Influence of a recycling agent of vegetable origin on complex modulus and fatigue performances of bituminous mixtures produced with RAP S. Mangiafico 1 , C. Sauzéat 1 , H. Di Benedetto 1 , S. Pouget 2 , F. Olard 2 , L. Planque 3 1 Univ. Lyon, ENTPE, LTDS (CNRS UMR 5513) 2 EIFFAGE Travaux Publics 3 BP France – Service bitumes
2 Outline Introduction Tested materials Experimental procedure Results and analysis Complex modulus • Fatigue • Conclusions
3 Introduction Bituminous mixtures produced with RAP reactivating aged RAP binder recuperate properties of aged binder helping binder blending ? Rejuvenators reducing final mixture stiffness at fixed temperature? Main literature findings: • not a real “rejuvenation” microstructure of rejuvenated aged binder ≠ virgin binder • effects on complex modulus and fatigue properties • dosage more important than nature/origin
4 Tested materials RAP binder Recycling agent content fresh binder = pen grade 70/100 3.5% by weight of RAP binder 35/50 15/25 % RAP (by wt. of 100% 0% 20% 40% 60% aggregates and RAP) 100% 0% 18.7% 37.8% 57.0% % RAP (by wt. of example: 70/100 + 20% RAP example: 35/50 total mixture) 13 mixtures regular procedure 7 mixtures regular procedure with recycling agent of vegetable origin 20 mixtures
5 Tested materials 100 • same grading curve Percent passing by weight [%] 90 • High modulus mixtures 80 ("Enrobé à Module Élevé", EME) 70 14-mm continuous 60 • 5.35% total bitumen content 50 RAP material 40 • LPC wheel-compacted slabs 30 20 • trapezoidal samples cut from 10 slabs 0 0.01 0.1 1 10 100 Sieve size [mm]
6 Experimental procedures Two-point bending tests on trapezoidal samples 25 mm complex modulus tests (2 samples) only |E * | @ 15 ° C, 10 Hz imposed sinusoidal (EN 12697-26:2012) displacement fatigue tests (18 samples) 250 mm 10 ° C, 25 Hz (EN 12697-24:2012) EIFFAGE Travaux Publics laboratory, Ciry-Salsogne 56 mm
7 Experimental procedures Fatigue parameters ε 6 and 1/b Example of Wöhler curve for mixture 35/50 log N = a + 1 8 b log ε log N ε 6 = 117 µm/m 1/b 7 1 ε 6 = 10 b 6−a 1/b = -5.49 ε 6 1 parameter 1/b not treated 5 e in the rest of the presentation: 4 for more details, log e 6 3 e please refer to the paper 1.8 1.9 2.0 2.1 2.2 2.3 log e
Res. & analysis: |E * |(15 ° C, 10 Hz) 8 20000 w/o agent |E * | (15°C, 10 Hz) [MPa] with agent 16000 + 12000 0 8000 4000 + average value obtained on two sets of samples 0 1) Reduction of stiffness when recycling agent is used 2) Mixes with agent show approx. constant stiffness with increasing RAP content dosage depends on RAP binder content: the more RAP, the more agent
Res. & analysis: |E * |(15 ° C, 10 Hz) 9 20000 w/o agent |E * | (15°C, 10 Hz) [MPa] with agent 16000 + normalized to 70/100 2.5 12000 w/o agent 0% | (15°C, 10 Hz) [-] 0 with agent x 2.0 normalized to 35/50 8000 normalized to 15/25 1.5 x 4000 x + average value obtained on two sets of samples 1.0 + 0 |E * |/|E * 0.5 + average value obtained on two sets of samples x same mixture: 100% RAP 0.0 1) Reduction of stiffness when recycling agent is used 2) Mixes with agent show approx. constant stiffness with increasing RAP content dosage depends on RAP binder content: the more RAP, the more agent + average value obtained on two sets of samples
Res. & analysis: |E * |(15 ° C, 10 Hz) 10 20000 ≤ 40% RAP: influence of w/o agent |E * | (15°C, 10 Hz) [MPa] agent on |E * |(15 ° C, 10 Hz) not with agent 16000 w/o agent | + dependent on virgin binder 1.10 normalized to 70/100 2.5 12000 w/o agent 0% | (15°C, 10 Hz) [-] 1.05 60% RAP: influence of agent 0 with agent x 2.0 normalized to 35/50 1.00 on |E * |(15 ° C, 10 Hz) 8000 (15°C, 10 Hz) [-] normalized to 15/25 0.95 depending on virgin binder 1.5 x with agent |/|E * 4000 0.90 x + average value obtained on two sets of samples 1.0 + 0 0.85 |E * |/|E * base bitumen: 15/25 0.5 0.80 + average value obtained on two sets of samples base bitumen: 35/50 |E * x same mixture: 100% RAP 0.75 0.0 base bitumen: 70/100 1) Reduction of stiffness when recycling agent is used 0.70 2) Mixes with agent show approx. constant stiffness with increasing RAP content 10% 20% 30% 40% 50% 60% 70% dosage depends on RAP binder content: the more RAP, the more agent % RAP + average value obtained on two sets of samples
Res. & analysis: fatigue - ε 6 11 160 w/o agent 150 ε 6 (10°C, 25 Hz) [µm/m] with agent 140 130 + 120 110 + 100 90 + average value obtained on two sets of samples 80 1) Higher variability than |E*| 2) Addition of agent helps fulfilling 130 µm/m requirement for EME mixtures 3) Increase of ε 6 when recycling agent is used with high RAP contents (≥ 40%)
Res. & analysis: fatigue - ε 6 12 160 Addition of RAP (with or without agent) is w/o agent 150 ε 6 (10°C, 25 Hz) [µm/m] almost always convenient in terms of ε 6 with agent 140 1.4 normalized to 70/100 130 normalized to 35/50 ε 6 / ε 6 0% (10°C, 25 Hz) [-] + normalized to 15/25 120 x 1.2 110 + 100 1.0 90 x x + average value obtained on two sets of samples + 80 0.8 x + + average value obtained on two sets of samples x same mixture: 100% RAP 0.6 1) Higher variability than |E*| 2) Addition of agent helps fulfilling 130 µm/m requirement for EME mixtures w/o agent 3) Increase of ε 6 when recycling agent is used with high RAP contents (≥ 40%) with agent
Res. & analysis: fatigue - ε 6 13 160 w/o agent 1.30 150 ε 6 (10°C, 25 Hz) [µm/m] with agent 1.25 140 1.20 1.4 normalized to 70/100 ε 6 with agent / ε 6 w/o agent 130 1.15 normalized to 35/50 (10°C, 25 Hz) [-] ε 6 / ε 6 0% (10°C, 25 Hz) [-] + normalized to 15/25 120 1.10 x 1.2 1.05 110 + 1.00 100 0.95 1.0 90 0.90 base bitumen: 15/25 x x + average value obtained on two sets of samples + 0.85 80 base bitumen: 35/50 0.8 x 0.80 + + average value obtained on two sets of samples base bitumen: 70/100 0.75 x same mixture: 100% RAP 0.70 0.6 1) Higher variability than |E*| 10% 20% 30% 40% 50% 60% 70% % RAP 2) Addition of agent helps fulfilling 130 µm/m requirement for EME mixtures w/o agent 3) Increase of ε 6 when recycling agent is used with high RAP contents (≥ 40%) with agent
14 Conclusions Addition of recycling agent causes reduction of |E * |(15 ° C, 10 Hz) • |E * |(15 ° C, 10 Hz) of mixtures with increasing RAP content • remains approximately constant: dosage of recycling agent depends on RAP binder content Influence of agent on |E * |(15 ° C, 10 Hz) depends on virgin binder • at 60% RAP content • Addition of recycling agent with high RAP contents (≥ 40%) causes increase of ε 6 • Addition of recycling agent can help fulfilling 130 µm/m requirement for EME mixtures
Influence of a recycling agent of vegetable origin on complex modulus and fatigue performances of bituminous mixtures produced with RAP Thank you for your attention
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