1. Mandatory Prepaving Conference
Micro-surfacing Construction
Section C(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.
Material
Proportion limits
Micro-surfacing emulsion residual asphalt
% of aggregate dry weight
Water and additives
No limit
Mineral filler
0-3% of aggregate dry weight
Section D(4)(c)

4. 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 25o C
Technical Bulletin 113
Controllable to 120 seconds
Section D(4)(c)

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

6. 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 A

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.
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 A

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

9. Materials, MICRO-SURFACING EMULSION Micro-surfacing Emulsion. b
Property
Test Method
Value
Saybolt Furol 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 C(3)

10. Materials, MICRO-SURFACING EMULSION
Micro-surfacing Emulsion Residue by Evaporation Properties
Property
Test Method
Value
20 oC, 10tad/sec, MPa
AASHTO T 315
Report only
25 oC
AASHTO T 49
40-90
Phase 50 oC, 10rad/sec,
PA (maximum)-PA base
Softening point, min, oC
AASHTO T 53 57
-12 oC, Mpa, and M-value
AASHTO T313
Section C(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 C(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 C(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 C(5)b

14. 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 C(5)b & c

15. 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 C(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 C(5)a & d

17. 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).

18. Construction- Surface Preparation-Existing Pavement
Section D 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 D 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 D 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 D(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 D(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 D(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 D(4)(a)(ii)

25. 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 C(2)

26. Quality Control-contractor Micro-surfacing Emulsion. b
Property
Test Method
Value
Saybolt Furol 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 C(3)

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

28. 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 C(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