Concrete: $0.30-4.50/sq ft
White-topping: $1.50-6.50/sq ft
Applications: All applications as an alternative to conventional black asphalt. Better suited to new construction, but a layer of light pavement can be laid over existing asphalt.
Service Life: Light-colored asphalt: 7-20 years
Concrete: 15-35 years (EPA)
White-topping: 10-15 years
Light-colored pavements are often made of concrete or traditional asphalt with high concentrations of limestone. They have a higher albedo (light reflectance) than traditional black asphalt and can be up to 30-40°F cooler on a hot and sunny day. In the northeast, light asphalt or white-topping are valid alternatives to traditional black pavements, while concrete pavements are rare because of the need to salt roads for winter (road salt dissolves concrete).
Black pavements are one of the main contributors to the urban heat island effect. Dark materials retain solar heat and can reach temperatures of up to 150°F on sunny days. The heat can be enough to burn skin, and in extreme cases, affect the soles of shoes and car tires.
Light-colored pavements, in contrast, can reflect sunlight away from the ground, dispersing heat rather than retaining it. In addition to added safety, this reduces the temperature of the surrounding air and any runoff from the road. The lower temperature keeps cars cooler, which leads to reduced gasoline evaporation and saves energy as drivers use less air conditioning.
Light asphalt can easily be cycled in during regular road repairs. While replacing newer pavement is cost-prohibitive and time-consuming, existing roads can also be “white-topped” with a layer of light aggregate as an easier way to reduce heat retention.
- Lowers road surface and air temperatures.
- Contributes to lower car temperatures, which leads to reduced fuel evaporation and lessens the need for air conditioning.
- Reduces stormwater runoff temperature for ecological benefits.
- Improves nighttime visibility, which leads to safer driving and less lighting required.
- LEED credits available for use of materials which reduce the urban heat island effect.
- Pavements are slightly more expensive than conventional asphalt. Concrete is much more expensive than asphalt, and takes longer to cure.
- Salting ice in the winter can dissolve or damage many concrete and limestone materials.
- It is more difficult to repair or access buried pipes and infrastructure through concrete.
- Reflected heat may warm surrounding buildings.
Regulatory Impacts and Requirements
Financing Options, Incentives, And Rebates
- Investments for Public Works and Economic Development Facilities grants – municipalities
- Community Development Block Grants – municipalities
- Airport Improvement Program – municipalities
- Interstate Maintenance Program, National Highway System, National Highway Performance Program, Surface Transportation Program – State-distributed Federal funding
- Transportation Infrastructure Finance and Innovation Act (TIFIA) Program – Federal
- MassWorks Infrastructure Program – municipalities
- Chapter 90 – MA State
- California’s highways are mostly made of concrete.
- Chicago Sustainable Streets Pilot Project, Chicago, IL
SAMPLE OF SUPPLIERS
*Indicates Boston-area supplier
Photo credit: California Highway System, publicdomainpictures.net