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 Submit laboratory test results and proposed Micro-surfacing mix design. Material Proportion limits Micro-surfacing emulsion residual asphalt 5.5-9.5% of aggregate dry weight Water and additives No limit Mineral filler 0-3% of aggregate dry weight Section 37-3.01D(4)(c)

International Slurry Surfacing Association test method Micro-surfacing Mix Design Tests Submit laboratory test results and proposed Micro-surfacing mix design. Property International Slurry Surfacing Association test method Specification Wet cohesion @30 minute (set), min kg-cm @ 60 minute (traffic), Min kg-cm Technical Bulletin 139 12 20 Excess asphalt, max, g/m2 540 Wet stripping, min, % Technical Bulletin 114 90 Wet track abrasion loss 6-day soak, max, g/m2 Technical Bulletin 110 810 Displacement Lateral, max, % Specific gravity after 1000 cycles of 57 kg max Technical Bulletin 147A 5 2.10 Classification compatibility, min, grade points Technical Bulletin 144 (AAA, BAA) 11 Mix time @ 25o C Technical Bulletin 113 Controllable to 120 seconds Section 37-3.01D(4)(c)

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

Micro-surfacing Aggregate Gradings Percent passing by aggregate type Materials Aggregate-must meet the following gradation -CT 202 Micro-surfacing Aggregate Gradings Percent passing by aggregate type Sieve sizes II III 3/8” 100 No. 4 94-100 70-90 No. 8 65-90 45-70 No. 16 40-70 28-50 No. 30 25-50 19-34 No. 200 5-15 Section 37-3.02A

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. Quality characteristic Test method Specification Sand equivalent, min California Test 217 65 Durability index, min California Test 229 Percentage of crushed particles, mina California Test 205 95% Loss Angeles Rattler Loss at 500 revolutions Maxb California Test 211 35% Section 37-3.02A

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

Materials, MICRO-SURFACING EMULSION Micro-surfacing Emulsion . b Property Test Method Value Saybolt Furol Viscosity @25o C AASHTO T 59 15-90 Seconds Sieve test, max a 0.30% Settlement, 5 days, max b ASTM D 244 5% Storage stability, 1 day, max 1% Residue by evaporation California Test 331 62% Section 37-3.02C(3)

Materials, MICRO-SURFACING EMULSION Micro-surfacing Emulsion Residue by Evaporation Properties Property Test Method Value G* @ 20 oC, 10tad/sec, MPa AASHTO T 315 Report only Penetration @ 25 oC AASHTO T 49 40-90 Phase angle @ 50 oC, 10rad/sec, PA (maximum)-PA base Softening point, min, oC AASHTO T 53 57 Stiffness @ -12 oC, Mpa, and M-value AASHTO T313 Section 37-3.02C(3)

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)

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

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

Equipment Shoulder 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

Equipment Scratch Course Box Wheel Path Depression (Rut) Box must have 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

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

Construction Procedures 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. Details the order of operations (processes).

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

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

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

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)

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)

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)

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)

Quality CONTROL-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. Quality characteristic Test method Specification Sand equivalent, min California Test 217 65 Durability index, min California Test 229 Percentage of crushed particles, mina California Test 205 95% Loss Angeles Rattler Loss at 500 revolutions Maxb California Test 211 35% Section 37-3.02C(2)

Quality Control-contractor Micro-surfacing Emulsion . b Property Test Method Value Saybolt Furol Viscosity @25o C AASHTO T 59 15-90 Seconds Sieve test, max a 0.30% Settlement, 5 days, max b ASTM D 244 5% Storage stability, 1 day, max 1% Residue by evaporation California Test 331 62% Section 37-3.02C(3)

Quality control-contractor Micro-surfacing Emulsion Residue by Evaporation Properties Property Test Method Value G* @ 20 oC, 10tad/sec, MPa AASHTO T 315 Report only Penetration @ 25 oC AASHTO T 49 40-90 Phase angle @ 50 oC, 10rad/sec, PA (maximum)-PA base Softening point, min, oC AASHTO T 53 57 Stiffness @ -12 oC, Mpa, and M-value AASHTO T313 Section 37-3.02C(3)

Pre-Application Inspection 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)

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

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

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

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

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