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Electrical (16000-16999)

624017 SILICONE COATED JOINT SEAL, 1 " LF

DE · 2025 Standard SpecificationsBook pages 335–344View official source ↗

CONCRETE OVERLAYS SECTION 625 325 SECTION 625 — CONCRETE OVERLAYS

625.1Description.

This work consists of providing materials and constructing a concrete overlay on concrete deck surfaces.

625.2Materials.

A.Latex -Modified Concrete (LMC) Section 1046.1

B.Polyester Polymer Concrete (PPC) Section 1046.2

C.Modified C lass D Portland Cement Concrete (MCD) Section 1046.3

625.3Construction.

625.3.1 Pre -Construction. Schedule a pre -construction meeting 14 calendar days in advance of starting construction for all overlay types. 625.3.2 Submittals. Provide required submittals for the applicable overlay system 14-days prior to the pre -construction meeting.

A.All Overlay systems

Submit a Construction plan that includes:

1.Surface Preparation procedures:

a.Milling and disposal of existing overlay(s).

b.Testing procedures to identify unsound concrete.

c.Removal and disposal method of unsound concrete and incidental waste.

d.Repair method for areas of unsound concrete.

e.Substrate scarification technique and procedure.

f.Cleaning of concrete substrate and maintenance of cleaned surface prior to overlay

application.

2.Concrete design and mixing procedures.

3.Overlay placement:

a.Joint locations and plan to ensure longitudinal joints are located along centerline or edge of

travel lanes.

b.Sequence of placement.

c.Placement widths.

d.Planned placement lengths.

e.Placement direction.

4.Equipment Descriptions for:

CONCRETE OVERLAYS SECTION 625 326 a. Performing surface preparation.

b.Measurement, Mixing, Placement, finishing, curing, and texturing overlay.

5.Method for isolation of expansion joints, inlets, manholes, scuppers, and other metal

obstructions.

6.Method for measuring and maintaining the overlay thickness.

7.Concrete curing procedures.

8.Provision of lighting for night work.

9.Protection plan for traffic and adjacent structures from construction activities.

10.Procedures for disposal of excess material and material containers.

11.Procedure for cleanup of all necessary equipment and disposal of cleanup waste.

12.Procedure for cleanup of material spills.

13.Experience and Personnel Qualifications.

a.Documentation that a representative from the latex modified or polyester polymer system

manufacturer will be present during overlay operations. The representative must have experience with installation of the specified system on projects of similar size and scope. Submit the manufacturer representative qualifications.

b.Or documentation as follows.

i.Documentation that the contractor has successfully completed a minimum of 3 overlay

projects using the specified material within the last 5 -years. Documentation must include a description of each project, location, owner/agency name and contact information, construction date, and overlay quantity. ii. Documentation that assigned supervisory personnel have experience managing projects using the specified material. Experience must be on a minimum of 3 overlay projects using the specified material. Documentation must include a description of each project, location, owner/agency name and contact information, construction date, and overlay quantity. iii. A manufacturer’s letter of certification that the contractor is an approved installer. iv. Documentation that approved qualifying personnel will oversee all operations.

14.Equipment descriptions for application of PPC primer coat or MCD bonding agent.

B.PPC Additional Submittals.

1.Manufacturer recommended installation instructions.

2.Materials information as required herein.

3.MSDSs for each material.

4.Independent test results within 1 year of start of overlay installation that demonstrate

specification conformance.

5.Certification that PPC mixing equipment meets calibration per Caltrans California Test CT 109 or

approved equal. Certification must be within 1 -year of project operations. CONCRETE OVERLAYS SECTION 625 327 625.3.3 Latex -modified Concrete.

A.Surface preparation .

1.Milling.

a.For existing concrete decks and approach slabs, mill off the depth of concrete or hot mix

specified in the contract.

b.For existing concrete decks and approach slabs with existing concrete overlays, mill off the

existing overlay.

2.On bridge decks or approach slabs with a hot mix overlay, and no additional concrete milling is

specified, scarify the exposed concrete surface an additional 1/8 -inch to 1/4 -inch deep to create a bond for the proposed overlay.

3.After the initial removal, inspect the deck and outline areas of unsound concrete for removal,

subject to the engineer’s approval. Repair areas of unsound concrete in accordance with Section 628 and as specified in the Plans .

4.Saw straight and vertical edges to transverse and longitudinal joints of previously placed

overlays before placing overlay against these surfaces.

5.Shot -blast or grit -blast the areas to receive the overlay no more than 24 hours before beginning

placement. Hydro demolition may be used when approved by the engineer. Blast -clean the vertical edge of any previously placed lanes of overlay to promote bo nd. If it is necessary to remove materials detrimental to achieving bond, clean with detergent followed by shot or grit - blasting and air -blast -clean.

6.Immediately before concrete placement, wet the clean surface with water to a saturated

surface dry (SSD) condition. Saturated surface dry (SSD) is a state where the concrete has absorbed as much water it can possibly absorb without ponding or puddles forming on the surface. Achieve SSD condition by placing wet burlap on the surface for a minimum of 24 -hours or by other means submitted for approval by the engineer . Use compressed air, free of oil, to blow out any standing water in areas of concrete removal.

7.Prevent contamination of the cleaned and wetted deck by placing a minimum 4 mil thick

polyethylene film or other material approved by the engineer that completely covers the deck surface prepared for overlay.

B.Mixing Equipment and Materials

1.Use approved proportioning and mixing equipment that is self -contained, mobile, and the

continuous mixing -type. Provide mixers that are:

a.Self-propelled and capable of carrying enough unmixed dry, bulk cement, sand, coarse

aggregate, latex modifier, and water to produce no less than 6 -cubic yards of latex modified PCC on the site;

b.Capable of measurement of cement introduced into the mix by a visible recording meter

equipped with a ticket print -out to indicate the quantity;

c.Provides control of the flow of water and latex emulsion into the mixing chamber and has a

flow meter that is adjustable for minor variations in the moisture of the sand and aggregate;

i.Calibrated to automatically proportion and blend all components of indicated composition

on a continuous or intermittent basis, as required by the finishing operation, and discharges CONCRETE OVERLAYS SECTION 625 328 mixed material through a conventional chute directly in front of the finishing machine. Calibration must be performed by an approved testing laboratory or by the Department with evidence of accuracy being a yield that is within a tolerance of 1.0 percent according to the following test: With the cement meter set on zero and all controls set for the desired mix, activate the mixer and discharge mixed material into a 0.25 cubic yard container 3 feet square by 9 inches deep. When the container is full the cement meter should show a discharge of 1.875 bags of cement.

d.Provide a mixer with enough capacity that allows placement and finishing operations to

proceed at a steady pace.

2.Mix the overlay concrete in an approved, clean mixer at the site. Add the proportioned

ingredients to the mixer in accordance with the recommendations of the manufacturer of the latex modifier.

a.Do not place bags identified by the manufacturer as dissolving or breaking up during mixing or

any other containers holding ingredients into the mix.

b.Meet the slump range of 4 to 6 -inches at the point of discharge.

c.Follow the latex manufacturer’s minimum mixing time recommendations to secure the correct

air content and slump.

d.Ensure that the overlay concrete remains uniform in composition and consistency when

discharged from the mixer.

e.The maximum time allowed between the start of mixing to the completion of discharge of the

overlay concrete at the worksite is 60-minutes.

C.Placement

1.When placing in hot weather, take appropriate measures to reduce the hazards of increased

rate of cement hydration, flash set, loss of water due to evaporation, high concrete ingredient temperatures, and the increased difficulty of concrete placement an d finishing. Ensure the temperature at the point of discharge does not exceed 85 degrees F.

2.Place the latex overlay concrete only when certain the ambient temperature will remain above

45 degrees F for the entire curing period.

3.Do not place an overlay adjacent to a previous overlay that has cured for less than 3 cure -days in

accordance with Section 625.3. 3.E. If ambient temperature falls below 45 degrees F during a cure day, the time below 45 degrees F will not be included in the 24 -hour period.

4.Immediately before placing the overlay, cover the concrete surfaces with a coating of bonding

grout consisting of the overlay material brushed onto the deck. Scrub the grout onto saturated surface -dry deck areas. Do not allow excess grout to collect in low areas. Apply the bonding grout for only a short distance in advance of the placement of the overlay. The engineer will require reapplication of the grout if the grout dries before overlay placement.

5.Place overlay concrete in accordance with Section 610.3.4 with a lift thickness in accordance

with the contract and a maximum overlay thickness lift of 2 1/2-inches.

6.The maximum allowable time between the discharge and the final finishing of the overlay

concrete is 10 -minutes. CONCRETE OVERLAYS SECTION 625 329 7. In case of a delay in the placement operation:

a.Protect the end of the placement from drying during delays of 1 -hour or less with several

layers of wet burlap.

b.For delays exceeding 1 -hour, install a construction dam or bulkhead;

c.When the delay exceeds 90 -minutes, discontinue further placement. To continue pouring,

provide a gap, between the ceased operation and the continuation, long enough for the finishing machine to clear the previously placed overlay concrete.

D.Consolidating and finishing.

1.Consolidate and finish, in accordance with Section 610.3.4. Use spud vibration in deep pockets,

edges, and adjacent to joint bulkheads. Provide a sufficient number of spud vibrators to simultaneously vibrate each edge of the pour behind the finishing ma chine. Hand -finish with a float along the edge of the pour or on small areas of repair. Perform edge -tooling at joints, except next to metal expansion dams, curbs, and previously placed lanes.

2.Use an approved finishing machine that complies with Section 610.3.4.D.4 and has a vibrating

pan to properly consolidate the mix.

3.Use a 10 -foot straightedge to check the overlay directly behind the finishing machine and

transversely along the edges of the overlay where hand -finishing takes place. Immediately correct irregularities exceeding 1/4 -inch in 10 -feet. Test the overlay concrete surface for smoothness, in accordance with Section 610.

4.Complete final finishing operations before a plastic film forms on the surface.

E.Curing .

1.within 1 -hour after finishing , cover the finished overlay surface with a layer of wet burlap and

with a minimum 4 -mil thick white, opaque polyethylene film. Lap sheeting a minimum of 6 - inches. For a period of 2 cure -days keep the burlap wet by the continuous application of water using soaker hoses. After the 2 -day wet cure period, remove the polyethylene and burlap and air cure for 3 cure -days. Record time, ambient temperature, and surface tempe rature throughout the curing period. Prohibit traffic on the overlay during this time.

2.Maintain the temperature at the overlay surface above 45 degrees F until completion of the

curing period.

3.Improper curing of the overlay may result in rejection of the overlay.

F.Seal all joints including the perimeter of patches with a Low Viscosity High Molecular Weight

Methacrylate Sealer that conforms to Section 1045.4. Seal or repair cracking in a manner approved by the engineer before opening to traffic. The Department wil l sound the deck and the Contractor will remove and replace delaminated areas in accordance with Section 628. Correct areas of ponding to provide drainage away from the bridge deck. Crack repairs, removal and replacement of delaminated areas and correction of ponding will be performed by the contractor at no additional expense to the Department.

G.Groove the surface in accordance with Section 610.

625.3.4 Polyester Polymer Concrete.

A.Material .

CONCRETE OVERLAYS SECTION 625 330 1. Shipping and Storing.

a.Ship material in containers, bearing the manufacturer’s label specifying the date of

manufacture, batch number, brand name, quantity, and the date of expiration or the shelf life date. Ensure that the label of at least 1 of the system components has the mixing ratio printed on it. If using bulk resin, notify the engineer in writing 10 -days before delivery of the bulk resin. The Department defines bulk resin as resin stored in containers larger than 55 -gallons.

b.Store materials in accordance with the manufacturer’s recommendation to ensure its

preservation until use. Ensure conformance with applicable fire codes that may require special storage facilities for some components of the overlay system.

2.Mix Composition.

a.Use polyester polymer concrete containing approximately 12 percent polyester resin by

weight of dry aggregate. Adjust the percentage during placement to enable proper finishing and texturing of the overlay surface.

b.Use an amount of polyester concrete initiator that will produce an initial set time between 30

and 90 -minutes. Use a Gillmore needle in accordance with the requirements of ASTM C266 to determine the initial set time. Use accelerators or inhibitors recommended by the resin supplier to achieve proper set times.

B.Surface Preparation .

1.During surface preparation and overlay application, take precautions to protect traffic from

construction activities. Provide shielding as required or directed by the engineer.

2.Before applying primer, clean the concrete deck area to remove materials that may interfere

with the bonding or curing of the overlay.

3.Use only equipment for surface preparation specified by the overlay manufacturer and

approved by the engineer. Unless otherwise specified, use automatic, self -propelled shot blasting units to clean concrete surfaces. Use a vacuum to recover spent abrasi ves. Use steel shot as abrasives for blast cleaning. In areas not accessible to machinery, clean with manual blast cleaning equipment. Use magnetic rollers to remove spent shot remaining on the deck after vacuuming.

a.Determine the size of shot, flow of shot, forward speed of shot blast machine, and the number

of passes necessary to provide a surface capable of a tensile bond strength greater than or equal to 250 PSI in accordance with ASTM C1583.

4.Clean steel surfaces that will contact the overlay in accordance with SSPC -SP10, Near -White

Commercial Blast Cleaning. The Department will not allow wet blasting methods for cleaning.

5.After completing the cleaning operation, ensure that there is no oil, grease, dirt, rust, loose

particles, spent abrasives, or other foreign material on any of the surfaces planned for the overlay.

6.Do not place the overlay until the engineer inspects and approves the cleaned surface.

7.Do not expose cleaned pavement surfaces to vehicular or pedestrian traffic other than what is

required for the overlay operation before overlay placement. If the pavement surface is contaminated before overlay placement, re -clean the area by abrasive bl asting to engineer’s satisfaction. CONCRETE OVERLAYS SECTION 625 331 8. Provide coverings to protect adjacent exposed areas not planned for an overlay. Clean and repair damage resulting from the overlay application to the engineer’s satisfaction.

C.Mixing .

1.Use continuous automated mixers that:

a.Contains an auger screw/chute device capable of thoroughly mixing initiated binder resin with

dry aggregate;

b.Contains a plural component pumping system capable of handling polyester resin and initiator

while maintaining proper ratios to achieve specified set / cure times. Initiated resin must flow through a static mix tube for a duration sufficient to completely mix the liquids;

c.Is equipped with a visible readout gauge that automatically measures and records the

following, a minimum of every 5 -minutes: aggregate and resin volumes, time, and date. Submit to the engineer the recorded volumes at the end of each day;

d.Produces a satisfactory mix consistently during the entire application process; and

e.Is a portable mechanical mixer of appropriate design and size as recommended by the PPC

System provider.

D.Placement .

1.Prime Coat.

a.Before applying the prime coat, ensure that the underlying concrete is fully cured and the area

is dry. Blow the area clean with oil -free compressed air. Apply the prime coat only when the surface temperature is between 50 degrees F and 100 degrees F.

b.Apply the prime coat to completely cover the surface receiving the polyester concrete. Use

the rate of spread recommended by the manufacturer. Allow the prime coat to cure a minimum of 15 -minutes before placing polyester concrete.

2.PPC Overlay.

a.Isolate expansion joints before overlaying or saw cut the joint within 4 hours after overlay

placement. The engineer will determine the exact time of the saw cut.

b.Place concrete within 15 and 120 -minutes after applying the prime coat.

c.Place the concrete only when the surface temperature is 50 degrees F or higher.

d.Place concrete before gelling and within 15 -minutes following the addition of initiator,

whichever occurs first. Discard polyester concrete not placed within this time frame.

e.Place the overlay at a minimum of 3/4 -inch depth.

f.Use a self -propelled slip -form paving machine modified or specifically built to place the PPC

overlay in a manner that meets contract requirements. Phased construction or limited quantity, as approved by the engineer, may submit an alternate operation f or approval prior to use. The paving machine must:

i.Use a vibrating pan to consolidate and finish the PPC. The paver primary pan must measure

not less than 2 -feet in the dimension parallel to the direction of paver travel. This measurement does not include finishing attachments, bolt on sections, or trailing pan extensions. CONCRETE OVERLAYS SECTION 625 332 ii. Use hydraulically controlled grade automation to establish the finished profile. The automation must be fitted with substrate grade averaging devices on both sides of the automation sensor of the sensor shall be constructed to work with string -line control. It is acceptable to match grade when placing lanes adjacent to previously placed accepted overlays . iii. Has sufficient engine power and weight to provide adequate vibration of the finishing pan while maintaining consistent forward placement speed. iv. Is capable of both forward and reverse under its own power.

v.Roller screeds will not be permitted.

E.Consolidating and Finishing .

1.Termination edges of the overlay may require finishing by hand trowel due to obstructions.

2.Use a ruler to check the overlay thickness before its initial set. If the engineer determines that

the minimum thickness was not attained, add an additional layer with a minimum thickness of 1/4-inch after the overlay hardens.

3.Apply the finish sand by either mechanical means or hand broadcasting immediately after strike -

off, before gelling occurs, and at a minimum rate of 2.75 ounces per square foot.

4.Ensure that the completed overlay surface is free of any smooth or glassy areas such as those

resulting from insufficient quantities of surface aggregate. Repair surface defects in the manner recommended by the manufacturer and approved by the engineer.

5.Texture the surface in accordance with Section 610.3.4.

F.Curing .

1.Protect overlay from moisture for a minimum of 4 -hours after finishing . Allow the overlay to

reach final cure and a minimum of 4 -hours after final finishing, before subjecting the overlay to traffic and equipment.

G.Surface Requirements .

1.Test the surface smoothness with a straight edge. Ensure that the surface does not vary more

than 1/4 -inch from the lower edge of a 10 -foot long straight edge placed in any direction. Adjust surfaces that fail to conform to the tolerance by grinding with an approved grinding tool.

2.The engineer will check the overlay surface immediately after it has hardened to ensure that no

depressions exist that will cause water ponding . Repair surface depressions in the manner recommended by the manufacturer and approved by the engineer . 625.3.5 Modified Class D Portland Cement Concrete.

A.Surface Preparation .

1.Prepare deck surface in accordance with Section 625.3.3.A.

2.Prior to placing the overlay, completely cover the concrete substrate surface with a concrete

bonding agent . The horizontal surface shall receive a latex bonding agent that conforms to ASTM C1059 Type II. All vertical edges at all overlay joints shall receive an epoxy bonding agent that conforms to AASHTO M235 Type V. Follow the bonding agent manufacturer’s application recommendations CONCRETE OVERLAYS SECTION 625 333 B. Mixing . Mix PCC in accordance with Section 1022.

C.Placement .

1.Do not place an overlay adjacent to a previous overlay that has achieved less than 50 percent of

design strength.

2.The temperature of all surfaces that come into contact with the mix shall be no less than 40

degrees F and no greater than 105 degrees F.

3.Place concrete a minimum of 1 1/2-inch thick.

4.Place overlay concrete in accordance with Section 610.3.4.B. In case of placement operation,

delay comply with Section 625.4.1.C.5.

5.Consolidate and finish concrete in accordance with Section 625.3.2.D. Use an approved finishing

machine that complies with Section 610.3.4.D.4

D.Curing .

1.Immediately following placement of the concrete keep the overlay surface moist by a water fog

spray applied without damaging the surface.

2.Start curing immediately after the free water leaves the surface and finishing is completed.

a.Cover the finished overlay surface with wet burlap in compliance with Section 1022.6.C . Keep

the burlap wet throughout the curing period by using soaker hoses to apply water in compliance with Section 1021.

b.Cover the wet burlap with a minimum 4 -mil thick white opaque polyethylene sheeting in

compliance with Section 1022.6.B . Use sheets of the widest practical width. Overlap sheets a minimum of 6 inches and seal with tape, mastic, glue or other approved method to form a waterproof cover over the entire overlay surface.

c.Secure the polyethylene sheet material to prevent displacement by wind. Immediately repair

sheets torn or damaged during the curing period. All curing operations must be performed without damaging the surface.

d.Surface damage incurred during the curing process will be repaired by the contractor at no

expense to the department.

3.Maintain the temperature at the overlay surface at 40 degrees F or greater for the entire curing

period.

4.Cure for 14 cure -days .

E.Sealing Joints.

1.Seal all joints, including the perimeter of patches, with a Low Viscosity High Molecular Weight

Methacrylate Sealer that conforms to Section 1045.4.

F.Surface Requirements .

1.Repairs.

a.Correct areas of ponding to provide drainage away from the deck surface .

CONCRETE OVERLAYS SECTION 625 334 b. Areas determined to be delaminated by the Department sounding the deck will have to be removed and replaced at the Contractor’s expense.

c.Crack repairs must be performed in accordance with Section 628.3.B .

2.Groove the surface in accordance with Section 610.3.4.i when the overlay concrete has reached

design strength.

3.Apply Silane Sealer that complies with Section 1045.3 to the grooved surface as specified in

625.4Method of Measurement.

A.The Department will measure:

1.Concrete overlay material by the cubic yard.

2.Concrete overlay installation by the square yard – inch.

625.5Basis of Payment.

A.The Department will pay for providing overlay material at the contract unit price per cubic yard.

Price and payment will constitute full compensation for the material and delivery to project site.

B.The Department will pay for placing overlay material at the contract unit price per square yard -

inch . Price and payment will constitute full compensation for:

1.Surface preparation;

2.placing the bonding grout or primer coat;

3.placing, consolidating, curing and grooving the concrete overlay; and

4.constructing and removing test patches.

C.The Department will pay for:

1.Removal and repair work below the initial milling in accordance with Section 628;

2.milling of concrete or hot mix in accordance with Section 760 ;

3.providing and placing silane sealer in accordance with Section 613 ; and

4.providing and placing the methac rylate sealer in accordance with Section 613.

D.The Department will make no additional payment for repair work as directed by the engineer.

ITEM DESCRIPTION UNIT 625000 PROVIDING POLYESTER POLYMER CONCRETE OVERLAY CY 625001 PROVIDING LATEX -MODIFIED CONCRETE OVERLAY CY 625004 PROVIDING MODIFIED CLASS D PCC OVERLAY CY 6250 10 LATEX -MODIFIED CONCRETE OVERLAY PLACEMENT SY-IN 6250 11 POLYESTER POLYMER CONCRETE OVERLAY PLACEMENT SY-IN 6250 12 MODIFIED CLASS D PCC OVERLAY PLACEMENT SY-IN

Source: Delaware Standard Specifications for Road and Bridge Construction, 2025 Edition. Pages 335–344 of 779.

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