U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000


Skip to content U.S. Department of Transportation/Federal Highway AdministrationU.S. Department of Transportation/Federal Highway Administration

Pavements

 

Approaches For Improving The Sustainability Of Pavement Recycling

Asphalt and concrete pavements are commonly recycled and reused construction materials. The products of asphalt and concrete pavement recycling can be used back in new asphalt or concrete mixtures, used as aggregates in base layers, or used in a number of other applications, such as fill, riprap and ballast.

Several recycling techniques and applications are available for both asphalt and concrete pavement materials, and pavement recycling is often regarded as an inherently sustainable activity. However, in order to realistically assess the relative benefits of recycling, all recycling options and their associated impacts on sustainability should be evaluated. Important factors that may potentially impact the costs and beneficial environmental impacts of pavement recycling include: technology (on-site vs. off-site activities), transportation costs, processing costs for various applications, disposal costs (of any unusable or undesirable portions of the pavement), and the quality of the recycled material products.

Tables 1 and 2 list general approaches to improving the sustainability of asphalt and concrete pavement recycling, respectively, and summarize the key economic, environmental and societal impacts and trade-offs of each approach. Chapter 8 (.pdf) of the Reference Document provides more detailed presentations and discussions of the impacts of each approach.

Table 1. Approaches for improving the sustainability of asphalt pavement recycling.
Asphalt Pavement Recycling Objective Approach for Improving Sustainability Economic Impact Environmental Impact Societal Impact
Increase Rate of Central Plant Recycling Improve plant technology (including improvements in heating time, positive dust control, use of double-barrel mixing, etc.). Requires initial capital investment for the producer, which may be reflected in bid prices. Can potentially reduce pavement production costs. May reduce GHG and particulate emissions. Increased recycling rates help to preserve virgin natural resources (aggregate and asphalt).
Increase the initial quality of pavement products and construction. Initial costs may be increased, but life-cycle costs may decrease with increased pavement life.. Energy required for material production may increase, but overall life-cycle energy and emissions may be reduced.
Use softening agents or rejuvenators. Can increase material production costs, but life-cycle costs may be reduced through increased pavement life. Life-cycle GHG emissions may be reduced with improved pavement performance and longer service life. Must consider upstream environmental impacts of these additives.
Maintain and manage multiple RAP stockpiles (use fractionation, protect from moisture). Can increase material production costs slightly but may decrease life-cycle costs. Can increase material production energy use (fractionation, stockpiling), but overall life-cycle energy and emissions may be reduced with improved performance.
Increase Rate of In-Place Pavement Recycling Use the proper types and amounts of additives or stabilizers. Can increase material production costs but may decrease life-cycle costs. Life-cycle energy and emissions may be reduced. Increased recycling rates help to preserve virgin natural resources (aggregate and asphalt).
Use structural asphalt overlays to improve weathering, cracking and fatigue resistance of recycled layers. Initial construction costs may be increased significantly, but life-cycle costs may be reduced due to slower deterioration of recycled layers. Environmental burdens of initial construction may be considerable, but life-cycle impacts may be lower.
Develop standards for mixture design and construction to improve quality. No costs to project. Life-cycle energy consumption and emissions may be reduced with improvements in pavement quality and performance life.
Table 2. Approaches for improving the sustainability of concrete pavement recycling.
Concrete Pavement Recycling Objective Approach for Improving Sustainability Economic Impact Environmental Impact Societal Impact
Increase the Use of Recycled Materials and Minimize Waste Optimize use of recycled materials through testing and characterization. Initial investments in project-level testing should be offset by increased rates of utilization that result in reductions in the requirement for virgin materials. Increased and more effective use of recycled materials will help reduce depletion of natural resources and emissions associated with the production and transport of new materials. Possible reductions in haul-related congestion, especially for on-site recycling. Preservation of natural sources and reduced need for landfills.
Customize the preparation of source concrete with respect to removal of asphalt overlays and patches and pavement breaking techniques. Potential increase in production costs. May be offset by improved use of recycled materials in high-type applications. Reduced waste through improved reclamation efficiency and use of recycled products. Reduced emissions from the production and transport of new materials.
Modify or adjust RCA production operations. Some operational adjustments may result in added initial costs (e.g., for customized crushing and screening); these may be offset by reduced natural aggregate costs and life-cycle costs. Reduced waste through improved reclamation efficiency and use of recycled products.
Reduce CO2Emissions over the Life Cycle Sequestration of CO2 by RCA. Minimal economic impact. Potential to offset CO2emissions from the raw materials used in cement production (not including fuels used in production). Reduced impact on cement production on climate change.
Reduce Virgin Material Usage and Material Transportation On-site recycling. Increased costs of mobilizing and setting up on-site recycling equipment. May be offset by reductions in fuel consumption and labor costs associated with off-site recycling and virgin material production. Reduced GHG emissions due to reductions in haul traffic. Reduction in haul truck traffic and traffic congestions, reduced need for landfills.
Updated: 06/27/2017
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000