8
Strategies for Improving the Sustainability of Asphalt Pavements
Table 1. Approaches to improving pavement sustainability with asphalt materials production.
Asphalt Materials
Objective
Sustainability Improving
Approach
Economic
Impact
Environmental
Impact
Societal
Impact
Reduce Virgin Binder
Content in Asphalt
Concrete
Use greater quantities of RAP
if same or better performance
can be realized.
Reduces cost of asphalt concrete if
RAP is available.
Dependent on performance, energy
costs of mixing, transportation.
Extends life of petroleum
resources. Reduced need for
landfill.
Use rubberized asphalt for
asphalt concrete.
Some increase in initial cost, impact
of mixture design higher, potential
payback in less material for thin
overlays, increased life.
Reduces impacts by decreasing
amount of materials needed over
time horizon.
Reduced exposure of public to
accidents in work zones.
Use RAS as partial
replacement for asphalt
binder if same or better
performance can be realized.
Reduces cost of asphalt concrete if
RAS is available.
Reduce impact from otherwise using
virgin binder.
Extends life of petroleum
resources. Reduced need for
landfill.
Use bio-binders. Impacts and trade-offs unknown. Impacts and trade-offs unknown. Impacts and trade-offs unknown.
Use sulfur-modified asphalt. Not well quantified. Potential difficulty in future recycling. Risks for worker health.
Reduce Virgin
Aggregate Content in
Asphalt Concrete
Use greater quantities of RAP
if the same or better
performance can be realized.
Reduced cost of asphalt concrete if
RAP available.
Dependent on performance, energy
costs of mixing, transportation.
Extends life of aggregate
resources. Reduced need for
landfill.
Reduce Consumed
Energy and Emissions
Generated to Produce
Asphalt Concrete
Use WMA to reduce mixing
temperatures.
Zero to small increase in cost. Reduced energy and GHG to make
asphalt concrete. Impact of
producing WMA additives needs to
be considered.
Reduced worker exposure to
fumes.
Change fuel used for heating
to reduce emissions, such as
natural gas.
May increase cost. Reduced emissions to make asphalt
concrete.
Reduced worker exposure to
fumes.
Reduce Energy
Consumed and
Emissions Generated
to Produce Asphalt
Concrete
Employ new, more efficient
plant designs to reduce
energy consumption and
increase the percent RAP and
RAS used.
Increased capital cost to upgrade
existing facilities. Reduced
operating cost due to decreased
energy consumption as well as
increased use of RAP and RAS.
Reduce emissions to produce asphalt
concrete through reduced fuel
consumption and higher percentage
use of RAP and RAS.
More efficient utilization of
recovered materials such as RAP
and RAS.
Extend Lives of Asphalt
Concrete Materials
Improved compaction
specifications, no trade-offs.
Some increase in initial cost for extra
contractor effort and inspection,
large payback in increased life.
Reduces impacts by decreasing
amount of materials needed over
time horizon.
Reduced exposure of public to
accidents in work zones.
Use WMA to obtain better
compaction.
Zero to small increase in cost,
payback in increased life.
Reduces impacts by decreasing
amount of materials needed over
pavement life cycle. WMA additives
needs to be considered.
Reduced exposure of public to
accidents in work zones.
Improved mixture designs. Some cost for new equipment,
training, payback from longer lives.
Reduces impacts by decreasing
amount of materials needed over life
cycle.
Reduced exposure of public to
accidents in work zones.
Use polymers. Some increase in initial cost, impact
of polymer production, potential
payback in increased life.
Reduces impacts by decreasing
amount of materials needed over life
cycle. Impact of producing polymer
additives needs to be considered.
Reduced exposure of public to
accidents in work zones.
Increased exposure of workers to
fumes.
Use rubberized asphalt. Some increase in initial cost, impact
of mixture design higher, potential
payback in less material for thin
overlays, increased life.
Reduces impacts by decreasing
amount of materials needed over
time horizon.
Reduced exposure of public to
accidents in work zones.
Increased exposure of workers to
fumes.
Use lime or liquid anti-strip to
decrease risk of early failure
due to moisture damage.
Slight increase in initial cost,
payback from extended life where
warranted.
Initial impact from manufacture of
materials, potential payback if life
would otherwise be shortened.
Increased worker exposure to lime
or chemicals.
Reduce Materials
Transportation Impacts
Use more locally available
materials.
Lower initial cost. Potential for
greater life-cycle cost if perform is
compromised. May have shorter
lives if performance-related
properties are poorer.
Reduces impacts of transportation of
materials, particularly important if
trucks would be used. May have
shorter lives if performance-related
properties are poorer.
Reduced exposure of public to
trucking.
Extend Lives of Seal
Coats
Use rubber or polymer
binders.
Some increase in initial cost, binder
production impact higher, potential
payback from increased life.
Increased impact due to production
of polymers. Potential payback from
improved life.
Polymers made from finite
petroleum resources.
Reduce Need for
Virgin Materials and
Transportation
Use in-place recycling (full-
depth reclamation, partial-
depth recycling). May have
high construction variability.
Can potentially reduce initial cost by
reducing transportation of virgin
materials and permitting thinner
overlays, and may extend life where
appropriately selected and
designed. May have high
construction variability.
Can reduce use of virgin materials
depending on life. Can reduce
transportation of materials. Energy
savings dependent on technology
and life. May have high construction
variability.
Fewer heavy trucks on the road
hauling materials.
Increase Pavement
Albedo where
Warranted (See
chapter 6)
Use lighter colored
aggregates, place light
colored chip seals, other
reflective surface treatments.
Cost may be greater if reflective
treatment not otherwise needed.
Can potentially reduce risk of rutting
of asphalt concrete. More materials
used if additional coating applied
that is not otherwise needed.
Needs to be evaluated on a case by
case basis (see chapter 6). If
warranted, specific impacts that are
positively impacted must be noted.
Unintended consequences should
also be examined.
Needs to be evaluated on a case
by case basis (see chapter 6). If
warranted, specific impacts that
are positively impacted must be
noted. Unintended consequences
should also be examined.