Asphalt emulsions in Hawaii are made for many different uses in roadwork.  This simple webpage helps to provide information on some of the more common uses in roadwork. For more information or questions contact us, or come by our manufacturing facility in Honolulu, Monday-Friday 7:00am – 3:30pm.

Some of the specific uses of asphalt emulsions in Hawaii include:

• Tack Coats
• Fog Seals
• Chip Seals and other surface treatments
• Slurry Seals and Micro Surfacing
• Cold Mixes

Tack Coat

Tack coat is a thin layer of asphalt that ensures the bonding between old and new asphalt layers; and between multiple asphalt lifts. The lack of tack coat may result in slippage and can cause concentrated stresses leading to total pavement failure. 

There are various types of tack coats specified for use here in Hawaii. Hawaii emulsions for tack coat that are readily for sale in bulk are SS-1H, CSS-1H, CQS-1H (can be used in slurry and tack coat), and LMCQS-1H (latex modified can be used in slurry and tack coat).  For more information contact us.

Hawaii Asphalt Paving Industry President Jon Young recently wrote an informative article titled “Tack Coat Materials”. The following excerpts are from that article on various Hawaii specifications. (Click here for the full article.)

“Standard Specifications for Public Works Construction, September 1986: Tack coat shall be either SS-1 or SS-1h emulsified asphalt.”

“City and County of Honolulu, Department of Design and Construction, Boilerplate Special Provisions: Tack coat shall be Type SS-1, SS-1h, CSS-1, or CSS-1h, emulsified asphalt.”

“Hawaii Department of Transportation, 2005 Standard Specifications: Emulsified Asphalt (Type SS-1, SS-1h, CSS-1 or CSS-1h)”

“The Whole Building Design Guide Unified Facilities Guide Specifications, used on military and other projects, provides the specification writer with four options for emulsified asphalt to be used for a tack coat: SS-1, SS-1h, CSS-1, and CSS-1h.”

“The Federal Aviation Administration’s (FAA) Standard Specifications for Construction of Airports, Advisory Circular (AC) No: 150/5370-10H states for a tack coat, the asphalt material shall be an emulsified asphalt appropriate to local conditions.”

“Of course, there are other specifications used for projects. The1986 Public Works Specification and the HDOT Standard Specifications are often used as a guide in preparing these other specifications or are referenced in these other specifications.”

Ready when you need it:
SealMaster Hawaii has multiple bulk storage tanks that can hold up to 40,000 gallons total of tack coat. With independent stirring, recirculating, and pumping capabilities they have product on hand to fill bulk tanks and distributor trucks of any size at any time.

Fog Seal

What?
A fog seal is an application of a specially formulated asphalt emulsion (a thin liquid oil) to an existing asphalt pavement surface. A fog seal gets its name from its spray application, sometimes referred to as “fogging.” Asphalt emulsions used in fog seal applications contain globules of paving asphalt, water, an “emulsifying agent” or surfactant, and sometimes a “rejuvenator.” Soap is a common form of a surfactant. In washing clothes or dishes, the surfactant helps remove the dirt and suspend the dirt particles in the wash water. Similarly, in asphalt emulsions, the surfactant keeps the paving asphalt globules in suspension until it is applied to the pavement surface when the water in the asphalt emulsion starts to evaporate. A “rejuvenator” is an asphalt additive which when applied to the existing pavement will slightly soften the pavement it is applied to creating a better bond. CSS-1H Product  

Why?
As asphalt pavement is subjected to traffic loads and ages, it oxidizes and cracks develop in the surface due in part to the pavement becoming more brittle. Oxidation is one of the reasons asphalt concrete pavement fades in color from the deep, rich black color everyone remembers from when the road was constructed or last resurfaced. Fog seal applications serve to seal narrow cracks, slightly restore lost flexibility to the pavement surface, provide a deep, rich black pavement surface color, and most importantly help preserve the underlying pavement structure.  

When?
On existing asphalt pavement, fog seals are typically applied on either an intermittent or cyclical basis. Location, weather, traffic loading, and pavement conditions are factors used to determine if a fog seal application is appropriate. Roadways selected for fog seal treatment are commonly those which have minor cracking, faded color, and where a fog seal would help extend the pavement life until resurfacing becomes necessary. Roadways chosen for cyclical fog seal applications would typically be treated every three to five years.  

How?
Fog seals are applied by a distributor truck. The distributor truck slightly heats the asphalt emulsion before spraying it onto the pavement. Once applied the surface has the appearance similar to the pavement having been spray painted black.

Information from Los Angeles County Public Works – Treatment Types

Chip Seal

What?
A chip seal is a two-step process which includes first an application of asphalt emulsion and then a layer of crushed rock to an existing asphalt pavement surface. A chip seal gets its name from the “chips” or small crushed rock placed on the surface.  

Asphalt emulsions used in chip seal applications contain globules of paving asphalt, water, an “emulsifying agent” or surfactant, polymer, and sometimes a “rejuvenator.” Soap is a common form of a surfactant. In washing clothes or dishes, the surfactant helps remove the dirt and suspend the dirt particles in the wash water. Similarly, in asphalt emulsions, the surfactant keeps the paving asphalt globules in suspension until it is applied to the pavement surface when the water in the asphalt emulsion starts to evaporate. The chips (small crushed rocks) are immediately applied after the asphalt emulsion is applied to the pavement surface. The polymer in the asphalt emulsion is a “hardener” which serves to improve the adhesion to the crushed rock and to the pavement surface. A “rejuvenator” is an asphalt or additive which when applied to the existing pavement will slightly soften the pavement it is applied to creating a better bond. Products  

Why?
Chip seals are placed under one of three scenarios, as a “wearing course” meaning vehicles drive directly upon it; as part of a “cape seal” meaning a chip seal is first placed, then covered by slurry seal or microsurfacing; or as an “interlayer” meaning a layer between underlying asphalt pavement and a new asphalt or rubberized asphalt surface.  

As asphalt pavement is subjected to traffic loads and as it ages, it oxidizes, becomes more brittle and cracking develops in the pavement structure. A chip seal serves to seal the narrow cracks, help bind together cracked pavement, provide a wearing (driving) surface, and protect the underlying pavement structure. Chip seals used as interlayers serve to retard reflective cracking which develops from the bottom of the pavement structure towards the top.  

When?
Chip seals are typically applied on an intermittent or one-time basis. Location, weather, traffic loading, and pavement conditions are factors used to determine if a chip seal application is appropriate. Roadways selected for chip seal treatments are commonly those which have moderate block (or “alligator”) cracking which is not spalling (or “popping out”), no rutting, an acceptable ride quality, and in which a chip seal would help extend the pavement life until resurfacing or rehabilitation can be performed.  

Roadways chosen for cyclical chip seal applications would typically be treated every seven to ten years.  

How?
A distributor truck first applies the asphalt emulsion to help seal the pavement surface. Using an asphalt emulsion is considered a “cold applied” chip seal even though the liquid temperature is typically between 110 and 150 degrees Fahrenheit. No smoke results from the application of emulsified asphalt. If modified paving asphalt is applied, it is considered a “hot applied” chip seal as the liquid application temperature is typically between 325 and 375 degrees Fahrenheit. Smoke will result from the application of modified paving asphalt but should not be of concern. Depending upon formulation, the distributor truck may be equipped with a smoke reduction device which reduces the level of blue smoke emitted. This is normal. These devices are subject to permitting and oversight by the jurisdictional air quality management district.  

Immediately following application of the asphalt emulsion, a “chip spreader” follows and applies crushed rock to the top of the asphalt emulsion. A dump truck dumps crushed rock into the chip spreader as it travels. The dump truck appears to be going in reverse but it actually is being towed backward by the chip spreader. Following chip application, rubber tired rollers follow closely behind. The purpose of the rollers is to push the chips down into the binder and enhance the bond between them. A steel drum roller commonly follows the rubber tired rollers on “hot applied” chip seals.  

After rolling and once the binder and chips have properly adhered, the surface is swept by power sweepers. The sweepers sweep the loose crushed rock which has not adhered to the underlying asphalt emulsion. Loss of crushed rock due to sweeping is a normal part of the operations. A chip seal would not be successful if the result was areas of the existing pavement not covered by crushed rock. The rate of crushed rock application is intended to result in a thickness of “one rock.”  

The final operation is placement of a “flush coat.” The flush coat consists of the application of a fog seal (see fog seal) followed by the application of very clean sand. The purpose of the flush coat is to help “lock down” the chips and absorb any excess asphalt emulsion. The result is a pavement surface that has a rough texture and a very deep, rich black in color.  

Information from Los Angeles County Public Works – Treatment Types

Slurry Seal

What?
A slurry seal is the application of a mixture of water, asphalt emulsion, aggregate (very small crushed rock), and additives to an existing asphalt pavement surface. A slurry seal is similar to a fog seal except the slurry seal has aggregates as part of the mixture. This combined mixture of the emulsion and aggregates represents “slurry.” Polymer is commonly added to the asphalt emulsion to provide better mixture properties. The placement of this mixture on existing pavement is the “seal” as it is intended to seal the pavement surface. Slurry seals are generally used on residential streets. Products  

Why?
Slurry seal is applied in order to help preserve and protect the underlying pavement structure and provide a new driving surface. Roads chosen for slurry seal applications generally have low to moderate distress and narrow crack width. Slurry seal applications serve to seal the cracks, restore lost flexibility to the pavement surface, provide a deep, rich black pavement surface color, and help preserve the underlying pavement structure.  

When?
Slurry seal is typically applied on either an intermittent or cyclical basis. Location, weather, traffic loading, and pavement conditions are factors used to determine if a slurry seal application is appropriate. Roadways selected for slurry seal treatment are commonly those which have slight to moderate distress, no rutting, and generally narrow crack widths, and where a slurry seal treatment would help extend the pavement life until resurfacing becomes necessary.  

Roadways chosen for cyclical slurry seal applications would typically be treated every five to seven years.  

How?
The asphalt emulsion and the aggregates are mixed in, and applied using, a purposely built truck, generally referred to as a “slurry truck.” Yes, I know, that’s rather obvious, but I didn’t make it up!  

Slurry trucks contain various compartments which hold the aggregate (fine crushed rock), water, polymer modified emulsion, and other additives, which are mixed in the on-board mixer. The slurry mixture flows out of the rear of the truck and onto the pavement within the confines of a box attached to the rear of the truck. The box serves to distribute the slurry mixture over the pavement. Workers with squeegees follow behind and assist in spreading the mixture, correcting areas not properly covered, and keeping the mixture off of concrete improvements such as gutters.

A piece of burlap is often dragged behind the slurry truck with the goal of producing a smooth texture while spreading the slurry seal. The texture of a slurry seal is different than that of asphalt pavement. The texture may have faint lines and be somewhat coarse. In addition, when the slurry is first placed the surface is tender and can be marked up by sudden turning movements. These impressions on the pavement are temporary as seasonal weather and traffic smooth out these imperfections over time.

Information from Los Angeles County Public Works – Treatment Types

Cold Mix

What?
Cold mix asphalt is the most affordable option to hot mix asphalt on the market, because it doesn’t need heat during the process.
Products

Why?
A fast, economical, easy to use pothole or large crack repair for parking lots, driveways, roads, streets, and more.

When?
The product can be applied in any weather conditions, wet or dry.  These products are made fresh locally and sold in 50lb bags, larger bulk bags, or raw bulk loaded into your truck.  Delivery options are also avalible.

How?
Remove loose material, debris, snow, and standing water from pothole prior to application. Apply the cold mix directly from bag. Fill to a height of 1/2″ above surrounding pavement. Tamp or compact into place with hand tamper or roller.

LABORATORY TESTING

“Knowing is half the battle” G.I. Joe

All products should be tested and meet the ASTM or AASTHO standards they fall under.

One of the benefits of using a manufacture that has a fully functioning lab in-house is that they can test and get quick results, so if anything needs to be adjusted they can make that adjustment before another batch is made.  SealMaster Hawaii is the largest manufacture of asphalt emulsions in Hawaii.  They have a full in-house and send samples to the mainland for validation testing.  Not only does Sealmaster Hawaii test what is required to meet ASTM standards, but they test many things not required by ASTM standards that allow them to make important adjustments to the manufacturing process before and after a batch of product is made, insuring they can repeatedly deliver a quality and consistent product to the end client over and over.  SealMaster Hawaii has been making thousands of gallons of asphalt emulsions products for years in Hawaii and really have the testing and manufacturing process dialed in

“Asphalt” – The magazine of the Asphalt Institute has an extensive amount of additional information on asphalt emulsions as well.

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