244 SECTION 570
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.
2.Tie Bars. Use epoxy coated, Grade 60 tie-bars as specified in Section 836.02 A, “Deformed Bars and Plain Steel Bars for Concrete Reinforcement” .
570.04 Construction Requirements
A.Concrete Repair.
1.General. Place forms as specified in Section 550.04 D.2, “Formed Paving” on all exposed edges. The Engineer will allow the use of two inch lumber if repairs are less than 15 feet in length. Do not use heavy equipment adjacent to concrete in place less than 48 hours.
a.Spall Repair.
1.General. Conduct removals by chipping or partial depth milling to remove the deteriorated or delaminated concrete. If when removing the pavement the Engineer determines the extent of damage requires a full -depth repair, change the repair to full -depth. Sandblast the patch area. Remove loose particles by air blasting. Direct air blasting operations away from traffic lanes. Evenly apply a thin coat of grout to the cleaned surface. Place the concrete before the grout dries. Sandblast and regrout the patch area if drying occurs. Place concrete for spall repairs when the air temperature is above 40˚F. Texture the repair by dragging a carpet of artificial grass longitudinally over the repaired ar ea.
2.Milling. Use milling machine that has a device for stopping at preset depths to prevent damage to dowel bars. Chip out spalling created by the milling process. Taper all sides of the repair 30° to 60° from horizontal. After the repair has cured, seal the edges of the repair with grout and reapply cure.
3.Chipping. Keep sawcuts beyond the patch outline to a minimum and seal sawcuts using a Type IV hot poured sealant. Remove concrete using a 15 pound chipping hammer with a wide flat bit and hand tools. Cut off and remove reinforcing bars discovered during the removal process. 246 b. Full Depth Repairs. Use the lift out method to remove concrete in full depth repair areas with minimal disruption to the subgrade and without damage to the remaining concrete. Do not operate equipment, other than compaction equipment, in areas where concrete has been removed. Fill voids deeper than 1 inch with aggregate and compact the material to the level of the existing subgrade. Place concrete for repair s less than 100 feet long the same day that removals are initiated. Place concrete for repairs longer than 100 feet within 48 hours of initiating removals. Dampen the faces of existing concrete before placing new concrete. Place, consolidate, finish, and cure concrete according to the following portions of Section 550.04, “Construction Requirements”: − 550.04 C, “Roadbed Condition” ; − 550.04 D, “Placing and Spreading Concrete” ; − 550.04 E, “Placing Reinforcing Steel and Tie Bars” ; − 550.04 F, “Uncontrolled Cracking” ; − 550.04 G, “Joints” ; − 550.04 H, “Finishing Concrete” , except parts 1.d, “Final Surface Finish” and 1.e, “Imprinting Pavement”; − 550.04 J, “Removing Forms” ; − 550.04 K, “Sealing Joints” ; and − 550.04 L, “Opening to Traffic” . Provide finished concrete that is flush with all adjacent pavement surfaces. Before the concrete sets, check the repair utilizing a 10 foot straight edge and correct areas that deviate by 1/8 inch or greater. Texture the repair by dragging a carpet of artificial grass longitudinally over the repaired area. If repairs involve multiple lanes, fill the gap between the lane under repair and the existing concrete with cold bituminous material. Remove this material before making the repair to the adjacent lane.
1.Repairs One Lane Wide. Use a bond breaker along the centerline joint. Tie bars are not required on repairs that are one lane wide. When the repair falls in a ramp, restore the longitudinal joints crossing the repair, but do not use tie bars.
2.Repairs Wider Than One Lane. Before placing the concrete in the second lane, install 30 inch #5 tie bars in the longitudianl joint using the original tie bar pattern. Drill holes for the bars and secure the bars in the holes using epoxy.
3.Impervious Membrane Cure. Use a curing compound that meets the requirements of Section 810.01 B.1, “Type 2”. Apply the cure at a m inimum 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.
2.Non-Reinforced Jointed PCC Pavement Repairs.
a.Concrete Removal. Make a full depth saw cut along the perimeter of the repair. If using more than one pass, make the final full depth saw cut immediately after the partial depth saw cut. If fixed joints are not used on the repair, make transverse saw cuts parallel to existing transverse joints. Extend transverse saw cuts only far enough into concrete to remain to ensure a full depth cut of the repair area, and seal the cut using a Type IV hot poured sealant. Remove concrete within 48 hours of the transverse sawing.
b.Work Sequence. Use the following work sequence after removing the concrete:
1.Perform subgrade repair, full depth concrete pavement repair, and partial depth spall repair.
2.Retrofit dowel bars, as specified in Section 575, “Dowel Bar Retrofit” .
3.Perform joint stitching.
4.Perform grinding.
a.12 foot driving lane
b.3 foot transitions in passing lane and outside shoulder
5.Clean and seal: a) Transvers Joints
b.Random Cracks
c.Logitudinal Joints
d.10 Foot Shoulder Joints
c.Dowel Bars. Drill 1 -3/8 inch diameter holes using a rigid frame-mounted drill. Clean the hole, inject epoxy into the hole, and insert dowels. Lightly coat the free end of each smooth dowel with grease, of the type specified in Section 550.04 G.2, ”Transverse Co ntraction Joints” . 248 d. Transverse Joint Sealing at Full-Depth Repairs. Seal smooth doweled transverse joints at full -depth repairs as specified in Section 550.04 G, “Joints” . Traffic is allowed on the new pavement from the end of the curing period to the beginning of the joint sealing. Seal fixed transverse joints at full -depth repairs as specified in Section 550.04 G, “Joints” . Use the sealant specified in Secti on 826.02 A.1, “Type I” . Shape the reservoir to 3/8 inch wide by 1 inch deep.
e.Longitudinal Joint Sealing. Shape the longitudinal joint reservoir 1/4 inches wide by 3/4 inches deep in areas of full depth repairs. Seal joints as specified in Section 550.04 G, “Joints” , using a Type IV hot poured joint sealant.
f.Opening to Traffic. Section 550.04 L, “Opening to Traffic” applies to this section.
3.Continuously Reinforced PCC Pavement Repairs.
a.Concrete Removal. Sawcut the edges of the repair with a diamond blade. Leave the edges free from frays or spalls on the pavement surface. If existing reinforcing steel is damaged or bent within the 18 inch lap area, replace the damaged reinforcing steel. Use a hammer that is 35 pounds or smaller in areas within 24 inches of the saw cut line.
b.Full-Width, Full-Depth Repairs. If both lanes are to be repaired, utilize the following order of operations when constructing the first lane: − Connect longitudinal rebars with mechanical splices, meeting the requirements specified in ACI Building Code for Reinforced Concrete, Chapter 12.14.3.4. − Use Class ASE concrete. − Place concrete between 4 p.m. and 8 p.m. Tie one rebar end and tie the other end less than 20 minutes before placing concrete.
B.Stitching. Do not install bars within 9 inches of existing transverse joints. Install the tie bars the same day the holes are drilled.
1.Drilling. Use hydraulic percussive type drills to mak e the holes. Mount the drills on a rigid frame.
2.Epoxy. Clean the holes before injecting the epoxy resin. Inject the epoxy in the bottom of the hole. Ensure the epoxy is level with the top of the pavement after bar insertion.
3.Tie Bars. Rotate the tie bars 180 degrees to 360 degrees during the insertion.
C.Grinding. Allow new concrete and dowel bar retrofit patch material to cure for a minimum of 24 hours before grinding.
1.Grinding Depth. Provide a uniform texture over the pavement surface. Remove a minimum of 1/16 inch of pavement at all locations except at culverts, dips, or other conditions. The Engineer will not require extra depth grinding to eliminate minor depressions in order to provide surface texture.
2.Grinding Direction. Perform grinding parallel to the centerline. Begin and end grinding at lines perpendicular to the pavement centerline within any one ground area.
3.Texture. Grind to a texture consisting of grooves between 0.090 and 0.130 inches wide. Distance between grooves shall be between 0.060 and 0.125 inches. Peaks of ridges shall be approximately 1/16 inch higher than the bottom of the grooves. Maintain the existing cross slope. Do not leave the area ground smooth or polished.
4.Transitions. Provide positive drainage by transitioning auxiliary or ramp lane grinding from the mainline edge.
5.Slope. Excluding longitudinal joints, provide a uniform transverse slope on the pavement surface with no more than 1/4 inch deviation in 10 feet when mea sured using a 10 foot long straightedge.
6.Slurry Removal. Continuously collect all slurry or residue resulting from the grinding operation. In areas with speed limits of 45 mph or less and in areas with curb and gutter, dispose of slurry as specified in Section 107.17, “Removed Material”. In areas with speeds greater than 45 mph and without curb and gutter, slurry may be place on the foreslope of the roadway. Prevent slurry from entering pipes, culverts, storm drains, ravines, streams, waterways, wetlands, and all other water conveyances. Install erosion control features as necessary to prevent contamination, or dispose of slurry as specified in Section 107.17, “Removed Material” .
D.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. 250 2. Straight Edge Method.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. 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.
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 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 1/4 inch toleranc e. The Engineer will determine if corrective action will be implemented based on the corrective action plan.
E.Joints.
1.Transverse Joint Cleaning and Sealing. Clean and reseal the portion of the transverse joint that were ground. Remove foreign material from vertical edges of the joint. Clean the joint using compressed air removing any incompressible material. Install backer rod before applying the silicon sealant.
2.Longitudinal Joint Cleaning and Sealing. Remove existing sealant, s andblast, and clean the joint. Fill the joint with Type IV hot pour.
3.Random PCC Crack Cleaning and Sealing. Remove existing sealant, sandblast, and clean the joint. Fill the joint with Type IV hot pour.
570.05 Method of Measurement
The Engineer will measure, completed and in place, as specified in Section 109.01, “Measurement of Quantities”, and as follows:
A.Spall Repair. If the Engineer requires a spall repair to change to a full -depth repair as specified in Section
570.04 A.1.a.(1), “General” , the Engineer will measure the entire area as full -depth repair and
in addition the Engineer will measure half of the area as spall repair.
B.Stitching. The Engineer will measure each tie bar installed as “Epoxy Coated Deformed Bars”.
C.Full-Depth Repair - End Preparation. For full depth repairs on continuously reinforce concrete pavement, the Engi neer will measure each end of the repair sections as “Full Depth Repair -End Preparation”.
D.Full-Depth Repair - End Prep -Mech Splice. The Engineer will measure each end of the repair section that requries mechanical splices as “Full-Depth Repair - End Prep -Mech Splice”.
E.Full-Depth Doweled. Include the cost of the end dowel bars in the contract unit price “___-Inch Concrete Pavement Repair – Full-Depth Doweled”. The cost for intermediate dowel bar assemblies is paid by “Doweled Contraction Joint Assembly”.
570.06 Basis of Payment
Pay Item Pay Unit PCC Pavement Grinding Square Yard Doweled Contraction Joint Assembly Linear Foot Full-Depth Repair - End Prep - Mech Splice Each Full-Depth Repair - End Preparation Each __-Inch Concrete Pavement Repair - Full-Depth Doweled Square Yard __-Inch Concrete Pavement Repair - Full-Depth Continuous Square Yard Longitudinal PCC Joint Cleaning & Sealing Linear Foot Transverse PCC Joint Cleaning & Sealing Linear Foot Random PCC Crack Cleaning & Sealing Linear Foot Spall Repair – Partial Depth Square Foot Epoxy Coated Deformed Bars Each Such payment is full compensation for furnishing all materials, earthwork, equipment, labor, and incidentals to complete the work as specified. Section 575 252 SECTION 575 DOWEL BAR RETROFIT
575.01 Description
This work consists of performing a dowel bar retrofit in concrete pavement.
575.02 Equipment
Item Section Concrete Equipment 155 Air Compressor 156.01 Use a gang saw capable of sawing all required slots on a transverse joint or crack in the wheel paths of a single lane of the pavement simultaneously. The gang saw should be able to cut the slots parallel to the direction of traffic flow and parallel to one another.
575.03 Materials
Item Section Portland Cement Concrete 802 Grout and Epoxy 806 Class 5 Aggregate 816 Joint Materials 826 Reinfor cing steel 836.02 Dowel bars 836.04
A.Patching Material Mix Design. Mix and place the patching material as specified by the manufacturer. Select one of the following patching materials: − Five Star Highway Patch; − Burke 928 Fast Patch; − American Highway Technology’s dowel bar retrofit mortar; or − An approved equal. A minimum of 5 working days before beginning dowel bar retrofit work, submit the manufacturer’s product literature and a concrete mix design for the patching material that meets a minimum compressive strength of 4,000 psi in 6 hours. Include all additives and materials to be used in the mix design.
B.Dowel Bars. Use dowel bars with tight fitting end caps made of nonmetallic materials that allow for 1/4 inch movement of the bar at each end. Submit sample end caps to the Engineer before use. Use support chairs that are non-metallic or that are epoxy coated as specified in ASTM A 775.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 279–286 of 550.