Anne Dony1 (adony@estp-paris.eu), Layella Ziyani1 (lziyani@estp-paris.eu), Ivan Drouadaine2 (ivan.drouadaine@aurovia.com),

Simon Pouget3 (simon.POUGET@eiffage.com), Stéphane Faucon-Dumont2 (stephane.faucon-dumont@eurovia.com), Delphine Simard3 (delphine.SIMARD@eiffage.com),

Virginie Mouillet4 (virgine.mouillet@cerema.fr), Jean-Eric Poirier5 (poirier@campus.colas.fr), Thomas Gabet6 (thomas.gabet@ifsttar.fr),

Laurence Boulangé3 (laurence.BOULANGE@eiffage.com), Aurélia Nicolai7 (aurelia.nicolai@entreprise-malet.fr), Carole Gueit5 (gueit@campus.colas.fr) 1 Université Paris Est, IRC-ESTP, 2 Eurovia CRM, 3 Eiffage Infrastructures, 4 Cerema DTerMed, 5 CST, Colas, 6 IFSTTAR, LUNAM Université, 7 Entreprise Malet

Context

Since the Grenelle Environment Roundtable, the stakeholders involved in road construction developed

recycling of bituminous materials and WMA (Warm Mixed Asphalt). In 2014, a collaborative research

program, called MURE (MUltiREcycling and warm mix asphalt) [1] started with two main objectives:

• To determine how many times a mix asphalt can be recycled,

• To couple recycling & warm mix asphalt technique.

The missions of the first working group (WG1) are:

• To develop an accelerated ageing process for bituminous mixtures at industrial scale,

• To propose a harmonized, reliable, repeatable and reproducible method of bitumen ageing

characterization in laboratory: FTIR (Fourier Transform InfraRed) spectroscopy.

Analysis of bitumen ageing by FTIR spectroscopy

Fig 1. FTIR bitumen spectrum with characteristic groups [6]

Experimental study

MURE National Project: FTIR spectroscopy study to assess ageing of asphalt mixtures

Round Robin Test Table 1: Integration limits (cm-1) for calculation of areas in transmission mode

Table 2: Integration limits for calculation of areas in ATR mode

(1) A lab calculated reference peaks separately; (2) another lab considered 12 peaks between 3100 and 707 cm-1

Results from transmission mode by spreading and ATR are in the same range, except in transmission

mode with preparation by dissolution.

Conclusions and prospects

• This study confirms the relevance of FTIR for qualifying bitumen ageing and its evolution with time,

especially the carbonyl index.

• The comparison between transmission and ATR modes leads to choose transmission mode as a more

repeatable method, and a preparation by bitumen spreading on transparent plate (fast, no use of solvent).

• The values of indexes depend on the choice of the limits. Fixing integration limits is practical when a

lot of spectra must be interpreted, but leads to inaccuracies. The valley-to-valley method could be a

good alternative for all the laboratories.

• For the national project MURE, a common method was written to explain and fix the methodology of

sample preparation and calculation method. Now this harmonized procedure could be used for all the

labs taking part in the project.

http://www.pnmure.fr/en/

Acknowledgements

The authors gratefully acknowledge the French Ministry of Ecology, Sustainable Development and Energy

for its financial support in the project. They also thank the IREX (Institute for applied research and trials in

civil engineering) for the administrative coordination of the project. Finally, they are thankful to the

students Denis Bouteiller and Rémi Ratail and Ms Olga Bulgaru for their technical contribution to this

work and to CReS TOTAL for its participation in the Round Robin tests

References

[1] J.-E. Poirier, C. Leroy, S. Pouget, The multirecycling of asphalt mixes (MURE) project, Eur. Roads

Rev. 23-24 (2014) 13–16.

[2] P. Marsac, N. Piérard, L. Porot, W. Van den bergh, J. Grenfell, V. Mouillet, et al., Potential and limits of

FTIR methods for reclaimed asphalt characterisation, Mater. Struct. 47 (2014) 1273–1286.

[3] V. Mouillet, F. Farcas, V. Battaglia, S. Besson, P. Petiteau, F. Le Cunff, Identification et dosage des

fonctions oxygénées présentes dans les liants bitumineux : Analyse par spectrométrie infrarouge à

transformée de Fourier : Méthode d’essai n°69, Laboratoire Central des Ponts et Chaussées (LCPC), 2010.

[4] C. de la Roche, M. Van de Ven, J.-P. Planche, W. Van den Bergh, J. Grenfell, T. Gabet, et al., Hot

Recycling of Bituminous Mixtures, in: M.N. Partl, H.U. Bahia, F. Canestrari, C. de la Roche, H. Di

Benedetto, H. Piber, et al. (Eds.), Adv. Interlab. Test. Eval. Bitum. Mater., Springer Netherlands, 2013: pp.

361–428.

[5] V. Mouillet, M.-S. Ginoux, N. Piérard, K. Mollenhauer, T. Gabet, J.-B. Gobert, et al., Methodology for

laboratory characterization of Reclaimed Asphalt, Re-Road - End Life Strateg. Asph. Pavements.

Deliverable 1.2 (2012).

[6] L. El Bèze, Recyclage à chaud des agrégats d’enrobés bitumineux : Identification de traceurs

d’homogénéité du mélange entre bitume vieilli et bitume neuf d’apport, PhD dissertation, University of

Aix-Marseille III, 2008.

Media partners

Repeatability of the FTIR tests

* Negative Ico brought back to zero with L1 limits Importance of the choice of limits

Increase in Ico after PAV bitumen oxidation

No significant differences between Excel and spectrometer software calculation.

Better repeatability with transmission mode - spreading preparation

Figs 2 and 3. Evolution of ICO in transmission and ATR modes

Bitumen ageing is caused by

irreversible oxidation and creates

carbonyl (C=O) and sulfoxide (S=O)

groups, two relevant markers. Many

methods are described for the

calculation of indexes [2-5]:

𝐈𝐂𝐎=𝐀𝟏

𝐀𝟎 ; 𝐈𝐒𝐎 =

𝐀𝟐

𝐀𝟎

A0: area of reference peaks (refering to

ethylene and methyl groups,

chemically stable throughout ageing)

A1: area of carbonyl peak

A2: area of sulfoxide peak

0,0

5,0

10,0

15,0

20,0

0 100 200 300 400 500 600

RTFOT progress (min)

Lab 3

Lab 4

Lab 6

Lab 7

ATR

Carbonyl peak (1700 cm-1)

Sulfoxide peak (1030 cm-1)

Reference peaks (1)

(1460 and 1375 cm-1) Superior limit Inferior limit Superior limit Inferior limit Superior limit Inferior limit

min 1719 1635 1055 979 1505 1318

max 1753 1680 1098 1028 1539 1399

Carbonyl peak (1700 cm-1)

Sulfoxide peak (1030 cm-1)

Reference peaks (1)(2)

(1460 and 1375 cm-1) Superior limit Inferior limit Superior limit Inferior limit Superior limit Inferior limit

min 1723 1645 1055 976 1485 1318 max 1731 1680 1101 1028 1538 1399

0,0

1,0

2,0

3,0

4,0

5,0

6,0

L1 - software L2 - software L1 - Excel L2 - Excel

KBr ATR KBr PAV ATR PAV

* * * * * *

Fig 4. ICO index for neat and PAV aged 35/50 pen. grade bitumen (transmission and ATR modes)

Round Robin tests (participation of 7 labs) Repeatability tests (1 lab)

• Use of 2 spectrometers

• 2 methods of preparation:

• transmission: bitumen spreading on a KBr

transparent plate or dissolution in a solvent

• ATR (Attenuated Total Reflection)

• Calculation method: fixed limits of wavenumber

for each lab, use of the spectrometer software

Analysis in FTIR spectroscopy

50/70 pen. grade bitumen

Ageing 8 x successively by RTFOT

method (163 °C – 75 min)

Total: 9 samples

35/50 pen. grade bitumen

Ageing by PAV method (100 °C,

air pressure of 2.1 bars

Total: 2 samples

• Use of 1 spectrometer

• 2 methods of preparation:

• transmission: bitumen spreading on a

KBr transparent plate

• ATR (Attenuated Total Reflection)

• Calculation method: 2 types of fixed limits

L1 & L2, use of the spectrometer software +

Excel (trapezoidal rule)

Analysis in FTIR spectroscopy

0,0

5,0

10,0

15,0

20,0

25,0

0 100 200 300 400 500 600

RTFOT progress (min)

Lab 1Lab 2Lab 3Lab 4Lab 4 - cyclohexaneLab 4 - perchloroethyleneLab 5 - L1Lab 5 - L2

Transmission