Rock to Road

News
Sustainability with green asphalt


April 23, 2013
By Aggregates and Roadbuilding

April 23, 2013, Lanham, Md. – Thanks to the adoption
of sustainable construction practices, the asphalt pavement industry saved
taxpayers more than $2.2 billion dollars during the 2011 paving season by using
recycled materials and energy-saving warm-mix technologies.

April 23, 2013, Lanham, Md. – Thanks to the adoption
of sustainable construction practices, the asphalt pavement industry saved
taxpayers more than $2.2 billion dollars during the 2011 paving season by using
recycled materials and energy-saving warm-mix technologies.

According to a survey conducted by the National
Asphalt Pavement Association (NAPA) in partnership with the Federal Highway
Administration (FHWA), about 66.7 million tons of reclaimed asphalt pavement
(RAP) and 1.2 million tons of reclaimed asphalt shingles (RAS) were collected
in the U.S. during 2011 for use in new pavements. Also, about 19 per cent of
all asphalt produced in the country that year was made using warm-mix asphalt
(WMA) technologies.

Advertisment

“With
warm mix, we can use less energy to produce high-quality pavements, and RAP and
RAS allow us reuse liquid asphalt, saving costs and preserving natural
resources,” said John Keating, NAPA 2013 chairman and president and COO East of
Oldcastle Materials Inc. “While use of these technologies has increased
dramatically, there is room to do more.”

The use of RAP and RAS during
the 2011 paving season translates to a saving of 21.2 million barrels of liquid
asphalt binder. When reclaimed asphalt pavement and shingles are reprocessed
into new pavement mixtures, the liquid asphalt binder in the recycled material
is reactivated, reducing the need for virgin asphalt binder. Using reclaimed
materials also reduces demands on aggregate resources. Warm-mix asphalt
technologies allow asphalt pavements to be produced at lower temperatures,
which means reduced energy demands, as well as fewer emissions during
production and paving.

Compared to a survey of the
2009 and 2010 construction seasons, the use of these sustainable practices has
continued to increase.

In 2011, RAP usage reached
66.7 million tons, a 7 per cent increase from 2010 and a 19 per cent increase
from 2009. More than 99 per cent of asphalt pavement reclaimed from roads went
back into new pavements. In the survey, 98 per cent of producers reported using
RAP in their mixes for new construction, pavement preservation, rehabilitation,
and other projects.

RAS usage also continued to
climb, increasing to 1.2 million tons in 2011 — an 8 per cent increase over
2010, and a 52.5 per cent increase since 2009. Since 2009, RAS usage has been
reported in 36 states. RAS includes both manufacturers’ scrap shingles and
post-consumer roofing shingles.

In 2010, FHWA made warm-mix
asphalt part of its Every Day Counts initiative to speed the deployment of
technologies that can improve highway projects’ quality, sustainability, and
safety. In 2011, total WMA tonnage in the U.S. was estimated at about 69
million tons, a 67 per cent increase from 2010 and a nearly 309 per cent
increase since 2009. Almost all WMA in the U.S. was produced using a foaming
process, which injects a small amount of water into the mix; warm-mix additive
technologies accounted for a little more than 4 per cent of the market.