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Chipseal Construction Section 37.2 Seal Coats.  Proper surface preparation  Use of right asphalt binder, asphaltic/polymer modified emulsion and clean.

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Presentation on theme: "Chipseal Construction Section 37.2 Seal Coats.  Proper surface preparation  Use of right asphalt binder, asphaltic/polymer modified emulsion and clean."— Presentation transcript:

1 Chipseal Construction Section 37.2 Seal Coats

2  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

3  Materials  Equipment  Construction Procedures  Quality Control  Quality Assurance to be covered Topics to be covered Section A Summary

4  Asphalt Binder, Asphaltic Emulsion, Polymer Modified Emulsion (PME)  Screened Aggregates MATERIALS Section A Summary

5  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 Equipment

6 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.

7 Sweeping (before and after) Hot Binder Application Aggregate Application Rolling

8 Construction- Surface Preparation-Existing Pavement Section D Surface Preparation

9 Construction- Surface Preparation-Existing Pavement Section D 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.

10 Construction- Surface Preparation-Existing Pavement Section D Surface Preparation  Remove all loose and extraneous material by brooming and vacuuming.  Ensure clean, dry surface before applying seal coat.

11 Construction –Applying asphaltic Emulsion Section F

12 Section F 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

13 Section F 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.

14 Construction-EMULSION/BINDER Application Section F(3) &(4)

15 Single Overlap Double Overlap Triple Overlap h Roadway Surface Construction – TYPES of EMULSION Overlap Section F(3) &(4)

16 Construction – EMULSION Application

17 Chip Seal Type Application Rate Range (gallons per square yard) Fine Medium Fine Medium Coarse Asphaltic Emulsion or Polymer Modified Asphaltic Emulsion Application (Residual) Rates Section F(3) &(4) APHALTIC EMULSION APPLICATION RATES

18 Chip Seal Type Application Rate Range (gallons per square yard) Fine Medium Fine Medium Coarse Asphalt (Paint)Binder Application Rates APHALT BINDER APPLICATION RATES

19 Construction – SCREENED Aggregate Application Section G (1), (2) &(3)

20 Construction – SCREENED Aggregate Application Section G (1)(2) &(3)

21 Screened Aggregates SPREAD RATES Chip Seal Type Spread Rate Range (Pounds per square yard) Fine12-20 Medium Fine16-25 Medium20-30 Coarse23-30 Section G (1), (2) &(3)

22  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 G (1) & (3)

23  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

24 Construction - Rolling Section H(1)

25 Construction - Rolling Section H(1)

26 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 H(1)

27 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

28 Construction - Brooming Loose Aggregate Section I Seal Coat Maintenance

29  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. Section I Seal Coat Maintenance

30 Quality CONTROL-CONTRACTOR  Polymer Modified Emulsions  Viscosity (AASHTO T59)  Sieve Test (AASHTO T59)  Demulsibility (AASHTO T59)  Torsional Recovery (California Test 332) Section ID (3)

31 Quality 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 ID (3)

32 Quality Quality CONTROL-CONTRACTOR  Screened Aggregates- CT 202 Gradation-Asphaltic Emulsion Section H (2) Percent Passing Sieve SizeCoarse ½” Max Medium 3/8” Max Med. Fine 5/16” Max Fine ¼” Max ¾” ½” 95– /8 ” 50–8090– No. 4 0–155–3030–6060–85 No. 8 0–50–50–100–150–25 No –50–50–50–50–50–5 No –30–30–3 No –20–20–2 0–20–2

33 Quality Quality CONTROL-CONTRACTOR  Screened Aggregates- CT 202 Gradation-Polymer Modified Emulsion Section H (3) Percent Passing Sieve SizeCoarse ½” Max Medium 3/8” Max Med. Fine 5/16” Max Fine ¼” Max ¾” ½” 85– /8 ” 0–3085– No. 4 0–50–150–5060–85 No –50–150–25 No –5 No –3 No –2

34 Quality - Preliminary Responsibilities Quality CONTROL - Preliminary Responsibilities  Project review-Contractor  Alignment, geometrics, shoulders, turnouts  Document review-Joint  Plans & Specifications  Equipment & Material checks-Contractor

35 Quality Control Inspection (cont.) 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 C Unsuitable Day

36 Control Quality Control Inspection Pre-Application Inspection  Surface preparation  Equipment inspection Asphaltic emulsion distributor Chip spreader Haul trucks Rollers- Adequate number of pneumatic rollers Brooms Section (D) Quality Control

37 Quality Control Pre- Application Inspection (cont.)  Determining asphaltic emulsion & screened aggregate application rates  Traffic control plan and setup Section F(3) & (4) Application Rates

38 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

39 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

40 Quality Control /ASSURANCE Post-Application Inspection  Cleanup  Opening to traffic

41 Thank you


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