Details:

Creators:
Hansen, Kent R. ; Copeland, Audrey
Hansen, Kent R. ; Copeland, Audrey Less -
Corporate Creators:
National Asphalt Pavement Association
Corporate Contributors:
United States. Federal Highway Administration. Office of Pavement Technology
Subject/TRT Terms:
[+]
Asphalt Pavements Contractors Recycled Materials State Departments Of Transportation Surveys Warm Mix Paving Mixtures
Publication/ Report Number:
IS-138
Resource Type:
Tech Report
Geographical Coverage:
United States
Corporate Publisher:
National Asphalt Pavement Association
Abstract:
One of the shared goals of the Federal Highway Administration (FHWA) and the National Asphalt Pavement Association

(NAPA) is to support and promote sustainable practices such as pavement recycling and warm-mix asphalt (WMA). The use of

recycled materials, primarily reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS), in asphalt pavements

reduces the amount of new materials required to produce asphalt mixes and material going to landfills. This is vital to the mission

of environmental stewardship and extending the service life of the nation’s infrastructure while lowering overall costs.

WMA technologies have been introduced to reduce the mixing and compacting temperatures for asphalt mixtures as a means

of reducing emissions. Additional benefits include improved compaction of asphalt mixtures leading to improved pavement

performance. As part of FHWA’s Every Day Counts initiative, WMA was chosen for accelerated deployment in federal-aid highway,

state department of transportation (DOT), and local road projects.

It is important for the industry to track the deployment of these technologies, which reduce costs, energy, waste, emissions,

and the amount of new materials required for road construction. FHWA has established two survey mechanisms for tracking the

use of recycled materials and WMA in asphalt pavements. The first survey tracks state DOT usage and the other tracks industry

usage. These have established a baseline of RAP, RAS, and WMA usage and tracked the growth of the use of these sustainable

practices in the highway industry since 2009.

The objective of this survey is to quantify the use of recycled materials, and WMA produced by the asphalt pavement

industry. Survey results show significant growth in the use of RAP, RAS, and WMA technologies from 2009 through 2012. The

asphalt industry remains the country’s number-one recycler by recycling asphalt pavements at a rate of over 99 percent and

almost all (98 percent) contractors/branches report using RAP in 2012. The amount of RAP used in asphalt mixtures has increased

by 22 percent, from 56 million tons in 2009 to 68.3 million tons in 2012. Assuming 5 percent liquid asphalt in RAP, this represents

over 3.4 million tons (19 million barrels) of asphalt binder conserved during 2012. The estimated savings at $600 per ton for

asphalt binder is $2.04 billion.

Use of both manufacturers’ scrap and post-consumer asphalt shingles used in asphalt mixes increased 165 percent from 2009

to nearly 1.9 million tons 2012. Assuming a conservative asphalt content of 20 percent for the RAS, this represents about 380,000

tons (2.1 million barrels) of asphalt binder conserved. The estimated savings at $600 per ton for asphalt binder is $228 million.

For 2012 contractors were asked about their use of other recycled materials in asphalt mixtures. Contractors in 13 states

reported using steel and blast furnace slag in asphalt mixtures. Ground tire rubber (GTR) was reported as being used in asphalt

mixtures in nine states. Other recycled materials used to a lesser degree include fly ash, bottom ash, foundry slag, cellulose fiber,

and glass. Due to the low response rate on other recycled materials no attempt was made to estimate the total quantities of other

recycled materials used.

In 2012, WMA was over 24 percent of the total asphalt mixture market. WMA use increased by nearly 26 percent from 2011

to 2012, and about 416 percent since 2009. Plant foaming is used most often in producing WMA, with over 88 percent of the

market. WMA additives accounted for about 12 percent of the market.


Format:
PDF
Alternate URL:
http://ntl.bts.gov/lib/51000/51100/51156/IS138-2012_RAP-RAS-WMA_Survey_Appendix_A_Final.pdf ; http://ntl.bts.gov/lib/51000/51100/51156/IS138-2012_RAP-RAS-WMA_Survey_Appendix_B_Final.pdf ;
Funding:
DTFH61-13-P-00074
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:14c69c180df1c7a36aa10c99950d01d08868f79aa9a71713dfb41dca8db99817
Download URL:
https://rosap.ntl.bts.gov/view/dot/26950/dot_26950_DS1.pdf
File Type:

Supporting Files

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