Mandatory Prepaving Conference

Mandatory Prepaving Conference

Micro-surfacing Construction

Section 37.3 .01C(3) Micro-surfacing

Mix Design MaterialsEquipmentConstruction Procedures Quality ControlQuality Assurance

Topics to be covered

Mix Design Proportion Limits

Submit laboratory test results and proposed Micro-surfacing mix design.

Mix design

Section 37-3.01D(4)(c)

Material Proportion limitsMicro-surfacing emulsion residual asphalt

5.5-9.5% of aggregate dry weight

Water and additives No limitMineral filler 0-3% of aggregate dry weight

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 1391220

Excess asphalt, max, g/m2 Technical Bulletin 139 540

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


Aggregate

Polymer Modified Asphaltic Emulsion

Mineral Filler

Materials

Section 37-3.02C(2), (3) & (4)

Aggregate-must meet the following gradation -CT 202

Micro-surfacing Aggregate Gradings

Materials

Section 37-3.02A

Percent passing by aggregate typeSieve sizes II III3/8” 100 100No. 4 94-100 70-90No. 8 65-90 45-70No. 16 40-70 28-50No. 30 25-50 19-34No. 200 5-15 5-15

Micro-surfacing aggregate-must meet the following quality characteristics

Aggregate Quality

a Crushed particles must have at least 1 fractured faceb California Test 211 must be performed on the aggregate before crushing.

Materials

Section 37-3.02A

Quality characteristic Test method Specification

Sand equivalent, min California Test 217 65Durability index, min California Test 229 65Percentage of crushed particles, mina

California Test 205 95%

Loss Angeles Rattler Loss at 500 revolutions Maxb


Homogeneous mixture of asphalt, polymer and emulsifier solution

Minimum 3% polymer by weight of residual asphalt

b

Materials, MICRO-SURFACING EMULSION

Section 37-3.02C

.

b

Materials, MICRO-SURFACING EMULSION Micro-surfacing Emulsion

Section 37-3.02C(3)

Property Test Method

Value

Saybolt Furol Viscosity @25o C AASHTO T 59 15-90 Seconds

Sieve test, max a AASHTO T 59 0.30%

Settlement, 5 days, max b ASTM D 244 5%

Storage stability, 1 day, max AASHTO T 59 1%

Residue by evaporation California Test 331

62%

Materials, MICRO-SURFACING EMULSION

Micro-surfacing Emulsion Residue by Evaporation Properties

Section 37-3.02C(3)


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

AASHTO T 315 Report only

Softening point, min, oC AASHTO T 53 57

Stiffness @ -12 oC, Mpa, and M-value

AASHTO T313 Report only

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

Materials-Mineral filler & other additives

Section 37-3.02C(4)

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

Equipment

Section 37-3.03C(5)a

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

Equipment

Section 37-3.03C(5)b

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

Equipment

Section 37-3.03C(5)b & c

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

Equipment

Section 37-3.03C(5)d & e

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

Equipment

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.

Construction- Surface Preparation-Existing Pavement

Section 37-2.03D Surface Preparation



Clean Pavement surface.

Remove loose particles of extraneous materials,

including paving and dirt.

Use non destructive methods such as flushing

and sweeping.



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

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.


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.


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

Section 37-3.03D(4)(a)(ii)

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.

Quality CONTROL-CONTRACTOR

Section 37-3.02C(2)

Quality characteristic Test method Specification

Sand equivalent, min California Test 217 65Durability index, min California Test 229 65Percentage of crushed particles, mina


Loss Angeles Rattler Loss at 500 revolutions Maxb


Micro-surfacing aggregateAggregate Quality

a Crushed particles must have at least 1 fractured faceb California Test 211 must be performed on the aggregate before crushing.

.

b

Quality Control-contractor

Micro-surfacing Emulsion

Section 37-3.02C(3)


Value

Saybolt Furol Viscosity @25o C AASHTO T 59 15-90 Seconds

Sieve test, max a AASHTO T 59 0.30%

Settlement, 5 days, max b ASTM D 244 5%

Storage stability, 1 day, max AASHTO T 59 1%

Residue by evaporation California Test 331

62%

Quality control-contractor

Micro-surfacing Emulsion Residue by Evaporation Properties

Section 37-3.02C(3)


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

AASHTO T 315 Report only

Softening point, min, oC AASHTO T 53 57

Stiffness @ -12 oC, Mpa, and M-value

AASHTO T313 Report only

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

Thank you

Documents

Mandatory Prepaving Conference