A slurry seal is a mixture of asphalt emulsion, crushed aggregate, and other additives that is spread over the surface of a pavement. It fills cracks, adheres firmly to the surface, and provides a weatherproof layer that extends the life of the pavement by 5-7 years. Application is fast, taking only 15 minutes for a typical residential street. It restores texture, protects the pavement from oxidation, and preserves the underlying pavement from further deterioration.

2. A mixture of asphalt emulsion,
crushed aggregate, mineral filler, water and other
additives
properly proportioned, mixed and spread as a surface
treatment. When applied the slurry seal shall have a
homogeneous appearance, fill minor cracks, adhere
firmly to the
surface and provide a weatherproof friction course.

3.  Very cost effective surface treatment that
extends the life of a pavement 5-7 years +
 Restores surface texture
 Will ultimately be placed at no more than 1.5
times the thickness of the largest stone
 Treatment that preserves the underlying
pavement from further oxidation related to
climatic conditions.
 Fast application. A typical residential street
will take 15 minutes to place and 2-4 hours to
cure to a point that will again support traffic.

4. Proven Technology

6. Early loss of surface fines
Protect the pavement from further
oxidation by providing a new wearing layer
Only minor cracking present. Anything
grater than 1/8” gets filled prior to slurry
application
Alligator cracking and Pot Holes are
repaired. Be careful of placing slurry over
fresh patches.

7. Project Candidates
Expectation
Specification
Mix Design
Materials
Equipment
Placement
Inspection

8. PCI 80 and above
Cracks greater that 1/8” filled
Alligator cracking has been repaired
No rutting
Only minor surface fines loss

12.  Keep the public in the loop.
 Try not to package a slurry project with an
overlay project
 Winter slurry color will vary more than
summer. Give it time.
 Most power steering scuffs will heal over
time. (Most slurries will take a change of all
seasons to complete its cure)
 Initial shed or light raveling will occur (large
stones that do not lay down may kick out)

13.  Caltrans Standard Specifications Section 37
http://dot.ca.gov/hq/esc/oe/construction_stan
dards.html
 Greenbook Section 203
http://www.bnibooks.com/products/standard-
specifications-public-works-construction
 International Slurry Surfacing Association
http://slurry.org/

14. Verification of material compatibility
Provides starting point for start up of the
project.
Targets optimum mixture but allows for
minor adjustment in the field.

15.  Too Much oil will provide a long lasting
surface but result in flushing and shoving
 Too little oil will result in color variation and
excessive rock loss up to and including 100%
raveling.
 Most materials will provide a good product
outside of the recommendation as long as
you evaluate the data. Particularly on the
slightly high side of the oil content.

16.  Aggregate (manufactured)
• Type 1
• Type 2
• Type 3
 Latex
 Mineral Fillers / Additives
 Emulsion
 Other
• Microsurfacing
• Tire Rubber Modified
• RAP

17. Residential Streets
Parking Lots Airports

18. Finest gradation of aggregate 1/8” top size
Fractured faces
Generally parking lots and bike lanes
Placed 8-12 lbs per square yd
Low speed traffic or high foot traffic type
areas
Airports

19. Residential Streets
County Roads Shoulders

20. Mid size aggregate top size ¼”
Fractured faces
Typically used on rural county roads,
arterial roads, Collectors and primarily
residential.
Application rate 10-20 lbs/SY

21. 4 Lane Highways
Interstates 2 Lane Highways

22. Most course gradation Max stone 3/8”
Fractured faces
Application Rate 13-30 lbs/SY
Typically used on highways, rural county
roads, arterial and collector roadways.

23. Benefits
Increases the softening point of the
residual asphalt
Improves early strength of seal (Reduces
Power steering burns)
Adds elastomeric properties to the residual
binder (Better stone retention)
Typical addition rate of 2.5% of the
emulsion

24.  Cement
• Can act as a retarder or accelerator of break
depending on emulsion and aggregate properties.
• Generally will make the mix tougher at least initially
• Is not compatible with all aggregate sources
 Aluminum Sulfate
• Generally acts as a retarder of break time in the field.
• Can act as a viscosity builder in the slurry preventing
separation of the oil and rock during application.

25. Generally a CQS-1H
• Cationic Quick Set (To a limited degree it uses the
mineral to assist in the break)
• Compatible with most aggregates (negative
charge offers resistance to stripping)
Other options could be a QS, SS or CSS

26.  Tire Rubber Slurry
• Color
• Multiple products
 Some old Some New
 Micro Surfacing
• Next Generation
• Night time
• Multiple Stone depth
• Chemical Break
 Multi Layer
• 2 over 3
• Cape Seal (Slurry on top of Chip)
 RAP
• Close to a type 2 gradation
• Lower Oil Content
• Recycled Green Value
• Color

27.  Truck Mount
• Better in residential and tight areas
• Most commonly used
• Multiple Manufactures
• Typically multiple trucks per project that require
calibration and adjustment
 Continuous Machines
• Same capabilities with the addition of the ability to
resupply while placing slurry
• Highways, Freeways
• Same machine places the entire project
• Reduced transverse joints.

31.  Gate settings
(Determine rock to oil
relationship and
product application
rates)
 Oil
 Water
 Fines Feeder
(Cement)
 Sulfate Feeder

32. Sets the depth of the slurry
Provides the uniform surface texture of the
slurry
May or May not be augured
Varied widths

34. Hand held Squeegees
Oil Tankers
Rock Trucks
Loaders
Conveyors
Sweeper
Traffic
Control

37. Things to consider
• Time of the year (Weather Conditions)
• Have large cracks been filled
• Is the surface clean and dry
• Trash trucks
• Schools and school traffic
• Sufficient Traffic Control
• Application rate over surface conditions
• Equipment Calibration

38. Things to Consider
• 50º F and rising
• Slight breeze may be beneficial. High winds may
make it a challenge to keep the surface clean
• Sunlight needed to cure. Much shorter work
windows in the cold months.
• Minimize hand work
• Overlaps should not be in the typical wheel paths
• Chance of Rain?

43.  You only get what you inspect
 Understand the process and the materials
 Use a check list
• http://www.fhwa.dot.gov/pavement/preservation/ppcl13.cfm
 If you have any questions lean on industry:
• Most suppliers and contractors are more than wiling to spend
some time and answer your questions.
 Learn what 25 tons of aggregate looks like in a stock
pile (verify application rate)
 Traffic Control
 Joints
 Hand work
 Starts / Stops

45. International Slurry Surfacing Association
The “Greenbook” Standard Specifications
for Public Works Construction
Caltrans Specifications section 37 and
MTAG Chapter 8
FP2

46. Todd Vargason
Ergon Asphalt and Emulsion
Todd.Vargason@Ergon.com
909-829-0505