548UNBONDED CONCRETE OVERLAY OF CONCRETE-SURFACED PAVEMENTS

PAVEMENTS

548.1DESCRIPTION—This work is the construction of an unbonded concrete overlay of concrete

pavements including surface preparation and joint sawing and sealing.

548.2MATERIAL—Section 501.2 with the following modification:

Mechanical Properties Test Method Minimum Average Roll Value (except as otherwise indicated) Color Visual Inspection Uniform (all same color fibers) Geotextile Type EN 13249, Annex F (Certification) Nonwoven, needle-punched, no thermal treatment to include calendaring Weight Per Unit Area ASTM D5261 14.0 oz/sq.yd Thickness Under Load (pressure) ASTM D5199 0.29 psi 0.12 inches 2.9 psi 0.10 inches 29 psi 0.04 inches Wide Width Tensile Strength ASTM D4595 685 lb/ft s Wide Width Elongation ASTM D4595 130% (maximum) Water Permeability (in normal direction under 2.9 psi load) ASTM D5493 0.02 feet/minute In-plane Water Permeability

(pressure) ASTM D4716 2.9 psi 0.10 feet/minute 29 psi 0.04 feet/minute Alkali Resistance EN 13249, Annex B

UV Resistance at 500 hours ASTM D4355 Retained strength 70% average with no value less than 60%

techniques approved by the selected geotextile manufacturer for project-specific use.

Courses. Section 410 and Bulletin 27.

7 inches use concrete reinforced with polypropylene fibers according to ASTM C1116, Type III 4.13 and ASTM C1116 (Ref: ASTM C1018) Performance Level 1 outlined in Section 21, Note 17 and Residual Strength. Use 100% virgin polypropylene (PE) manufactured to an optimum gradation for use as concrete reinforcement. Use a synthetic fiber that is a monofilament or bundled monofilament with a minimum length of 1.0 inches and a maximum length of 2 1/2 inches and has a maximum aspect ratio (length divided by the equivalent diameter of the fiber) of 150. Add a sufficient quantity of synthetic fiber(s) to the concrete mixture to have a residual strength ratio (R150,3) of 20.0 percent according to Illinois Modified ASTM C1609. Do not exceed the maximum dosage rate of 5.0 pounds per cubic yard, unless the manufacturer can demonstrate, through a field demonstration, that the concrete mixture will be workable and fiber clumping is not a problem. Add the synthetic fibers to the concrete and mix in accordance with the manufacturer’s recommendation.

548.3CONSTRUCTION—Section 501.3 and modified as follows:

1.a General. Areas with unstable slabs and slab fragments (e.g. slabs or fragments that move or rock visibly under normal traffic loads) that would otherwise result in non-uniform support of the overlay must be stabilized or repaired before placement of the interlayer material.

1.b Concrete Pavement Patching. Section 516, except delete Section 516.3(p)

1.c Slab Stabilization. Section 679, except delete Sections 679.3(a)2, 5, and 9.

1.d Slabjacking. Section 681

1.e Flexible Base Replacement. Section 316.

1.f Shallow Repairs. Repair surface defects with a patching material that consists of an asphalt material, a cementitious material, or a similar pavement repair material meeting the approval of the Representative before placing the overlay. When using a geotextile interlayer, fill all surface defects measuring greater than 4 square inches and 1 inch deep in the surface of the traffic lanes, with a patching material and compact to a flat, tight surface. When using an asphalt interlayer, shallow defects can be filled with an asphalt interlayer material as the interlayer is placed provided that the material in the defect can be properly compacted along with the interlayer; oth erwise, the defects must be filled with repair material before placement of the interlayer.

vacuum truck, or other approved means before applying pavement interlayer.

3.a Geotextile Interlayer Placement. Mill joints with greater than 1/4-inch faulting. Place geotextile flat on the repaired and cleaned existing pavement surface. Overlap edges of geotextile by 8 inches ± 2 inches. Do not allow more than three layers of the geotextile to overlay in any location. Sequence rolling out geotextile to ensure good lapping practice and prevent folding or tearing by construction traffic. Extend free edge of geotextile interlayer a minimum of 4 inches beyond edge of pavement. Terminate interlayer in a drainable layer or at a daylighted location (e.g. ditch foreslope). Do not impair free drainage of the geotextile. Secure geotextile in accordance with the geotextile manufacturer’s instructions. Avoid allowing construction traffic on the geotextile whenever possible. Delay geotextile installation on areas subject to potentially damaging traffic, such as crossovers, until immediately before concrete placement. Minimize sharp turns and braking on geotextiles. Keep geotextile clean and free of loose debris before overlay placement. Dampen geotextile but do not saturate, before overlay placement. Do not allow the surface temperature of the fabric to exceed 120F before the overlay placement.

3.b Asphalt Interlayer. Place a nominal depth of 1 inch of Superpave Mix Design as specified in Section 410.3. If joint faulting exceeds 1/2 inch, place a scratch course at the joint or mill/grind joints to reduce faulting. Use a rubber tire roller. Do not allow the surface temperature of the pavement to exceed 120F before the overlay placement. Control the asphalt surface

temperature by misting the surface, using white-pigmented curing compound, whitewashing with lime water, or other method approved by the Representative.

If dowel baskets are moving during the paving operation, suspend paving operations until a plan for securely anchoring the baskets is approved by the Representative and implemented.

Leave shipping wires intact unless a Magnetic Tomography-Based Device is to be used for dowel placement verification. Secure dowel bar assemblies with anchors to hold the dowel bars in the correct position and alignment while preventing movement during concrete placement in accordance with the following:

• Provide a QC Plan for anchoring dowel basket assemblies.

• Fasten the baskets to the substrate surface so that they do not move vertically or horizontally more than 1/4 inch.

• Type, location, number, and length of anchors are dependent upon field conditions.

• Before starting concrete pavement placement and before each day of concrete pavement placement, demonstrate the fastening method to the Representative for approval.

Identify and mark any transverse expansion joints in the existing pavement. To allow for slab movement before sawing, precut the expansion joints in the plastic concrete. As soon as sawing is possible, saw two full -depth cuts on each side of the precut joi nt following the edges of the underlying expansion joint and remove the concrete between the saw joints.

locations, nor are they required to be offset by any minimum distance.

lane geometry, concrete placement width and the following guidance:

Unbonded Overlay Thickness Maximum Nominal Panel Dimensions > 6 inches to < 8 inches 6 ft × 6 ft ≥ 8 inches to ≤ 10 inches 12 ft × 12 ft > 10 inches 12 ft × 15 ft

The aspect ratio (longer dimension/shorter dimension) of any panel should be as close to 1.0 as is feasible and should not exceed 1.5.

pavement edges and must be no less than D/4 anywhere. Clean joint of all deleterious material after sawing. Seal all transverse and longitudinal joints. Consider concrete panels with cracking outside of the sawed joints defective.

no joint spacing is indicated, develop a joint layout plan to be accepted by the Department and lay out joints before placement of concrete. Avoid placing longitudinal joints in the wheel paths.

In general, maximum panel dimensions should not exceed 18 times the concrete overlay thickness, and the length of the longer panel dimension divided by the shorter panel dimension should not exceed 1.5. The Representative may allow slight deviations from nominal panel dimensions to match joints in adjacent pavement or structures, or to avoid the construction of panels with dimensions or shapes that would otherwise be subject to premature cracking.

for creating concrete overlay joints. Saw joints as soon as concrete has sufficiently hardened to allow sawing without excessive raveling resulting from the sawing operation and to prevent random cracking. The use of “early entry” saws is recommended.

determining a project -specific sawing window. If necessary, conduct sawing operations continuously, both day and night, regardless of weather conditions. Saw joints with a green cut saw to a depth of D/3 and a minimum width of 1/4 inch. If initial saw cuts do not extend through the slab edge to avoid “blowouts” or edge damage of green concrete, extend these cuts through the edge as soon as it can be done without causing damage. Omit sawing if a crack occurs at or within 1.5 feet of a joint location, before or during sawing, and address as specified in Section 590. Clean joints of all deleterious material after sawing.

forming curing compound, remove curing materials from overlay, at the location where a joint is to be cut. Remove only sufficient covering to provide space necessary for sawing joints. As soon as the joint is sawed, replace the covering. The maximum time period allowed for pavement curing covers to be removed is 1/2 hour. If white-pigmented, liquid membrane-forming curing compound is used, cure the joint area, as specified in Section 501.3(l)1.c.

Additional longitudinal joint requirements are as specified in Sections 548.3(i)4, (i)5, (i)6, (i)7, (i)8, and (i)9.

Apply curing materials after finishing and texturing, and within 30 minutes of the dissipation of bleed water. Maintain the curing materials until the pavement has achieved sufficient strength for opening to traffic as specified in Section 548.3(q). Add the following paragraph: Provide adequate insulating blankets to prevent rapid heat loss if the air temperature is 40F or less. Insulation may be removed when the air temperature exceeds 40F or when the average compressive strength of the concrete exceeds 3,600 pounds per square inch. Remove insulation in a manner such that the rate of temperature change at the concrete surface does not exceed 40F within any 1-hour period. Take temperature readings of the concrete surface during insulation removal. Concrete that experiences a higher rate of temperature change may be deemed defective.

1.c White, Poly-alpha-methylstyrene (PAMS) Liquid Membrane Forming Curing Compound. Replace the second sentence of the second paragraph with the following: Apply curing compound evenly to provide a uniform, solid white opaque coverage on all exposed concrete surfaces. Apply at a minimum rate of 1 gallon (± 0.1 gallon) per 150 square feet for pavements > 6 inches and per 125 square feet for pavements ≤ 6 inches or according to the manufacturer’s recommendations, whichever is greater. If conditions warrant, the curing compound can be applied in two equal rates of application, with the first applied as stated previously and the second applied immediately after sawing operations have been completed. Joint faces must be protected from exposure to curing compound or cleaned thoroughly before sealant installation.

Section 506.3(o)

Construct transitions at the limits of the concrete overlay as indicated. In areas where transitions contain existing treated base course or concrete pavement directly below the overlay, place geotextile as a debonding layer as specified in Section 548.3(e)3.a.

548.4MEASUREMENT AND PAYMENT—

For producing the cement concrete needed for the overlay and delivering it to the jobsite. Computed based on the indicated depth of the overlay and the placement area. Includes all work associated with the construction of the concrete overlay except pre- overlay repairs. Excludes cement concrete material used in transition areas.

The unit price includes all required materials and placement/installation including sweeping.

The unit price includes all required materials and placement/installation including sweeping. The cost of necessary joint fault reduction efforts is incidental to this item of work.

The unit price includes all associated items of work within the limits of the transitions.