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Mandatory Prepaving Conference

Mandatory Prepaving Conference. Micro-surfacing Construction. Section 37.3 .01C(3) Micro-surfacing . Topics to be covered. Mix Design Materials Equipment Construction Procedures Quality Control Quality Assurance. Mix design. Mix Design Proportion Limits

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Mandatory Prepaving Conference

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  1. MandatoryPrepaving Conference Micro-surfacing Construction Section 37.3 .01C(3) Micro-surfacing

  2. Topics to be covered • Mix Design • Materials • Equipment • Construction Procedures • Quality Control • Quality Assurance

  3. Mix design • Mix Design Proportion Limits • Submit laboratory test results and proposed Micro-surfacing mix design. Section 37-3.01D(4)(c)

  4. Micro-surfacing Mix Design Tests • Submit laboratory test results and proposed Micro-surfacing mix design. Section 37-3.01D(4)(c)

  5. Materials • Aggregate • Polymer Modified Asphaltic Emulsion • Mineral Filler Section 37-3.02C(2), (3) & (4)

  6. Materials • Aggregate-must meet the following gradation -CT 202 • Micro-surfacing Aggregate Gradings Section 37-3.02A

  7. Materials • Micro-surfacing aggregate-must meet the following quality characteristics • Aggregate Quality a Crushed particles must have at least 1 fractured face b California Test 211 must be performed on the aggregate before crushing. Section 37-3.02A

  8. Materials, MICRO-SURFACING EMULSION • Homogeneous mixture of asphalt, polymer and emulsifier solution • Minimum 3% polymer by weight of residual asphalt b Section 37-3.02C

  9. Materials, MICRO-SURFACING EMULSION Micro-surfacing Emulsion • . b Section 37-3.02C(3)

  10. Materials, MICRO-SURFACING EMULSION Micro-surfacing Emulsion Residue by Evaporation Properties Section 37-3.02C(3)

  11. Materials-Mineral filler & other additives • Portland cement is used as mineral filler • Must be Type I, Type II or Type III cement • Other additives may be added to control the emulsion set time depending upon weather conditions Section 37-3.02C(4)

  12. Equipment • Truck mounted mixer-spreader unit or continuous self loading mixing machine • Capable of proportioning micro surfacing emulsion using a positive displacement pump. • Must be calibrated in compliance with Caltrans Material Plant Quality Program (MPQP) • Variable Rate Emulsion Pump must be calibrated & sealed in calibrated condition under Caltrans MPQP Section 37-3.03C(5)a

  13. Equipment • Spreader boxes ≥ 8 ft. wide must have; • Baffles or motor driven reversible augers • Ensure uniform application on superelevated sections and slopes • Must have a series of strike off devices at rear • The leading strike off device must be; • Fabricated of suitable material such as steel or natural rubber • Designed to maintain close contact with the pavement during spreading • Capable of obtaining the specified thickness • Capable of being adjusted to the various pavement cross sections Section 37-3.03C(5)b

  14. Equipment • The final strike-off device must be ; • Fabricated of flexible material that produces a uniform smooth texture in the finished surface • Cleaned daily and changed if longitudinal scouring occurs in the micro-surfacing • Shoulder Equipment • Edge box shoulders must form clean, straight joints and edges Section 37-3.03C(5)b & c

  15. Equipment • Scratch Course Box • Scratch course box must have an adjustable steel strike-off device for final strike-off • Wheel Path Depression (Rut) Box must have • 5-6 feet adjustable strike-off device to regulate depth • Hydraulic augers capable of: • Moving the mixed material from the rear to the front of the filling chamber • Guiding larger aggregate into the deeper section of the wheel path • Forcing the finer material towards the outer edges of the spreader box Section 37-3.03C(5)d & e

  16. Equipment • Pneumatic Tired Rollers ≥ 3000 lbs. Load per wheel for scratch & rut fill courses • Self Propelled Power Brooms & Vacuums • If using truck mounted mixer spreaders for placement, minimum of two mixer spreaders required at site Section 37-3.03C(5)a & d

  17. ConstructionProcedures • Proper surface preparation • Fog the pavement surface if necessary • Place approved micro surfacing mixture in wheel path depressions (ruts) with a rut box • Do not apply more than 0.12’ thick layer at a time • Apply multiple times to fill the depressions • Allow Mat to Cure or Cool • Allow traffic to compact micro surfacing for 12 hours before placing next micro surfacing layer.

  18. Construction-Surface Preparation-Existing Pavement Section 37-2.03D Surface Preparation

  19. Construction-Surface Preparation-Existing Pavement • Clean Pavement surface. • Remove loose particles of extraneous materials, including paving and dirt. • Use non destructive methods such as flushing and sweeping. Section 37-2.03D Surface Preparation

  20. Construction-Surface Preparation-Existing Pavement • Cover all exposed facilities before micro surfacing application. • Reference all covered facilities properly for easy location. • After micro surfacing application, expose the covered facilities. • All starts and stops on roofing felt to ensure clean sharp joints • Fog the roadway surface before the spreader box Section 37-2.03D Surface Preparation

  21. Construction-REPAIR WHEEL PATH DEPRESSION • Fill wheel path depressions & irregularities with a scratch course, where specified. • If the depressions are ≥1/2” use wheel path depression (rut) box to fill the depressions • Place layers not ≥0.12’ in one pass. • Allow for 12 hours compaction by traffic before placing the next layer. Section 37-3.03D(2)(c)

  22. Construction –Applying MICROSURFACING • After filling the wheel path depressions & irregularities with a scratch course, place the final micro surfacing layer. • Allow Micro surfacing to cure and set. • Open to traffic after brooming. Section 37-3.03D(2)(c)

  23. Construction-Joints • Longitudinal and transverse joints must be; • Uniform • Straight • Neat in appearance • Butt type joints • Without material build up • Without uncovered areas • On centerlines, lane lines, edge lines or shoulder lines • With not more than 3” overlaps Section 37-3.03D(4)(a)(i)

  24. Construction- WEATHER restrictions • Place when both pavement and air temperatures ≥50 oF and rising. • Do not place if pavement and air temperatures ≤50 oF and falling. • Expected high temperature ≤65 oF within 24 hour of placing. • No placement if rain is imminent or air temperature is expected to go below ≤36 oF. Section 37-3.03D(4)(a)(ii)

  25. QualityCONTROL-CONTRACTOR • Micro-surfacing aggregate • Aggregate Quality a Crushed particles must have at least 1 fractured face b California Test 211 must be performed on the aggregate before crushing. Section 37-3.02C(2)

  26. Quality Control-contractor Micro-surfacing Emulsion • . b Section 37-3.02C(3)

  27. Quality control-contractor Micro-surfacing Emulsion Residue by Evaporation Properties Section 37-3.02C(3)

  28. Quality Control Pre-Application Inspection • Surface preparation • Equipment inspection • Continuous self loading mixing machine or truck mounted mixer spreader , min. 2 nos. • Spreader box • Shoulder equipment/Edge box • Scratch course box & wheel path depression box • Brooms Section 37-3.03C(1), (2) &(3)

  29. Quality Control Pre-Application Inspection (cont.) • Micro surfacing application rate • Traffic control plan and setup

  30. Quality ASSURANCE - construction Inspection • Micro surfacing aggregate application rates • Start & stop operations • Traffic Control & Trucking operation • Rolling

  31. Quality ASSURANCE - construction Inspection • Longitudinal joints – ensure no material buildup • Transverse joints – ensure clean joints, start and stop on roofing felt • Brooming to ensure absence of loose aggregate

  32. Quality Control /ASSURANCE Post-Application Inspection • Cleanup • Opening to traffic

  33. Thank you

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