shell bitumen - wam foam asphalt production at lower operating temperatures … · 2016-01-15 ·...

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3rd Eurasphalt & Eurobitume Congress Vienna 2004 – Paper 137

WAM FOAM ASPHALT PRODUCTION AT LOWER OPERATING TEMPERATURES AS AN ENVIRONMENTAL FRIENDLY ALTERNATIVE TO HMA

O.R. Larsen1, Ø. Moen1, C. Robertus2, B.G. Koenders3

1 KOLO VEIDEKKE a.s., Central laboratory, Langbakken 16, P.O. Box 55, N-1431, Ås, Norway2 Shell International Petroleum Company Limited, Shell Centre, London SE1 7NA, United Kingdom3 Shell Global Solutions (France) S.A.S., Route Départementale 3, B.P. 97, 76650 Petit Couronne, France

ABSTRACT

A co-operation between Kolo Veidekke and Shell initiated work on Warm Asphalt Mix-tures (WAM*) with laboratory experiments back in 1995. The work resulted in the WAM Foam process which was presented for the first time at the Eurasphalt&Eurobitume congress in 2000. WAM Foam is a new process for producing asphalt of hot mix qual-ity, at lower operating temperatures (100-120°C) in a conventional asphalt plant with only minor modifications to the equipment. Asphalt production and quality have been further investigated by several field trials, full-scale applications (about 48000 tonnes of dense asphalt concrete have been laid) and extensive laboratory testing during the last four years. The road sections have been monitored closely and appear to be as durable as those made with hot mix technology. Lower production temperatures result in energy savings of approximately 30% and in an equivalent reduction of CO2 emis-sions. Simultaneously, reductions in other emissions and in fume exposure have been observed, resulting in an improved work environment for both plant operators and asphalt workers. Several plant emission measurements have been performed by an external expert agency and the reductions have been confirmed for the WAM Foam process. In light of the increased focus on the environment in the asphalt industry, the WAM Foam process could play an important role in reducing the industry’s greenhouse gas emissions.

Keywords: Energy saving, Environment, Foam, Fumes, Workability

1. INTRODUCTION

The growing health, safety and environmental awareness of the general public and within the industry as a whole has resulted in significant efforts to save non-renewable fossil fuels, conserve energy and reduce emissions and exposures. In the asphalt industry there is considerable interest in exploring the possibilities of producing and paving asphalt mixtures at intermediate temperatures (80-120 °C). Advances in technology, coupled with growing environmental concerns, have led to research into “more environmentally friendly” asphalt production processes.The driving force for the interest is to combine the benefits of the lower operating temperatures with asphalt mixture quality and durability on the road that are equal to the properties that can be obtained

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ISH3rd Eurasphalt & Eurobitume Congress Vienna 2004 – Paper 137

with hot mixtures. At intermediate temperatures, the range of 90-120 °C is of particular interest. At lower temperatures, e.g. 60-70 °C, the binder will already have a certain level of stiffness and therefore not give enough workability and compactability. Above 120 °C energy savings are obviously less, but it should be remembered that lower operating temperatures are still beneficial for fume and smell reductions.The benefits from lower operating temperatures are significant. But lower operating temperatures are difficult to put in practice since requirements on coating, workability, compaction and final asphalt performance have to be fulfilled.In 1995, Kolo Veidekke and Shell initiated a joint development programme to develop a process for manufacturing asphalt at lower temperatures that has equivalent properties to traditional hot mixed asphalt. A number of approaches that we have investigated have been discussed previously [1-3]. In this paper the emphasis is on the use of foamed bitumen in the warm asphalt mixture process (WAM Foam). This WAM Foam is a process in which a soft bitumen grade and a foamed hard bitumen grade are combined in the asphalt production process in order to achieve a reduction in operating temperatures.Work in our laboratories and in external laboratories has shown that good coating and good compaction can be achieved [3-5]. Once the volumetric properties are similar, the mechnical properties of the warm mixtures are equal to those of the hot mixtures.In the past four years the WAM Foam technique has progressed from a development trial stage into a production stage. Many sections have been paved in Norway, Sweden and the UK. At the time of submission of this paper approximately 48000 tonnes of WAM Foam asphalt had been produced. Day-to-day production and laying experience has been obtained in both batch-mixing plants and in drum-mixing plants. Investigations in the use of recycled asphalt have also been carried out.

* WAM is a Shell trademark

2. WARM ASPHALT MIXTURE PROCESS

In the warm asphalt mixture process using foam (WAM Foam) two different bitumen grades are used.• The viscosity of the soft component is chosen such that at a temperature of 100 °C it can coat the

mineral aggregates.• The hard component is added in the form of foam. Depending on the pavement requirement, the hard

component has a penetration at 25 °C between 10 and 100 dmm. Standard penetration grades such as 10/20, 20/30, 35/50, 40/60 and 70/100 are suitable hard components.

• The required penetration level of the final binder determines the blend ratio of soft and hard binder components. This ratio is easily determined from penetration measurements of blends of the initial components.

If required, an adhesion improver can be used in the binders, as for hot mixtures, to reduce water sen-sitivity.

A WAM Foam modified asphalt plant mixes the soft bitumen first with the mineral aggregate inorder to achieve a pre-coating. In the second step the foamed bitumen is introduced.Foamed bitumen is produced by injection of a small amount of tap water into hot bitumen. The fine droplets of water come into contact with the hot bitumen (typically 160 °C to 170 °C). After the nozzle (pressure reduction) the rapid evaporation of water produces a very large volume of foam: theoretically 1 liter of water forms about 1200 liters of steam. The steam expands until a film of bitumen holds the steam and air in bubbles. The foam is usually characterised in terms of its expansion ratio and its half-life.

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An important factor in foaming is the nozzle design and the injection pressure in order to obtain a good water droplet spray in contact with the hot bitumen. The foaming characteristics of a specific bitumen are further influenced by numerous factors:• Temperature of the bitumen. For most bitumens the foaming characteristics are improved with higher

temperature.• The expansion ratio increases with an increase in the amount of water added, whilst the half-life

decreases. The water helps in creating the foam, but the foam can collapse rather fast due to rapidly escaping steam.

• It is known that e.g. silicone compounds can be effective anti-foaming agents. On the other hand, compounds have also been identified that can increase the expansion ratio and the half-life of the foam from seconds to minutes.

3. WAM FOAM PROCESS IN THE ASPHALT PLANTS

The lower temperature operation of the dryer combined with the moisture from the foam raise a number of potential issues regarding the operations in the ashalt plant.

Generally, dryers are designed to be most efficient when heating and drying aggregates at a given mois-ture content. If the moisture content is higher, the rate at which the aggregates are fed to the dryer must be reduced. Asphalt cannot be produced any faster than the aggregate can be dried and heated.For efficient dryer operation, the air combined with fuel for combustion must be in balance with the amount of fuel being fed into the burner. With fuel oil, lack of sufficient air or excess flow of fuel oil can lead to incomplete combustion of the fuel. With gas operated plants this situation is different.The WAM Foam modified asphalt plants in Norway operate the dryer at a temperature of about 120-130°C without any problems with burner instabilities or in the dust collection system. At these temperatures less dust is collected and there is a lower loading of the filter installation.No moisture was found in the aggregates and no problems were experienced in the screening units and in the hot bins. In order to compensate for the pressure build-up in the mixer while foaming it was found that a good air extraction system is needed.

In a batch-mixing plant the foamed bitumen is produced by injecting the tap water into the bitumen pipe (in a special nozzle system) just before the bitumen enters the mixer. In such a plant the foam is produced in a discontinuous way. An airgun has been installed to blow the foaming chamber and pipes clean after each foam injection.

In a drum-mixing plant the foam can be produced in a continuous way. This has some operational advan-tages, which makes the WAM Foam process most suitable for a drum-mixer. Insulation of pipes and the cleaning is not necessary to the same degree as for the discontinuous process in the batch-mixer.

The production capacity was maintained for all types of mixtures. When recycled asphalt pavement (RAP) was used at a level of 15% to 25% in the production of wearing course asphalt in a drum-mixing plant, the amount of water coming from RAP was about three times higher than the amount of water that was coming from the foam. When RAP was added to the mixture the temperature of the dryer was raised a little to compensate for the extra drying capacity, as would have been done for hot mixture production.

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4. FROM ROAD TRIALS TO LARGE SCALE COMMERCIAL PRODUCTIONS

The first WAM Foam field trial was carried out in May 1999 using a Midland MixPaver (modified for foaming) on the road close to the Hobøl asphalt plant of Kolo Veidekke in Norway. The MixPaver was used because foam equipment had not yet been installed in the asphalt plant. In the MixPaver equip-ment, bitumen foam was produced on the paver, mixed with the aggregate that was precoated with the soft binder in the batch plant, and subsequently laid on the road. Even though this trial was carried out under extremely adverse weather conditions (even some snowfall), the whole paving operation was car-ried out with satisfactory results. For the second WAM Foam trial in May 2000 the asphalt mixture was produced in a batch asphalt mixing plant. Foam equipment built into the asphalt plant enables foamed bitumen to be introduced directly into the pug mill. The first larger scale road trial (one lift wearing course) was carried out in September 2000 on the main road RV120, see Figure 1. A reference hot mix section was also laid.

The mixture was a dense asphalt concrete Ab11 with a 85 pen (final) binder. The asphalt concrete was produced in a batch plant (3300 kg/batch). On the road the Demag DF 110P paver and the Bomag 164 (roller) and 8 tonnes vibratory roller were used. In Tables 1 and 2 the voids contents as measured with the Seaman (nuclear density meter) are given.

The Asphalt Technological Institute (ATI) has monitored the development of (average) rutting, longi-tudinal smoothness and surface texture two times per year (spring and fall). The rutting performance is shown in Figure 2. The first set of data for 5 September 2000 was the condition of the road before the paving of the new one-lift wearing course.

The large increase after the first winter period is due to studded tyres that wear off the mortar on the surface. This is typically observed on all Norwegian roads where the percentage of studded tyres on cars in the winter period is close to 60%. The road has now gone through three winters.

In the UK in April 2001, a trial was held: a WAM Foam 20 mm Dense Road Basecourse (DRB) mate-rial with an equivalent of 40/60 pen bitumen and a conventional hot 20 mm DRB with 40/60 pen were manufactured and paved [6]. The WAM Foam mixture was paved and compacted with conventional paving and compaction equipment. The texture of the asphalt mixture is identical to that of a conven-tional hot 20 mm DRB mixture. Specimens for testing were cored only a few days after the material had been compacted and the mechanical properties were measured. Test specimens were also cored from the conventional hot 20 mm DRB pavement for comparative data. The densities and air voids of the WAM Foam mixture are very similar to those of the conventional hot mixture. The stiffness modulus at 20 °C of the WAM Foam 20 mm DRB was identical to that of the conventional hot mixture. Fatigue measurements were carried out in the Nottingham Asphalt Tester (NAT). The graph of the applied strain (microstrain) versus cycles to failure shows that statistically the fatigue properties are the same.

In 2001 productions of WAM Foam in a batch mixing plant and a continuous drum mixing plant were started in Norway for normal (commercial) paving works. Compared to the few hours of production during the field trials, the day-to-day production provided more information on the plant operational issues which might arise when operating at lower temperatures.

Because of the positive results obtained in these field trials the project moved into the large scale com-mercial production stage, in particular in Norway. An overview of a number of commercial paving jobs

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done so far in Norway is presented in Table 3. In total about 48000 tonnes of asphalt produced accord-ing to WAM Foam process was paved from 2000 to 2003. The examples show that different types of mixtures were produced (dense graded mixtures Agb, Ab and stone mastic asphalt, Ska) with different final binder pen grades and various combinations of hard bitumen and soft bitumen components. They also include different applications: paving of road sections, hand laying and rut filling.

The FV82 road gives another example of a wearing course for which it is possible to show the behav-iour of the road after a number of years. A section was laid on this road with a dense asphalt concrete WAgb11 with 180 pen (final) binder (160/220 grade). The asphalt concrete mixture was produced in a batch plant (3300 kg/batch). On the road, the Demag DF 90P paver and the rollers, Bomag 151 oscilla-tions and HAM 3 wheels static roller (9 ton) were used. Some details about the production are presented in Table 4: tonnes produced, fuel consumption, filter temperature and moisture in aggregate. The mois-ture content in aggregate is that of the stones before entering the drying drum. No problems were found with the filters during production. The fuel consumption was reduced by 31.5%. In Table 5 the results of the voids content measurements for both the warm mixture and the hot mixture section are shown.

Rut depth measurements were carried out on the WAM Foam section and on the reference hot mix sec-tion. The average rut depth is obtained by first scanning a cross section (initial profile) of the road using an ultrasonic device and then carrying out a continuous measurement along the road section. The aver-age value for every 20 m is calculated and stored as a datapoint. The outcome of these measurements, displayed in Figure 3, covers a period from October 2000 to June 2003. The results associated with 16 October 2000 were obtained before laying the new layers. The results for 1 September 2001 were obtained after laying of a levelling course (mixture prepared with cold recycling foam technique, 100% RAP). The results obtained on 22 October 2001 are those after paving with the WAM Foam mixture (WAgb11) and the hot mixture (Agb11). The measurements carried out later were done to monitor the development of the rut depths.

The longitudinal smoothness (International Roughness Index, IRI) is displayed in Figure 4 for both the WAM Foam mixture (WAgb11) and the hot mixture (Agb11). In Figure 5 the mean profile depth is shown. The measurements are carried out with a laser and the average value for every 25 cm is a datapoint and the results are a measure for the surface texture on the road. The results shown in Figure 5 were obtained after one winter period and they are within the range of 0.8-1.3 mm which is considered the range for good skid resistance.

The benefits of lower asphalt operating temperatures are savings in fuel consumption, reductions in overall emissions of associated “green house” gases and a reduction of fumes generated from the hot materials during application on the road. Measurements on fume emissions in the plant during a trial in 2000 were described previously [2,3]. More recently fuel consumption and gas/dust emissions were measured during large scale asphalt mix production in a drum-mixing plant in Skarnes, Norway. During this production 15% recycled asphalt was used in the mixture. Veritas (DNV in Norway) carried out the measurements and the results are presented in Table 6. Reductions in fuel consumption above 30% were found and, in addition, dust emission was reduced by about 50%.

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7. CONCLUDING REMARKS

WAM Foam production temperatures between 100°C-120 °C result in fuel/energy savings of approxi-mately 30% and an equivalent reduction of CO2 emissions. At the same time lower potential fume exposure, no smell for the workers and a reduction in plant emissions are observed resulting in an improved environment for both plant operators and asphalt workers. Comparison of the WAM Foam process with the traditional hot mix process based on these “environmental” measures clearly demon-strates the important role that WAM Foam could play in the future of the asphalt industry.The WAM Foam process can be used on both continuous drum plants and in batch mixing plants.By adjusting the ratio of soft binder and hard binder, equivalent (final) binders have been produced from a 40/60 pen grade up to a 330/430 pen grade. As for hot mixtures the temperature during the paving and compaction operations must be adjusted according to the type of bitumen grade used.The WAM Foam process is suitable for basecourse and wearing course mixtures. The traffic intensity on the paved roads ranges from 1500 vehicles per day to 22000 vehicles per day.WAM Foam mixtures can be paved and compacted with standard paving and compaction equipment. “Best practice” protocols should be used to achieve optimal results, e.g. compaction should take place directly behind the paver. Cores can be taken as soon as the pavement has reached ambient temperature. The average volumetric composition of the WAM Foam mixture is very similar to the composition of a hot mixture using the same materials when proper paving techniques are applied. Consequently, in those cases the mechanical properties of the WAM Foam mixtures are equal to those of the hot mixtures. On the road, the behaviour of the WAM Foam sections and the reference hot mixture sections is equal in terms of (average) rut depth, longitudinal smoothness and surface texture.

REFERENCES

[1] B.G. Koenders, D.A. Stoker, C. Bowen, P. de Groot, O. Larsen, D. Hardy, K.P. Wilms, Innova-tive process in asphalt production and application to obtain lower operating temperatures, 2nd Eurasphalt&Eurobitume congress, Barcelona, 20-22 September 2000, Book 2, session 3, pp. 831-840.

[2] P.C. de Groot, C. Bowen, B.G. Koenders, D.A. Stoker, O. Larsen, J. Johansen, A comparison of emissions from hot mixture and warm asphalt mixture production, Proceedings IRF congress, Paris, June 2001, paper O022.

[3] B.G. Koenders, D.A. Stoker, C. Robertus, O. Larsen and J. Johansen, WAM Foam, asphalt pro-duction at lower operating temperatures, 9th International Conference on Asphalt Pavements, ISAP 2002, Copenhagen.

[4] K.J. Jenkins, A.A.A. Molenaar, J.L.A. de Groot, M.F.C. van de Ven, Foamed asphalt produced using warmed aggregates, Association of Asphalt Paving technologists (AAPT), Colorado, March 2002.

[5] Workshop foamed bitumen (schuimbitumen: recente ontwikkelingen), 11 June 2003, Road and Hydraulic Engineering Division, Delft and Delft University of Technology, Faculty of Civil Engineering, The Netherlands.

[6] D. Strickland, Development of WAM Foam technology, paper presented at 2nd International Conference: “Addressing Government sustainability and recycling targets for contruction and related industries, John Moores University, Liverpool, February 2003, UK.

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Figure 1: WAM Foam mixture and hot mixture paving and compaction on RV120 in Norway

402EECongress2004N00137 Session 1

��

��

��

50 2,420 6,3

100 2,508 3,2

150 2,511 2,8

200 2,486 3,8

250 2,497 3,4

Specs 3-4,5

Average 3,9

��

��

��

350 2,522 2,4

400 2,448 5,3

Specs 3-4,5

Average 3,9

��

��

RV 120 Hobøl

Rutting [mm]

0

5

10

15

20

25

Lane 1 Lane 2 Lane 1 Lane 2

WAM Foam HMA

Ru

ttin

g [

mm

]

05.09.2000

04.10.2000

15.05.2001

26.09.2001

21.05.2002

03.10.2002

04.06.2003

Table 1: Voids content as measured with the Seaman on the road for WAM Foam


��

��

��

50 2,420 6,3

100 2,508 3,2

150 2,511 2,8

200 2,486 3,8

250 2,497 3,4

Specs 3-4,5

Average 3,9

��

��

��

350 2,522 2,4

400 2,448 5,3

Specs 3-4,5

Average 3,9

��

��

RV 120 Hobøl

Rutting [mm]

0

5

10

15

20

25


WAM Foam HMA

Ru

ttin

g [

mm

]

05.09.2000

04.10.2000

15.05.2001

26.09.2001

21.05.2002

03.10.2002

04.06.2003

Table 2: Voids content as measured with the nuclear density meter on the road for the hot mixture

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RV 120 HobølRutting [mm]

0

5

10

15

20

25


WAM Foam HMA

Rutting [mm]

05.09.2000

04.10.2000

15.05.2001

26.09.2001

21.05.2002

03.10.2002

04.06.2003

Figure 2: Comparison of rutting performance for WAM Foam mixture and hot mixture for a period of 3 years402EECongress2004N00137 Session 1

��

2000 WAb 11 50/70, V1500 70/100 batch RV 120 Hobøl

2001 WAgb 11R15 50/70, V2000 drum RV 24

2001 WAgb 11 50/70, V2000 160/220 batch FV 82

2001 WAgb 11 70/100, V1500 160/220 batch RV 120 Kirkebygda

2002 WAgb 11, WSka 11 10/20, V3000 40/60, 50/70 batch Grandeveien, Drøbak

2002 WAgb 11 30/50, V4000 70/100 batch FV33 Siggerud-Oslo grense

2002 WSka 11 50/70, V2000 70/100 batch Exit/entrance ramp

Highway Korsegården

2002 WSka 11 (trackpaver) 50/70, V2000 70/100 batch E6 Asurthern-Oslo grense

2002 WAb 11 50/70, V4000 70/100 batch RV 120 Elvestad

2002 WAgb 11 R15 50/70, V2000 160/220 drum Seljesvingen

2003 WAb 11 50/70, V1500 70/100 batch E18 Østfold grense

2003 WSka 11 (trackpaver) 50/70, V1500 70/100 batch E18 Vinterbro

2003 WSka 11 (trackpaver) 50/70, V1500 70/100 batch RV 152 Kolbotn

2003 WSka 11 (trackpaver) 50/70, V1500 70/100 batch RV 152 Drøbak

2003 WSka 11 (trackpaver) 50/70, V1500 70/100 batch FV 76 Ottarsrud

2003 WAb 11 (trackpaver) 50/70, V1500 70/100 batch RV 115 Østfold

2003 WSka 11 50/70, V1500 70/100 batch RV 152 Kolbotn centre

2003 WAb 11 50/70, V1500 70/100 batch RV 155 Krokhol

2003 WAb 11 50/70, V1500 70/100 batch RV 22 Trøgstad

��

WAgb 11 and WAb 11 are dense grade mixtures with 0/11 mm aggregate

WSka 11 is stone mastic asphalt with 0/11 mm aggregate

R15 has 15% RAP in the mixture

For the soft grade as an example: V2000 is a soft binder with a dynamic viscosity of 2000 mPa.s at 60 °C

��

��

��

��

��

��

��

��

3/9 941 6,05 78 2,9

5/9 1146 6,29 74 1,8WAgb 11

(WAM)6/9 302 5,89 76 2,0

Average ��

10/9 635 8,75 95 2,3

11/9 1120 9,32 103 2,4

12/9 1634 8,69 98 2,4

13/9 1346 8,87 98 2,6

Agb 11

(HMA)

14/9 809 8,85 102 -

Average ��

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��

��

��

��

��

��

��

��

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��

WAgb11 Seaman C-200 9 3,0 – 5,4 % 4,1 � 0,9 % 2,0 – 7,0 %

WAgb11 Core 12 3,0 – 5,6 % 4,5 � 1,1 % 2,0 – 7,0 %

Agb 11 hot mix Core 7 2,9 – 4,5 % 3,6 � 0,5 % 2,0 – 7,0 %

��

Table 3: Large scale productions in Norway with asphalt produced according to WAM Foam

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WAgb 11 and WAb 11 are dense grade mixtures with 0/11 mm aggregateWSka 11 is stone mastic asphalt with 0/11 mm aggregateR15 has 15% RAP in the mixtureFor the soft grade as an example: V2000 is a soft binder with a dynamic viscosity of 2000 mPa.s at 60 °C


��


2001 WAgb 11R15 50/70, V2000 drum RV 24

2001 WAgb 11 50/70, V2000 160/220 batch FV 82


















��





��

��

��

��

��

��

��

��

3/9 941 6,05 78 2,9

5/9 1146 6,29 74 1,8WAgb 11

(WAM)6/9 302 5,89 76 2,0

Average ��

10/9 635 8,75 95 2,3

11/9 1120 9,32 103 2,4

12/9 1634 8,69 98 2,4

13/9 1346 8,87 98 2,6

Agb 11

(HMA)

14/9 809 8,85 102 -

Average ��

��

��

��

��

��

��

��

��

��

��

��

WAgb11 Seaman C-200 9 3,0 – 5,4 % 4,1 � 0,9 % 2,0 – 7,0 %

WAgb11 Core 12 3,0 – 5,6 % 4,5 � 1,1 % 2,0 – 7,0 %

Agb 11 hot mix Core 7 2,9 – 4,5 % 3,6 � 0,5 % 2,0 – 7,0 %

��

Table 4: Production data for comparison between WAM Foam and Hot Mix Asphalt


��


2001 WAgb 11R15 50/70, V2000 drum RV 24

2001 WAgb 11 50/70, V2000 160/220 batch FV 82


















��





��

��

��

��

��

��

��

��

3/9 941 6,05 78 2,9

5/9 1146 6,29 74 1,8WAgb 11

(WAM)6/9 302 5,89 76 2,0

Average ��

10/9 635 8,75 95 2,3

11/9 1120 9,32 103 2,4

12/9 1634 8,69 98 2,4

13/9 1346 8,87 98 2,6

Agb 11

(HMA)

14/9 809 8,85 102 -

Average ��

��

��

��

��

��

��

��

��

��

��

��

WAgb11 Seaman C-200 9 3,0 – 5,4 % 4,1 � 0,9 % 2,0 – 7,0 %

WAgb11 Core 12 3,0 – 5,6 % 4,5 � 1,1 % 2,0 – 7,0 %

Agb 11 hot mix Core 7 2,9 – 4,5 % 3,6 � 0,5 % 2,0 – 7,0 %

��Table 5: Voids content on the road and of cores on the Agb11 warm asphalt mix section and hot mix section

FV 82 Frogn Average rut depth [mm]

0,0

2,0

4,0

6,0

8,0

10,0

12,0

14,0


WAM Foam HMA

16.10.2000

01.09.2001

22.10.2001

21.05.2002

16.10.2002

04.06.2003

Figure 3: Rut depth measurements on the FV82 from October 2000 to June 2003 for the WAM Foam WAgb11 and hot mixture Agb11

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FV 82 Frogn IRI

0,0

0,5

1,0

1,5

2,0

2,5

3,0


WAM Foam HMA

IRI [mm/m]

01.09.2001

22.10.2001

21.05.2002

16.10.2002

04.06.2003

Figure 4: Longitudinal smoothness (IRI) of the road up to two years after laying

FV 82MPD (Mean Profile Depth) [mm]

0,00

0,20

0,40

0,60

0,80

1,00

1,20


WAM Foam HMA

21.05.2002

04.06.2003

Figure 5: Mean profile depths for warm asphalt mixture and hot mixture after winter period


��

��

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��

��

��

��

��

��

Agb 11R15 ca. 4,5 2888 49 1,5

WAgb 11R15 ca. 2,7

(-40%)

1980

(-31,4%)

35

(-28,5%)

0,3

(-61,5%)

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Table 6: Comparison of fuel consumption, gas and dust emissions in drum mixing plant between hot mix and WAM Foam productions at identical production rates

shell bitumen - wam foam asphalt production at lower operating temperatures … · 2016-01-15 ·...

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