The end-users of decorative asphalt are major public agencies, commercial and residential developers, as well as individual homeowners. Top Grade’s decorative asphalt products are called StreetPrint, DuraTherm and LogoTherm. Each has each its special application.
California Builder & Engineer magazine asked Steve Drak
|Color coatings are part of the finished process.|
e, a project manager with Top Grade, to give an overview of this niche asphalt market that has been helping them to weather these tough economic times.
• Which came first, decorative concrete or decorative asphalt?
Decorative concrete. The first patented concept was called Bomanite.
• Why choose decorative asphalt over decorative concrete?
1. Continuous surface
Pavement and decorative surfaces blend seamlessly, with no water infiltration into the subgrade or differential expansion/contraction of materials. Unlike other paving materials, asphalt expands and contracts with changes in the temperature, making it resistant to problems associated with other materials that can crack, warp and become uneven. The method we use – StreetPrint – provides a safe, smooth and attractive surface longer.
2. Streamlined installation and scheduling
Eliminates the need for multiple trades on the job. We simply reheat and texture the existing asphalt surface. Access is maintained, and time and money are saved.
With considerable engineering advantages, enhanced pavements often cost less than other alternatives involving first placing AC, then saw cutting & placing concrete, installing concrete unit pavers, and finally patching back AC edges.
By applying Streetbond coatings, there is a potential LEEDS benefit, reducing Urban Heat Island effects.
• How fine are the aggregates in these decorative asphalt applications?
Typically, 1/2-inch medium aggregate is used, but the asphalt is the same material that would be specified by the project engineer of record for the particular use. There are no special requirements for StreetPrint.
• Are there special asphalt binder mixes required for various decorative asphalt applications?
• Are the decorative asphalt applications hot-mix only, or warm-mix (typical application temperature)?
The StreetPrint installation happens after the placement of asphalt by reheating it to approximately 280 degrees Fahrenheit. We have experience installing only over hot mix placements, but if the installation temp will not harm warm mix, then there should be no issue.
• What is the basic difference between StreetPrint and DuraTherm applications?
StreetPrint involves imprinting a pattern into the asphalt surface and applying a fortifying coating over the top to achieve the custom color and appearance desired. StreetPrint is an ideal way to beautify lower traffic index areas such as walkways, medians, parking lot enhancements, and subdivision entrances.
|Typical sequence for applying templates and finishing imprints in the asphalt.|
DuraTherm is similar to StreetPrint in that the heated asphalt surface is imprinted with the desired template pattern; but the grooves are sized to allow a special pre-formed thermoplastic inlay to be melted into the pattern impressions (flush with the asphalt surface), bonding it to the asphalt substrate. DuraTherm is extremely resistant to wear and is designed to stand up to high traffic index areas.
• What are the steps involved in placing these asphalt applications?
1. Heat asphalt surface
2. Imprint pattern template
3. Apply fortifying coating
1. Heat asphalt
2. Imprint desired pattern template
3. Inlay pre-cut DuraTherm thermoplastic material
4. Heat-set DuraTherm to bond to asphalt surface
• How long does asphalt and paint have to be cured before pedestrian and/or vehicle traffic can resume?
The StreetBond coating system (it is NOT paint, but a highly engineered coating system using specialized layers – four “coats” typically) can have foot traffic as soon as it is dry (typically 20 minutes to 1 hour depending on temperature and humidity). Vehicular traffic should wait until 90-percent cure (typically four to eight hours depending on temperature and humidity).
• Are there special construction techniques and special equipment needed for installation of the asphalt?