628.1Description.
This work consists of repairing or rehabilitating concrete structures.
628.2Materials.
A.Portland Cement Concrete (PCC) Section 1022 and
B.Reinforcement and Splice Couplers Section 1037
C.High Molecular Weight Methacrylate Crack Sealer Section 1045
D.Non-Shrink Grout Section 1047.2
E.Epoxy Grout Section 1047.4
F.Low or Medium Modulus, Neutral-curing, Silicone Crack Sealant ASTM D5893
G.Polyurethane Crack Sealant ASTM C920
H.Mortar Sand Section 1003
I.Concrete Adhesives Section 1024
J.Tap-Con Screws Engineer Approval
628.3Construction.
628.3.1 Pre-Work Meeting Schedule a pre-work meeting with representatives from the Department, the contractor, and other involved parties to scope the work.
628.3.2 Submittals.
A.Submit the contractor qualifications for each of the respective repair and rehabilitation operations
verifying successful completion of at least 3 separate repair or rehabilitation projects within the last 5 years using the proposed manufactured products. The engineer may accept a manufacturer’s letter of certification for an approved installer. Ensure that qualified personnel perform and oversee repair and rehabilitation operations.
B.Submit a detailed concrete repair work plan which summarizes the results of the pre-work
meeting no less than 3 working days before beginning repair work. Include the following in the plan:
1.A description and approximate location of all planned repair and rehabilitation work.
2.Proposed materials to be used in the work and material placement methods.
3.Equipment to be used in all aspects of the concrete repair and rehabilitation operations.
4.All details and methods needed to attain sufficient early strength that will allow opening the
roadway to traffic in a timely manner when contract time constraints do not allow the cure times specified in Section 610.
5.For cracks, submit the crack width and surface orientation.
6.For non-riding surface spalls, submit classification as either a shallow spall or deep spall,
approximate spall size, and spall orientation.
7.For riding surface spalls, submit the cavity depth and approximate spall size.
C.The work plan must be approved by the engineer before work can begin. The work plan may be
divided into segments of work which match the proposed sequencing for the work.
D.After approval of the work plan, request approval of material sources in accordance with Section
and include any relevant material requirements from the approved work plan. 628.3.3 Crack Repairs.
A.Structural Repair.
1.Limitations.
a.Crack widths of 0.002-inch to 0.25-inch.
b.Any surface orientation, including inverted surfaces.
2.Repair Method: Use epoxy injection in accordance with the following:
a.Personnel requirements.
i.Individual performing epoxy injection repairs must be trained by the epoxy injection system
manufacturer to install and operate pressure injection equipment or ii. the epoxy injection repairs must be overseen in person by the epoxy injection system manufacturer’s technical representative.
b.Perform epoxy injection according to the process listed below or manufacturer
recommendations. If the methods conflict between these specifications follow the manufacturer recommendations.
i.Install injection ports or tees spaced 6-inches to 12-inches apart for vertical repairs and 6-
inches to 18-inches apart for horizontal repairs. ii. Do not set ports or tees closer together than the thickness of the concrete member if full- depth penetration is required. iii. Select the depth and spacing of holes for the ports or tees to ensure no further damage occurs to the member under repair and that is appropriate to the flow characteristics and injection pressure of the epoxy for crack widths and depths present. iv. Set ports or tees in dust-free holes made with vacuum drills or chipping hammers.
v.After anchoring the ports or tees in the hole with epoxy binder, seal the crack surface with
epoxy binder between the ports or tees to ensure retention of the pressure injected epoxy within the confines of the member. vi. Apply epoxy binder to clean dry surfaces and substrate at temperatures no less than 50 degrees F. vii. After the injected epoxy has hardened, grind ports or tees flush with the concrete surface. Finish the repaired area to match the existing concrete surface.
B.Sealing Repair:
1.Repair Methods and Limitations.
Sealing repair method and material required to use the following table to determine sealing repair and material: Table 628.3-1. Sealing Repair Methods and Material Requirements. Material Crack Surface Orientation Crack Width Structure Type Application Method Low Viscosity Epoxy or High Molecular Weight Methacrylate Horizontal Maximum 8% slope 0.002” – 0.25” All Poured Gravity Fed Polyurethane or Silicone Horizontal Sloped Vertical Inverted 0.125” – 1” All Gun or Trowel
Non-Shrink Grout
Horizontal Sloped Vertical
≥ 1”
All
Trowel
2.Low Viscosity Epoxy or High Molecular Weight Methacrylate
a.Remove surface contaminants by blowing out the crack with oil-free compressed air.
b.Prepare the surface and damming material per manufacturer recommendation. Take
measures to prevent sealing material leakage when a crack has propagated to a non- horizontal surface.
c.Perform repairs when surface and ambient temperatures are within the manufacturer
recommended ranges.
d.Mix material components in accordance with the manufacturer’s recommendations.
e.Apply sealing material in accordance with the manufacturer’s recommendations.
f.Cover surface areas where excessive sealing material remains with a light broadcast of dry
mortar sand that complies with Section 1003 at the time recommended by the manufacturer. Use a quantity of sand necessary to absorb the excess sealing material.
g.Following all manufacturer curing methods and recommendations prior to opening to traffic.
3.Polyurethane or Silicone
a.Seal cracks in horizontal surfaces with self-leveling sealant. Seal all other surfaces with non-sag
sealer.
b.Rout cracks by grinding to create a V-shaped groove with the crack centered in the groove.
Routed grooves must be a maximum 1/2-inch depth.
c.Remove contaminants by blowing out crack with oil-free compressed air.
d.Ensure the ambient and surface temperatures are within the manufacturer’s recommended
placement range before applying the sealant.
e.If required, apply primer as recommended by the manufacturer.
f.Apply sealant in accordance with manufacturer's recommendations to form a smooth surface.
g.Cure sealant in accordance with the manufacturer’s recommendations. Curing must be
completed prior to opening to traffic.
4.Non-Shrink Grout.
a.Tool the crack to create a dovetail slot that is a minimum 1-inch depth with a base and at least
1/4-inch greater than the crack width
b.Remove contaminants from the tooled crack by blowing the crack out with the oil-free
compressed air or by pressure washing.
c.Ensure that the ambient and surface temperatures conform to the manufacturer’s
recommendation during grout mixing, placement, and curing.
d.Non-shrink grouts that do not contain a pre-mixed bonding agent require application of an
epoxy bonding agent the conforms to AASHTO M235 Type V or latex bonding agent that conforms to ASTM C1059 Type II to all surfaces that are in contact with the repair grout. The epoxy bonding agent must comply with Section 1024.3 and be applied in accordance with the manufacturer’s recommendations.
e.Mix non-shrink grout in accordance with the manufacturer’s recommendation to a dry-pack
consistency.
f.Apply non-shrink grout by troweling the material into the tooled crack in approximately 1/2-
inch lifts. Tamp each lift with a wood or steel tool that will fit into the crack. Trowel the final lift flush with the concrete surface. Cracks in sloped or vertical surfaces require form placement after troweling to prevent material sagging.
g.Cure in accordance with manufacturer recommendations.
628.3.4 Non-Shrink Grout Repair.
A.Repair non-shrink grout used to fill shear keys between precast concrete elements, or various
pockets and voids associated with precast concrete elements, as follows:
1.Remove deteriorated grout in accordance with Section 628.3.5. taking care not to damage the
adjacent precast concrete elements. If damage occurs, repair concrete in accordance with Section 628.3.5.
2.Clean the concrete surface by blowing off dust and debris with oil-free compressed air.
3.Wet the concrete surfaces before placing grout. Do not allow standing water to remain in the
area receiving grout.
4.During grout placement, prevent falling material from reaching the roadway, waterway, or
railroad area below.
5.Prepare, place, and cure in accordance with the manufacturer’s recommendations.
628.3.5 Spall and Delamination Repair.
A.Limitations.
1.This section does not apply to prestressed elements or bridge decks
B.Definitions:
1.Shallow spalls are spalls that do not extend below the top mat of reinforcement.
2.Deep spalls are spalls that extend below the top mat of reinforcement.
3.PCC masonry rehabilitations are deep-spall patches that exceed the 0.5 cubic yard threshold in a
single area.
C.Materials.
1.PCC for shallow spall repairs shall comply with Section 1023.
2.PCC for deep spall repairs shall comply with Section 1022. Use Class A concrete.
3.Use concrete adhesives that comply with Section 1024.3.
D.Repair Methods.
1.Repair to the depth noted in the contract. The dimension may change in field if the engineer
deems it necessary. If, due to field conditions, removal of deteriorated concrete includes a bearing seat not specified in the contract or any area meeting the threshold for rehabilitation of PCC masonry not specified in the contract, notify the engineer immediately. Obtain the engineer’s approval before resuming work in these areas.
2.When destruction of the bond between existing concrete and reinforcing steel occurs, remove
the concrete adjacent to the bar to a depth that will allow the repair concrete to bond to the entire surface of the exposed bar. Modify the repair area limits to meet the reinforcement lap splice or mechanical coupler requirements.
3.Saw cut the edges of the repair area
a.Perpendicular to the concrete face at least 1-inch deep, without damaging reinforcing bars.
b.A minimum of 6-inches beyond the visibly spalled, disintegrated, delaminated, deteriorated,
loose, or honeycombed concrete.
4.Remove spalled, disintegrated, delaminated, deteriorated, loose, honeycombed, and unsound
concrete. Collect debris and prevent material from falling on the roadway, waterway, or railroad area below. Remove material from the site and dispose of in accordance with Section 106.8. Remove slurry produced by concrete wet sawing that enters prepared areas before placing the patch.
a.For shallow spalls, remove concrete above the top of the reinforcement bar. Use a 15-pound
pneumatic hammer unless otherwise noted in the contract. The engineer may approve use of alternative tools. Do not remove concrete below top of reinforcement bar unless approved by the engineer.
b.For deep spalls and rehabilitation of PCC masonry, remove concrete a minimum of 1 inch
behind the existing reinforcement without damaging the reinforcement. Use a 15-pound pneumatic hammer for work on a superstructure or a 30-pound pneumatic hammer for work on a substructure, unless otherwise noted in the contract. The engineer may allow use of alternative tools. Limit removal at any 1 location as noted in the contract and as the engineer deems necessary due to field conditions.
5.For deep spall and PCC masonry rehabilitation, repair existing bar reinforcement as follows:
a.Replace, splice, or supplement the existing bar reinforcement when an existing bar has a loss
of 20 percent or more of the original cross section, is broken, or is damaged during the repair. The engineer will decide which bars need repairs and how to make the repairs as follows:
b.Replace with a new bar of the same type and equal or greater cross-sectional area as the
existing bar.
i.Replace the entire length of the existing bar where possible.
ii. Replace the damaged length by cutting the existing bar and using a mechanical coupler to splice the new bar to the existing bar. iii. Supplement an existing bar by installing a new bar as a lap splice. Extend the bar 30 bar diameters in each direction from where the section loss or breaks ends. Remove the damaged portion of the existing bar.
c.Clean to bright metal for black bars only or to visible epoxy coating for epoxy-coated bars by
removing rust, coatings, or other material using grit-blast, wire-brushing, or other approved means. Apply a 2-part epoxy coating by brush to areas of the existing epoxy-coated reinforcing steel that exhibit flaked or scratched surfaces at a thickness of 10-mils or greater. Do not epoxy-coat the concrete surface beyond the bars. Do not epoxy coat existing black bar.
d.Clean and prepare the concrete surface area in accordance with the concrete adhesive
manufacturer’s recommendations.
6.For shallow spall repairs, install tap-con screws as recommended by the manufacturer to the
cleaned concrete surface. Place the screws at 6-inches center to center each way with a minimum 1/2-inch clear cover, with at least 2 screws installed in a shallow spall repair. Apply the concrete adhesive as recommended by the manufacturer. Apply the patch mortar in lifts of no more than 2 inches or as recommended by the manufacturer. Hand-trowel the top application of patch mortar to obtain a smooth, final surface.
7.For deep spalls and PCC masonry rehabilitation, apply the concrete adhesive as recommended
by the manufacturer and place concrete in accordance with Section 610. When necessary, provide formwork in accordance with Section 604.
8.For deep spalls, substitute patching material conforming to Section 1023 for the Class A mix
design, upon the engineer’s approval, except for bridge seat areas. Use Class A concrete for spall depths greater than 6-inches.
9.For PCC masonry rehabilitation, use Class A concrete.
10.Form expansion or contraction joints in the concrete repair material at existing joint locations.
11.Finish the repaired area to match the existing concrete surfaces and architectural details.
E.Cure premixed packaged materials in accordance with manufacturers recommendations. Cure
ready mix PCC materials in accordance with Section 610.3.6.B.1.b. 628.3.6 Concrete Riding Surface and Milled Surface Deck Repair.
A.Repair decks of a concrete riding surface or of a milled concrete surface that will receive an
overlay as follows:
1.Provide shielding to protect traffic in accordance with Section 604. 2.The engineer will inspect the entire deck surface, or milled areas of exposed deck surface, to
indicate the type and extent of repairs, if any.
3.Saw cut in accordance with Section 628.3.5.D.3 except that the minimum depth of a vertical face
is 1/2-inch.
4.Remove deteriorated deck areas down to sound concrete, in accordance with Section
628.3.5.D.4. Do not operate mechanical chipping tools at an angle in excess of 45 degrees measured from the surface of the deck. For spalls on riding surfaces, chip down the perimeter of the patch to make a 1/2-inch minimum depth vertical face from the top of the adjacent riding surface.
5.When the removal depth of an existing concrete deck spanning over a roadway, waterway, or
railroad reaches 1/2 of the existing concrete deck thickness, and deeper removal is anticipated, provide and erect temporary protective shielding under the deck to prevent falling material from reaching the roadway, waterway, or railroad area below.
6.Refer to Section 628.3.5.D.5 for further guidance on cleaning, repairing, or replacing existing
reinforcement.
7.After completely removing deteriorated concrete, clean the concrete surface in accordance with
Section 628.3.5.
8.Patch spalled concrete, voids, and other defects as follows:
a.The Department will not require any special treatment for cavities less than 1/2-inch deep on
milled surfaces. Fill with the concrete overlay material.
b.For cavities 1 1/2-inches or less deep on riding surfaces, fill the space with pre-blended rapid-
set patch mortar.
c.For cavities 1 1/2-inches or more in depth, fill with Class D concrete.
d.When the deck will receive an overlay, shot or grit-blast the patch surfaces repaired to assure
proper bonding with the overlay. For riding surface repairs using Class D concrete, apply a broom or hand-tine finish. For riding surface repairs using pre-blended rapid-set patch mortar, cover the area with a light broadcast of dry mortar sand meeting the requirements of Section 1003 before the pre-blended rapid-set patch mortar hardens.
B.Cure premixed packaged materials in accordance with manufacturers recommendations. Cure
ready mix PCC materials in accordance with Section 610.3.6.B.1.b.
C.Open repair area to traffic only after the material is cured in accordance with manufacturers
recommendations.
628.3.7Drilling holes and placing dowels
A.Drill holes at the locations and to the minimum depth shown in the contract.
B.Drill holes at the diameters and use anchoring epoxy grout or concrete adhesive in accordance
with the anchoring material’s manufacturer’s recommendations and as approved by the engineer.
C.Follow the manufacturer’s recommendations for surface preparation and application procedures.
D.Place anchoring material using a nozzle or wand that will deposit the material to the back of the
hole.
E.Do not push or pour the anchoring material into the holes.
F.Install the dowel bar using a twisting motion to completely coat the dowel surface.
G.Support the dowel in proper alignment until the anchoring material has cured in accordance with
the manufacturer’s recommendations.
H.Repair damage caused by the drilling operations to the engineer’s satisfaction.
628.4Method of Measurement.
A.The Department will measure the quantity of:
1.Epoxy injection as the number of linear feet of cracks injected and accepted.
2.Grouting and sealing cracks as the number of linear feet of cracks routed, sealed, and accepted.
3.Grout as the number of cubic feet of grout placed and accepted;
4.Shallow and deep spall repair as the number of cubic feet repaired, placed and accepted.
5.Rehabilitation of existing PCC as the number of cubic yards of concrete removed and repaired.
6.Concrete deck repair as the number of square feet of repairs made at the various depths,
complete in place and accepted.
7.Drilling holes and installing dowels as the number of each hole drilled, grouted, and accepted.
B.The Department will measure dowels and anchor bolts under separate items.
628.5Basis of Payment.
A.The Department will pay for accepted quantities at the contract unit price.
B.Price and payment for epoxy injection constitute full compensation for providing all materials,
surface preparation, application, cleaning the areas of spills and other contaminates, and abrading the concrete surface areas.
C.Price and payment for routing and sealing cracks constitute full compensation for providing and
placing all materials, crack routing, and surplus material removal.
D.Price and payment for repair of existing grout constitute full compensation for providing and
placing all materials, removal and disposal of deteriorated grout, and surface preparation.
E.Price and payment for spall repair, PCC masonry rehabilitation, and concrete deck repair
constitute full compensation for:
1.Providing and placing all materials;
2.Providing and erecting temporary protective structure;
3.reinforcement bar cleaning;
4.existing reinforcement bars splicing or replacement;
5.deteriorated concrete removal and disposal; and
6.surface preparation.
F.Price and payment for drilling holes and installing dowels constitute full compensation for
providing and placing all materials.
G.The Department will pay for:
1.Concrete overlays under Section 625; 2.concrete sealing with methacrylate under Section 613; 3.concrete or hot mix milling under Section 760; and 4.dowels and anchor bolts under separate items
ITEM DESCRIPTION UNIT 628001 REPAIR OF CONCRETE STRUCTURES BY EPOXY INJECTION LF 628010 CRACK SEALING BRIDGE DECKS, APPROACH SLABS, SIDEWALKS, ETC SF 628011 CRACK SEALING BRIDGE DECKS, APPROACH SLABS, SIDEWALKS, ETC LF 628020 ROUT AND SEAL CRACKS LF 628030 REPAIR OF EXISTING GROUT CF 628040 SHALLOW SPALL REPAIR CF 628041 DEEP SPALL REPAIR CF 628042 REHABILITATION OF PCC MASONRY CY 628043 REHABILITATION OF PCC MASONRY CY 628050 DECK REPAIR, 1/2" TO 1" DEPTH SF 628051 DECK REPAIR 1" TO 3" DEPTH SF 628052 DECK REPAIR, 3” TO < FULL DEPTH SF 628053 DECK REPAIR, FULL DEPTH SF 628070 DRILLING HOLES AND INSTALLING DOWELS EACH
Referenced in this section
Sections that cite this one
Delaware revises spec sections through supplementals and new editions. We check this one every week and email you the day it changes. Free, no account.
Source: Delaware Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 347–0 of 786.
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