine travels shall be excavated to line and grade when required by a machine designed for this purpose and approved by the Engineer or by a machine which operates concurrently with the trimming of the subgrade or subbase.
2. Subgrade Preparation.
An electronically controlled machine shall be used to trim the subgrade or subbase to grade to the satisfaction of the Engineer.
3. Placing, Consolidating, and Finishing Equipment.
The slip form paving machine shall be designed for the specific purpose of placing, consolidating, and finishing concrete pavement slabs without use of fixed side forms. Edges of the concrete slab as built by the machine shall be approximately vertical. The machine shall be self propelled and shall be equipped with means for spreading the concrete to a uniform depth before it enters the throat of the machine. The machine shall vibrate the concrete to the full width and depth being placed in a single passage. This vibration shall be accomplished with vibrating tubes or arms working in the concrete or a vibrating pan operating on the surface of the concrete. The amplitude, rate of vibration, and locking device for depth shall be as specified in Article 2301.07, A. The slip form paver shall produce a surface reasonably free of voids and tears.
When the slip form paver is operated with one or both tracks on previously placed concrete, the tracks shall be rubber faced or shall travel on cushions of wood or belting to prevent damage to the pavement surface.
The paver shall be equipped with automatic horizontal and vertical grade controls.
4. False Forms.
When approved by the Engineer, false forms may be used on slip form pavement work in areas that are to be subsequently abutted with other lanes of pavement in the 20 feet to 30 feet (5 m to 10 m) preceding a day's work joint, or in areas requiring vertical edge support.
C. Curing Equipment.
If liquid curing compounds are used, approved mechanical spraying equipment operating on the forms or outside the pavement edges shall be used to apply liquid curing compounds on surfaces of pavements of uniform width for a continuous length of over 5000 feet (1500 m). This equipment shall be provided with a shield to prevent undue loss of curing compound by wind action. Hand spraying equipment may be used on all vertical edges, hand finished sections, and all other pavement surfaces.
D. Finishing Equipment, Hand Method.
For placing and finishing concrete by hand methods, the following shall apply:
The rate of vibration shall be between 3500 to 6000 vibrations per minute, and the amplitude of vibration shall be sufficient to be perceptible on the surface of the concrete more than 12 inches (0.3 m) from the vibrating unit.
The screed shall be true to crown and may be of wood or metal. It shall be adjustable for crown, or a separate screed for each variation in crown shall be furnished.
E. Finishing Tools.
The Contractor shall provide all finishing tools necessary for proper finishing of the concrete. This includes straight edges for checking and correcting finished concrete surfaces.
F. Washing Water.
An adequate supply of water suitable for washing testing equipment shall be maintained at a convenient location, as directed by the Engineer, near the site of concreting operations without additional compensation.
BRIDGE APPROACH SECTIONS
Bridge approach sections shall be constructed as shown in the contract documents. All approach pavement reinforcing steel shall be epoxy coated. Clear distance from face of concrete to near reinforcing steel shall be 2 inches (50mm), unless otherwise noted in the contract documents. The Bridge Approach Section shall be Class C Concrete, with coarse aggregate durability in accordance with Article 4115.04.
SETTING OF FORMS.
When fixed side forms are used, they shall be set accurately to the required grade and alignment and shall be founded and secured to maintain that grade and alignment while concrete is being placed and finished and until it is time for the forms to be removed. Forms shall be set on properly compacted materials.
Except as provided below, forms shall be set with the base and top of the form at the respective designed elevations of the subgrade and surface of the pavement at its edge.
With specific approval of the Engineer, forms having a height greater than the designed thickness of the edge of the pavement may be used when set as follows:
A. Side Forms.
Side forms may be set with their tops at the designed elevation of the finished surface of the pavement and their bases at an elevation lower than the design base, subbase, or subgrade elevation, provided material is excavated to meet the lower edge of the form with a straight, lateral slope not steeper than one vertical to four horizontal. All additional excavation and concrete required by this method shall be at the Contractor's expense.
B. Integral Curb Forms.
Forms for integral curb must be rigidly attached to the supporting side forms using all fastenings provided by the manufacturer. Special care shall be taken to remove all water and laitance from the edge of the pavement before the curb is placed.
After forms are set and locked, they shall be tamped on both sides of each form throughout its entire length with a suitable tool. This tamping shall force suitable material into contact with the base of the form for its entire length and width. Forms that are to support mechanical finishing machines shall be tamped. Tamping of forms set on bases or subbases may be waived if the excavation and bedding of the forms meet the Engineer's approval. Should the earth or subbase supporting the form become softened by rain or standing water so that the form is not adequately supported, the form shall be reset on suitable material before concrete is placed.
Forms shall be cleaned before being reset. They shall be coated with form oil before concrete is placed against them. The oil for this purpose shall produce an oil film on the form that will prevent adherence of concrete to the form.
2301.10 SUBGRADE CONSTRUCTION.
Unless a subbase is specified, the subgrade for standard pavement shall be prepared according to Section 2109.
Subgrade construction for slip form pavement shall be as follows:
When the contract documents include a bid item for Class 10 excavation, the Contractor shall do all work necessary for proper preparation of the subgrade.
When the contract documents do not include a bid item for Class 10 excavation, it may be assumed that the subgrade has been or will be shaped and compacted by others. Acceptable tolerance for that work is described in Article 2102.12,except that at approaches to existing improvements or structures, corrections will be based on a practical minimum cut and fill for the project.
The Contractor shall shape and compact the subgrade in accordance with the applicable following method:
A. Subbase Not Specified.
If no subbase is specified, the subgrade shall be prepared in accordance with requirements of Section 2109.
B. Subbase Specified.
If a subbase under the pavement is specified, the subgrade shall be prepared according to the requirements for that type of subbase.
C. Proof Rolling Requirements.
Subgrades with or without subbase shall be proof rolled not more than 1 week prior to trimming of the final grade. Proof rolling shall be performed by making a minimum of one passage with equipment meeting the requirements of Article 2001.05. All areas which do not meet the requirements of Article 2107.05 shall be treated as specified by Section 2109.
The pad line which will support the slip form paving machine and texturing machine shall be constructed substantially to line and grade in a manner so that one of the final operations in its construction will involve cutting in firm, compacted material with a form line excavating machine or other approved equipment. Any subsequent filling in this path may involve wetting and will require thorough consolidation and a recheck for line and grade.
The treatment of subgrade or subbase shall be in accordance with Section 2109.
At the time concrete is placed, adequate provisions shall have been made for drainage away from the area to be paved except on the sides of super elevated curves or in the area of core-outs for bridges or other structures.
2301.11 FIXTURES IN PAVEMENT SURFACE.
All utility accesses, intakes, valve holes, or other fixtures encountered within the area to be paved shall be adjusted to conform to the finished surface of the pavement to be built.
Prior to placement of concrete, the outside of the fixtures shall be cleaned of foreign material for the depth of the concrete.
Fixtures shall be constructed as shown in the contract documents. Fixtures that fall in a form line may be boxed out if a finishing machine is being used. The boxed out concrete shall not be cut or divided on the original form line.
2301.12 PLACING REINFORCEMENT.
Reinforcement shall be installed prior to vibration so as to be in the intended position in the completed pavement. Bars may be supported by approved chairs or may be placed in position by a machine or method subject to approval of the Engineer.
When welded wire fabric reinforcement is used, the concrete shall first be struck off at the elevation specified for the fabric reinforcement, and the sheets of fabric shall be placed as indicated in the contract documents. The sheets of fabric shall be flat, and care shall be used in handling and placing the fabric to ensure its installation in the proper position. The balance of the concrete shall then be deposited and vibrated in a manner to not displace or distort the fabric. Sheets that have become bent or kinked may be rejected.
Alternate methods of placing welded wire fabric reinforcement will be considered for approval.
Load transfer devices may be required in the contract documents. These assemblies shall be accurately placed as shown and shall be securely staked or fastened to the base to line and grade to prevent their movement during subsequent concrete paving operations. Assemblies may be placed in fresh PCC concrete of a Class A subbase, as provided in Article 2114.02, B, to assure a firm connection for the subsequent paving operation. Mechanical dowel bar inserters will not be allowed.
Assemblies that are damaged prior to placement shall not be used. Assemblies damaged after placement shall be replaced prior to paving. Horizontal and vertical alignment of the load transfer bars shall not exceed 1/4 inch (5 mm) from parallel to line and grade. Each assembly shall be placed so the bars are in a horizontal plane at T/2 ± 1/2 inch (15 mm).
The Contractor shall check, with a suitable template or other device approved by the Engineer, the placement of each assembly and the position of the bars within the assembly. If the assembly is found to be placed outside any one of these tolerances, the placement shall be corrected.
Cutting the tie wires of the load transfer assemblies shall be the option of the Contractor.
When dowels or tie bars or other articles are to be anchored in existing concrete, a grout system shall be used as listed in Materials I.M. 491.11 or 491.22 and according to the manufacturer's instructions, subject to the approval of the Engineer.
For horizontal installation of dowels or tie bars, either a pressure injection system with mechanical proportioning and mixing or encapsulated chemical anchors shall be used.
Installation shall be as follows:
The drilled or preformed hole to receive the grout shall be of the dimensions and spacing shown in the contract documents. When not shown in the contract documents, the hole shall be of a nominal maximum diameter 1/8 inch (3 mm) larger than the outside diameter of the dowel or bar, or as recommended by the manufacturer. Immediately prior to placing the grout, the hole shall be blown clean with compressed air. The grout shall be pressure injected into the rear of the hole.
Sufficient grout shall be used so that when the bar, insert, or other article to be grouted is placed in position, there will be an excess of grout forced out the front of the hole. The article to be grouted shall be rotated in the insertion process to ensure complete coating with the grouting material. Hand proportioning and mixing will not be allowed.
Grouting installations utilizing approved encapsulated anchors shall be in accordance with manufacturer's recommendations.
For vertical or angled installations the procedures shall be similar to those for horizontal installation except that pourable grouts may be used. Pourable grouts must be mechanically mixed.
2301.13 PROPORTIONING AND MIXING OF CONCRETE MATERIALS.
The proportioning and mixing materials shall meet the following requirements:
A. Storage and Handling of Aggregates.
Aggregates shall be stored and handled to avoid contamination and frequent variations in specific gravity, gradation, or moisture content of the materials used.
1. Fine and coarse aggregate stored in piles or bins shall be kept entirely separate. When aggregates are trucked to the proportioning plant, the trucks shall dump off a ramp or into a walled pit. In either case, they shall dump onto a floored area. This floor shall consist of a substantial platform or a layer of similar aggregate at least 18 inches (0.5 m) thick placed entirely below the elevation of the surrounding ground.
2. The number of changes from one material to another having different frictional characteristics, class of durability, or average specific gravity shall be reduced to the minimum which the Engineer considers practical.
3. The moisture content of aggregates at time of proportioning or placement in proportioning bins shall be so that water will not drain or drip from a moisture sample. Aggregates shall be handled in a manner that will prevent variations of more than 0.5% in moisture content of successive batches. Coarse aggregates having an absorption greater than 0.5% shall be thoroughly wetted and allowed to drain for at least 1 hour before being used.
4. Fine aggregate shall be drained at least 24 hours after washing and before batching.
5. Aggregates from two sources shall not be commingled in stockpiles or in the finished pavement, except with approval of the Engineer.
B. Storage and Handling of Cement and Fly Ash.
Cement shall be stored in suitable weatherproof enclosures and shall be handled to prevent loss. Section 4101 shall apply to cement which has developed lumps or which has been stored for extended periods.
Fly ash shall be transported and stored in suitable weatherproof enclosures in a manner to keep it dry. Proportioning equipment shall meet requirements of Article 2001.20, A.
C. Measurement of Materials.
Measurement of materials shall be in accordance with requirements for the type of equipment used and the following additional requirements:
1. Cement scales shall be operated within a delivery tolerance of 1.0% of the mass of cement per batch. When operated manually, scales shall be balanced to tare before each batch is weighed and after each batch is discharged. On all bid items involving more than 6000 square yards (5000 m2) of pavement or base, except items made up of irregular areas such as crossovers, turn lanes, and etc., the cement and fly ash scales shall have automatic controls which meet the requirements of Article 2001.20, A. Use of manual controls will not be permitted for a period longer than 1 working day after a failure of the automatic controls, except with permission of the Engineer.
On work requiring automatic cement scales, the performance of the scale will be determined near the end of the first full day of production and thereafter at a frequency of approximately each 10,000 cubic yards (10,000 m3) of concrete produced, by comparing the accumulated mass of cement proportioned with the corresponding accumulated mass of cement shipped to the project. The cooperation of the Contractor will be required. Cement scale performance determinations are not required when a permanent, commercial ready mix plant is used to furnish less than 10,000 cubic yards (10,000 m3) of concrete for a contract.
The performance of a fly ash scale, if present, will be determined as above.
2. Aggregate scales shall be operated within a delivery tolerance of 1.0% for each aggregate.
3. Water shall be measured within a delivery tolerance of 1.0% of the intended quantity.
4. Admixtures shall be measured with approved equipment and procedures that assure the quantity measured shall be within a delivery tolerance of 3.0% of the batch quantity. Mechanical dispensing equipment shall be cleaned and flushed out daily and at more frequent intervals if necessary to ensure proper operation.
D. Mixing of Materials.
Concrete materials shall be either mixed at the site of placement or mixed in a construction or stationary mixer to be used for work on the project only, or ready mixed or transit mixed concrete. During any one individual placement; the same cement, aggregates, and admixtures shall be used throughout the placement unless otherwise approved by the Engineer. With approval of the Engineer, concrete mixtures may be furnished from multiple plants provided the same materials are used in each mixture and mix consistency can be maintained.
1. Concrete Mixed in a Construction or Stationary Mixer.
Concrete materials shall be mixed as provided in Article 2001.21 for the equipment used. The method of handling batches and charging the mixer shall assure complete introduction of each batch separately without loss of materials.
The concrete, as discharged from the mixer, shall be uniform in composition and consistency. If this condition is not produced because of the size of the batch, the size of the batch may be reduced or the mixing time increased, or both, until this result is obtained.
Concrete transported without continuous agitation shall not be used if the period elapsed between the time the concrete is mixed and the time it is placed is greater than 30 minutes. With the approval of the Engineer, an approved retarding admixture may be used at the rate prescribed in Materials I.M. 403, and the mixed-to-placed time period may be extended an additional 30 minutes.
Concrete transported with agitation shall not be used when the time between start of mixing and placement is more than 90 minutes.
The methods of delivering and handling the concrete shall be so that objectionable segregation or damage to the concrete will not occur, and that which will facilitate placing with a minimum of handling.
The compartment in which concrete is transported to the work site shall be thoroughly cleaned and flushed with water at intervals which may be necessary to insure that hardened concrete will not accumulate in the compartment. Flushing water shall be discharged from the compartment before it is charged with the next batch.
Plant operation and procedures shall be subject to the Engineer's approval.
2. Ready Mixed Concrete.
Ready mixed concrete is defined as concrete for which the required materials are as follows:
a. Proportioned in a central plant and mixed in a stationary mixer for transportation in trucks with or without agitation.
b. Proportioned and then mixed in a transit mixer prior to or during transit.
Concrete material shall be mixed as provided in Article 2001.21 for the type of equipment used. When necessary to add additional mixing water at the site of placement, the batch shall be mixed at least an additional 30 revolutions of the drum at mixing speed.
For main portions of the work designed to support public vehicular traffic, it must be demonstrated to the Engineer before the work starts that each vehicle in which concrete will be delivered to the work is capable of discharging concrete having a slump not over 2 inches (50 mm) at an overall rate for its entire load of not less than 1.25 cubic yards (1 m3) per minute. The concrete shall be delivered at a rate sufficient to maintain a sustained rate of progress of not less than 100 feet (30 m) per hour for the width and depth of slab to be placed. The Engineer shall be assured that an adequate and properly staffed dispatching system will be utilized.
Ready mixed or transit mixed concrete may be used for other portions of the work under other restrictions specified for bid items involving 6000 square yards (5000 m2) of pavement or less, and may be used for irregular pavement areas such as crossovers and turn lanes.
Concrete transported without continuous agitation shall not be used if the period elapsed between the time the concrete is mixed and the time it is placed is greater than 30 minutes. With the approval of the Engineer, an approved retarding admixture may be used at the rate prescribed in Materials I.M. 403, and the mixed-to-placed time period may be extended an additional 30 minutes.
Concrete transported with agitation shall not be used when the time between start of mixing and placement is more than 90 minutes.
The methods of delivering and handling the concrete shall be such that objectionable segregation or damage to the concrete will not occur, and that which will facilitate placing with a minimum of rehandling.
The compartment in which concrete is transported to the work shall be thoroughly cleaned and flushed with water at intervals that are necessary to ensure that hardened concrete will not accumulate in the compartment. Flushing water shall be discharged from the compartment before it is charged with the next batch.
Plant equipment, operation, and procedures shall be subject to the Engineer's approval.
2301.14 PLACING CONCRETE.
The contract documents will show the width in which it is contemplated that the pavement will be constructed, and unless otherwise shown, the pavement shall be constructed in a single pass.
Pavement constructed using ready mixed concrete shall be placed in single lane widths only and in compliance with the following provisions, unless otherwise permitted by the Engineer. Permission will be based on evaluation of type, quality, and quantity of equipment to be used and its anticipated rate of production.
At the Contractor's option, pavements may be placed in single traffic lane widths under the following conditions:
The Contractor shall submit a proposed plan of operation for the approval of the Engineer. Any additional dowels, tie bars, or extra concrete, required to conform to the approved, modified method of operation, shall be furnished by the Contractor without extra compensation.
The concrete shall be deposited upon the supporting surface in a manner which will minimize segregation and disturbance of reinforcement. Except when welded wire fabric reinforcement is used, concrete shall be deposited to the full depth of the pavement in a single operation. When welded wire fabric is used, Article 2301.12 shall also apply.
The operation of vibrating units shall be substantially as recommended by the manufacturer and in a manner which complies with the requirements of Article 2301.07, A.
Vertical edges of pavements and backs of curbs shall be cured in accordance with Article 2301.19.
All honeycombed areas on pavement edges shall be satisfactorily repaired immediately after removal of forms.
The Contractor shall backfill behind curbs, as directed by the Engineer, to prevent a flow of water in this area and subsequent undermining of pavement.
2301.15 MULTIPLE LANE CONSTRUCTION.
Unless written approval has been secured for alternate methods described in Article 2301.14, all lanes and sections of pavement shall be constructed to the widths shown in the contract documents.
Expansion and contraction joints shall be constructed to be continuous across all lanes and shall not be staggered.
The edge of the pavement adjacent to the steel form or at any supplemental form or bulkhead that will be abutted by a subsequent slab shall be edged with a tool having a radius of 1/8 inch (3 mm) or less. The cutting edge of the tool moving along the form shall extend downward beyond the rolled edge of the form to its vertical face. The edge on abutting lanes shall be tooled in the same manner.
When keyed joints are required, the keyway shall be fastened to the form by a method that will ensure construction of the keyed joint. These fasteners shall be such that they can remain in place until the concrete has been placed adjacent to and above the keyway.
2301.16 FINISHING AND TEXTURE.
Promptly after the concrete has been placed and consolidated, it shall be finished. Following the finishing operations, texture shall be applied to the surface.
After the concrete has been consolidated, the surface shall be struck off to the true section by the screed. The surface shall be finished true to line and grade.
No additional water shall be directly applied to the surface by spray wand, brush, or other methods. Burlap may be attached behind the screed and a small amount of water may be used to wet the burlap to facilitate finishing operations. The surface shall not be wetted so as to create a slurry.
The edge shall be true and uniform. Hand corrections may be needed if this is not accomplished by the paver.
When finishing by hand methods, concrete shall be consolidated by use of vibrating units operating in the concrete. Unless the vibrating apparatus is of a type that the full width of concrete is consolidated in a single passage, a definite system or pattern shall be used in the operation of the vibrator so the full width of concrete in each linear foot (meter) of lane will receive adequate and uniform consolidation. The system and methods of vibrating shall be subject to approval of the Engineer. Vibrating equipment shall, under no circumstances, be used as a tool for moving concrete laterally on the grade.
The use of a float on the surface of the pavement is the option of the Contractor.
Microtexture is constructed to produce a roughened surface on the driving areas of the pavement.
Artificial turf, coarse carpet, or burlap shall be dragged longitudinally over the finished surface to produce a tight, uniform, textured surface. Burlap may be dampened to prevent adhesion of PCC mixture. When, for any reason, the desired texture normally obtained by the drag in not secured, the Engineer may require that the final finish be a broom finish, in lieu of or in addition to the drag finish. The broom finish shall be obtained by dragging a suitable broom transversely across the surface of the plastic concrete.
Macrotexture is constructed through the placement of grooves in the surface of a pavement, normally while the concrete is plastic. The Contractor has the option of either transversely or longitudinally macrotexturing. This process is often referred to as tining.
When longitudinal grooving is utilized on mainline pavement, transverse grooving may be utilized on other pavement on the same project.
All mainline pavement, where the speed limit is greater than 35 mph (60 km/h), and the traveled portion of ramps shall receive macrotexture. Macrotexturing is not required on radii, crossovers, paved medians, shoulders, and other irregular areas.
Gapped sections of mainline pavement utilizing longitudinal texture shall be transversely or longitudinally grooved. Hand methods may be used on these mainline sections.
When surface corrections are made in the hardened concrete, no macrotexture replacement is required.
Unless otherwise specified, bridge approach sections shall be grooved or otherwise finished in the same manner as either the adjacent bridge or pavement surface.
When finishing by hand methods, except for mainline pavement and ramps as described above, only microtexture will be required.
The grooving shall be done with a mechanical device such as a wire broom or comb. The broom or comb shall have a single row of tines 1/8 inch ± 1/64 inch (3 mm ± 0.5 mm) in width. The depth of groove in the plastic concrete shall be 1/8 inch (3 mm) as a target with a ± 1/16 inch ( ± 1.5 mm) tolerance.
a. Transverse Grooving.
For transverse grooves, the tines shall be randomly spaced from 3/8 inch to 1 5/8 inch (10 mm to 40 mm) with no more than 50% of the spacing exceeding 1 inch (25 mm).
On pavement where transverse tining is to be used, a 4 inch to 6 inch (100 mm to 150 mm) wide strip of pavement surface shall not be tined for the length of each transverse joint, providing an untined surface centered over the transverse joint.
b. Longitudinal Grooving.
For longitudinal grooves, the tines shall be uniformly spaced at 3/4 inch (20 mm) intervals.
Longitudinal tining shall be accomplished by equipment with horizontal and vertical string line controls to ensure straight, uniform depth grooves. A 2 inch to 3 inch (50 mm to 75 mm) wide strip of pavement surface shall be protected from longitudinal surface grooving for the length of and centered about the longitudinal joint.
The tining operation shall be done at such time and manner that the desired surface texture will be achieved while minimizing displacement of the larger aggregate particles and before the surface permanently sets. Where abutting pavement is to be placed, the grooving shall extend as close to the edge as possible without damaging the edge. If abutting pavement is not to be placed, the 6 inch (150 mm) area nearest the edge or 1 foot (300 mm) from the face of the curb shall not be grooved. All uniform width slabs of 20 feet (6.1 m) or narrower and less than 600 feet (200 m) in length, as well as mainline and ramp pavement during equipment breakdowns, may be grooved by hand methods.
The pavement shall have a smooth riding surface. The pavement shall be constructed to the following tolerances:
The pavement shall be periodically checked longitudinally with a 10 foot (3 m) straightedge. The surface shall not deviate from a straight line by more than 1/8 inch in 10 feet (3mm in 3 m). If slip form methods are used, the 6 inches (150 mm) nearest the edge may exceed the 1/8 inch (3 mm) tolerance but shall not exceed 1/2 inch deviation in 10 feet (13 mm deviation in 3 m).
Where abutting pavement is to be placed adjacent to the pavement being checked, the surface shall not deviate by more than 1/4 inch (6 mm) when checked 1 inch (25 mm) from the edge with a 3 foot (1 m) straightedge used transversely and a 10 foot (3 m) straightedge used longitudinally.
Section 2316 shall apply to smoothness of pavement and bridge approach sections for Primary projects and when specifically required for other projects.
2301.17 INTEGRAL CURB.
When integral curb is required, it shall be constructed preceding the initial set in the concrete, but following the finishing of the main paving slab, except as provided for in Article 2301.18.
Before concrete for the curb is placed, any free water, laitance, dust, leaves, or other foreign matter which may have collected on the edge of the slab shall be removed.
Concrete which has dried, partially hardened, or requires retempering shall not be used.
In placing curb concrete, sufficient consolidation shall be done to secure adequate bond with the paving slab and to eliminate honeycomb in the curb. Care shall be used to avoid disturbing the alignment of forms or the flow line of the gutter.
The final finish on curbs will be secured by hand methods, including use of the 6 foot (1.8 m) straightedge, after removal of the face form or shaping with the curb slip form. The resulting surfaces of both curb and gutter shall be checked by use of the 10 foot (3 m) straightedge and corrected if necessary. In removing face forms, care shall be used to avoid slumps and to avoid disturbance of partially set concrete. The work of constructing integral curb shall proceed as rapidly as finishing operations on the paving slab will permit and in all cases shall be completed in the same working day as the slab is placed, except for the length of section required at the end of the day's run to accommodate the mechanical placing and finishing equipment. In the section left for subsequent placement of curb, the surface of the paving slab along the line of the inside slope of the curb shall be depressed so that the new concrete placed for curb shall be not less than 1 1/2 inches (40 mm) thick. This section of curb shall be tied to the slab by No. 3 (Size 10) hooked steel bars spaced at 1 foot (300 mm) intervals. The surface of the slab back of the key notch shall be roughened, and a depression shall be created around each dowel so that it will project at least 2 inches (50 mm) into the curb concrete.
When curb is built on slabs traversed by headers or contraction or expansion joints, the joints shall be extended through the curb directly over the joint in the slab. All headers and contraction and expansion joints shall be extended through the curb in the same thickness as in the main slab.
All curbs shall be edged, protected, and cured the same as other parts of the paving slab.
2301.18 END OF RUN.
Whenever 30 minutes or more have elapsed since the last concrete has been deposited on the subgrade or if such a delay is anticipated, an approved header shall be installed.
Header joints shall not be constructed within 5 feet (1.5 m) of an intended or previously placed contraction joint. Header joints shall not be constructed opposite a contraction joint in multiple lane construction.
When a header joint is installed, resumption of paving which abuts the header shall not commence for a minimum of 6 hours.
When delivery of concrete is resumed, it shall be placed adjacent to the exposed face of the header, thoroughly consolidated, and finished with an edging tool at the joint. Sawing and sealing of this joint is not required.
When the end of the day's run occurs in curb section, sufficient curb shall be omitted to accommodate equipment which must be backed out of the way. Construction of the portion of curb omitted shall be as shown in the contract documents and in accordance with Article 2301.17.
A. Headers Constructed in Plastic Concrete.
The header shall be constructed true to line and grade with the face perpendicular to the surface and at right angles to the centerline of the pavement. The tie bar reinforcement shall be level, true to line and grade, and normal to the header joint.
Concrete collected by a finishing machine during its first passage shall not be used adjacent to the header board. Concrete screeded over the header during finishing shall be promptly removed.
Concrete shall be well consolidated against the header and finished with an edging tool.
The header board and all supports shall be removed before paving is resumed.
B. Headers Constructed in Hardened Concrete
The Contractor may pave past the location of the header. After the concrete has hardened, the pavement shall be sawed perpendicular to the centerline of the pavement, creating a vertical face. Holes for the tie bar reinforcement shall be drilled and reinforcement grouted into the holes, in accordance with Article 2301.12. The paving operations may begin adjacent to the header after a minimum of 1 hour after the placement of the reinforcement bars.
2301.19 CURING AND PROTECTION OF PAVEMENT.
After finishing operations have been completed, concrete pavement shall be cured in accordance with Article 2301.19, A.
When an insulation blanket is required, this cover shall consist of a layer of closed cell polystyrene foam protected by at least one layer of plastic film, rated by the manufacturer with an R-value of at least 0.5, or two layers of burlap between 4 mil (100 µm) thick sheets of plastic or an approved alternate.
Placement of the insulating cover may be delayed for up to 4 hours to accommodate initial sawing of joints. The cover may be temporarily removed to perform sawing or sealing. The cover may be permanently removed when the concrete has attained the flexural strength required for opening.
Vertical edges of pavement and backs of curbs shall be cured by the same method used for curing the surface.
Bridge approaches, medians, curbs, widening, and ramps shall be cured in accordance with Article 2301.19, A.
A. Curing with White Pigmented Liquid Curing Compound.
Curing compound shall be applied in a fine spray to form a continuous, uniform film on the surface and vertical edges of the pavement slab as soon as the free water has appreciably disappeared, but no later than 30 minutes after finishing. With approval of the Engineer, the timing of cure application may be adjusted due to varying weather conditions and concrete mix properties to ensure acceptable macrotexture is achieved. The rate of application shall be not less than 0.067 gallon per square yard covering 15 square yards per gallon (0.3 L/m2 covering 3 m2/L).
Care shall be taken to ensure that liquid curing materials shall be well agitated in the supply drum or tank immediately before transfer to the distributor, and kept thoroughly agitated during application. Application shall be by means of power spraying equipment capable of producing a fine spray which will not damage the surface of the concrete. Hand operated sprayers may be used for spraying the sides and irregular areas.
If forms are used, within 30 minutes after their removal, the vertical edges of the pavement shall be coated with curing material, applied at the same rate as on the surface.
If the coating is damaged within 72 hours after being applied, due to other operations, the affected areas shall be re-coated without delay. Coating of the sawed surface with curing compound will not be permitted on joints that are to be sealed. When pavement is opened to traffic prior to 72 hours after application of the curing coating, a re-coating will not be required.
Curing shall be with a white pigmented curing compound meeting requirements of Section 4105.
B. Cold Weather Protection.
All concrete pavement, including exposed edges of the slab, shall be cured according to Article 2301.19, A, prior to applying protection. In addition, concrete less than 36 hours old shall be protected as follows, and payment will be made as provided in Article 2301.35.
|Night Temperature Forecast||Type of Protection (1)|
|35°F to 32°F (2°C to 0°C)||One layer of burlap for concrete.|
|31°F to 25°F (-1°C to -4°C)||Two layers of burlap or one layer of plastic on one layer of burlap.|
|Below 25°F (-4°C)||Four layers of burlap between layers of 4 mil (100 µm) plastic or equivalent commercial insulating material approved by the Engineer.|
|(1) The protection shall remain until
one of the following conditions is met:
b. Opening strength is attained.
c. Forecasted low temperatures exceed 35°F (2°C) for the next 48 hours.
d. Forecasted high temperatures exceed 55°F (13°C) for the next 24 hours and subgrade temperatures are above 40°F (4°C).
Paving operations shall be shut down in time to comply with protection requirements outlined above. In good weather, the header shall be placed at least 45 minutes before sunset. During cold weather, more time must be allowed for finishing and protection. All finishing and covering operations shall be performed prior to darkness. Temperature restrictions and protection requirements may be modified by the Engineer.
When the pavement is placed directly on natural subgrade, Section 2109, earth check dams shall be constructed immediately after passage of the slip forms or removal of the forms to prevent water from flowing along the edge of the pavement and undermining the slab. They shall not be spaced or be of a width to provide an approach over which a vehicle may be driven onto the pavement.
C. Rain Protection.
For protection against the effects of rain on paving, the Contractor shall have available, near the site of the work, materials for proper protection of the edges and surface of concrete. Protective material may consist of sheets of burlap, paper, or plastic film. Planks or other material with suitable stakes that can be used as temporary forms shall also be on hand.
It shall be the Contractor's responsibility to protect the pavement from damage due to rain. Failure to properly protect concrete may constitute cause for removal and replacement of defective pavement.
2301.20 SAFETY FENCE FOR PAVEMENT.
In addition to the requirements of Article 1107.09, the Contractor shall install a safety fence for the full width of the slab near the end of each day's run.
This safety fence shall be supported by setting posts near to the edge of the slab. These posts shall extend at least 2 feet (0.6 m) into the ground. Between these posts, a 48 inch (1.2 m) nominal height orange mesh safety fence meeting the requirements of Article 4188.03 shall be stretched and secured to the posts. The twisted ends of the wire shall be cut off flush with the twist so that a tool would be required to cut or otherwise release the fastening.
The fence span between the posts shall be supported with not less than four equally spaced plastic drums weighted to make them stable and difficult to move. These drums shall be as approved in accordance with Materials I.M. 488.02.
On urban work where it is not feasible to set posts, steel drums or sand box supports may be substituted for the end posts.
A similar safety fence shall be placed parallel to and within 50 feet (15 m) from the edge of the slab at all public road and side street intersections. These fences shall be constructed similar to the day's run safety fences.
All safety fences shall be installed within 1 hour of the completion of finishing and curing operations at the fence location to prevent traffic from entering on and damaging the pavement slab. All safety fences shall remain in place and shall be maintained by the Contractor until the concrete has attained the strength and age requirements of Article 2301.31.
Intermediate safety fences may be required for the purpose of opening the slab for access to a side road, side street, or entrance.
2301.21 REMOVAL OF FORMS.
Side forms and curb forms shall be left in place not less than 6 hours after the concrete is placed, unless earlier removal is required by Article 2301.22. Care shall be exercised in removal of forms to prevent cracking, spalling, or over stressing the concrete. All stakes in any form shall be removed before the form is raised. If the method of form removal causes damage to the concrete, the Engineer may require forms to remain in place for more than 6 hours.
2301.22 SAWING JOINTS.
All joints shall be sawed in a single cutting operation for a specific joint substantially true to line to the dimensions shown in the contract documents. Joint sawing shall begin as soon as the concrete has hardened sufficiently to permit sawing without raveling or moving of aggregate.
Joints shall be sawed before uncontrolled cracking takes place. Control joints may be sawed by any saw designed for concrete sawing. If necessary, sawing operations shall be continuous regardless of weather or daylight conditions. Sawing of a joint shall be discontinued if a crack develops ahead of the saw. A heavy span saw, which is supported on the new pavement, will not be allowed for sawing pavements and concrete overlays less than 7 inches (180 mm) in depth.
If the pavement has been covered or protected due to cold weather, rain, or snow, joints shall be sawed by conventional saw equipment only.
Joints requiring compression sealant materials to be installed according to Article 2301.25, shall be sawed so that the compression sealant material can be installed and function correctly.
Should uncontrolled cracking or random transverse cracking occur, the pavement shall be repaired at no additional cost to the Contracting Authority. Repair methods shall be as approved by the Engineer.
When the normal section of pavement is reduced by box-outs such as for intakes, a contraction joint shall be constructed, beginning at one end of the box-out and extending to the pavement edge. This joint shall be constructed by sawing. Alternate types of transverse joints will be considered for approval.
If the length of box-out exceeds 15 feet (4.5 m), a contraction joint shall be constructed at both ends.
2301.23 EXPANSION JOINTS.
Preformed joint material shall be installed perpendicular to the pavement surface. The Contractor shall exercise care throughout the construction of the pavement to ensure that the joint material remains in proper position. The Contractor shall set substantial reference stakes or markers showing the exact location of the joint prior to the placement of concrete adjacent to the joint. After the mechanical finishing equipment has passed over the joint, the joint shall be checked for movement. If movement has occurred in excess of 1/2 inch (10 mm), the installation shall be corrected to its intended position immediately. After the surface finishing has been completed, the joint shall be edged as shown with minimum disturbance to adjacent concrete. Supplemental vibration equipment will be required for proper consolidation of the concrete.
2301.25 SEALING JOINTS.
Unless otherwise provided, before any portion of the pavement is opened to the Contractor's forces or to general traffic, expansion joints and sawed longitudinal and transverse joints shall be sealed with one of the appropriate materials described in Section 4136.
The joint opening shall be sawed or prepared to the designated dimensions and cleaned. The joint shall then be sealed as designated in the contract documents with material meeting requirements of Section 4136.
Joint sealer, in accordance with Article 4136.02, A, shall be used to seal all sawed joints in PCC pavement, shoulders, medians, crossovers, and side road pavements unless otherwise specified in the contract documents.
Within 3 hours after the joint has been wet sawed to the finished dimension, the residue from wet sawing shall be flushed away from the sawed faces by a high pressure water blast, operating with a minimum pressure of 1000 psi (7000 kPa). Within 3 hours after the joint has been dry sawed to the finished dimension, the residue from dry sawing shall be blown from the joint.
Sand cleaning will not be required for joints narrower than 3/8 inch (10 mm), and cleaning of joints shall be as described above. For joints 3/8 inch (10 mm) and wider, sand cleaning shall be used as follows:
When the joint surfaces appear dry by visual examination, the upper 3/4 inch (20 mm) of the joint faces shall be cleaned by sandblast methods, using a mechanical guide, followed by joint cleaning with air blasting. Air compressors shall provide moisture and oil free compressed air. The angle of approach of the sandblast nozzle to each vertical face of the reservoir shall be approximately 30 degrees and the sandblast nozzle must have a guide which inserts in the joint and assures positive location and directional control of the nozzle.
Immediately prior to installation of the backer rod and sealant, the joint shall be cleaned with an air blast. Backer rod will not be required for joints constructed using a shallower depth early, green-concrete saw. When a backer rod is to be installed, the backer rod shall be of the proper size and type and shall be installed dry, with a suitable tool. For transverse joints, the backer rod shall extend to the edge of the pavement.
Joint sealer shall be prepared and installed in the joint and to the proper level as shown in the contract documents and as recommended by the manufacturer. Hot poured sealers shall be heated in a thermostatically controlled heating kettle of a type approved by the Engineer. The material shall be heated to the temperature required for use, but not above that recommended by the manufacturer. When a silicone sealer is installed, the joint faces shall be primed if recommended by the sealer manufacturer. The silicone sealer shall be forced into the joint with a suitable tool as recommended by the manufacturer. Self leveling silicone sealers do not require tooling. After sealing, excess sealer shall be removed from the pavement surface.
Joint sealer shall be placed only when the pavement and ambient air temperatures are 40°F (4°C) or higher. When near this minimum, additional air blasting or drying time or both may be necessary to assure a satisfactory bond to the joint surfaces. When this sealer cannot be properly placed due to late fall work, the Contractor shall submit a joint construction plan and sealing details to the Engineer for approval before paving can begin. The cleaning, sealing, and resawing if required, shall be delayed until the following spring. This delay shall be subject to approval of the Engineer. Joints shall be prepared, cleaned, and sealed after surface correction, if any, or seals damaged from the correction work shall be repaired. When sand cleaning is required, joints shall be sealed the same day they are sand cleaned. Sealing shall be done only when the joint surfaces appear dry by visual examination.
The Engineer may limit the wheel loads and axle loads of equipment operating on the pavement during this operation, if prior to the age and strength specified in Article 2301.31. Additional tests to determine the modulus of rupture may be required.
If early pavement opening is specified, the cleaning, sealing, and resawing, if required, shall be accomplished after the pavement is opened to traffic if hot pour sealing material is used.
The methods of installing preformed elastomeric seals shall be those recommended by the manufacturer and subject to approval by the Engineer. The seal shall be in one piece for the full length of the transverse joint.
2301.27 CONCRETE MEDIAN STRIP.
Where the contract documents call for construction of concrete median strip between adjacent slabs, the Contractor shall construct the median strip to conform to the dimensions shown and to the following provisions:
The subgrade for the median strip shall be constructed to the elevation shown in accordance with Article 2109.03.
Concrete shall be of the class specified for the pavement, and methods of placement and finishing shall meet requirements of Section 2301, except that hand methods may be used and the surface texturing will not be required. Joints shall be sawed and sealed as required for jointed pavement. When spacing is not designated, the distance between joints is to be as required for jointed pavement. Joints in the median shall match joints in the abutting pavement.
Gore areas will be considered median strips. When constructed or reconstructed while the highway is open to public traffic, Class M concrete shall be used.
2301.29 RESTRICTION OF OPERATIONS BECAUSE OF WEATHER.
Concrete shall not be placed when stormy or inclement weather will prevent good quality work. Aggregates containing frozen lumps shall not be used, and concrete shall not be placed on a frozen subgrade. Concrete mixing and placement may be started, if weather conditions are favorable, when the air temperature is at least 34°F (1°C) and rising. At time of placement, concrete must have a temperature of at least 40°F (4°C). Mixing and placing shall stop when the air temperature is 38°F (3°C) or less and falling. During cold weather conditions, concrete less than 36 hours old shall be protected in the manner specified in Article 2301.19, B.
2301.30 NIGHT OPERATION.
Concrete shall not be placed when darkness would prevent good quality work in placing and finishing operations. Unless shown in the contract documents or approved by the Engineer, placing and finishing operations under artificial light will not be permitted, and work shall be organized accordingly.
2301.31 TIME FOR OPENING PAVEMENT FOR USE.
The time for opening pavement for use will be based on the restrictions listed in the table below, with flexural strength determined from beam specimens made during the progress of the work.
|Strength Class of Concrete||Minimum Age||psi (MPa)|
|A||14 calendar days(1)||500 (3.45)|
|B||14 calendar days||400 (2.80)|
|C||7 calendar days(2)||500 (3.45)|
|M||48 hours||500 (3.45)|
(1) 10 calendar days for concrete 8 inches (200 mm) or more in thickness.
(2) 5 calendar days for concrete 9 inches (230 mm) or more in thickness.
Unless otherwise specified in the contract documents, at the Contractor's option, the time for opening pavement may be determined through the use of the maturity method as described in Materials I.M. 383. When the maturity method is used, the time for opening pavement will be based on strength requirements only, as specified in the table above. The Contractor shall furnish all labor, equipment, and materials necessary for the development of the maturity-strength relationship as described in Materials I.M. 383.
Determining that sufficient strength has been achieved for opening a section of pavement shall remain the responsibility of the Engineer when the maturity method is used. The Contractor's maturity testing may be used as the basis for this determination. The Contractor shall provide sufficient documentation of maturity testing before a section may be opened to traffic.
The following shall apply when the maturity method is used:
A. Should circumstances arise which are beyond the Contractor's or Engineer's control and strength cannot be determined by maturity method, the minimum age, minimum flexural strength, and fly ash restrictions shall apply.
B. Any change of a material source or proportion in the concrete mixture shall require a new maturity curve.
Personnel performing maturity testing shall be Level I PCC certified technician with training for maturity testing. This certified technician may supervise other persons who may then perform the temperature testing of the constructed pavement.
In cases where early opening of pavement is desirable, the Engineer may require the use of Class M concrete mixtures. Such sections of pavement may be opened to traffic in accordance with the limitations in the above table.
In addition, Class F fly ash and Type IP and Type I(PM) cements shall not be used in Class M concrete mixtures. At the Contractor's option, Class C fly ash may be substituted for up to 10%, by weight (mass), of the cement in Class M concrete mixtures.
Shoulders shall be constructed according to Section 2121, 2122, or 2123, as indicated in the contract documents.
2301.33 SURFACING APPROACHES TO INTERSECTING ROADS, DRIVEWAYS, AND TURNOUTS.
Surfacing approaches to intersecting roads, driveways, and turnouts shall be done as provided in Section 2315.
2301.34 METHOD OF MEASUREMENT.
A. Portland Cement Concrete Pavement.
The quantity of Standard or Slip-Form Portland Cement Concrete Pavement of the type specified in square yards (square meters), will be the quantity shown in the contract documents and applies to pavement, concrete pavement widening greater than 6 feet (1.8 m), side street connections, crossovers, ramps, acceleration and deceleration lanes or auxiliary lanes, and concrete paved shoulders having the same design thickness. The coring requirements for thickness do not apply to detour pavements, paved drives, and temporary pavements. The thickness of pavement constructed will be determined from core depths as follows:
The division of lots, number of lots, lot sizes, and core locations shall be in accordance with Materials I.M. 346.
At locations determined by the Engineer, the Contractor shall cut samples
from the pavement, as directed above, by drilling with a core drill of a size
that will provide samples with a 4-inch (101.6 mm) outside diameter. The
Contractor shall restore the surface by tamping low-slump concrete into the
hole, finishing and texturing. The Engineer will witness
the core drilling, identify, and measure the cores immediately.
The Engineer will will The Contractor shall identify and deliver the
cores to the field laboratory or plant inspector. The Engineer will measure
the cores and determine the thickness index in accordance with
Materials I.M. 346.
After measurement on the grade, the Contractor shall
deliver the cores to the District Materials Office. When cores are not measured
on the grade, the Engineer will take immediate possession of the cores.
Coring of pavement and other work for thickness determination may be waived by the Engineer for sections of the same design thickness less than 5,000 square yards (4200 square meters). Only sections which are cored shall be included in the thickness index determination. Areas not cored shall be paid for at the contract unit price.
C. Integral Curb.
Construction of integral curb shall be incidental to the other items of the work and will not be measured for payment.
D. Intentionally Left Blank.
E. Concrete Median.
The quantity of Concrete Median, in square yards (square meters), will be the quantity shown in the contract documents. This will be calculated to the nearest 0.1 foot (0.1 m) of the length along the surface and the overall width of median when no integral curb is involved, or the width from back to back of curb when integral curb is involved.
F. Bridge Approach Sections.
The quantity of Bridge Approach Section, in square yards (square meters), will be the quantity shown in the contract documents.
1. When the contract provides a unit price per station (meter) for earth shoulder finishing and a price per cubic yard (cubic meter) for excavation, excavation required for preparation of natural subgrade will be measured as provided in Article 2102.13, except that the volume measured for payment will include only the materials actually removed above the elevation of the pavement subgrade and between vertical planes 1 foot (0.3 m) outside the edge of the finished pavement.
Other work connected with preparation of natural subgrade will not be measured for payment.
2. When the contract provides a unit price for earth shoulder construction, whether a unit price per cubic yard (cubic meter) of excavation is provided in the contract or not, excavation required for preparation of natural subgrade will not be measured for payment. Unless otherwise provided in the contract documents, work connected with preparation of natural subgrade will not be measured for payment.
H. Driveway Surfacing Material.
Driveway surfacing material placed at intersecting roads, drives, and turnouts will be measured in tons (megagrams) or cubic yards (cubic meters), as provided in the contract and in Section 2315. Excavation required for placement of this material will not be measured for payment.
I. Portland Cement Concrete Pavement Samples.
Portland Cement Concrete Pavement Samples of finished pavement or other courses furnished according to Article 2301.34, A, or when required in the contract documents, will not be individually counted for payment.
J. Saw Cut and Joint Sealing.
Saw cut for constructing joints in new pavement will not be measured for payment.
Saw cut for cutting old existing pavement, which is to be abutted with new pavement, will not be measured for payment.
Joint sealing will not be measured for payment.
K. Safety Fence for Pavement.
Safety fence for pavement constructed in accordance with Article 2301.20 will not be measured for payment.
2301.35 BASIS OF PAYMENT.
A. Portland Cement Concrete Pavement.
The Contractor will be paid the contract unit price for Standard or Slip-Form Portland Cement Concrete Pavement of the type specified per square yard (square meter) and applies to pavement, concrete pavement widening greater than 6 feet (1.8 m), side street connections, ramps, acceleration and deceleration lanes or auxiliary lanes, and concrete paved shoulders having the same design thickness. Payment for the quantities of pavement in square yards (square meters) will be at a percentage of the contract unit price in accordance with the following schedule:
|Thickness Index Range
|Percent Payment||Thickness Index Range
|0.00 or more
(0.00 or more)
|103||-0.56 to -0.60
(-13.98 to -15.24)
|-0.01 to -0.05
(-0.01 to -1.27)
|102||-0.61 to -0.65
(-15.25 to -16.51)
|-0.06 to -0.10
(-1.28 to -2.54)
|101||-0.66 to -0.70
(-16.52 to -17.78)
|-0.11 to -0.15
(-2.55 to -3.81)
|100||-0.71 to -0.75
(-17.79 to -19.05)
|-0.16 to -0.20
(-3.82 to -5.08)
|99||-0.76 to -0.80
(-19.06 to -20.32)
|-0.21 to -0.25
(-5.09 to -6.35)
|98||-0.81 to -0.85
(-20.33 to -21.59)
|-0.26 to -0.30
(-6.36 to - 7.62)
|97||-0.86 to -0.90
(-21.69 to -22.86)
|-0.31 to -0.35
(-7.63 to -8.89)
|96||-0.91 to -0.95
(-22.87 to -24.13)
|-0.36 to -0.40
(-8.90 to -10.16)
|95||-0.96 to -1.00
(-24.14 to -25.40)
|-0.41 to -0.45
(-10.17 to -11.43)
|94||-1.01 to -1.05
(-25.41 to -26.67)
|82||-0.46 to -0.50
(-11.44 to -12.70)
|93||-1.06 to -1.10
(-26.68 to - 27.94)
|-0.51 to -0.55
(-12.71 to -13.97)
|92||-1.11 or less
(-27.95 or less)
Use the following formula to determine the thickness index for the section of pavement thickness:
TI = (x - S) - T
TI = thickness index for the section
x= mean core length for the section
T = design thickness
S = core length standard deviation (of the sample) for the section.
The pavement represented by cores deficient from design thickness by 1 inch (25 mm) or greater shall be replaced. The deficient areas and the replacement of the deficient cores will be determined in accordance with Materials I.M. 346.
At the Contractor's option, cores that are three standard deviations or greater than design thickness may be removed from analysis for thickness index determination. The number of cores removed shall not exceed 10% of the total cores in a section. Cores removed from the analysis shall not be replaced.
Gaps in the pavement less than 500 feet (150 m), required by staging, will be considered irregular areas for analysis of pavement thickness determinations.
The percent payment for projects which have all core lengths greater than design thickness will be at least 100%.
C. Integral Curb.
Construction of integral curb will not be paid for separately.
D. Intentionally Left Blank.
E. Concrete Median.
The Contractor will be paid the contract unit price for Concrete Median per square yard (square meter).
F. Bridge Approach Sections.
The Contractor will be paid the contract unit price for bridge approach pavement per square yard (square meter). This payment shall be full compensation for excavation for modified subbase and subdrain; furnishing and installing subdrain; furnishing and installing subdrain outlet; furnishing and installing polymer grid; furnishing and placing porous backfill; furnishing and backfilling modified subbase; saw cutting; furnishing and installing reinforcing steel, tie bars, and dowel assemblies; placing, finishing, texturing, grooving, curing, all joint construction; and all other materials and labor to construct the Bridge Approach Section as shown in the contract documents.
1. When the contract provides a unit price per station (meter) for earth shoulder finishing and the contract also provides a price per cubic yard (cubic meter) for excavation, the Contractor will be paid the contract unit price per cubic yard (cubic meter) for excavation in connection with preparation of subgrade and building of shoulders.
When the contract provides a unit price for earth shoulder construction, the excavation required for preparation of subgrade and construction of shoulders will not be paid for as a separate item. It shall be considered incidental to construction of pavement and earth shoulder construction and included in those contract prices.
2. When no price per cubic yard (cubic meter) for excavation is provided in the contract and no unit price is provided for earth shoulder finishing or earth shoulder construction, excavation necessary for preparation for subgrade shall be considered incidental to construction of pavement and included in that contract unit price.
H. Driveway Surfacing Material.
For the quantity of driveway surfacing placed, the Contractor will be paid the contract unit price as provided in Section 2315.
I. Portland Cement Concrete Pavement Samples.
For furnishing Portland Cement Concrete Pavement Samples of finished pavement or other course according to Article 2301.34, A, or when required in the contract documents, the Contractor will be paid the lump sum contract price. This payment shall be full compensation for furnishing all such samples for all courses or items of work.
K. Safety Fence for Pavement.
The cost of Safety Fence for Pavement shall be incidental to the price for pavement.
Deduction will not be made from the area of pavement for fixtures with an area less than 9 square feet (1 m2). When the adjustment of a fixture to the finished grade line involves a change in elevation of 1 foot (0.3 m) or less, this adjustment shall be made without extra compensation. When this adjustment involves a change in elevation more than 1 foot (0.3 m), this work shall be paid for as extra work, as provided in Article 1109.03, B.
When any of the types of additional protection described in Article 2301.19, B, is necessary, additional payment will be made as extra work at the rate of $1.00 per square yard ($1.20 per square meter) of surface protected. Payment will be limited to protection necessary within the contract period. Protection necessary after November 15 will be paid for only when the work is authorized by the Engineer.
The Contractor shall furnish concrete for test specimens and shall transport the specimens and molds between the grade and plant as directed by the Engineer, without additional compensation.
The above prices shall be full compensation for furnishing all tools, equipment, labor, and materials necessary for construction of the pavement in accordance with the contract documents.
The cost of furnishing, installing, and monitoring vibrators; and vibrator monitoring device, shall be considered incidental to the contract unit price for PCC pavement.