for Highway Construction Page 280 of 715 SECTION 420 – CONCRETE PAVEMENT REHABILITATION
420.01 Description .
Perform concrete pavement rehabilitation as follows:
1.Repair the roadway 1 lane at a time with traffic being maintained on the remaining lane. Limit the work areas to 2 miles in length, with only the active work area closed within the 2- mile limit. Obtain approval for night work. Open lanes to traffic at night, except for those areas that are in the curing process. Separate work areas by at least 3 miles.
2.Schedule concrete slab replacement operations to ensure removal and replacement are completed during 1 working day. If unforeseen circumstances prevent concrete placing, temporarily fil l the cavity with crushed base before leaving the project site. Crushed base used to temporarily fill cavities is considered incidental work.
3.Compl ete the work in the following order:
a.A - Slab Replacement (full or part ial).
b.B - Repairing Spalls.
c.C - Subsealing – Grout Method.
d.D - Grinding.
e.E - Repairing Cracks and H – Resealing Joints .
f.F - Reconstruction of Plant Mix Shoulders and 606.
g.G - Sealing Edge Joints . NOTE: C will not precede D by more than 30 calendar days and E /C by 60 calendar days. Grind subsealed pavement and seal crack joints the same construction season.
4.Rehabilitation work is specified in 409.
A.Slab Replacement. Remove and replace concrete pavement in failing areas
B.Repairing Spalls. Core or saw around the perimeter of the specified area, chip or sandblast the spall repair area, and patch the cavity with rapid- hardening concrete or epoxy mortar.
C.Subsealing. Provide pavement subsealing by determining a gro ut hole pattern, dril ling holes through the portland cement concrete pavement , pumping grout through the holes into the voids, and patching the drilled holes with mortar.
D.Grinding. Grind the portland cement concrete pavement surface to eliminate joint faulting, restore proper drainage, and provide riding characteristics and skid resistance or any combination as specified. for Highway Construction Page 281 of 71 5 E. Repairing Cracks. Repair cracks in concrete pavement by routing or sawing with a small diameter segmented saw, cleaning, and sealing. Complete crack repairs conc urrently with joint repair work.
F.Reconstruction of Plant Mix Shoulders. Reconstruct and reseal the plant mix shoulder as specified and include cutting, joint preparation, grade control, stockpiling, and clean- up. Stockpile tailings fr om the milling operation at the designated location.
G.Sealing Edge Joints . Cut a sealant reservoir and seal between the existing plant mix shoulder and the concrete pavement .
H.Resealing Joints . Remove the existing joint materials and clean and reseal Portland cement concrete pavement joints to be rehabilitated.
420.02 Materials.
A.Slab Replacement. Meet materials and testing requirements as determined. Meet the requirements of AASHTO M 235, or ASTM C 881; Type I or II, Grade 2 or 3, with class selected to match field temperature of epoxy for grouting tie bars and dowels. Obtain approval to use quick setting, non- shrink mortar or other alternative materials for grouting tie bars and dowels into existing slabs.
B.Repairing Spalls. Provide rapid- hardening concrete meeting ASTM C928 modified as follows:
1.Water will be the only liquid component.
2.Calcium chloride or metallic aggregate is not allowed.
3.Minimum compressive strength of 2,500 psi at 3 hours, 4,000 psi at 1 day, and 6,000 psi at 28 calendar days.
4.Furnish certified test reports showing compliance. OR Epoxy binder for mortar conforming to AASHTO M 235 or ASTM C881, Type III, Grade 1 or 2 with class selected to meet field temperature.
C.Subsealin g. Provide grout consisting of portland cement and water as specified in 705, and fly ash in accordance with ASTM C618 Class C or Class F. Obtain written approval to use other admixtures. Provide materials certification for fly ash as specified in 106.04. Ensure the grout plant has a positive displacement cement injection pump and a high- speed colloidal mill. Operate the colloidal mixing machine between 800 and 2,000 revolutions per minute, with a rotor operating in close proximity to a stator, creating a high shearing action and subsequent pressure release to make a homogenous mixture. If limestone dust grout is approved for use, a paddle type mixer may be substituted for the high- speed colloidal mixer. Ensure the injecti on pump is capable of 300 psi when pumping grout slurry mixed to a 12- second flow cone time. for Highway Construction Page 282 of 71 5 Proportion grout ingredients by volume consisting of 1 part cement, 3 parts fly ash, and enough water to provide a grout efflux time ranging between 10 and 16 seconds when measured in accordance with Idaho Field Test Manual (Army Corps of Engineers Test Method CRD -C79-58). Control the flowability with time measurements at the beginning of the grouting operation and periodically throughout the injection process. Do not hold mixed material in the mixer or injection sump pump for more than 1 hour after mixing . The Department will not pay for any wasted material held for longer times. Accurately measure dry cement and fly ash by weight, if in bulk, or provide packaged containers of uniform volume. Introduce water into the mixing process through a meter or scale with a totalizer to measure the amount of water used during each wor k shift. Use mortar that meet 705 to patch holes in pavement slabs, or commercial , rapid -setting, concrete patching material meeting ASTM C928. Provide materials certification for comme rcial, rapid- setting mortar as specified in 106.04.
D.Grinding. None specified.
E.Repairing Cracks. Provide sealant types as specified: Hot-Poured Sealant ...................................................................................................................... 704 Cold-Applied Sealant ............................................................................................................... 704.05
F.Reconstruction of Plant Mix Shoulders. Meet the following requirements: Superpave Hot Mix Asphalt .......................................................................................................... 405
G.Sealing Edge Joints . Provide the sealant types as specified: Hot-Poured Sealant ................................................................................................................. 704.02 Cold-Applied Sealant ............................................................................................................... 704.05 Provide heat resistant backer rod material in accordance with the manufacturer’s written instructions (e.g., cotton or cellulose upholstery cord, premolded urethane foam). Ensure the backer rod is slight ly larger in diameter than the width of the sawed joint. Furnish various size backer rods to accommodate variations in joint widths.
H.Resealing Joints . Provide the sealant type as specified: Hot-Poured Sealant ...................................................................................................................... 704 Cold-Applied Sealant ............................................................................................................... 704.05 Provide heat -resistant backer rod material as recommended by the manufacturer (e.g., cotton or cellulose upholstery cord, premolded urethane foam). Ensure the backer rod is slightly larger in diameter than the width of the sawed joint. Furnish various size backer rods to accommodate variations in joint widths. for Highway Construction Page 283 of 71 5 420.03 Construction Requireme nts.
A.Slab Replacement. Remove concrete slabs designated for full or partial replacement without damaging the surrounding pavement or base. Make full depth saw cuts around the perimeter of the slab area to be removed to prevent damage to the concrete that is to remain in place. Do not use impact methods (e.g., drop hammers, hoe rams) to facilitate slab removal. The Contractor may leave tie bars in place if they can be straightened and cleaned. If tie bars are sawed off or destroyed during slab removal, install new bars at the spacing specified by drilling and grouting them into the adjacent slabs. Grout load transfer (dowel) bars into the adjacent slabs and then lubricate before placing the concrete as specified. Obtain approval of the template when drilling holes for dowels and tie bars. Preserve and maintain the existing base in close accordance to the original grade, except where removal of unstable materials is directed. Load removed concrete, unstable material, and debris as it is removed and dispose in an approved location. The Contractor is responsible for determining a suitable disposal area. Meet 409, except a 4- inch slump is allowed when hand methods are used or a 3- inch slump for when machine methods are used. Align transverse joints with existing joints. Provide joint design and sealant as specified. Install replacement concrete as specified in 409.03, except slipform pavers will not be required. The Engineer will not allow plastic strip joints as permanent joint filler . Use increased concrete slab depth to fill minor irregularities below grade as directed. Where leveling or excavation and backfill of unstable areas are directed, use plant mix to provide a non- erodible base directly under the replacement slab. Provide plant mix leveling at least 1 inch thick. In reconstructed areas, place at least a 3 inch thick plant mix base. Preserve the existing transverse and longitudinal joint system when placing fresh concrete in the replacement slabs. At locations where new concrete is to be placed against existing concrete, set 2- inch strips of foam tape or other approved material in place before pouring concrete. Thoroughly remove strips by sawing when preparing the joints for sealant. When replacing adjacent or consecutive slabs, control shrinkage cracking with stress relief joints saw cut at interim joint locati ons. The Engineer will decide when the replacement slabs will be opened to traffic. The Engineer will not allow the Contractor's equipment or traffic on the new slabs until test specimens have attained a minimum compressive strength of 2,500 psi. When using higher cement factors to achieve early strength, additional air entraining agent may be required to ensure entrained air content of the fresh concrete is within the normal range of 4 to 7 percent. No separate payment will be made for additional air entraining agent.
B.Repairing Spalls. Repair pavement spalls as specified or as directed. The Engineer will mark spalls to be repaired on the pavement surface. Unless otherwise specified, repair spalls in a rectangular shape, except in cored areas. Perimeter cut the area to be repaired to a depth of 2 inches with a diamond blade saw or bit. After sawing or coring, chip the cavity out to sound concrete with a jackhammer or other suitable equipment weighing less than 40 pounds to minimize damage to the surrounding concrete. Use a small, hand held chipping hammer for Highway Construction Page 284 of 71 5 for final chipping. Promptly clean loose material from the pavement minimum depth. Make arrangements and use a suitable disposal area for broken concrete and other waste. Prepare, place, and cure the patch in accordance with the manufacturer's written instructions. Restrict traffic on the patches for at least 4 hours. Maintain existing pavement joints and cracks to the full depth of the cavity by forming through the patch as necessary with at least ¼ inch compressible material. Ensure patching materi al does not enter the joint or crack below the cavity.
C.Subsealing. Drill holes 2 inches or less in diameter through the pavement and underlying base to the depth as specified by air or hydraulic equipment. Protect the pavement surrounding each hole from damage. Limit the breakout at the bottom of the drill hole to 10 percent or less of the pavement thickness. Limit drilling operations to less than 1 work shift ahead of the grouting operations. Locate the holes in the configuration as specified. Drill at least 2 consecutive slabs before beginning grouting operations and continue throughout each run or work period. Pre-wet and wash the holes as necessary to obtain thorough distribution of the injected material. Pump grout with less than 100 psi pressure, through the holes until voids under the pavement slab are filled. Limit slab movement or rising as a result of pressure grouting to 0.050 inch or less. Provide and use suitable devices to monitor slab movement during pressure grouting. Inject grout into only 1 hole at a time on any slab or adjoining slabs. When grout appears at any longitudinal or transverse joint, crack, or adjacent hole, or when monitoring devices show slab movement, stop pressure grouting immediately at that hole. Allow water dis placed fr om the void structure by the grout to flow out freely. Do not allow excessive loss of the grout through cracks, joints, or from back pres sure in the hose or in the shoulder area. If continued grouting is no longer feasible, stop subsealing operations at that location. The Department will pay for holes drilled at the contract unit price for materials used. Perform pressure grouting when temperatures are above 45°F, during suitable weather, and when the subgrade materi al is not frozen. Take necessary precautions to prevent grout from being pumped or wasted into any drainage facility or other open structure. Upon completion of the grouting operation, remove grout from the drilled holes to a depth of at least 4 inches below the pavement surface. Clean the holes and fill with mortar and finish flush with the concrete pavement surface. At the end of each work period, leave the work area in a clean, swept, and neat condition. If cracks develop between adjacent grout injection holes, either from drilling or pumping, repair these cracks using an epoxy injection method satisfactory to the Engineer. T he Engineer may require replacement of the entire panel or a designated portion. Either method will be at no additional cost to the Department. Keep traffic off of a grouted slab for at least 1 hour after grouting.
D.Grinding. The Engineer will not require grinding on bridge decks and roadway shoulders, unless specified or required to improve drainage. for Highway Construction Page 285 of 715 1. General. Schedule and proceed with construction operations to produce a uniform finished surf ace. Grind to eliminate joint or crack faults and ensure positive lateral drainage is maintained on a constant cross slope between grinding extremities in each lane. Transition auxiliary or ramp lane grinding from the mainline edge to provide positive drai nage and acceptable r iding surface. Grind the area specified until the pavement surfaces of adjacent sides of transverse joints and cracks are in the same plane and the pavement surface deviations are 0.25 inch or less when tested with a 10- foot straightedge. Ensure the faulting is eliminated at joints and cracks, the overall riding characteristics are within the acceptable limits, and the depth of material removed is sufficient for the pavement surface to be textured, including the bottom of rut s. The Engineer will not require extra depth grinding to eliminate minor local depressions. The Contractor will remove solid grinding residue before it is blown away by traffic or wind and will prevent residue from flowing across lanes used by traffic or i nto gutters or drainage facilities. Any damage to these facilities will be corrected at no cost to the Department. The Contractor will dispose of the grinding residual.
2.Equipment. Furnish grinding equipment meeting the following:
a.Self-propelled.
b.Designed to smooth and texture portland cement concrete pavement with diamond blades.
c.Effective wheel base of at least 12 feet.
d.Cut or plane width at least 3 feet.
e.Shape and dimension that does not encroach on traffic movement.
f.Does not cause raveling, aggregate fractures, spalls, or joint damage.
3.Surface Finish and Testing . Meet the smoothness requirement s of 409.03.K. Produc e a pavement surface that is true to grade and uniform in appearance with longitudinal corrugations that present a narrow ridge, corduroy appearance. The peaks of the ridges will be approximately 1/16 inch higher than the bottoms of the gr ooves with approximately 53 to 57 evenly spaced grooves per foot. Remove fins resulting from grinding before opening to traffic. Inspect transverse joints and transverse cracks to ensure that adjacent surfaces are in the same plane. Grind ar eas where misalignment of the planes of the surfaces on adjacent sides of the joint or crack are in excess of 1/16 inch until the surfaces are flush. Make smoothly feathered transitions at transverse boundaries between ground and unground areas of concrete. Ensure vertical misalignment between ground and unground concrete surfaces at longitudinal boundaries does not exceed 1/8 inch. If re quired, perform additional grinding with appropriate cross slope adjustment to feather out the misalignment.
E.Repairing Cracks. Meet 420.03.H. Repair as specified.
F.Reconstruction of Plant Mix Shoulders. Provide milling machines or grinders with the following characteristics:
1.Power operated. for Highway Construction Page 286 of 71 5 2. Self-propelled.
3.Sufficient power, traction, stability, and capability for removing a thickness of asphalt ic concrete to the desired profile depth and c ross slope in 1 pass.
4.Capable of accurate and automatic establishing and maintainin g of profile grades along each edge of the cut by reference from the existing concrete pavement by means of a ski or matching shoe, or from an independent grade control.
5.Controls dust and other particulate matter created by the cutting head. Mill the plant mix shoulder to the depth, width, and slope as specified. The Engineer may require the pavement milling operations be referenced from an independent grade control rather than a ski in those areas where this type of control is appropriate. Obtain approval for operations to establish and maintain independent grade control. Load and haul tailings from the milling operation to the stockpile site the same day. Remove loose material by sweeping. The Engineer may require sweeping with a pick -up type broom where milling residue cannot be satisfactorily removed otherwise. Prevent milled plant mix material from being spilled or swept onto any lanes used by traff ic. Promptly remove loose material from these areas. Schedule operations to ensure 2 miles of separation between the milling and paving operations is not exceeded. Meet 405. Apply a tack coat of diluted CSS -1 at a rate of 0.05 gallon per square yard to the milled surface before placing the plant mix surfacing. Saw cut the sealant reservoir between the reconstructed plant mix shoulder and the existing concrete pavement to the width and depth specified. Ensure sawing removes plant mix material from the PCC slab. Where irregularities make this impractical, use hand tools to complete the removal of any remaining bituminous material not tightly bonded to the slab. Apply sealant in accordance with the manufacturer's written instructions. The Engineer requires a backer rod.
G.Sealing Edge Joints . Saw the edge joint sealant reservoir to the dimensions specified. Meet the material storage, joint preparation, and sealant application in accordance with the manufacturer’s requirements.
H.Resealing Joints . Perform joint resealing in accordance with the sealant manufacturer’s requirements. Place sealant when the pavement surface and weather conditions are dry. Remove all of the existing material from the joints with a plow, ripping teeth, wire brush, saw, or other equipment as approved, to the Engineer’s satisfaction. Do not use equipment that will cause spalling of the pavement surface beyond the limits of the joint. The Engineer will not allow gang saws to remove existing material from joints formed with tape. Dispose of material removed from the joints in an approved manner. Saw the sealant reservoir to the width and depth as specified with a power -driven saw equipped with diamond blades. Repair any damage (e.g., spalling, fractures) to the concrete pavement at no cost to the Department. Before sawing the sealant reservoir in new concrete, ensure the concrete has reached a compressive strength of 2,500 psi. As soon as each joint is cut, thoroughly clean scale, dirt, dust, old sealant residue, and other foreign material from the sides and adjacent pavement surface for a width of approximately 1 inch on each side at the joint. for Highway Construction Page 287 of 71 5 Accomplish this by sandblasting or jet waterblasting. Remove sawing and sandblasting residue from the pavement surface before it is blown by traffic or w ind. Clean, repair, and cure spalls, fractures, breaks, or voids in the surface of the joint before installing the joint sealant. Immediately before the placement of the backer rod and the sealant, clean the joints by sandblasting using at least 100 psi of compressed air. Stop work if there is oil or moisture in the compressed air, and do not resume work until suitable adjustments have been made. Submit a copy of the manufacturer's written instructions pertaining to the st orage and application of the sealant at least 7 calendar days before beginning installation of the sealant. When silicone joint sealant is used, have a technical representative onsite for at least the first 2 full days when joint preparatio n and sealing is taking place. Comply with the written instructions and/or recommendations made by the technical representative and approved by the Engineer. Apply the sealant material into the joint using equipment and techniques in accordance with the manufacturer’s written instructions. Recess the finished joint seal surface as specified.
420.04 Method of Measurement.
The Engineer will measure acceptably completed work as follows:
1.The quantity of drilled holes will be per each.
2.The quantity of grout actually used for subsealing will be by the cubic feet of grout, dry measure. Dry measure, when using bulk material, is computed on the basis that 94 pounds of cement equals 1 dry cubic foot, and 75 pounds of fly ash equals 1 dry cubic foot. Prepackaged material will consist of 1 cubic foot sacks of the materials. W ater is incidental and will not be included in grout measurements. The Engineer will presume cracks emanating radially from the grout injection holes to have been caused by improper injection techniques. The Engineer will reduce grout quantity for each 5 lineal feet of such crack measured by 1 cubic foot.
3.The quant ity of pavement grinding, milling pavement from the existing plant mix shoulder, pavement removal and, placing and finishing pavement will be by the square yard. The Engineer will measure pav ement grind ing by multiplying the finished ground width, regardless of the number of passes with the grinder, by the total ground length. Pavement removal is computed using the average squared dimensions. Measurement includes removal, disposal, replacement dowel and tie bars , base leveling, preparation, and any other work necessary to prepare the forms for replacement concrete. Placing and finishing p avement will be based on the top surface of the pavement using the average squared dimensions. Measurement includes placing, finishing, curing, and joint construction.
4.The quantity of sealing, resealing joints, crack repair, and sealing edge joints will be by the foot.
5.Plant mix surfacing will be by the ton of mix used in the accepted surface and include the weight of the aggregate, asphalt , and additives in the mixture.
6.Furnished concrete pavement and excavation of unstable material will be by the cubic yard. Concrete measurement is based on batch weights and excavation is computed using the average for Highway Construction Page 288 of 71 5 square d dimensions of the excavated area multiplied by the average depth. Measurement includes providing and delivering the concrete.
420.05 Basis of Payment .
The Department will pay for accepted quantities as follows: Pay Item Pay Unit Drill Hole, Subseal .................................................................................. Each Grout ...................................................................................................... CF Grind Concrete Pavement ...................................................................... SY Resealing Joints ..................................................................................... FT Milling Pavement .................................................................................... SY Plant Mix Surfacing ................................................................................. Ton Sealing ................................................................................................... FT Repairing Pavement Cracks ................................................................... FT Repairing Spalls ..................................................................................... SF Pavement Removal ................................................................................ SY Furnish Concrete Pavement ................................................................... CY Placing & Finishing Pavement ................................................................ SY Excavate Unstable Material .................................................................... CY Sealing Edge Joint s ................................................................................ FT The Department will consider brooming incidental work and the cost included in the milling pavement contract unit price. The Department will consider asphalt , additives, and CSS -1 tack coat as incidental and the cost included in the plant mix surfacing contract unit price. The Department will consider backer rod and sealant incidental work and the cost included in the sealing contract unit price. The Department will consider the cost of repairing damaged or destroyed dowels, base, and plant mix shoulders and slabs as incidental to the pavement removal contract unit price. The services of the technical representative are incidental and the cost included in the contract unit price. 421-429 for Highway Construction Page 289 of 715 SECTIONS 421 -429 - RESERVED for Highway Construction Page 290 of 71 5 SECTION 430 – COLD IN -PLACE RECYCLED (CIR) PAVEMENT
430.01 Description.
Cold mill the existing bituminous pavement to the width and depth as specified, mix emulsified asphalt recycling agent (EARA), recycling additive (dry portland cement or hydrated lime slurry) and water with the millings, re -lay and compact the mixture in place. Produce a hydrated lime slurry onsite. Direct application of dry quicklime to the roadway is not allowed.
430.02 Materials.
The Department defines EARA as an emulsion used for CIR designed to allow acceptance of rolling traffic at 75°F and 50 percent humidity within an optimal time of 2 hours.
1.Emulsion. Ensure EARA meets the property requirements specified in 702. Ensure additives added to the emulsion mix to provide the quick set properties are approved by the man ufacturer.
2.For cold- milled bituminous material, meet the following gradation requirement: Sieve Size Percent Passing 1¼ inch 100
3.Lime. Use granular quicklime (CaO) or hydrated/slaked lime (Ca(OH)2) to produce the lime slurry. Provide quicklime as specified in 720.06.A. The Engineer will require certification that the chemical composition and physical property have been met.
4.Cement. Use Type II portland cement as specified in 701.
5.Water. Provide water without harmful soluble salts and a quality that the asphalt will not separate from the emulsion before the CIR pavement is in place.
6.Materials Acceptance. Asphalt emulsion and aggregate is accepted based on the following:
a.EARA. A manufacturer’s certification is required, including the viscosity and residue percent obtained at the plant. Sample the EARA twice a day from a random truck or trailer onsite in accordance with AASHTO T 40 and ship to the Central Materials Laboratory within 3 calendar days for viscosity and evaporation residue verification testing. When the EARA does not meet s pecifications, a price adjustment will be made as specified in the Department Laboratory Operations Manual Section
350.02 03.
Perform field testing for the purpose of ensuring the asphalt emulsion has not broken excessively during transportation to the project site. Before introduction to the pug mill mixer , check each load of emulsion for “shod” by sieving as described in AASHTO T 59 (sodium oleate solution is not required). Submit the results.
b.Cold milling. Before starting compaction , submit the gradation test at the minimum required frequency of 1 test per lane mile.
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 316–325 of 768.