Santa Clara River Trail Final Master Plan - Development Services ...

Chapter 6: Design Guidelines, Maintenance Schedules and Best Practices
Asphalt
Asphalt is the most common surface treatment for multi-use paths. The material composition and
construction methods used can significantly affect the longevity of the pathway. Thicker asphalt sections
and a well-prepared subgrade will reduce deformation over time and reduce long-term maintenance
costs. Asphalt is suitable for a wide variety of trail users and is less jarring on people’s joints than
concrete. Figure 7 shows a typical section of an asphalt trail.
Figure 7. Asphalt Trail Cross-Section
The edges of asphalt often crumble over time, and the material is prone to cracking, doming, heaving, and
settling. To improve the lifespan of the trail, provide an adequate pavement structural section to support
the maintenance vehicles that will be using the trail.
Based on observations and analysis of similar existing asphalt paths, the pavement surfacing will need an
overlay or extensive replacement and renovation every 15 to 20 years. However, this extensive
replacement could be mitigated and the expense reduced with preventative maintenance measures such
as chip-sealing every five to eight years. Chip seal is not recommended for use near the river due to the
potential for excess oil to be washed off the surface. Deteriorated sections are easier to remove and
replace than concrete.
Use of Recycled Materials in Asphalt 5
Asphalt typically used for a paved trail can be composed of recycled materials that otherwise would end
up in a landfill in-lieu of new base material. This reuse of materials reduces hauling-related energy
consumption and construction waste management. These materials include:
Glassphalt: A mixture of traditional asphalt and recycled glass. The glass is used to replace some
of the sand that would otherwise be found in asphalt. Glassphalt can be installed using the same
equipment and procedures as conventional asphalt.
Reclaimed Asphalt Pavement (RAP): RAP can be used as an aggregate in the hot recycling of
asphalt paving mixtures. RAP is routinely accepted in asphalt paving mixtures as an aggregate
substitute and as a portion of the binder in nearly all 50 states. Substitution rates of 10 to 50
percent or more, depending on state specifications, are normally introduced in pavements, and
5 Bondurant, Julie and Thompson, Laura. (2009). Trail Planning in California Communities.
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