422.01  Description

422.02  Materials

422.03  Equipment

422.04  Weather Limitations

422.05  Test Strip

422.06  Surface Preparation

422.07  Polymer Binder Application

422.08  Cover Aggregate Application

422.09  Construction Operation

422.10  Quality Control

422.11  Acceptance

422.12  Method of Measurement

422.13  Basis of Payment


422.01  Description.  This work consists of preparing and applying a single or double chip seal with a polymer binder.

422.02  Materials.  Furnish polymer emulsified binder conforming to 702.16 Type A

For cover aggregate material, use washed limestone or dolomite meeting the gradation below and 703.05.  Submit a letter to the Engineer and (DET) containing the JMF gradation of the cover aggregate showing all sieve sizes.  Determine the JMF gradation by taking the average of five samples taken from different locations of stockpiled aggregate immediately before starting the job.  If the five samples deviate more than ±3.0 percent passing on the No. 8 (2.36 mm) sieve, rework the stockpile, take five new samples, and redetermine the JMF gradation.  The JMF shall include both a dry gradation value and a washed gradation value for passing the No. 200 (75 mm) sieve.

Sieve Size

Total Percent Passing

1/2 inch (12.5 mm)


3/8 inch (9.5 mm)

85 to 100

No. 4 (4.75 mm)

10 to 30

No. 8 (2.36 mm)

0 to 10

No. 16 (1.18 mm)

0 to 5

No. 200 (75 mm)

2.0 max [1]

[1]  Washed gradation value


422.03  Equipment.  Provide equipment conforming to the requirements of this section.  Obtain approval of equipment before starting the job.

Use equipment for polymer binder distribution conforming to 407.03, except ensure that it has a computerized rate control that automatically adjusts the polymer binder pump to the unit ground speed.  Use appropriate spray nozzles for the material and rate specified.

Use Type II pneumatic tire rollers conforming to 401.13, except the maximum capacity shall not apply.

Use self-propelled aggregate spreaders with a variable width aggregate hopper capable of placing from 8 to 16 feet (2.4 to 4.8 m) in any increment and a computerized rate control that automatically adjusts the aggregate output to the unit ground speed.  Equip spreaders with pneumatic tires, a screen to remove oversized material, revolving cylinders, and adjustments necessary to produce a uniform distribution of particles at the specified rate.

Use power sweepers or rotary brooms in initial surface preparation and for removing loose particles.  Use pickup type sweepers in areas where the aggregate shoulder does not exist.  Do not sweep loose aggregate onto lawns, curbed areas, and intersections.

Furnish accurate thermometers for determining any of the applicable temperature requirements of this specification.

422.04  Weather Limitations.  Place the chip seal when the pavement and atmospheric temperature is 60 °F (16 °C) or above.  Do not place chip seal if any of the following conditions exist:

A.     Impending weather conditions do not allow for proper curing or if temperatures are forecasted below 50 °F (10 °C) within 24 hours from the time of work.

B.      The existing pavement temperature is 140 °F (60 °C) or above.

C.      Before May 1 or after September 1.

422.05  Test Strip.  Construct a continuous 1000-foot (300 m) long by lane width test strip.  The Engineer will review the test strip the next workday.  Determine the polymer binder application rate, aggregate application rate, and aggregate gradation during the test strip.  If the review shows the test strip meets the requirements of 422.11 and the application rate and quality control tests show all is in control compared to the JMF, then progress with the work.  Should problems be noted, the Engineer may require another test strip.

The Department will waive the test strip if the Contractor has constructed a Department accepted test strip using the same materials and JMF in the same season.

422.06  Surface Preparation.  Clean the pavement according to 407.05.  If necessary, clean areas of the pavement with a hand broom.  Do not place material until the Engineer approves the surface.

422.07  Polymer Binder Application.  Before applying polymer binder, ensure that sufficient cover aggregate is available for immediate application.  For single chip seal, apply the polymer binder at a minimum rate of 0.37 gallon per square yard (1.68 L/m2).  For double chip seal, apply the polymer binder at a minimum rate of 0.34 gallon per square yard (1.54 L/m2) for the first course and 0.37 gallon per square yard (1.68 L/m2) for the second course.  Maintain the polymer binder temperature from 150 to 185 °F (65 to 85 °C) during construction, including the start of each day.  Reheat the polymer binder at a rate of no more than 25 °F (14 °C) per hour, when the polymer binder is allowed to cool below 150 °F (65 °C).

If the target rate is not the optimum application rate due to the gradation of the aggregate or due to existing surface conditions of the pavement, immediately notify the Engineer and document the new rate by stationing.  The Contractor may adjust the rate of application specified in the Contract with the approval of the Engineer as necessary to achieve satisfactory embedment and retention of the cover aggregate.

Do not allow the polymer binder to streak on the road surface.  If the Engineer determines that streaking is occurring, cease operations until the Engineer is satisfied that streaking has been eliminated.

At the beginning and at the end of a contract section, start and stop the application on a removable protective cover (paper, metal sheets, or other suitable material) sufficiently wide enough to allow full application on the surface being treated.  Make transverse and longitudinal laps in such manner to ensure that the texture of the finished surface is uniform and continuous.  To prevent lapping at transverse junctions, promptly shut off the polymer binder spray at the end of the application.  Before continuing the application, place a removable protective cover a sufficient distance back from the joint on the cover aggregate so the sprayers are operating at full force when the distributor has attained the predetermined speed upon reaching the uncovered surface.  Upon completion, remove all removable protective covers.

422.08 Cover Aggregate Application.  Immediately after applying the polymer binder, apply cover aggregate uniformly without ridges or laps at the specified rate adjusted as directed by the Engineer to produce a minimum of excess loose particles.  Spread the material in such manner that the tires of the truck or aggregate spreader at no time contact the uncovered and newly applied polymer binder.  Before rolling, correct deficiencies in the application of cover aggregate in a manner satisfactory to the Engineer.

After rolling, protect the surface from traffic damage during the period required for the polymer binder to cure sufficiently and prevent dislodging of the aggregate particles by normal traffic.  During this period and as directed by the Engineer, correct deficiencies in cover aggregate by spreading additional aggregate or by light brooming.

Apply cover aggregate at a rate necessary to provide full coverage of the polymer binder and to avoid tracking.  If the target rate is not the optimum application rate due to the gradation of the aggregate or due to existing surface conditions of the pavement, immediately notify the Engineer and document the new rate by stationing.

422.09  Construction Operation.  Establish stations at 1000-foot (300 m) intervals on the entire project before placing materials.  Clearly identify and maintain the stations until project completion.

Keep the polymer binder distributor, aggregate spreader, and rollers as close to each other as possible.  Do not allow the polymer binder distributor to be more than 150 feet (45 m) ahead of the aggregate spreader.

Perform rolling immediately after placing the aggregate, but before the polymer binder sets up.  Do not leave aggregate unrolled for more than 5 minutes.  Perform a minimum of two complete roller passes over the aggregate.  A single complete pass is forward and backward over the same path.  For each new pass, overlap the previous pass by about one-half the width of the roller.  Use a minimum of three rollers, and roll in a longitudinal direction at a speed not greater than 5 miles per hour (8 km/h).  Do not operate rollers at speeds that cause pick-up or dislodging of aggregate particles.

After the polymer binder sets, and before placing a second course for double chip seals, and within 4 hours, sweep the pavement using a power broom or pickup sweeper as needed to remove all loose aggregate.  If the Contractor cannot sweep the pavement within the 4-hour period due to problems associated with the polymer binder, breaking, humidity, or other unknown, the Engineer may suspend the operation until the problem is resolved or more suitable conditions are obtained to maintain the 4-hour time frame for sweeping.  The Engineer may direct additional sweeping in subsequent days to remove loose particles.  Extend sweeping 1 foot (0.3 m) beyond the edge of pavement to help prevent migration of loose aggregate back onto the pavement.  The Engineer will approve all cleaning.

For double chip seal, allow the first course to cure at least 4 hours before placing the second course of chip seal.  Before placing the second course, ensure that the first course is cured, swept, and capable of withstanding construction traffic without damage.  Correct damage to the underlying chip seal before placing the final chip seal.

Place the longitudinal construction joint on a lane line or as directed by the Engineer.  For double chip seal, place the longitudinal construction joint for the first course 6 inches (150 mm) off the centerline and place the second course so the longitudinal joint is at the centerline.

Before opening to traffic, post the roadway with “Loose Stone” signs and a “35 mph” speed plaque mounted below the sign.  Ensure that signs conform to Item 614.  Place these signs at a maximum of 0.5-mile (0.8 km) intervals.  Remove the signs as directed by the Engineer.

On two-lane roads or pavements where traffic is maintained on a chip seal constructed that workday, a traffic control pilot vehicle operated at no more than 25 miles per hour (40 km/h) is required in the immediate work area.

Protect all utility castings, monument boxes, and other similar items using tarpaper or other approved material.  Remove protection before sweeping and opening to traffic.

422.10  Quality Control.

A.      General.  Use the methods described in this section to measure compliance.  If the Contractor’s test results exceed any of the identified quality control tolerances, the Contractor shall stop placement and immediately notify the Engineer and DET.  Identify the cause of exceeding any of the identified quality control tolerances and document in detail the corrective action necessary to bring the deficiency into compliance.  The Engineer will give approval before resumption of work.  Upon resuming work, take another sample and immediately provide the test results to the Engineer.  If the tolerances are exceeded, stop the work.  Do not resume work until approved by the Engineer and DET.  The DET can obtain samples of materials at any time.

B.      Polymer Binder.  For the polymer binder application rate, as determined by a yield check, do not exceed a tolerance of ±0.02 gallon per square yard (0.09 L/m2) from the established application rate.  Label and retain one sample per day for the Department.

C.      Coarse Aggregate.  Sample and test aggregate according to AASHTO T 2, AASHTO T 248, and Supplement 1004 (AASHTO T 11 where required).  If problems persist with dry gradation results, perform washed gradations.

Reject truckloads of aggregate if water is seen coming from the truck bed.

Reject aggregate that does not meet the following requirements:

No. 4 (4.75 mm) sieve from JMF


No. 8 (2.36 mm) sieve from JMF


No. 200 (75 mm) sieve from JMF

±1.0%, 2.5% upper limit

Aggregate moisture content (by dry weight)

4.0% maximum


D.      Documentation.  Provide the Engineer a daily report with the following:

1.       Control section, project number, county, route, and Engineer.

2.       Date, air temperature, pavement temperature, and humidity.

3.       Polymer binder temperature.

4.       Beginning and ending stations.

5.       Yield checks on polymer binder (three per day, minimum).

6.       Yield checks on aggregate (three per day, minimum).

7.       Gradation, moisture content, and station (one at the start of daily production, minimum).

8.       Length, width, and total area.

9.       Condition of “Loose Stone” signs with “35 mph” speed plaques.

10.     Contractor representative’s signature.

Provide a bill of lading for polymer binder and aggregate as requested or at project completion.

422.11  Acceptance.  During the application of the chip seal, inspect the chip seal for deficiencies resulting from poor workmanship, flushing, tracking from equipment, surface patterns, loss of stone, and sweeping.  Inspect workmanship for untreated areas, minimum overlap on longitudinal joints, and minimum overlap on construction joints.

Verify the following for daily acceptance:

A.     Finished surface has no more than four tears or untreated areas greater than 1 inch (25 mm) wide and 4 inches (100 mm) long in any 120-square yard (100 m2) area.

B.      Joints appear neat and uniform without buildup, uncovered areas, or unsightly appearance.

C.      Longitudinal joints have less than a 2-inch (50 mm) overlap on the adjacent passes.

D.      Transverse joints have no more than 1/4-inch (6 mm) difference in elevation across the joint as measured with a 6-foot (2 m) straightedge.

E.      Chip seal edge is neat and uniform along the roadway lane, shoulder, and curb lines.

F.      Chip seal edge has no more than 2-inch (50 mm) variance in any 100 feet (30 m), along the roadway edge or shoulder.

For project acceptance, the Contractor and Engineer will review the completed work 25 to 35 days after placement.  The finished work must meet the following requirements:



Surface patterns

Alternate lean and heavy lines
(Ridges or streaking over the surface)


Distinctive appearance
(Excess polymer binder on surface)

Loss of cover aggregate

Patches or lines of aggregate lost from surface

[1]  Do not exceed the extent of any surface defect by more than 20 percent of any 120-square yard (100 m2) area.  The beginning of any 120-square yard (100 m2) area will be the start of any individual defect.


Perform all corrective work to the satisfaction the Engineer.

422.12  Method of Measurement.  The Department will measure Single Chip Seal Course with Polymer Binder or Double Chip Seal Course with Polymer Binder by the number of square yards (square meters), completed and accepted in place.  The Department will determine the width by measuring the actual width of the chip seal.  The Department will determine the length along the centerline of each roadway or ramp.

422.13  Basis of Payment.  The Department will not pay for materials, equipment, and labor to make corrections.

The Department will pay for accepted quantities at the contract prices as follows:

Item           unit                                Description

422             Square Yard                     Single Chip Seal with
                       (Square Meter)                Polymer Binder

422             Square Yard                     Double Chip Seal with
                       (Square Meter)                Polymer Binder