Mandatory Prepaving Conference

Chipseal Construction

Section 37.2 Seal Coats

Proper surface preparation

Use of right asphalt binder, asphaltic/polymer modified

emulsion and clean aggregate screenings

Adherence to the project specifications, including traffic

control

Check equipment before start

Chip seal in good weather conditions

Keys to Success

MaterialsEquipmentConstruction Procedures Quality ControlQuality Assurance

Topics to be covered

Section 37-2.01A Summary

Asphalt Binder, Asphaltic Emulsion,

Polymer Modified Emulsion (PME)

Screened Aggregates

MATERIALS

Section 37-2.01A Summary

Distributor Trucks

Screened Aggregate Spreaders

Self Propelled Screened Aggregate Spreader

Self Propelled Power Brooms & Vacuums

Pneumatic Tired Rollers

Width ≥ 4’

Weight ≥ 3000 lbs. per Wheel

Equipment

Section 37-2.03 Equipment

Construction Procedures Proper Surface Preparation

Apply Binder/Asphaltic Emulsion/Polymer Modified

Emulsion at Specified Rates & Temperatures

Apply Screened Aggregates at Specified Rates

Roll-as Specified Number of Coverages

Allow Mat to Cure or Cool

Broom Loose Aggregate

Apply a Flush Coat

Open to Traffic After Curing Flush Coat.

Sweeping (before and after) Hot Binder Application

Aggregate Application Rolling

Construction- Surface Preparation-Existing Pavement

Section 37-2.03D Surface Preparation

Construction- Surface Preparation-Existing Pavement

Section 37-2.03D Surface Preparation

Cover all exposed facilities before seal coat

application.

Reference all covered facilities properly for easy

location.

After seal coat application, expose the covered

facilities.

Construction- Surface Preparation-Existing

Pavement

Section 37-2.03D Surface Preparation

Remove all loose and extraneous

material by brooming and vacuuming.

Ensure clean, dry surface before

applying seal coat.

Construction –Applying asphaltic Emulsion

Section 37-2.03F

Section 37-2.03F Applying Emulsion

In confined areas apply the emulsion with a squeegee,

rake or other means authorized by the Engineer.

Cover adjacent areas not intended for sealing with

suitable material.

At longitudinal joints, emulsion overlap must be

dispersed with squeegees before the application of

screenings or rakes.

Construction –Applying asphaltic Emulsion

Section 37-2.03F Applying Emulsion

Construction –Applying asphaltic Emulsion

Align longitudinal seal coat joints with designated

traffic lanes. Ensure adequate overlap (4”-8”), as directed

by engineer.

Plan emulsion application with lane closure

requirements, stop an hour before darkness.

Construction-EMULSION/BINDER

Application

Section 37-2.03F(3) &(4)

Single OverlapDouble OverlapTriple Overlap

h

Roadway Surface

Construction – TYPES ofEMULSION Overlap

Section 37-2.03F(3) &(4)

Construction – EMULSION Application

Chip Seal Type Application Rate Range(gallons per square yard)

Fine 0.15-0.30Medium Fine 0.25-0.35

Medium 0.25-0.40Coarse 0.30-0.40

Asphaltic Emulsion or Polymer Modified Asphaltic Emulsion Application (Residual) Rates

Section 37-2.03F(3) &(4)

APHALTIC EMULSION APPLICATION RATES

Chip Seal Type Application Rate Range(gallons per square yard)

Fine 0.15-0.30Medium Fine 0.25-0.35

Medium 0.25-0.40Coarse 0.30-0.40

Asphalt (Paint)Binder Application Rates

APHALT BINDER APPLICATION RATES

Construction – SCREENED Aggregate Application

Section 37-2.03G (1), (2) &(3)

Construction – SCREENED Aggregate Application

Section 37-2.03G (1)(2) &(3)

Screened Aggregates SPREAD RATES

Chip Seal Type Spread Rate Range(Pounds per square yard)

Fine 12-20Medium Fine 16-25

Medium 20-30Coarse 23-30

Section 37-2.03G (1), (2) &(3)

No Traffic on emulsioned areas

Uniform spread rates per specifications over entire lane width

Broom Excess screenings.

Aggregate screenings no roll after dropping.

Aggregate screenings should stop when the spreader stops

Do not spread aggregate screenings ≥ 2500’ ahead of completed initial rolling

Construction – SCREENED Aggregate Application

Section 37-2.03G (1) & (3)

The application always starts with neat straight edges.

The aggregate spreader follows closely behind the distributor truck (50ft.)

Screened aggregates for Polymer Modified Asphaltic Emulsion application are in a damp condition.

The application looks uniform.

Enough trucks are on hand to keep steady supply of chips.

Check for streaks and gate plug.

Screened aggregate sample is secured from the middle of stockpile or chip machine belt for testing.

Construction – SCREENED Aggregate Application –BEST

PRACTICES

Construction - Rolling

Section 37-2.03H(1)

Construction - Rolling

Section 37-2.03H(1)

Construction - Rolling Correct all ridges, piles, bumps or depressions.

Ensure straight joints, no more than 4” overlap

Longitudinal joints at lane lines

Use pneumatic rollers

Initial rolling with pneumatic roller one coverage

Three coverages of pneumatic roller for final rolling

Broom excess aggregate screenings before opening to

traffic

Section 37-2.03H(1)

Construction - Curing of Emulsion

Curing time depends on ambient temperature and

relative humidity

Emulsion break should begin just after first roller

pass

Emulsion curing might take 2 to 6 hours, depending

upon asphaltic emulsion type & base asphalt

Construction - Brooming Loose Aggregate

Section 37-2.03I Seal Coat Maintenance

Seal coat surfaces must be maintained for 4 consecutive days from the day screened aggregates are applied.

Remove excess screened aggregates from surface by brooming. Exact brooming time & intervals determined by engineer

Use pilot cars to control traffic.

Schedule placement to ensure end of 1 way traffic control an hour before darkness.

Seal coat maintenance

Section 37-2.0I Seal Coat Maintenance

Quality CONTROL-CONTRACTOR

Polymer Modified Emulsions

Viscosity (AASHTO T59)

Sieve Test (AASHTO T59)

Demulsibility (AASHTO T59)

Torsional Recovery (California Test 332)

Section 37-2.0ID (3)

Quality CONTROL-CONTRACTOR

Screened Aggregates

CT 211, Loss at 100 revolutions ≤ 10%

Loss at 500 revolutions ≤ 40%

CT 302, Film Stripping ≤ 25%

C T 227 Cleanliness Value ≥ 80 for Asphaltic

Emulsions

C T 227 Cleanliness Value ≥ 86 for PMEs

Section 37-2.0ID (3)

Quality CONTROL-CONTRACTOR Screened Aggregates- CT 202 Gradation-Asphaltic

Emulsion

Section 37-2.02H (2)

Percent PassingSieve Size

Coarse ½” Max

Medium3/8” Max

Med. Fine5/16” Max

Fine¼” Max

¾” 100 -- -- --

½” 95–100 100 -- --

3/8” 50–80 90–100 100 100

No. 4 0–15 5–30 30–60 60–85

No. 8 0–5 0–10 0–15 0–25

No. 16 -- 0–5 0–5 0–5

No. 30 -- -- 0–3 0–3

No. 200 0–2 0–2 0–2 0–2

Quality CONTROL-CONTRACTOR Screened Aggregates- CT 202 Gradation-Polymer

Modified Emulsion

Section 37-2.02H (3)

Percent PassingSieve Size

Coarse ½” Max

Medium3/8” Max

Med. Fine5/16” Max

Fine¼” Max

¾” 100 -- -- --

½” 85–100 100 -- --

3/8” 0–30 85–100 100 100

No. 4 0–5 0–15 0–50 60–85

No. 8 -- 0–5 0–15 0–25

No. 16 -- -- 0–5 0–5

No. 30 -- -- 0–3 0–3

No. 200 0–2 0–2 0–2 0–2

Quality CONTROL - Preliminary Responsibilities

Project review-Contractor

Alignment, geometrics, shoulders, turnouts

Document review-Joint

Plans & Specifications

Equipment & Material checks-Contractor

Quality Control Pre-Application Inspection (cont.)

Weather requirements Check the local weather conditions for the proposed paving

day.

Ensure that the proposed paving operation can be

completed, including the emulsion cure within the favorable

weather window.

Reschedule paving operations if rain is predicted within the

next 48 hours.

Section 37-2.03C Unsuitable Day

Quality Control Pre-Application Inspection

Surface preparation Equipment inspection

• Asphaltic emulsion distributor• Chip spreader• Haul trucks• Rollers- Adequate number of pneumatic rollers• Brooms

Section 37-2.01(D) Quality Control

Quality Control Pre-Application Inspection (cont.)

Determining asphaltic emulsion &

screened aggregate application rates

Traffic control plan and setup

Section 37-2.03F(3) & (4) Application Rates

Quality ASSURANCE - construction Inspection Asphaltic emulsion application & rates

California Test 339

Screened aggregate application & rates

Vialit (French)Test ≥ 90% Retention

Traffic control & trucking operation

Rolling

Quality ASSURANCE - construction Inspection

Longitudinal joints – ensure no aggregate buildup

Transverse joints – ensure clean joints, start and stop on construction paper

Brooming to ensure absence of loose aggregate

Quality Control /ASSURANCE Post-Application Inspection

Cleanup

Opening to traffic

Thank you