227 SECTION 550
550.01 Description
This work consists of constructing concrete pavement.
550.02 Equipment
Item Section Concrete Equipment 155 Air Compressor 156.01 Fogger 156.02
550.03 Materials
Item Section Portland Cement Concrete 802 Grouts and Epoxy 806 Epoxy for Spall Repairs 806.02 Hot Applied Joint Sealant Type IV 826.02 A.2 Preformed Elastomeric Compression Joint Seal 826.02 E Reinforcing Steel, Dowel Bars, and Tie Bars 836 Dowel Bars for Pavement Joints 836.04 Provide aggregate that meets the requirements of Section 802.01 C.4, “Well Graded Aggregate” . Develop a mix design with a maximum water -cement ratio of 0.40 when placing concr ete with a slip form paving machine. Use the water -cement ratio shown in Section 802.01 B.2, “Concrete Class Designation” for all other paving methods.
550.04 Construction Requirements
A.General. Stockpile sufficient aggregate material to produce a minimum of 25 percent of the remaining quantity of concrete. Do not mix, place, or finish concrete without adequate natural or artificial lighting. Do not stockpile or mix material on the pavement. Pad equipment used to handle epoxy coated bars where the equipment is in contact with the bars. Lift bundles of bars with multiple supports or a platform bridge to prevent abrasion in the bundle. Transport bundles without dropping or dragging. Do not expos e bars to ultraviolet rays for 60 or more calendar days after fabrication, including the time the bars are placed before concrete placement. If covering the bars, provide ventilation to prevent condensation. The Engineer will reject bars if damage to the epoxy coating exceeds 2 percent of the surface area of the coated reinforcing bar in any 1 foot length. Repair remaining bars as recommended 228 by the manufacturer. Remove rust before making repairs. The Engineer will reject bars if the patched area, excluding the cut ends, exceeds 5.0 percent of the surface area.
B.Mix Design
1.General. Develop a mix design. Perform the tests for the mix design as specified in the Field Sampling and Testing Manual . Submit the completed mix design and all test data a minimum of 14 days before beginning paving operations. During the development of the mix design, develop a maturity curve as specified in ASTM C 1074. The water/cement (w/c) ratio used to develop the maturity curve is the target w/c ratio for the mix. Provide mix with a w/c ratio with a tolerance of 0.01 from the target w/c ratio. Deliver the samples and the mix design, including the test results, to the Materials and Research Division a minimum of 14 calendar days before beginning paving operations. The same day the material is delivered, notify the Engineer that the samples have been delivered. Provide the Engineer with a copy of the mix design and the test results at the same time they are submitted to the Materials and Research Division. The Department requires a maximum of 14 calendar days to verify mix designs before the Engineer will allow paving operations to begin. The Engineer will verify the maturity curve on the first day of concrete placement according to ASTM C 1074, as modified in the Field Sampling and Testing Manual.
2.Samples. The Engineer will verify the mix design. The materials used in the mix design shall be the same as those used on the project. Attach a tag to the samples identifying the Department’s project number and type of m aterial. Supply samples of material based on the minimum sample size specified in Table 550-01. Provide additional material upon request. Table 550 -01 Minimum Mix Design Sample Size Material Sample Size Cement 100 lb SCM1 35 lb Aggregate 1000 lb Admixtures 1/2 pint each 1 If SCM is not part of the mix design, provide 135 lb of cement.
C.Roadbed Condition. Do not operate mixing equipment or haul material on the finished grade except when the operation of this equipment off the finish grade is impractical due to restricted access. Place concrete on a smooth, compacted, and moist roadbed. Do not place concrete over standing water or mud.
D.Placing and Spreading Concrete.
1.General. Do not use materials containing frost or lumps of frozen material. Do not place concrete on or against frozen ground. The Engineer will reject loads of concrete with air content outside the limits specified in Section 802.01 H, “Air Content” . The Engineer will test each subsequent load of concrete to determine the air content until the concrete is within the limits Placement of concrete will not be allowed until the Engineer has determined the air content is within the limits. Adjacent concrete may be used as a side form in the following conditions: • In place for a minimum of 18 hours; • Saw cuts are complete for the full length of the area to be used as a form; and • Only foot traffic or light weight power screed are used on the surface. Construction traffic is allowed on the concrete surface once the concrete has met the requirements of Section 550.04 L, “Opening to Traffic”. If concrete placement is interrupted and it appears that the head of concrete is drying out, cover the unfinished face with wet burlap. Keep the burlap damp. Remove burlap and plastic sheeting and uniformly blend the concrete with the fresh concrete when resuming placement operations. Install a transverse joint as specified in Joints” , if 45 minutes elapses between the placement of successive batches or loads. Use a mechanical spreader for initial strike off and to spread concrete uniformly across the full width of the slab. The Engineer may approve other methods of spreading where a mechanical spreader is not feasible. The Engineer will allow the use of approved portable vibratory equipment if full width vibratory equipment is not feasible. Do not over vibrate. R emove and replace areas with excessive surface mortar and segregated material. Protect the thermocouple wire that the Engineer places into the plastic concrete.
2.Formed Paving. Securely stake the side forms. Reset forms that are disturbed or show evidence of an unstable foundation. After staking, recompact the grade with a mechanical tamper at both the inside and outside edges at the base of the forms. 230 Install forms that do not deviate from the proposed alignment by more than: − 1/8 inches vertically; and − 1/2 inches horizontally. Provide a minimum of two hours before paving to allow the Engineer to inspect the forms.
3.Slip Form Paving.
a.String Line. Use and maintain a taut string line for operating the automatic equipment controls.
b.Consolidation Vibrator Operation. Operate internal vibrators within a frequency range of 4,000 to 8,000 vibrations per minute. Operate surface vibrators within a frequency range of 3,500 to 6,000 vibrations per minute. Reduce vibrator frequency when forward motion of the paver is reduced and stop vibrators when forward motion of the paver is stopped. Use a vibrator monitor that records at intervals of 25 feet or 5 mi nutes, whichever occurs first. Provide both electronic and printed records each day that state: − time; − station; − speed; and − operating frequency of individual vibrators. Do not delete the data from the vibratory monitoring system until the records are in their final form and given to the Engineer. The Engineer will allow one of the records to be produced in an office. Provide the original record before taking the data into the office. Provide an electronic record that is a comma or spaces delimited text file, adequate for insertion into a computerized spreadsheet software package. Provide a written explanation each week that details: − vibrator setting changes; − out of tolerance vibratory operations; and − monitoring device malfunctions.
E.Placing Reinforcing Steel and Tie Bars.
1.General. Use reinforcing steel and tie bars free of material that could impair the bond between the steel and concrete. Place the reinforcing steel and tie bars on approved supports a minimum of 2000 feet ahead of the paving operation. On smaller placements, place reinforcement in advance of the pavement as far as practical. 231 Provide a micro covermeter on projects with over 20,000 square yards of concrete paving for the use of the Engineer to confirm bar locations.
2.Tie Bars. Position the tie bars within the following tolerances: − 1 inch vertically; and − 3 inches transversely. When installing tie bars in a sawed longitudinal joint, secure the location of the tie bars using tie bar baskets or other approved fixed supports. Place tie bars used in longitudinal construction joints using one of the following methods: − Into the side of plastic concrete when using a slip form paver; − Through holes in the side forms; or − Using approved two-piece connectors. If the specified tolerance is not obtained by the insertion of tie bars into the side of the plastic concrete, support the tie bars approved fixed supports or two-piece connectors.
3.Reinforcing Steel. Place reinforcement for continuously reinforced concrete to within 1 inch of the specified location, both horizontally and vertically. Use plastic, plast ic coated, or epoxy coated bar supports to support epoxy coated reinforcing bars. Use plastic coated wire for tying epoxy coated reinforcing bar. Under the observation of the Engineer, verify the placement of reinforcement in the plastic concrete pavement at the start of paving each day and every 500 feet during paving.
F.Uncontrolled Cracking. Use any means and methods necessary to saw the joints in the concrete pavement to prevent uncontrolled cracking. Repair or remove and replace concrete pavement where uncontrolled cracks have occurred. Perform removal and replacement work as specified in Section 570, “Concrete Pavement Repair” . If the cracks have occurred due to Contractor operations the repairs wi ll be at no additional cost to the Department. If the Contractor can provide proof to the satisfaction of the Engineer that the uncontrolled cracking was not the fault of Contractor operations, the Department will pay for the repairs as specified in Section 104.02, “Contract Revisions” . Submit a corrective action plan that details how the uncontrolled cracked area will be repaired or removed and replaced within 7 days after the uncontrolled cracking occurs. Once the corrective action plan is approved, complete the corrective action plan within 30 days. Include in the plan dowel bar assemblies when applicable. Restore any base or subgrade that is damaged during the removal and replacement process at no additional cost to the Department. Restore drainable base by using Class 7 aggregate. 232 G. Joints.
1.General. Repair spalls deeper than 1/4 inch by patching with an epoxy mortar. Perform patching when the ambient and pavement temperatures are greater than 40°F. Clean the spall area. Prime the spall surface with a brush application of epoxy binder. Mix the epoxy binder as recommended by the manufacturer. Insert material in the joint that will not bond to the epoxy to form the faces of the spall patch. Blend dry concrete sand into the mixture to give an epoxy mortar of trowelable consistency. Place and finish the epoxy mortar in the spall area. Place dry concrete sand on the finished epoxy mortar surface. After the epoxy mortar has cured, remove the inserts.
2.Tran sverse Contraction Joints. Mark the location of the joints to be sawed or formed on the plastic concrete surface. Saw the joints on mainline and shoulders. On small areas or tapers, create the joints by sawing, inserting preformed inserts, or forming 1 inch deep grooves in the pavement surface. Stake a metal dowel bar assembly to the roadbed that holds the dowel bars within 1/8 inch of the proposed alignment and elevation. Mark the position of the assembly to locate the transverse joint over the center of the dowel bars. Do not cut the assembly ties running parallel to the dowel bars. Place dowel bar assemblies a minimum of 2000 feet ahead of the paving operation. Use dowel bars that have a uniform coat of Tectyl 506 applied by the manufacturer, field applied NLGI Grade #2 multipurpose lithium grease, or an approved equal that has been applied to the full length of the dowel bars.
a.Sawed Joints. Begin relief sawing as soon as the concrete has hardened sufficiently to permit sawing without raveling or moving of aggregate. Remove residue from joints immediately after sawing is completed using pressurized water. If side forms are in place, saw within 1/2 inch of the forms. If impervious membrane cure has been removed due to sawing or flushing operations during the curing period, reapply cure to the area within 30 minutes of the cure being removed.
b.Formed Joints. Construct formed joints by installing a pre-formed insert into the plastic concrete before final surface finishing. Vibrate the inserts into place or install in a groove formed by a vibrating cutter bar. Ensure the inserts top edges are flush with the concrete surface. Correct surface deformations caused by installation of inserts using hand-finishing methods and straight-edge the surface across the joint as specified in 233 “Straightedging” . Remove inserts, except those designed to remain, without damage to adjacent concrete.
3.Transverse Expansion Joints. Install dowel bar assemblies in the expansion joint. Secure the dowel bars within 1/8 inch of the proposed alignment and elevation with a metal dowel bar assembly device staked to the roadbed. Coat the free half of each dowel with a thin uniform coat of Tectyl 506, NLGI Grade #2 multipurpose lithium grease, or an approved equal. Cover the free half of each dowel with a metal or plastic dowel cap or sleeve after application of release agent. Use caps or sleeves that fit the dowel bars tightly and the closed ends are watertight. Install preformed expansion joint filler. Connect abutting ends of individual sections of filler without any gap. Pre-punch the filler to fit around the dowels. Support the preformed filler perpendicular to the pavement surface by one of the following: − An expansion joint assembly that is staked into the subgrade − A load transfer assembly or a device designed to remain in the pavement − A suitable installing bar or header Protect the top edge of filler with a removable, non-aluminum channel cap that has flanges a minimum of 1.5 inches deep. Do not place concrete against the joint until the Engineer has approved the installation of the expansion joint assembly. Maintain equal pressure on both sides of the preformed fill er while placing concrete. Vibrate the concrete on each side of the joint. After the concrete has been finished, remove the protective channel cap and edge the concrete on each side of the joint. Remove excess concrete that flowed around the ends of the joint. Seal the expansion joint with a low modulus silicone sealant.
4.Transverse Construction Joint. Install a transverse construction joint at the end of each day’s pour and when the time between placement of successive batches or loads of concrete exceeds 45 minutes. Install transverse construction joints halfway between normally spaced transverse joints. Stake a metal deformed splicer bar assembly to the roadbed that holds the deformed splicer bar within 1/8 inch of the proposed alignment and elevation. Pave over the assembly far enough to maintain the elevation of the top of the slab. Make a full depth saw cut to expose the deformed splicer bar and install the deformed insert. Dispose of the excess concrete. On shoulders or urban projects, if the Engineer determines it is not feasible to install a deformed splicer bar basket assembly, form a transverse construction joint by installing a header shaped to conform to the cross -section of the slab. Use a header designed to 234 accommodate proper placement of dowel bars or reinforcement extending across the joint. Construct a rigid header, secured to prevent bulging or displacement. Consolidate the concrete adjacent to the header using an internal vibrator or other approved methods. Remove segregated concrete. After the pavement has been finished, edge the surface adjacent to the header.
5.Longitudinal Joints. Complete sawing of longitudinal joints no more than 7 days after concrete placement. Remove sawing residue by flushing the joint w ith water. If impervious membrane cure has been removed due to sawing or flushing operations during the curing period, reapply cure to the area within 30 minutes of the cure being removed.
H.Finishing Concrete.
1.General.
a.Water. Do not use water to facilitate finishing.
b.Floating. Use long-handled floats with blades that are at least 5 feet by 6 inches.
c.Straightedging. Use a 10 foot straightedge parallel to the pavement centerline to reveal any irregularities. Strike off high areas and fill low areas with fresh concrete. Consolidate the areas corrected and refinish them with a long-handled float. Start the float at the edge of the pavement and slowly move it to the crown and back again to the edge. Only float enough to seal the surface. Recheck the corrected areas with the 10 foot straightedge. Dispose of surplus water and laitance on the pavement surface outside the forms. Overlap successive advances of the straightedge no less than 1/2 the length of the straightedge. Continue straightedge testing and corrections until the entire surface is free from observable depression below the straightedge.
d.Final Surface Finish.
1.General. Uniformly texture the surface by dragging a seamless strip of stiff-fiber artifici al grass carpet longitudinally along the full width of the pavement in a single pass. 235 Use and maintain a taut string line for operating the carpet drag. Attach the leading edge of the carpet drag to a bridge. If the Engineer determines it is not feasible to use a bridge or string line, other texturing methods will be allowed. Maintain a clean carpet free of encrusted concrete. Provide a minimum texture depth of 0.031 inches.
2.Roadways with Speed Limits Less than 45 MPH. The Engineer will test the texture achieved by the carpet drag in accordance with ASTM E 965 and the Field Sampling and Testing Manual. The Engineer will determine the test location. If three or more lots have texture depths less than 0.031 inches but greater than or equal to 0.025 inches, perform diamond grinding on those lots. Perform diamond grinding any lot having a texture depth of less than 0.025 inches. Perform grinding as specified in Section 550.04 M.4, “Grinding.” The Engineer will determine the limits of any failing test by running additional tests at 100 foot intervals before and after the failing test. The Engineer will determine the location of the additional tests.
3.Roadways with Speed Limits 45 MPH or Greater. Run a clean, metal tine longitudinally along the surface immediately following the carpet drag. Exclude areas within 3 inches of the edge of the slab and longitudinal joints. Run the tine continuously across transverse joints. Use a tine that provides: − 1/8 inch ±1/64 i nch groove width; − 3/16 inch ±1/16 inch groove depth; and − 3/4 inch spacing of between grooves. If the concrete has becomes too stiff to receive the metal tine finish, use diamond bladed equipment to produce the longitudinal grooves.
e.Imprinting Pavement. Use devices capable of imprinting the numerals between 3 and 4 inches in height and at least 1/4 inch deep. Create impressions after texturing the pavement. Imprint numbers and markings into the surface: − 20 inches from the edge of the concrete to the bottom of the number; − Parallel to centerline; and − Readable from the outside shoulder. Imprint survey station numbers at every station that is divisible evenly b y 5 (ex. 5+00, 10+00, etc.) and imprint tick marks at 100 foot intervals between the station markings. Imprint the reference point (RP) number into the pavement at each RP. Imprint edgedrain outlet locations with a “0” (zero). On two-way roadways, impri nt the station numbers in the direction of stationing. At the beginning and end of each day’s placement, place the station number to the nearest foot at the right edge of slab. Imprint the month, day, and year at the beginning and end of each day’s placement. Place these imprints on the opposite edge of the slab from that used for station imprints and so that the numbers can be read in the direction of concrete placement.
2.Additional Requirements for Formed Concrete. Use machine methods to screed and consolidate the concrete. If a screeding machine breaks down, discontinue the mixing of concrete until screed machine is operational. The Engineer will allow manual screeding of concrete that was mixed before breakdown. Simultaneously operate two transverse screeding machines to finish each section of concrete. Operate the screeding machines at the same speed as the concrete placement operations. Avoid stopping the screeding machines. The Engineer will allow the use of one screeding machine if conc rete is placed at a rate of less than 250 feet per hour. Operate the single screeding machine at least twice over the area. Ensure concrete or mortar carried ahead of the screeds is not deposited on or adjacent to any joint. Produce a surface with a uniform texture.
I.Curing Concrete.
1.General. Apply the final cure within 30 minutes of screeding the concrete. Use wetted fabric cure or an impervious membrane cure. Obtain the Engineer’s approval to change the cure method. If weather conditions cause rapid drying of the pavement surface, use a fogger to apply a fine mist to the concrete surface for interim curing. Begin fogging immediately behind the tining float. Maintain the fogging to produce a sheen on the surface until the curing is applied. Apply the fog over the entire placement width. Reduce fogging only if excess water accumulates on the surface. Do not apply water with brushes. Cure concrete pavement for a period of at least 72 hours. Suspend curing when the pavement has attained the minim um strength specified in Traffic” for opening pavement to public traffic. 237 During the curing period, only equipment necessary for curing and for sawing joints will be allowed on the concrete. If the ambient temperature falls below 40°F, maintain the concrete surface temperature between 40°F and 90°F for the duration of the curing period. If ASE concrete is used, maintain the surface temperature between 50°F and 90°F. Conduct heating operati ons to avoid sudden temperature changes in the concrete. Before removing any enclosures, decrease the concrete’s surface temperature to the air temperature at a rate not to exceed 15°F per hour. The Engineer will suspend paving operations if cure is not properly applied. If hair cracking develops before placing the curing cover, modify curing procedures to prevent loss of moisture. Cease concrete placing and mixing if hair cracking continues. Submit a detailed temperature maintenance plan before placing concrete, if the ambient temperature is expected to drop below 40°F.
2.Wetted Fabric Cure. Cover the concrete pavement with wet mats of cotton, burlap, or geotextile fabric. Place fabric mats to cover the entire concrete pavement surface. Cover the exposed sides of the concrete pavement after removing forms. Keep the fabric mats wet continuously during the curing period. If replacing the mats with impervious membrane, leave the mats in place a minimum of 12 hours.
3.Concrete Curing Compound. Use a curing compound that meets the requirements of Section 810.01 B.2, “Type 2, Class B”. Apply the cure at a minimum rate of 1 gallon per 150 square feet of pavement in one or two applications. If applying two coats, apply the second application within 30 minutes of the first application. Protect joints that require sealing from infiltration of the curing compound. Immediately cover the exposed sides of the concrete pavement with curing compound if removing forms exposes curing concrete before the expiration of the curing period. Immediately reapply curing compound to damaged areas within the curing period.
J.Removing Forms. Do not remove forms until the concrete has hardened to the extent that forms can be rem oved without damage to the concrete. 238 Before applying curing compound, repair honeycombed areas using freshly mixed mortar. Use mortar having the same proportions of cement and sand as the concrete pavement. Adjust the placement methods if honeycombing oc curs.
K.Sealing Joints.
1.General. Apply joint sealant to clean and dry joints. Use an air compressor to clean the joints. Apply joint sealant when the air temperature is 40°F or higher. Seal the joints no more than ten days after placement of concrete and before opening to construction and public traffic. Fill the joint from the bottom up with sealant.
2.Preformed Elastomeric Compression Joint Seal. Apply the lubricant-adhesion to the joint groove walls or the preformed joint seal or both. Install the seal between 1/8 inch and 1/4 inch below the pavement surface. Install the seal using machine tools in a manner that prevents curling or twisting in the joint groove. The Engineer will allow the use of hand tools on ramps or locations where mac hine tools are not practical. Install the seal with no splices when joints are 30 feet or less in length. Construct joints over 30 feet in length using no more than 2 splices. Extend the preformed joint seal one inch beyond each edge of the concrete pavement. Do not stretch the preformed joint seal more than 5 percent.
L.Opening to Traffic. Construction and public traffic will be allowed on newly placed concrete after the joints have been sealed and the concrete has attained a minimum compressive strength of 3,000 psi or a minimum flexural strength of 450 psi. Pavement placed during development of the maturity curve may be opened to traffic when one of the following criteria has been met: − the maturity factor of the placed concrete meets or exceeds the initial maturity factor as determined by the strength-maturity curve being developed; or − at a particular test age, the average strength of the three beams used for development of the strength-maturity curve meets 450 psi.
M.Tolerance in Surface and Ride Quality.
1.General. The Engineer will use a 10 foot straightedge to determine surface tolerances and ride quality. The Engineer may use the straightedge module in Proval.
2.Roadways with Speed Limits 45 MPH or Greater. Use diamond grinding equipment to correct high spots of more than 1/8 inch and less than 1/2 inch in 10 feet. Ensure the deviation after grinding is less than 1/8 inch. 239 If the deviation exceeds 1/2 inch high or low, submit a corrective action plan that includes either grinding or removal and replacement of the pavement. If the corrective action plan contains grinding, the pavement must be ground to within the 1/8 inch tolerance. The Engineer will determine if corrective action will be implemented based on the corrective action plan. If the corrective action plan is approved and consists of grinding, the Engineer will direct the Contractor to obtain cores in these areas, as specified in Section 550.04 N.1, “Contr actor Coring”, and will make a determination of the pavement thickness as specified in Section 550.04 N.2, “Determination of Pavement Thickness” .
3.Roadways with Speed Limits Less than 45 MPH. Use diamond grinding equipment to correct high spots of more than 1/4 inch and less than 5/8 inch in 10 feet. Ensure the deviation after grinding is less than 1/4 inch. If the deviation exceeds 5/8 inch high or low, submit a corrective action plan that i ncludes either grinding or removal and replacement of the pavement. If the corrective action plan contains grinding, the pavement must be ground to within the 1/4 inch tolerance. The Engineer will determine if corrective action will be implemented based on the corrective action plan. If the corrective action plan is approved and consists of grinding, the Engineer will direct the Contractor to obtain cores in these areas, as specified in “Contrac tor Coring”, and will make a determination of the pavement thickness as specified in Section 550.04 N.2, “Determination of Pavement Thickness ”.
4.Grinding. Use equipment that does not cause strain or damage to the underlying surface of the pavement. Do not cause excessive ravels, aggregate fractures, spalling, or disturbance of the joints. Perform grinding in the longitudinal direction so grinding begins and ends at lines normal to the pavement centerline. Do not overlap more than 2 inches between passes and ensure the depth variance between adjacent passes is less than 1/8 inch. Feather the grinding at the beginning and end of each pass. Ensure the surface of the ground pavement has a texture consisting of groov es between 0.090 and 0.130 inches wide. Keep the peaks of the ridges approximately 1/32 inch higher than the bottom of the grooves. Grind high shoulders to provide drainage and safety. Grind the full width of the lane and daylight grinding on the shoulder by performing a feather pass. Grind a minimum length of 30 feet. Join grind sections if the distance between grind sections is less than 60 feet. When grinding in areas with speeds less than 45 MPH, areas with curb and gutter, and areas adjacent to waterways continuously collect all slurry or residue resulting from the 240 grinding operation. Dispose of the slurry or residue as specified in Section 107.17, “Removed Material”.
N.Acceptance.
1.Contractor Coring. The Engineer will designate locations for obtaining pavement cores a minimum of 28 days after concrete placement. After grinding is complete, obtain one core in each lot under the observation of the Engineer. The Engineer will request additional coring, based on the test results in Sections 550.04 N.2, “Determination of Pavement Thickness” and
550.04 N.3,
“Determination of Concrete Strength” . Obtain the requested cores at no additional expense to the Department. Fill the core hole with fresh concrete mix and use a vibrator to consolidate the concrete in the holes. Screed the new concrete off and apply curing compound to the new concrete. The Engineer will take possession of the cores immediately after they are obtained. A lot is defined as: − 4,000 square yards of concrete pavement of constant thickness and placement width; − Fractional areas between 1,000 and 4,000 square yards; and − Individual ramps, cross -overs, intersections, shoulders, or other irregular areas of pavement not included in the main line. Fractional areas with less than 1,000 square yards are part of the adjacent lot.
2.Determination of Pavement Thickness.
a.General. The Engineer will determine the concrete pavement thickness as specified in AASHTO T 148. When determining the average pavement thickness, the Engineer will record the length of cores that exceed the designed thickness using Table 550-02. Table 550 -02 Excess Core Length Length Used for Calculations 0.0 to 0.5 inch Actual core length Over 0.5 inch Design thickness plus 0.5 inch
b.Thickness Deficient by less than 0.2 inch. If the initial core is deficient in length by less than 0.2 inch from the specified pavement thickness, the Engineer will not request additional cores for determining thickness in that lot.
c.Thickness Deficient by 0.2 inch and less than 1.0 inch. When the initial core is deficient in length by 0.2 inch and less than 1.0 inch, the Engineer will request two additional cores from the lot at intervals separated from each other and from the first core by at least 1/4 the length of the lot. 241 If neither of the two additional cores is deficient in length 1.0 inch or more, the Engineer will compute the average thickness of that lot of pavement as the average length of the three cores and will process a contract price adjustment as specified in Section
550.06 C, “Thickness Tolerance Contract Price Adjustments” .
If either of the additional cores is deficient in length by 1.0 inch or more, Section 550.04
N.2.d, “Thick ness Deficient by 1.0 inch or More” will apply.
d.Thickness Deficient by 1.0 inch or More. When the pavement thickness is deficient by more than 1.0 inch the Department will not pay for the deficient material and the Engineer will determine the serviceability of the deficient area as specified in Section 105.07 A. “Performance of Work” . If the Engineer determines that the deficient area is serviceable, the material may remain in place. If the Engineer determines that the deficient area is not serviceable, remove and replace the deficient concrete. The Department will pay for the replacement material, provided it meets the specifications. When the length of the initial core is deficient by more than 1.0 inch, the Engineer will request exploratory cores at a minimum of 10 foot intervals parallel to the centerline in each direction from the random core until, in each direction, an exploratory core is obtained which is not deficient in length by more than 1.0 inch. The deficient area is the placement width and the length between the midway points of the last two exploratory cores at each end of the deficient area. The Engineer will calculate the average thickness of the remainder of the lot from at least two additional cores obtained outside the area that is deficient by more than one inch. The Engineer will not use exploratory cores in computing average thickness for determining adjusted unit price.
3.Determination of Concrete Strength. The Engineer will determine the strength of the in-place concrete by testing the initial core used to determine pavement thickness from each lot. The test will be conducted in accordance with AASHTO T 22. When the concrete strength does not meet the specified strength, the Department will not pay for the deficient material and the Engineer will determine the serviceability of the deficient area as specified in Section 105.07 A. “Performance of Work” . If the Engineer determines that the deficient area is serviceable, the material may remain in place. If the Engineer determines that the deficient area is not serviceable, remove and replace the deficient concrete. The Departm ent will pay for the replacement material, provided it meets the specifications. If the test shows that the concrete has not met the specified strength, the Engineer will request exploratory cores at a minimum of 10 foot intervals parallel to the centerli ne in each direction from the random core until, in each direction, an exploratory core is obtained which meets the specified strength. The deficient area is the placement width and the length between the midway points of the last two exploratory cores at each end of the deficient area. 242 4. Reinforcing Steel Placement for Continuously Reinforced Concrete Pavement. The Engineer will measure vertical location of the reinforcement from the cores taken for determining pavement thickness and strength. The Engineer will determine the depth of the reinforcement below the top surface of the core from the average depth of the exposed steel members on the vertical surface of the core. The Engineer will consider each layer separately where two layers of reinforcement are evident in the core. The Engineer will make all measurements from the top surface of the core to the center of the exposed member, or if the member has been dislodged, to the center of the groove remaining on the vertical surface of the core. The Engineer will process a contract price adjustment in accordance with D, “Reinforcing Steel Placement Contract Price Adjustments” if the reinforcing steel is more than 1.0 inch and less than 2.0 inches outs ide the specified location. If the vertical location of the reinforcement is 2.0 inches or more outside the specified location or the reinforcement is less than 2.0 inches from the top or bottom of the pavement slab, the Engineer will make a determination of serviceability as specified in Section
105.07 A. “Performance of Work” .
The Engineer will not request additional cores for these determinations.
550.05 Method of Measurement
The Engineer will measure, completed and in place, as specified in Section 109.01, “Measurement of Quantities”.
550.06 Basis of Payment
A.General Pay Item Pay Unit __IN Reinf Concrete Pavement CI__ Square Yard __IN Non -Reinf Concrete Pavement Cl__ Square Yard __IN Continuous Reinf Concrete Pavement Cl__ Square Yard __IN Non -Reinf Concrete Pavement Cl__ - Doweled Square Yard Such payment is full compensation for furnishing all materials, equipment, labor, and incidentals to complete the work as specified.
B.Thickness Tolerance Contract Price Adjustments. The contract price adjustment for each lot will be determined by multiplying the lot size of by the contract unit price for concrete pavement and the appropriate Contract Price Adjustment Factor in Table 550-05. No price adjustments will be made for lots with a pavement thickness deficient by 0.2 inch or less. Table 550 -05 Pavement Thickness Contract Price Adjustments Deficiency in Pavement Thickness (Inches) Contract Price Adjustment Factor Over 0.2 to 0.3 90% 243 Table 550 -05 Pavement Thickness Contract Price Adjustments Deficiency in Pavement Thickness (Inches) Contract Price Adjustment Factor Over 0.3 to 0.5 80% Over 0.5 to 0.6 70% Over 0.6 to 0.7 60% Over 0.7 to 1.0 50% The Department will not pay more than the contract unit price for any pavement that has an average thickness in excess of that specified.
C.Reinforcing Steel Placement Contract Price Adjustments. For continuously reinforced pavements, the Engineer will process a contract price adjustment for each lot of pavement with reinforcing steel that is outside the specified location based by multiplying the lot size by the contract unit price for concrete pavement and the appropriate Contract Price Adjustment Factor in Table 550-06. No price adjustments will be made for lots with reinforcing steel within 1.0 inc h of the specified location. Table 550 -06 Deviation from specified location Contract Price Adjustment Factor 1.0 inch and less than 1.5 inches 10% 1.5 inches and less than 2.0 inches 20% Section 570 244 SECTION 570 CONCRETE PAVEMENT REPAIR
570.01 Description
This work consists of repairing concrete pavement.
570.02 Equipment
Item Section Concrete Equipment 155 Air Compressor 156.01
570.03 Materials
A.General. Item Section Portland Cement Concrete 802 Grouts and Epoxy 806 Impervious Membrane Cure 810.01 B.1 Class 5 Aggregate 816 Joint Materials 826 Deformed and Plain Steel Bars for Concrete Reinforcement 836.02 A Dowel Bars for Pavement Joints 836.04
B.Concrete for Repairs.
1.Full Depth Repairs. Use Class AAE concrete with cement that meets the requirements of Section 804.01, “Cement” , for full depth repairs.
2.Spall Repairs.
a.Concrete. Use Class AE concrete with cement that meets the requirements of Section 804.01, “Cement”, for spall repairs.
b.Grout. Mix equal parts by weight of Portland cement and fine aggregate. Mix with sufficient water to produce a stiff grout.
C.Joint Stitching.
1.Epoxy Resin. Use an epoxy resin that meets AASHTO M 235, Type I, Grade 3. Mix the epoxy resin as specified by the manufacturer.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 262–278 of 550.