Reuse and recycling of asphalt

Dariusz Słotwiński, President of PSWNA

28-30.09.2011, Ożarów Mazowiecki

What is EAPA • EAPA is the European industry association which represents the manufacturers of bituminous mixtures and companies engaged in asphalt road construction and maintenance Its mission • To promote the good use of asphalt in the creation and maintenance of a sustainable European road network.

Objectives EAPA • to promote the effective and sustainable use of asphalt • to collect and exchange information, know-how, best practice • to promote knowledge and understanding • to represent its members in the institutions of the EU • to promote the image of the asphalt paving industry in Europe. • to innovate measures and best practice to improve the HS&E conditions of all employed in the industry • to participate in European standardisation activity • to promote new developments such as WMA and higher levels of asphalt recycling

Recycling - Reuse •



Recycling: same function as in the original application (adding the reclaimed asphalt to new asphalt mixes) Re-use: utilisation a lesser function than in the original application (reclaimed asphalt as foundation, fill or base course material)

Recycling since 1970s

History • In 1955 – 1958 surface layers were recycled in a “primitive” way with addition of oil • Because of Energy Crisis in 1973-1974 recycling of asphalt started because of bitumen savings

In the Netherlands • 1976: Renofalt, using steam to heat old asphalt • 1982 Introduction of drum mixer in NL • 1990 Introduction of MARS (Microwave Asphalt Recycling system)

Asphalt recycling • • •

Started at least 35 years ago Built up an important record in recycling Use of “waste” in asphalt since many years

Milled surface

Recycling techniques Central Plants: • Batch mixing plant (hot) • Drum mixer plant (hot) • Cold recycling

In-situ recycling • Hot mix recycling • Cold mix recycling / re-use

10 - 40 %

30 - 80 %

35 %

up to 50 %

Some facts (2009) • Yearly asphalt production in Europe 326 million tonnes • 4159 Stationary asphalt plants • 795 Mobile plants • 1642 Fit for hot recycling ( = 33,4 %)

Asphalt in Figures 2009

Asphalt in Figures 2009 Summary Available in Europe

52.716.960 tons

Recycling / reuse (based on recycling / reuse data)

86,5 %

Old pavements with tar • Do not use tar containing RAP for hot recycling • Cold use of RAP containing tar could be possible (depending on national legislation)

View of asphalt industry •

The industry strongly supports all efforts to increase the percentages of reclaimed asphalt into new hot mix asphalt

• •

1st goal is recycling of RAP 2nd option is reuse of RAP

Stimulating recycling The industry strongly supports • Support increase of use of RAP • Reuse of RAP at the highest possible level • Tender documents should give possibilities to use RAP • The road owner should take of their RAP • Reclaimed asphalt should be a product • Plant modifications if > 10% RAP added

EAPA Position papers

May 2008

May 2004

Arguments to promote recycling

Economic Benefits

Source materials: Don Brock, Astec Industries, Inc.

Increasing asphalt recycling • • • •

Stronger support from the authorities engineering community / consultants Adapt asphalt specifications Regulations with regard to dumping / tipping of re-useable material RAP should be regarded as a building material and not as a waste

Conclusion • • • •

Recycling is a challenge for the industry Asphalt is 100% recyclable and should remain Client can stimulate recycling Legislation can stimulate recycling

•

Recycling is important / responsibility of product-owner / road-owner

Political trends and issues • • • •

Sustainable development Minimizing environmental impact Optimising the use of natural resources Increased restrictions on the dumping of reusable material • Economic stimulation to encourage the recycling and/or re-use

Use of waste from others Only use other products if there are • No disadvantages for health and safety of workers • No environmental impacts, now or in the future • Future recyclability and reuse of asphalt remains • No negative impact on the technical product performance of asphalt

Cold in central plant RAP mixed with • bitumen emulsion / foamed bitumen and or • cement

Developments of Recycling / Re-use in Gemany as an example

37

Production of Asphalt and amount of RAP (1982 – 2010)

38

Amount of RAP and the use / re-use of RAP (1987 – 2010) Wiederverwendung Aufkommen

16 14

[Mio. Tonnen]

12 10 8

6 4

2 0

D

Use of RAP

3,0

11,5

sonstige Verwertung [Mio. t]

Wiederverwendung in Asphaltmischgut [Mio. t]

40

Percentage of re-use of RAP 90%

Wiederverwendungsrate

80%

70%

60%

50%

Asphalt = THE material for re-use ! Also good examples are e.g. : Glass, Iron

40%

30%

Jahr

41

Recent developments • Selective milling and separate Storage of RAP • Sieving of RAP and selective addition of RAP • Dry storage of RAP • Use of Parallel drum

42

3 different feeders for RAP

43

Separate feeders for RAP

44

Milling of separate layers

Separated storage

Covered storage

47

Reducing moisture content in RAP

48

Asphalt plant with parallel drum

49

Parallel drum

… Inside

Parallel drum 50

Use of Parallel drums in Germany and Netherlands Germany

Netherlands

667 Asphalt plants

44 Asphalt plants

Total produktion: 51,0 Mio. t

Total produktion: 10,2 Mio. t

Year: 2007

Year: 2007

19 % 98 %

2%

81 %

AMA ohne Paralleltrommel

AMA mit Paralleltrommel

EN 13108 Asphalt standards • Surface courses with < 10% reclaimed asphalt • Regulating courses, binder courses and bases with < 20% reclaimed asphalt no (additional) requirements

EN 13108 Asphalt standards • Surface courses with > 10% RAP • Regulating courses, binder courses and bases with > 20% RAP: • Penetration or the softening point of the binder in the resulting mixture shall meet the penetration or softening point requirements of the selected grade.

EN 13108-8 “Reclaimed Asphalt”

Recycling with rubber Możliwość wielokrotnego wykorzystania Przydatność do wielokrotnego użycia nie została jeszcze dostatecznie zbadana, ponieważ przez częściowe podgrzewanie błonki lepiszcza asfaltowego w granulacie asfaltowym w suszarce mogą również powstawać temperatury powyżej 180°C. Z technicznego punktu widzenia możliwość wielokrotnego wykorzystania według obecnego stanu podana jest w takim samym stopniu jak dla tradycyjnych asfaltów z lepiszczem wg TL-Asphalt.

Recycling with rubber Since little work on the recyclability of rubber-asphalt pavements has been reported in the literature, and many questions have been raised concerning problems which could arise from recycling rubber-asphalt pavements, these questions must be addressed from a theoretical perspective by NCDOT and subsequently from laboratory and field project evaluation. If recycling of rubber-asphalt pavements cannot be accomplished with current technology then the use of rubber-asphalt will not be a viable solution to the solid waste problem of scrap tires. Two questions which must be answered are: (1) What is the effectiveness of the addition of recycling agents, both chemical and viscosity graded asphalt cements, to rubber-asphalt RAP, and (2) What are the effects of recycling rubber-asphalt on air quality?

Recycling with rubber Concerning the effectiveness of recycling agents or virgin asphalt cement on rubber-asphalt and rubber-modified mixes, rubber-modified mixes should not pose a significant problem with recycling due to the fact that the rubber does not act as a binder, only an aggregate. Given this the rubber does not significantly affect the viscosity of the aged asphalt cement. Rubber-asphalt, however, is the binder which must be penetrated by the recycling agent or virgin asphalt to rejuvenate the aged asphalt. Since the aged rubber-asphalt has a higher viscosity than convention asphalt, the penetration of the recycling agent or virgin asphalt will be reduced, thus affecting the quality of the recycled material. Laboratory testing must be conducted in order to determine if rubber-asphalt mixes can be recycled, the methods necessary for recycling, and the performance of the recycled mix. If recycling is not possible disposal of rubber- asphalt RAP may be necessary by NCDOT maintenance forces in lane/shoulder stabilization uses. It is not anticipated that rubber-modified mixes will exhibit this problem.

Recycling with rubber Concerning air quality, at the present level of RAP uses (10-20%) the amount of rubber present by either method would be less than 1 percent of the total recycled mix using either Rubber-asphalt or rubber-modified mixes. At these levels, air quality should not be significantly affected. Designing an asphalt mix which utilizes rubber-asphalt or rubber-modified RAP should also be considered in any subsequent laboratory study. It is not anticipated that the incorporation of small amounts of rubber-asphalt or rubber-modified RAP will significantly change the mix design process. However, it should be realized during this process that the RAP does contain rubber and some differences in the mix properties may exist due to the presence of a small amount of rubber. As the percentage of rubberasphalt or rubber-modified RAP is increased it may be necessary to follow the same design procedure for a new mix utilizing rubberized RAP as one would follow for a new rubber- asphalt or rubber-modified mix.

Can Asphalt-Rubber be recycled? Many agencies engage in the recycling of paving materials. A-R has been successfully recycled on many occasions. One of the most recent reports is by the City of Los Angeles. LA., recycled a 12 year old A-R pavement on Olympic Blvd. They also performed an air quality impact of grinding, transporting and processing the asphalt rubber. The results of the testing showed that the recycled A-R reclaimed from Olympic Blvd. Met specifications and passed all test and is recyclable using either microwave technology or conventional mix design technology. The Air Quality testing report employee exposure to air contaminants well below the CAL/OSHA permissible exposure limits (PEL) and in most cases, below the detection limit.