Pavement Maintenance II Part 1a: SurfaceTreatments Idaho Roads Scholar Program

Objective Investigate types of surface treatments and where they are most beneficial.

Surface Treatments: Purpose Typically used to: n Seal cracks n Waterproof surface n Improve friction n Improve rideability n Rejuvenate surface

Candidate for…?

Surface Treatments Types n Fog Seal n Slurry Seal n Chip Seal n Cape Seal n Scrub Seal

Light application of diluted, slow-setting asphalt emulsion without aggregate cover. Description Purpose  Seal pavement  Inhibit raveling  Enrich hardened/oxidized asphalt  Provide delineation with shoulder Fog Seal

Fog Seal Benefits n Seals small cracks & surface voids n Prevents raveling of chip seals n Prevents snow plow damage n Darkens new chip seals

Fog Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Feasible Not Appropriate Feasibility

Fog Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Effective Marginal No Impact Effectiveness

Fog Seal n A fog seal is one of our least expensive tools to use and also one of our least used tools. It consists of the following steps: u Clean the pavement surface. u Then clean it again! u Provide for traffic control. u Spray the liquid asphalt. u After allowing for cure time blot up any puddling.

Fog Seal

n Most common product used: CSS- 1 dilute n Cost for CSS-1 dilute in Boise: $ per ton. n Cost to apply a fog seal: $0.10 to $0.20 per square yard n A maximum of a three year life

Slurry Seal Mixture of well-graded aggregate and slow setting asphalt emulsion Description Purpose  Seal surface cracks.  Correct raveling/oxidation.  Fill minor surface irregularities and restore friction. Good application to use in subdivisions where curb exposure is an issue.

Slurry Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Feasible Not Appropriate Feasibility

Slurry Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Effective Marginal No Impact Effectiveness

Slurry Seal n A slurry seal utilizes an emulsified asphalt and a small aggregate that is mixed through a mobile pug mill and then is squeegeed onto the pavement. It consists of the following steps: F Clean the pavement surface. F Work is normally performed under a road closure. F Apply the slurry seal. F Wait for cure time. (Usually about???)

Slurry Seal

n Most common seal used: Type II (1/4-10) n Cost to apply: $0.85-$1.20 per square yard. n Has an average of a five to ten year life. n Should seal cracks prior to applying slurry seal. n Requires very clean rock.

Chip Seal Application of asphalt and aggregate chips rolled onto the pavement Purpose  Seal pavement  Enrich hardened/oxidized asphalt  Retard reflection cracking on HMA overlays  Improve surface friction Description

Chip Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Feasible Not Appropriate Feasibility

Chip Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Effective Marginal No Impact Effectiveness

Chip Seal n A Chip Seal provides a little heavier seal and consists of a spray applied liquid asphalt and then rock added to it. A typical Chip Seal consists of the following steps: F Clean the pavement surface. F Provide for traffic control. F Spray the liquid asphalt. F Apply the rock into the asphalt F Roll with pneumatic rollers. F Sweep loose rock up.

Chip Seal

n Most common product used: Polymer modified emulsion. n Cost for emulsion in Boise: $ per ton. n Cost to apply a chip seal: $0.90 to $1.40 per yard. n A typical life of 7 to 12 years.

Chip Seals--Rules of Thumb n Don’t use on bleeding or rutted pavements n Pre-fog seal any new patches n Use clean chips n Wait for warm weather (>70ºF) n Spread chips immediately behind emulsion spray n Roll slowly (walking speed) with rubber roller

Cape Seal n Combination of a chip seal, a slurry seal and usually a crack seal application. n Good process to use where curb exposure is a concern.

Cape Seal Clark Co 1993

Macro Sealing n Application of asphalt and aggregate chips rolled onto the pavement n Single machine applied n Eliminates distance between distributor and chip spreader n Same results as a chip seal

Macro Surfacing

Scrub Seal Application of sand or small-sized aggregate on broomed layer of polymer-modified asphalt Purpose  Fill and seal small cracks and voids  Enrich hardened/oxidized asphalt  Preparation for another treatment Description

Scrub Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Feasible Not Appropriate Feasibility

Scrub Seal Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Effective Marginal No Impact Effectiveness

Scrub Seal n Developed by ADOT n Designed to “arrest light deterioration” n Fills cracks without the labor intensive work n Rejuvenates properties of the old asphalt lost due to oxidation

Scrub Seal - How to apply n Asphalt agent applied by distributor n Scrubbed into the cracks & surface n Sand is then applied over asphalt and scrubbed into cracks & surface again. n Rolled with a pneumatic roller n Traffic removes excess sand n Road opened in about 2 hours

Review Investigate types of surface treatments and where they are most beneficial.

Surface Treatments Types - Review n Fog Seal n Slurry Seal n Chip Seal n Cape Seal n Scrub Seal

Review cont. n 2 layers of rock on layer of asphalt n 60% - 70% aggregate coverage n Adjust for existing pavement condition n Go lighter on new AC patches n Take time to calibrate n Binder protects road - Chips protect the binder n Cubicle chips better than flat chips n Always have clean surface / Equip.

Questions? Surface Treatments