Micro-surfacing

Sponsored by: Minnesota LTAP Center

Presented by: Michael Marti, P.E.SRF Consulting Group, Inc.

Dan Wegman, P.E.SemMaterials

History of Micro-surfacing

• Developed in Europe in 1970’s• Introduced in U.S. in 1980

– Now used in more than 30 states

• Used for rut filling and texturing

What is Micro-surfacing?

• Surface treatment 3/8” to 1/2” thick• Sometimes mislabeled as a polymer modified

slurry seal• Advantages over slurry seal are

– Chemical breaking process• Faster curing time

• Can be applied at night

– Can be placed in a thicker layer

What is Micro-surfacing?

• It is a mixture of– Polymer modified emulsion– Crushed aggregate– Mineral filler– Water– Additive

Conveyor

Crushed Aggregate

Spreader boxWater Spraybar

Mineral filler

Mixer

Micro-surfacing mix

.

Micro-surfacingPaving Machine

Polymer-modified Emulsion, Water, and Chemical Additive

Micro-Surfacing Application

Spreaderbox

Crushedaggregate

Cementadditive

water

PolymerModifiedEmulsion

DirectionMixing time

15 to 45 seconds

Mixture Brown &Homogeneous

Breaking Time60 to 120 seconds

Traffic in Approximately One Hour

Mixture Black

Water Flows

How is Micro-surfacing used?

• On asphalt and concrete pavements it can– fill ruts– restore skid resistance– address oxidized, raveled, and flushed surfaces– reprofile (leveling)– provides wear course– be used as an interlayer

Performance varies with...

• Climate• Traffic• Existing pavement• Materials / mixture design• Construction quality

Condition of existing pavement

• Structurally sound• Moderate- and high-volume roads

Weather conditions

• Air temperature at least 50°F• Pavement temperature at least 50°F• No rain• No freezing within 24 hours

Construction considerations

• Repair / seal joints and cracks; cure• Clean the surface of the road• Tack coat

– dry or raveled surface– concrete

Micro-surfacing performance

• Wheel rut resistance - Excellent• Skid resistance - Excellent• Raveling resistance - Good• Treatment for flushing - Good• Interlayer - Good• Resistance to reflection cracks - Low

Rut Box