Section 2530. Partial Depth Finish Patches.

2530.01 DESCRIPTION.
Partial depth finish patches shall consist of removing pavement in areas designated in the contract documents or by the Engineer to be patches. This includes furnishing and placing patching material to provide a new traffic surface, and restoring the adjacent shoulder as shown in the contract documents. This work is in areas where the size, shape, and depth of patch depends on the extent of pavement deterioration and must be determined during the removal operation.

2530.02 TYPES OF PARTIAL DEPTH FINISH PATCHES.
Partial depth finish patches may be identified and constructed as one of the following types:

A. Partial Depth PCC Finish Patches.
These patches are square or rectangular in shape. The edges shall be sawed. Removal may be by milling or other equipment. This type of patch will be identified by tabulation in the contract documents. The size and location for each lane will be shown.

B. Partial Depth Regular HMA Finish Patches.
These patches are in the shape of a square or rectangle. They have square corners and straight edges to allow almost all of the removal by a milling machine. An air hammer or saw may be necessary to complete removal along edges and at corners. This type of patch will be identified by tabulation in the contract documents. The size and location in each lane will be shown.

C. Partial Depth Irregular HMA Finish Patches.
These patches are not square or rectangular in shape. They have at least one side that is not straight or one corner that is not square which will prohibit complete removal by a milling machine. Other equipment such as an air hammer or saw may be necessary to accomplish the removal. This type of patch will be identified by tabulation in the contract documents. This tabulation will be an estimate of the number of patches per lane mile, and the estimated total area of patch.

2530.03 MATERIALS.
Materials for partial depth finish patches shall meet the requirements for the type of material specified.

A. Hot Mix Asphalt Patching Material.
The patching material for HMA patches shall meet the requirements of Section 2303. The mixture size shall be 3/8 or 1/2 inch (9.5 mm or 12.5 mm) unless otherwise designated in the contract documents. The mixture shall meet or exceed 300,000 ESAL HMA criteria.

Tack coat bitumen for HMA patches shall be as specified in Article 2303.02, E.

B. Portland Cement Concrete Patching Material.
The patching material for PCC patches shall meet one of the following requirements. When patching encroaches on an adjacent lane which is open to traffic or when there is patching on two lane pavements or other locations where overnight closures are not permitted, Class A or Class B patching material shall be used. On pavements with three or more lanes and where overnight closure is permitted, Class C patching material shall be used.

1. Class A Patching Material.
Class A patching material shall be a modified Portland cement type manufactured to provide rapid set and high early strength. It shall meet the requirements of Materials I.M. 491.20.

When a mortar is furnished, coarse aggregate shall be added in the quantity recommended by the manufacturer.

2. Class B Patching Material.
Class B patching material shall be high early strength rapid set (5 hour) PCC meeting the requirements of Materials I.M. 529 and the following requirements:

The patching material shall be a Class M mixture with calcium chloride. Class M mixtures with calcium chloride shall not contain fly ash. When calcium chloride is used in a mixture, the concrete shall be placed within 30 minutes after the introduction of the calcium chloride. Coarse aggregate shall meet the requirements of Section 4115 and Section 4109, Gradation No. 5.>

When Class B patching material is furnished for partial depth patches, it may also be furnished for full depth patches.

3. Class C Patching Material.
Class C patching material shall be a PCC mixture with an early set that will allow time of opening to traffic in 24 hours to 36 hours as directed by the Engineer. Coarse aggregate shall meet the requirements for Class B patching material. Class M mixture meeting the requirements of the current Materials I.M. 529 without the addition of calcium chloride shall be used.

When Class C patching material is furnished for partial depth patches, it may also be furnished for full depth patches.

4. Modifications to Mixtures for Class B and Class C Patching Material.
The following modifications shall apply to the PCC mixtures for Class B and Class C patching material:

a. Slump.
Slump, measured in accordance with Materials I.M. 317 prior to addition of calcium chloride solution, shall be between 1 inch and 2 1/2 inches (25 mm and 65 mm) as a target range, allowing a maximum of 3 inches (75 mm). If calcium chloride solution is not to be added, the slump shall be between 1 inch and 3 inches (25 mm and 75 mm) as a target range, allowing a maximum of 4 inches (100 mm).

When a Type A Mid Range water reducing admixture is used, the slump, tested prior to the addition of calcium chloride, shall be between 1 inch (25 mm) and 4 inches (100 mm) as a target range, allowing a maximum of 5 inches (125 mm).>

b. Air Entrainment.
The entrained air content of the unconsolidated concrete will be determined according to Materials I.M. 318, prior to addition of calcium chloride if it is to be added. The air entrainment when calcium chloride is to be added shall be 5.0%, with a tolerance of ± 2.0%. The air entrainment when no calcium chloride is to be added shall be 6.5%, with a tolerance of ± 1.5%.

c. Temperature.
The temperature of Class B patching material, as delivered to the job site, shall be as required in paragraph d. The temperature of Class C patching material, as delivered to the job site, shall be greater than 65°F (18°C). Heating of water, aggregate, or both may be necessary to meet this requirement. The cost of heating shall be considered incidental to patching.

d. Cement.
Cement for Class M concrete mixtures shall meet the requirements of Section 4101.

The cement types and maximum allowable substitution rates shall be as follows:

Patch Class Cement Type

Maximum Allowable
Substitution

 Minimum Mix
Temperature
B Type I, Type II
Type IS		 0% Fly Ash
0% Fly Ash		 75ºF (24ºC)
80ºF (27ºC)*
C Type I, Type II
Type IS		 10% Fly Ash
0% Fly Ash		 65ºF (18ºC)
70ºF (21ºC)*
* When a Type A Mid Range water reducing admixture is used, the minimum mix temperature shall be that required when Type I/II cement is used 75ºF (24ºC).

The maximum substitution for Type IS shall not exceed 25%.

e. Calcium Chloride.
Where calcium chloride is required, it shall be furnished in water solution form and added to the mix, at the job site. The calcium chloride solution shall be a commercial 32% solution, or equivalent, prepared by the Contractor:

PROPORTIONS FOR 32% CALCIUM CHLORIDE SOLUTIONS (ENGLISH)
Type of Solid Calcium Chloride Pounds Solid per gallon of water Solution produced per gallon of water
Type 1 - Regular Flake (77% material)
Type 2 - Concrete Flake or pellets (94% material)		 7
5		 1.35
1.18

PROPORTIONS FOR 32% CALCIUM CHLORIDE SOLUTIONS (METRIC)
Type of Solid Calcium Chloride Grams Solid per liter of water Solution produced per liter of water
Type 1 - Regular Flake (77% material)
Type 2 - Concrete Flake or pellets (94% material)		 840 g/L
600 g/L		 1.35
1.18

The solution shall be added at the rate of 2.75 gallons per cubic yard (13.6 L/m3) of concrete. Calcium chloride solutions of different concentrations may be approved by the Engineer, provided appropriate adjustments in the total concrete composition are made.

Caution>. The mixture shall be agitated until the calcium chloride is completely in solution, and agitation shall be continued, as necessary, to maintain uniformity. The calcium chloride will crystallize out of a 32% solution at 20°F (-7°C), so the solution must be maintained at a higher temperature at all times.>

Except when using continuous mixing equipment described in Article 2001.20, D, the calcium chloride solution shall be present in the mix for at least 2 minutes of mixing.

f. Water Reducer.
A Type A Mid Range water reducing admixture may be used at the Contractor's option. It shall be one listed in Materials I.M. 403, and use shall be at the dosage recommended by the manufacturer.

g. Aggregate Durability.
Unless otherwise specified, coarse aggregate shall have the proper class of durability, as defined in Article 4115.04.

h. Transit Mix Concrete.
Transit mix concrete shall be from a plant from which the concrete can be delivered and placed within 60 minutes from the the start of mixing. The time may be extended to 90 minutes when a retarding admixture, used in accordance with Materials I.M. 403 including temperature dosage guidelines and at the Contractor's expense, is added at the plant. Continuous mixing equipment using volumetric proportioning may be used in accordance with Article 2001.20, D.

i. Prepackaged Mixture.
A prepackaged mixture, proportioned as specified above for Class B or Class C matching material may be furnished as a Class B or Class C patching material with the approval of the Engineer. The coarse aggregate for prepackaged mixtures shall be limited to that meeting requirements of Article 4115.05. The prepackaged mixtures shall be mixed in an on-site paddle type mixer or proportioned and mixed with continuous mixing equipment using volumetric proportioning in accordance with Article 2001.20, D.

C. Joint Boards.
Joint boards for recreating joints and cracks shall be a resilient filler, cellulosic fiber, paraffin coated cardboard, or other compressible material of the proper shape to recreate the joint during placement of the patch material. Boards for recreating transverse joints shall be in one piece, so as to have no horizontal joints. Boards for recreating longitudinal joints shall be in one piece. One piece boards will not be required in lengths exceeding 4 feet (1.2 m). For joints and open transverse cracks, a board with a nominal width of 1/4 inch (5 mm) shall be used. Metal strips may be used for narrow cracks. Boards and metal strips shall extend into the pavement to the bottom of the patch. Use of a bond breaker on board surfaces is encouraged.

D. Joint Sealer.
Joint sealer and backer rod shall meet requirements of Section 4136. Unless otherwise specified, only hot poured joint sealer shall be used.

2530.04 EQUIPMENT.
Existing surface material may be removed by a milling machine, jack hammers, or similar equipment. Hand equipment may be necessary to achieve a vertical edge and the designated shape.

Sawing equipment will be required at feathered runout edges from a milling operation.

The following additional equipment will be required for PCC patches:

Sandblasting equipment is intended for cleaning of the prepared patch area on PCC pavements.

Preparation of the patch area shall be completed using equipment no heavier than a 15 pound (7 kg) air chisel. A 30 pound (14 kg) air chisel may be used if its use does not result in significant damage to the patch area and edges.

Compressed air for cleaning the prepared area shall be oil and moisture free.

An on-site paddle type concrete mixer will be required for mixing Class A patching material or other prepackaged mixtures.

2530.05 CONSTRUCTION.
The tabulations for partial depth finish patches shown in the contract documents are for estimating purposes only.

The Engineer will designate the location and limits of these patches. The shape and depth may be irregular so that hand operated equipment may be necessary for all or some of the removal. The existing pavement material shall be removed within the designated area to sound concrete as determined by the Engineer. All material removed which is not designated for salvage shall become the property of the Contractor and be removed in accordance with Article 1104.08.

A. Hot Mix Asphalt Patches.
Partial depth HMA finish patches shall be constructed as follows:

1. Preparation of Patch Area.
Removal shall be to a minimum depth of 3 inches (80 mm). Where this depth is adequate, the surface shall be made reasonably even. The maximum depth is 75% of the pavement thickness, but not more than 9 inches (230 mm).

Removal shall be such that the edges of all patch areas shall be vertical to a depth of 1 1/2 inches (40 mm). Minor rounding of the bottom edge is permissible. Exposed reinforcing steel shall be cut and removed. The patch area shall be cleaned.

Where removal to the depth described above leaves unsound concrete within the limits of the patch area, the Engineer may designate a part of the patch area as a full depth patch. The concrete shall be removed for the full depth, but removal to a depth greater than 12 inches (300 mm) will not be required. The subgrade or subbase material shall be consolidated with a mechanical tamper or other compaction equipment as directed by the Engineer.

2. Placing HMA Patch Material.
After removal of the old pavement, the edges and bottom of the patch area shall be lightly tacked. The HMA patch mixture shall be deposited in layers; the upper 5 inches (130 mm) shall be deposited in at least two layers, the top layer not exceeding 2 inches (50 mm) in thickness, when compacted. Lifts should be at least 3 times the mixture size. Each layer shall be thoroughly compacted, while hot, using appropriate compaction equipment. Succeeding layers may be placed as soon as the preceding layer has been properly compacted. The final layer shall also be smoothed with a steel tired finish roller meeting requirements of Article 2001.05, B or F ; a roller meeting requirement of Article 2001.05, F, may be a small roller suitable for this type of operation. This final compacted surface shall be level with, or not more than approximately 1/4 inch (6 mm) above, the surrounding pavement.

The patch shall not be opened to traffic until the mixture has cooled to provide stability, except that barricades on two lane roadways shall not be left in place overnight. If the patch becomes distorted beyond the smoothness requirements for any reason, the Contractor shall smooth the surface within 1 working day, by blading, scraping, filling, or by other means.

Prior to final acceptance, a finish patch shall be level with, or not more than 1/8 inch (3 mm) above, the adjacent pavement, and shall have a smooth riding surface.

When joint and crack sealing work is part of the contract, joints and cracks that cross areas of HMA finish patches shall be sawed to a width of 1/8 inch to 1/4 inch (3 mm to 6 mm) to the depth of the patch with a maximum depth of 3 inches (80 mm) within 3 working days after placement. If joint and crack sealing is not work of the contract, this work shall not be done.

All edges of HMA patches shall be sealed with a coat of CRS-2 bitumen applied with a "V" shaped squeegee tool. The width shall be 3 inches (80 mm) centered on the joint. Sand shall be used to blot excess bitumen material.

B. Portland Cement Concrete Patches.
Partial depth PCC finish patches shall be constructed as follows:

1. Preparation of Patch Area.
If a joint or crack is within a patch area, the edge of that patch shall be at least 6 inches (150 mm) beyond the joint or crack.

Each patch will have a generally rectangular area. The PCC concrete in that area shall be removed to a minimum depth of 3 inches (80 mm). Many areas will require removal of unsound PCC concrete to a greater depth to reach sound concrete. The maximum depth is 75% of the pavement thickness but not more than 9 inches (230 mm).

Milling will be allowed, but the depth within the designated patch area shall be at least 3 inches (80 mm). Concrete shall be removed from feathered runouts to a depth of 3 inches (80 mm) if within the designated patch area or to a depth of 2 inches (50 mm) if outside the designated patch area. These edges shall be vertically sawed. The prepared area shall have reasonably straight and vertical edges, not to exceed 1 inch (25 mm) in saw cut depth. Sawing will be required around the remainder of the patch perimeter, unless the Contractor demonstrates that an edge can be produced that is true and vertical, without sawing.

When removal to the maximum depth leaves unsound concrete within the patch area, the Engineer may designate a part of the patch area as a full depth patch. The concrete shall be removed for the full depth of the existing pavement, but not more than 12 inches (300 mm). The subgrade or subbase material shall be consolidated with a mechanical tamper or other compaction equipment as directed by the Engineer.

When it is necessary to go below reinforcing steel to reach sound concrete, the reinforcing steel shall be cut flush with the perimeter edges of the patch and removed.

The patch area is to be cleaned by sandblasting followed by cleaning with compressed air. The completed surfaces shall appear surface dry to visual examination.

A joint or crack in the patch area shall be recreated with a joint board of the proper size and shape. The board shall extend to the bottom of the area to be patched, so as to separate completely all patching material on both sides. It shall be of a width approximately equal to the joint or crack. For wide openings, several thicknesses may be used.

2. Placing PCC Patch Material.
A cement-sand-water grout of creamy consistency shall be scrubbed onto the patch surfaces, including edges, and the patch material shall be placed before the grout dries.

Class A patching material shall be mixed with water and coarse aggregate, if required. The properly mixed material shall be placed in the patch area, consolidated and worked into place in a manner that will provide good bonding. It shall be leveled with the adjacent pavement to provide a smooth riding surface. Patches longer than 1 foot (0.3 m) shall be textured in the manner of the adjacent pavement surface.

This work shall be done according to the patching manufacturer's recommendations and limitations, subject to approval of the Engineer. These recommendations shall be furnished to the Engineer. After 1 hour, the joint board shall be removed in a manner that does not damage the patch. The area may then be returned to public traffic.

Class B and Class C patching material shall be mixed and placed in the patch area, consolidated by vibration in a manner that will provide good bonding, and leveled to provide a smooth riding surface. Patches longer than 1 foot (0.3 m) shall be textured in the manner of the adjacent pavement surface.

3. Protecting and Curing.

a. Class A patching material shall be cured in accordance with the manufacturer's recommendations. The minimum curing time shall be in accordance with Materials I.M. 491.20, Appendix A.

b. Class B patching material shall be covered immediately with an insulating blanket-type cover as specified in Article 2301.19. The blanket-type cover shall be covered with insulation board. The board shall be cellulosic fiber sheathing with a nominal 3/4 inch (19 mm) thickness, similar to that specified in ASTM C 208. The board may be wrapped with plastic film to protect it from rain. The board shall be placed over the patch and adjacent surface and held tightly in place with weights to retain all possible heat in the concrete.

These patches shall be cured for the minimum time specified in Article 2529.02 for the mixture used.

c. Class C patching material shall be cured according to Paragraph b, above. Patches may be covered immediately with white pigmented curing compound; then the specified cure may be delayed as much as 2 hours.

Patches with Class M concrete shall be cured a minimum of 36 hours or as directed by the Engineer.

After the required curing period, the insulation blanket and the joint forming board may be removed in a manner that does not damage the patch, or removal may be delayed until the sealing is to be done provided no damage results from the delay.

4. Surface Finish.
Prior to final acceptance, a finish partial depth patch shall be level with the adjacent pavement and shall have a smooth riding surface.

5. Joint and Crack Sealing.
Where joints and cracks cross areas of partial depth PCC patches, the patch shall be sawed, cleaned, and sealed in accordance with Article 2301.25. Sealing shall be completed within 5 working days after the patch is placed. When joint and crack sealing is included in the contract, sealing shall be accomplished and paid for as part of that work.

2530.06 LIMITATIONS OF OPERATIONS.
Traffic shall be maintained to use the pavement during construction operations unless the road is closed. All operations shall be conducted with minimum inconvenience to traffic. On two-lane roads, operation shall be limited to one traffic lane at a time except for minor encroachment in the adjacent lane for sawing and installing forms when traffic is maintained. For multiple lane roadways, the work area may include one lane in each direction.

When approved by the Engineer, patch areas may extend up to 2 feet (0.6 m) into an adjacent lane as allowed in the traffic control plan. In this case, a flagger will be required at that location until the work is completed. Class A patching material shall be used in these patches.

The work schedule shall be adjusted so all work for each patch, including removal of barricades and equipment, except the cure period for PCC Class C concrete, will be completed on the same day it is started between the hours of 30 minutes after sunrise to 30 minutes before sunset. An adjacent lane must be opened to traffic prior to the old pavement being removed from a patch area. If unforeseen conditions result in excavated areas being left overnight, a sufficient number of flaggers shall be assigned to warn and direct traffic until the patches are complete. Extra payment will not be made for the necessary flaggers.

PCC patching material shall only be placed when the ambient air and pavement temperatures are 45°F (7°C) or above.

The Engineer may limit advance sawing.

If an emergency makes a DW joint necessary, the excavated area following the joint shall be temporarily filled with a suitable hot or cold paving mixture or stable granular material, as directed by the Engineer. The Engineer may direct that the lane remain closed to traffic overnight.

For HMA patches on two-lane highways and PCC patches with High Early Strength (Class A or Class B) patching material, the work schedule shall be adjusted so all barricades and equipment are removed from the travel lanes and shoulders from 30 minutes before sunset to 30 minutes after sunrise.

For PCC patches without calcium chloride, where there is a possibility of turning into or returning to a closed lane during the cure period, a Type II Barricade shall be erected in front of each patch being cured during nonworking hours. These barricades need not be spaced closer than 150 feet (45 m).

Articles 1107.08>, 1107.09 and 1108.03 shall also apply.>

2530.07 AREA RESTORATION.
When the patch is completed, if forms have been used, they shall be removed. Any excavated space along the outside pavement edge shall be filled with material similar to that in the existing shoulder, satisfactory to the Engineer, and thoroughly compacted before the section is opened to traffic.

2530.08 METHOD OF MEASUREMENT.
The Engineer will determine the quantities involved in satisfactory construction of partial depth finish patches for the areas specified as follows:

A. Partial Depth PCC Finish Patches.
The Engineer will calculate the area of each patch in square feet (square meters) from surface measurements. The area of each patch less than 1 square foot (0.1 m2) will be counted as 1 square foot (0.1 m2) for payment purposes. If the patch area is increased by the Contractor to accommodate milling equipment, only the area designated by the Engineer will be measured for payment.

The Engineer will also calculate the area of patches in square feet (square meters) which have been directed to be constructed full depth.

B. Regular Partial Depth HMA Finish Patches and Irregular Partial Depth HMA Finish Patches.
The Engineer will measure the area for each patch and the weight (mass) of HMA placed in partial depth patches in accordance with Article 2303.05. Regular patches and irregular patches will be calculated and totaled separately. If the patch area is increased to accommodate milling equipment, only the quantities for the area designated by the Engineer will be measured for payment. Asphalt binder and tack coat will not be measured separately for payment.

The Engineer will also calculate the area and weight (mass) of patch material placed in HMA patches which have been directed to be constructed full depth. The Engineer will deduct quantities not used.

2530.09 BASIS OF PAYMENT.
For construction of the various types of partial depth finish patches, satisfactorily constructed, at the areas specified, the Contractor will be paid as follows:

A. Partial Depth PCC Finish Patches.
For the number of square feet (square meters) of partial depth PCC finish patches constructed, the Contractor will be paid the contract unit price per square foot (square meter). This payment shall be full compensation for removal of all pavement, preparing the patch area, furnishing and placing all material, construction of joints, sawing, finishing, curing, and restoration of the area.

When parts of PCC partial depth finish patches are constructed to full depth at the direction of the Engineer, the Contractor will be paid for the areas of those parts at 2.0 times the contract price per square foot (square meter) for partial depth PCC patches.

B. Partial Depth HMA Finish Patches.
The Contractor will be paid for both the patch area and the quantity of HMA placed in the patch.

1. Regular Partial Depth HMA Finish Patches, by Area.
For the number of square yards (square meters) of regular partial depth HMA finish patches constructed, the Contractor will be paid the contract unit price per square yard (square meter).

2. Irregular Partial Depth HMA Finish Patches, by Area.
For the number of square yards (square meters) of irregular partial depth HMA finish patches constructed, the Contractor will be paid the contract unit price per square yard (square meter).

3. Hot Mix Asphalt Mixture.
For the total number of tons (megagrams) of HMA used to construct regular and irregular partial depth HMA finish patches, including that designated for full depth patches, the Contractor will be paid the contract unit price per ton (megagram).

When parts of HMA partial depth regular or irregular patches are constructed to full depth at the direction of the Engineer, the Contractor will be paid for the areas of those parts at 1.0 times the contract unit price per square yard (square meter) for the respective type of patch in addition to the payment for the contract price for the patch.

These payments shall be full compensation for removal of the old pavement, preparing the patch area, furnishing and placing the HMA patching material, including asphalt binder in the mixture and necessary tack coat bitumen, sawing and sealing, sealing the patch edges, and restoration of the area. When joint and crack sealing is included in the contract, joint sealing of the patches shall be accomplished and paid for as a part of that work.