529FULL DEPTH PRECAST/PRESTRESSED CONCRETE PAVEMENT SLABS

CONCRETE PAVEMENT SLABS

529.1DESCRIPTION—

for intermittent patching and continuous applications with cast-in features for establishing load transfer, lane- to-lane ties and uniform support under the slabs and all activities and materials incidental to site preparation for same. The work includes, but is not limited to, the following:

• Taking pavement cores of existing pavement in traffic lanes to verify the existing pavement thickness, a minimum of one per lane at each full depth repair location for a repair area of less than 100 feet in length. If length of repair is greater than 100 feet, perform coring at minimum 100-foot intervals. Additional cores may be required as directed by the Representative before the design of the precast concrete pavement slabs to verify existing pavement conditions.

• Engineering and design of the precast paving slabs

• Saw-cutting and removal of existing pavement

• Existing or new subbase preparation

• Furnishing and installing accepted bedding material, as required

• Fine grading of the subbase and bedding

• Installation of load transfer units (dowel bars) at transverse joints

• Installation of tie bars along the longitudinal joints

• Fabrication and furnishing precast paving slabs including all concrete, reinforcing steel, dowel bars, tie bars, and quality control.

• Transportation and storage

• Placement of precast slabs including erection equipment

• Slab undersealing

• Patching of dowel bar and tie bar slots and other designated blockouts, ports , and embedments

• Temporary asphalt pavement wedge transition

• Diamond grinding

• Joint sawing, if applicable, and joint sealing

• All material certification(s) and testing of material(s)

529.2MATERIAL—From a manufacturer listed in Bulletin 15. All materials must meet all requirements as

specified in Section 106.

• Epoxy Coated Tie Bars. Section 705.2

• Epoxy Coated Dowel Bars. Section 705.3

• High Performance Dowel Bars. Section 530

• Hot or cold applied joint sealer only. Section 705.4(a), (b), (c), (g), and (h)

• Epoxy Coated Tie Bars. Section 705.2

• Epoxy Coated Dowel Bars. Section 705.3

• High Performance Dowel Bars. Section 530

• Hot or cold applied joint sealer only. Section 705.4(a), (b), (c), (g), and (h)

• Cement Concrete. Section 714.3

• Epoxy Grout. Section 1080.2(g)

• Curing Materials. Section 711.2(a)

• Class AA accelerated cement concrete for patching utility casting blockouts. Section 704

according to ASTM A775 and as specified in Section 1002.1. If indicated on the Contract Drawings, dowel bars and other appurtenances of Load Transfer Units must meet the requirements as specified in Section 530.

specified in Section 703.1 and the gradation according to manufacturer’s recommendations . The bedding thickness will not exceed 1/2 inch.

The mixture consists of Portland cement and Cement Concrete Sand that meets the material requirements as specified in Section 703.1 Cement Concrete Sand, Type A. A minimum compressive strength of 500 pounds per square inch must be achieved at the time of opening to traffic. Do not exceed a bedding thickness of 2 inches. At least 28 days before installation of the slabs, mix a minimum of one trial batch of the bedding material according to the recommendations of the manufacturer under the same time and temperature conditions expected during actual installation. Make and test cubes according to AASHTO T 106. Provide independent laboratory test results to the Representative that the required compressive strength can be achieved.

Provide grout material according to manufacturer's recommendations . The final mix must be capable of being pumped into the slots and attain a minimum compressive strength of 2,500 pounds per square inch before the slabs are opened to traffic. Mix and use prepackaged grout material according to manufacturer's recommendations. Make and test grout cylinders according to PTM No. 521. At least 28 days before installation of the pre -cast pavement, mix a minimum of one trial batch of the dowel grout according to manufacturer's recommendations under the same time and temperature conditions expected during actual installation. Provide independent laboratory test results to the Representative that the required compressive strength can be achieved. Use the same mix for actual installation as was used for the demonstration.

Design, mix and use bedding grout material according to manufacturer's recommendations. The final mix must be capable of being pumped into the voids beneath the slabs and attain a minimum compressive strength of 1,000 pounds per square inch before the slabs are opened to traffic and 2,500 pounds per square inch in 12 hours. Submit the mix design and pump equipment to be used to the Representative for approval. Make and test grout cylinders as specified in PTM No. 521. At least 28 days before installation of the slabs, mix a minimum of one trial batch of the bedding grout according to manufacturer's recommendations under the same time and temperature conditions expected during actual installation. Provide independent laboratory test results to the Representative that required flowability and compressive strength has been achieved. If Setting Bolts or Strongback Beam is used to set the slab to required elevation, test the grout cylinders for the required time for grout to attain a compressive strength of 50 pounds per square inch. Use the same mix for actual installation as was used for the demonstration.

and use bedding grout material according to manufacturer's recommendations . The final mix must be capable of being pumped into the voids beneath the slabs. At least 28 days before installation of the slabs, mix a minimum of one trial batch of the bedding grout according to manufacturer's recommendations under the same time and temperature conditions expected during actual installation. Provide independent laboratory test results to the Representative that required material conforms to requirements as specified in Section 679.2(c). Use the same mix for actual installation as was used for the demonstration.

D3574 and being capable of being fully compressed under the weight of the slab.

steel. Ensure the mechanical coupling device develops a minimum of 125 percent of the specified yield strength of the reinforcement steel. If the reinforcement steel has either galvanizing or an epoxy coating, use a mechanical coupling device with a matching coating system. Provide certification of compliance as specified in Section

106.03(b)3

Course (Scratch), PG 64S-22, 0.3 to < 3 Million ESALs, 9.5 mm Mix, SRL-L – Section 413.

529.3CONSTRUCTION—As indicated on the contract drawings, and as shown on the accepted shop and

working drawings, and as follows:

provide any concrete mix designs to be used on the project to the Representative for acceptance. The mix designs must include trial batch test data demonstrating that each mix design will achieve the minimum required compressive and flexural strength. The representative may request flexural strength test results be obtained at any time thereafter; h owever, flexural strength tests are not required for acce ptance of precast slabs. If the contractor cannot provide flexural strength test results that meet or exceed the minimum values stated in Section 529.3(c), the Representative may request the contractor to direct the manufacturer to retrial batch the concrete mix design.

Provide Shop Drawings, Working Drawings, and Manufacturer’s quality control plan, to the Representative at least 21 calendar days before the pre-production meeting. The Representative has 21 calendar days to review submission before providing notice to the Contractor of acceptance or rejection.

account for ambient average daily temperatures and exposure conditions at the project site to determine correct panel size and expansion joint locations. Use standard values for the expansion coefficient found in the AASHTO Mechanistic-Empirical Pavement Design Guide for aggregate expansion.

prestressed) and a minimum length of 6 feet, and width based on the proposed longitudinal joints shown on the Shop Drawings. Adjust slab length to match transverse joints between slabs with existing, adjacent transverse joints as much as possible. Lay out precast slab transverse joint locations in a manner that will allow for expansion and contraction at the existing and proposed joints. Provide blockouts in the slabs for existing utility castings and proposed drainage structures.

thickness.

to be either broom, turf drag, or longitudinal or transverse tine finished as specified in Section 501.3(k). Perform top surface texture before applying curing materials.

Drawings. Cast the dowels and bars square to the edge and parallel to the top surface of the slab within ±1/8 inch of the locations shown on the Shop Drawings.

in the slabs to accommodate dowels and tie bars to within ±1/8 inch of the locations shown on the Shop Drawings.

indicated on the Shop Drawings.

placed per accepted Shop Drawings. Recess each lifting device in the slab a minimum of 1 inch below the surface. After acceptance of each slab installed in the roadway, fill all exposed lifting device with an accepted cementitious grout.

to the underside edge of the slab to prevent grout leakage and to create discrete grout chambers between corresponding ports. Indicate the locations of all the gaskets clearly on the slab Shop Drawings.

Indicate the locations of all the slab setting bolts clearly on the slab Shop Drawings.

authorized Shop Drawings. Slabs are rejected if the fabricated dimensions are not within the tolerance shown in Table A:

TABLE A – Slab Fabrication Tolerances Slab Feature Tolerance Length and width ± 3/16 inch Thickness ± 1/8 inch Difference in diagonals not to exceed 3/16 inch Edge Squareness (in relation to top and bottom surfaces) 1/8 inch in 10 inches

following items in the working drawings:

• Locations of all cores to be taken from existing pavement.

• A slab layout drawing that shows the location of each slab in the finished pavement appropriately marked and numbered.

• Layout drawings that indicate the placement, spacing and diameter of any required grout reservoirs in the precast pavement.

• A work plan for grouting slabs and contingency plan if a slab cannot be grouted in time for opening to traffic.

• Installation drawings that indicate the placement of the slabs, any required bedding layer , and the placement of any required supplemental aggregate material for subbase or subgrade soil remediation. These drawings will also indicate the required strength that any grout must obtain before slabs may be opened to traffic.

that the minimum concrete compressive strength will be 4 ,925 pounds per square inch and the minimum concrete flexural strength will be 650 pounds per square inch. Include the following items in the shop drawings:

• Reinforcing size and position

• Detailed piece drawings showing the locations and sizes of dowels, tie bars, slots for the transverse dowels and longitudinal tie bars, utility casting blockouts, and all three-dimensional geometry related to widths, lengths, thicknesses, and warps of each slab. Add 1/4 inch of sacrificial concrete to the top surface of each slab. The sacrificial concrete will not be included in the design calculations for any slab nor will it be considered as contributing to depth of cover over reinforcement. The sacrificial concrete may or may not be milled off the slab during construction at the discretion of the representative.

• Provide the following information for the precast slab leveling system if the setting bolt method is used:

ͦ Size and thickness of the steel bearing plates with supporting design documentation, including calculations and test data verifying that the plates can support the required loads without excessive settlement or vertical deflection. Calculations for the plates must consider the possibility of ungrouted slabs if there is a potential for opening to traffic before bedding and dowel slot grout is placed and sufficiently hardened as specified in Section 529.3(f)8 and (f)9. ͦ Corrosion protection details of the steel bearing plates ͦ Slab setting bolt and insert design and details ͦ Name of fabricator listed in Bulletin 15

• A production note sheet indicating the source of materials, testing methods, weights of each slab, tolerances and all details relating to yard storage (including the size and position of required dunnage), shipping and handling.

• For prestressed, precast slabs, indicate the type of prestressing tendons to be used, layout of the prestressing tendons, the prestressing force to be applied, and the calculations that indicate the level of prestress available at the mid-slab location.

Representative will conduct the meeting.

fabrication of the precast slabs, hold a precast pavement planning meeting with the Representative, inspection personnel, CQAD representative, SMS representative, project superintendent, project foreman, project surveyor, grout installers, sawcutters, the technical representative of the precast concrete slab system, precast slab fabricator, and all other subcontractors who will be involved in the precast pavement construction work. Submit Contractor’s QC plan, repair plan, and emergency MPT plan at least 21 calendar days before the precast pavement planning meeting. The Representative has 21 calendar days to review the submission. As a minimum, the following items will be covered during this meeting:

• Review the process for accurately surveying to provide needed dimensions for the precast slabs .

• Review the process for installing the precast slabs.

• Determine the slab sizes necessary for the project.

• Develop a Resource Loaded Schedule.

• Determine when manufacturer must begin production to meet project schedule.

• Review Contractor’s QC Plan, repair plan, and emergency MPT plan.

• Plan for gathering the field data necessary for the Shop and Working Drawing preparation.

• Identify the equipment and materials necessary to complete the work.

• Schedule of field measurements of existing repair locations for purposes of developing detailed Shop and Working Drawings.

the start of precast slab production at the fabricators facility with the Representative, SMS representative, inspection personnel, the technical representative of the precast concrete slab system, precast slab fabricator’s production, quality control and engineering staff, and the project superintendent or their designee. As a minimum, the following items will be covered during this meeting:

• Review the fabricator’s accepted Shop drawings.

• Review the fabricator’s production plan.

• Review the fabricator’s approved materials and approved mix design .

• Review the fabricator’s accepted QC plan.

• Review QA procedures and roles and responsibilities.

• Review slab marking and ID requirements.

• Review storage requirements.

• Review shipping and documentation requirements.

start of the slab installation with the Representative, CQAD representative, inspection personnel, project superintendent, project foreman, project surveyor, grout installers, the technical representative of the precast concrete slab system, precast slab fabricator, and a ll other subcontractors who will be involved in the precast pavement construction work. The technical representative of the precast concrete slab system will provide recommendations on the installation techniques and requirements of the precast concrete slab system. Aspects to be discussed during the meeting include, but are not limited to:

• Laying out saw cuts for the new slabs.

• Sawing, cutting depth and width.

• Removing existing pavement without damaging pavement to remain.

• Lifting capacity of installation equipment and required footprint (available area within lane closure) .

• Review contractor accepted repair procedure. . • Setting up rails for grading.

• Calibrating and using specialized equipment.

• Installing and grading the bedding material.

• Laying out slab point marks.

• Placement of the new slabs.

• Installing the dowel and grout material.

• Review Contractor’s accepted emergency MPT plan.

The technical representative is required to be onsite for:

• The first 2 days of slab installation at a minimum.

• If corrective work is necessary.

• As directed.

technical representative of the PCPS system at least 21 calendar days before the planned start of slab installation for acceptance. Ensure the plan indicates, at a minimum, the following information as required: Instructions, methods, and equipment for lifting, moving, protecting, lowering, and adjusting the slabs into position. Provide size, weight, load distribution and lifting capacity of all installation cranes, excavators, and all other special lifting equipment. Provide evidence the equipment does not impose detrimental loads on any pavement, precast or otherwise, it occupies. As a minimum, the installation will also require the following:

• Rigging to be used for lifting the slabs.

• Routes to be used by the delivery trucks.

• Plans for maintenance and protection of traffic.

• Proposed method and equipment used for fine grading, if required.

• Method to level the slab.

• Materials proposed for dowel and bedding grout.

• Grout mix designs to be used for each grout.

• Equipment to be used for mixing and installing the grouts.

• Description and notes for saw cutting and method of removal of existing pavement that will minimize disturbance to the subbase.

guidance provided by the Technical Representative throughout the installation process.

removed, determine the theoretical surface elevations and dimensional sizes of the new slabs based on the proposed longitudinal joint locations. Survey and analyze elevations of the existing abutting pavement to remain, as required, to establish the surface elevations of the new slabs. Use these elevations for fabrication of the new slabs. Provide accurate survey layout of the proposed longitudinal joints before sawcutting.

3.a Use a diamond saw to sawcut the full depth of the limits of the precast slabs and the proposed longitudinal joints.

3.b Do not use a wheel saw with carbide steel tips.

3.c Remove existing concrete or composite pavement using the lift out method. The lift out method consists of installing lifting devices and lift out the existing concrete or composite pavement in the area enclosed by the full-depth saw-cuts, in one or more pieces, without disturbing the existing subbase.

3.d Dispose or reuse removed pavement as specified in Section 104.06.

3.e The slab may be sawcut and the lift out holes may be drilled up to 5 calendar days before the concrete removal.

3.f Only remove concrete that can be replaced during the workday.

3.g Establish longitudinal joint between precast slabs and existing pavement by overcutting the existing longitudinal joint sufficient to provide a straight and smooth joint. Only sawcut and remove the existing pavement enough as required to establish a suitable joint.

the required subgrade elevation for the PCPS installation method for the theoretical bottom of the new concrete slab. Before placing the slab, remove remaining existing OGS when pres ent. Remove any soft, wet, or unsuitable subbase and subgrade material in the area of the slab replacement as directed. Place and compact No. 2A Coarse Aggregate, as specified in Section 703.2, as specified in Section 350. Shape the final surface of the su bbase to a firm and even surface within a tolerance of plus or minus 1/2 inch of grade and contour.

tolerances as specified in Section 529.3(f)6 and (f)7, and according to the manufacturer’s recommendations.

Place slabs using one of the methods described below or per the method designated for the accepted PCPS system.

5.a Placement and Fine Grading of Bedding Material . Perform all fine grading of the bedding material using a laser or otherwise mechanically controlled screeding device. Use screeding device capable of grading fully compacted bedding material and of being adjusted to the required cross slope and to the required tolerance of each pavement slab. Other grading devices and methods are allowed, if they are capable of grading fully compacted bedding material to the required tolerance. Provide a pavement slab bed that serves as the grade control for the slabs placed upon it, such that slabs need not be adjusted for grade after they have been placed. Grade and check the surface to ensure it does not vary from the theoretical plane more th an 1/8 inch over a length of each slab. Use personnel trained in use of the screeding device. Examine the bedding surface using a straight -edge and depth gage accepted before placing the slabs. Provide a straight -edge not less than 10 feet long, and a depth gage not less than 6 feet long with the depth set equal to the thickness of the slab. Correct surface variations greater than the 1/8 inch in the bedding material before placement of the slab.

5.b Setting Bolts. Set the slab at the desired elevation using four symmetrically located threaded setting bolts to control the elevation of the slab. Preposition f our steel plates, of a minimum size and thickness indicated on the shop drawings on the prepared base before placing the slab at the designated location. Position plates to coincide with the location of the setting bolts in the slab. Use cementitious or polyurethane bedding material, as designated for the accepted PCPS system, to fill the gap between the compacted base and the slab bottom. Remove the setting bolts from the slab as soon as the cementitious bedding material has attained a compressive strength of 50 pounds per square inch or within 15 minutes after injection of the polyurethane material. Slab placement technique requires fabricating threaded sleeves in the slab. Secure the sleeves in the concrete as detailed in the fabricator Shop Drawings to resist pop -out of the sleeves during the slab - setting operation.

5.c Polyurethane Leveling. Grade the compacted subbase about 0.5 to 1 inch below the design elevation of the slab bottom. Place slabs in the repair area and raise to the correct elevation by injecting polyurethane material under the slabs using grout holes. Ensure that there is no excessive uplift of the slab, that the slab is raised uniformly across the full slab, and that the polyurethane provides uniform support under the slab.

5.d Strongback Beams. Set the slabs at the desired elevation using the elevation of the existing pavement at each side of the repair area by fastening each slab to two strongback beams that extend about 2 feet beyond the repair area. Fasten beams to the slab using the lift inse rts and long bolts with the lifting hooks while the slab is on the delivery truck. Use cementitious or polyurethane bedding material to fill the gap between the compacted base and the slab bottom. Remove the strongback b eams from the slab as soon as the cementitious bedding material has attained a compressive strength of 50 pounds per square inch or within 15 minutes after injection of the polyurethane material.

placement of any slabs, marking out the trailing ends and leading edges of all slabs to ensure proper placement and fit. Ensure the marks account for proper joint widths. Install dowel bars and joint ties as indicated and as specified in Section 705 .3. Coat the dowel bars and the vertical edges of the slab as per the accepted detailed installation plan, with bond breaker before setting any slabs to break the bond between the concrete slab and the dowel grout. Do not exceed 1/4 inch finished vertical differential across any joint. Check the vertical differential before setting the next slab. Remove the slab and regrade the subbase or bedding material until the differential is 1/4 inch or less before setting the next slab. Alternatively, i f the finished vertical differential across any joint is greater than 1/4 inch and, not more than 1/2 inch, above the elevation of any adjacent slab or pavement, the precast slab may remain in place and be subject to diamond grinding to achieve the required tolerance at no additional cost to the Department, as accepted. The thickness of all precast slabs must include a sacrificial thickness of 1/4 inch when delivered to the project site to accommodate the diamond grinding to bring the precast slabs into tolerance. Diamond grinding the precast slab greater than 1/4 inch is

not allowed. Remove any slab and regrade the subbase or bedding material if that slab presents a finished vertical differential greater than 1/2 inch above any adjacent slab or pavement. Protect dowel and tie bars exposed at the end of a setting period. Remove and replace any slab if any exposed dowel or tie bars in that slab do not meet specifications at the time any adjacent slab is ready to be placed, as directed. For repair areas that require more than one work shift to complete the entire repair, proceed with work in the direction of traffic flow. If a temporary vertical drop-off condition from precast slab to the existing pavement is greater than 2 inches, provide temporary asphalt pavement wedge transition as specified in Section 901. Do not leave a permanent vertical differential between any repair section and any permanent pavement section of more than 1/4 inch.

1/2 inch and is a minimum of 1/4 inch along its entire length. Any transverse joint that is less than 1/4 inch at any point along its length must be sawcut to obtain a minimum of 1/4 inch. The width of the longitudinal joints must not exceed 3/4 inch. If the slabs are opened to traffic before the dowel slots are grouted or patched, shim all open joints to prevent drift of the slabs in any direction under traffic. Seal all longitudinal and transverse joints as specified in Section 501.3(n).

7.a Load Transfer at Transverse Joints. Use the load transfer method at transverse joints provided for the accepted PCPS system or as indicated in the accepted fabricator Shop Drawings. The following methods may be used to provide load transfer at transverse joints:

7.a.1 Using slabs with dowel slots at the slab bottom at one transverse edge and embedded dowels at the other transverse edge, as indicated in the accepted fabricator Shop Drawings. For repair applications, drill and install dowels in the existing pavement.

7.a.2 Using slabs with conventional dowel slots at one transverse edge and embedded dowels at the other transverse edge, as indicated in the accepted fabricator Shop Drawings. In this method, the dowel slots have wider mouths, about 2 1/2 inches wide at the surface. Patch the surface slots during the same lane closure as used for placing the slabs using the details indicated in the accepted fabricator Shop Drawings.

7.a.3 Using slabs with narrow -mouth dowel slots at the surface, as indicated in the accepted fabricator Shop Drawings. Narrow-mouth dowel slots are approximately 1 inch wide at the slab surface and tapering out to approximately 3 inches wide about 1 inch below mid -slab depth. This technique allows the slabs fabricated with surface dowel slots to be left in place in the repair area without immediately patching the slots. Use the following installation steps:

• For repair applications, drill the dowel holes in the existing pavement before the placement of the slab.

• Position the dowels in the longer surface slots in the slab before slab placement.

• During the same or the next lane closure, slide the dowel bars into the corresponding narrow - mouth surface slots. The dowel bars are held in place, at proper alignment, using a magnetic clamp or a similar device.

• Patch the slots during the same lane closure as the slab placement or during a subsequent lane closure.

7.b Tie Bars Along Longitudinal Joints. Install tie bars along the longitudinal joints as indicated in the accepted fabricator Shop Drawings for precast slabs placed in continuous paving sections greater than 65 feet in length. Do not place tie bars in a manner that will reduce or prevent the movement of existing joints adjacent to the precast slabs. Use one of the following steps to install tie bars:

7.b.1 Drill and install tie bars in the existing pavement. Locate tie bars indicated in the accepted fabricator Shop Drawings. Use slabs with the tie bar slots at the slab bottom.

7.b.2 Use the cross-stitching technique as indicated in the accepted fabricator Shop Drawings.

following methods, as designated for the accepted PCPS system:

8.a Dowel Slots at the Slab Bottom. Place the approved rapid-setting dowel slot grout through grout ports into each slot. Place the grout into the slab perimeter joint gap until the grout material is at the top of the joints. Use bond-breaking material on the joint faces of the existing pavement so the dowel grout material will not bond to the existing pavement. Align the saw -cut along the existing pavement beside the joint during joint sawing for the sealant reservoir.

8.b Dowel Slots at the Surface. (Conventional or Narrow-mouth). Patch the dowel slots as specified in the dowel retrofit method, Section 527.3(d). Ensure that no patch material flows into the joint gap.

8.c Finishing. Finish off the top of the grout ports, insert holes, and a ll surface damage repairs with the same finish as the rest of the slab surface. Do not allow traffic on the slab until the grout has reached a minimum compressive strength of 2,500 pounds per square inch.

bedding material using the accepted cementitious or polyurethane undersealing grout material as demonstrated in the trial batching procedure. Distribute grout ports uniformly across the slab area as indicated in the accepted fabricator Shop Drawings. Use a minimum of four grout ports per slab. Pump or pour the bedding grout into the grout port on the end of the slab until it comes out of the corresponding port at the other end of the slab, ensuring full bedding of the slab in that chamber. Fill all remaining ports in the same manner. Monitor the grout level in previously filled ports and add grout as required to keep it level with the top of the slab. Minimize spillage and necessary cleanup of the slab surface. After the bedding grout has taken initial set, and before it hardens completely, remove the bedding grout from the top 2 inches of each bedding grout port and replace with slot patching grout, patching material or other accepted higher-strength rapid -setting patching material. Ensure the grout reaches a minimum strength of 2,500 pounds per square inch before opening to traffic.

are met:

10.a Dowel Slots at the Slab Bottom or Narrow-Mouth Surface Slots. If opening slabs to traffic before installation of dowel and bedding grouts, install a minimum of two incompressible shims in each transverse joint to prevent ungrouted slabs from hitting and spalling under traffic conditions. If ungrouted slabs settle or develop edge differentials under traffic conditions that are greater than 1/4 inch, remove the ungrouted slabs, regrade the bedding surface, and reset the slabs before grouting. If the settled slab cannot be removed because it is in the middle of a run of new slabs, diamond grind the surface of the pavement, as specified in Section 514, until the edge differential is less than the allowable 1/4 inch. Ungrouted slabs may be temporarily opened to traffic as specified in Section 529.3(f)10.c. Grouted slabs can be opened to traffic after the dowel and bedding grout have reached the minimum acceptable strength.

10.b Dowel Slots at the Conventional Surface. If conventional surface dowel slots are used, open slabs to traffic only after the grout for dowels and tie bars (if applicable) and the bedding grout have reached the minimum acceptable strength.

10.c Temporarily Opening to Traffic Before Grouting. Minimize the exposure of precast slabs to traffic before patching or grouting the dowel slots. Slabs without effective load transfer at transverse joints or without slab undersealing for slabs placed directly on the bedding will not be exposed to traffic for a period of more than 3 days.

or construction damage to slabs as directed and at no additional cost to the Department. All damage is subject to inspection on a case -by-case basis. Of particular importance is damage to the top surface and

edges that occurs before and during installation. Recurring damage or distress is cause for discontinuing installation until the cause of the recurring damage can be determined and the problem mitigated.

11.a Spalls. Repair all spalls as specified in Section 501.3(t).

11.b Cracks. For cracks wider than 0.007 inches and greater than D/3, where D is the slab depth, replace the slab at no additional cost to the Department. For cracks, wider than 0.007 inches and a depth less than D/3, repair according to recommendations in the latest version of Control of Cracking in Concrete Structures (ACI 224R). Submit the appropriate procedure before performing the repair for acceptance. For cracks 0.007 inches wide or less, seal cracks using high molecular weight methacrylate. After cleaning the surface of the slab along the crack, mix the methacrylate according to the manufacturer's recommendations. Pour and squeegee sealer into the cracks. Approximately 20 minutes after the crack has been sealed, apply commercial quality, dry blast sand to the methacrylate before opening the slabs to traffic.

529.4MEASUREMENT AND PAYMENT—