Experimental Investigation of Wearing Course Mixtures Prepared with Reclaimed Asphalt Pavement and Rejuvenators based on the BTSV Method

Transcription

1 Experimental Investigation of Wearing Course Mixtures Prepared with Reclaimed Asphalt Pavement and Rejuvenators based on the BTSV Method Stephan Büchler Axel Walther Augusto Cannone Falchetto Tokyo, Japan, November 20-21, 2017

2 Outline Introduction Materials and Testing Results Summary and Conclusions Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

3 Introduction RAP is commonly recycled in asphalt pavement construction. However, for higher RAP content a decrease in penetration and increase in complex modulus and stiffness are observed. Rejuvenators can be used to improve the characteristics of the final mixture. Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

4 Introduction Objective Investigate the possibility of designing mixtures with RAP and rejuvenators. Based on: Bitumen Typisierungs Schnell Verfahren - BTSV (Binder-Fast- Characterization-Test) Conventional laboratory testing - stiffness modulus, fatigue behavior and low temperature performance Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

5 Materials and Testing Materials Table 1 Composition and properties of RAP Figure 1 Double-shaft paddle mixer Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

6 Materials and Testing Materials The BTSV method is based on Dynamic Shear Rheometer (DSR) tests and is used to determine the amount of rejuvenator to achieve the target viscosity for the extracted RAP binder: Temperature rate of ΔT=1.2 C/min Constant shear stress of 500Pa in oscillation mode Constant test frequency of f=10rad/s The state of softening is represented through two parameters: the softening temperature (T BTSV ), obtained at a value of complex shear modulus of G*=15.0kPa (which is derived from the conventional ring and ball method), and the corresponding phase angle (δ BTSV ). Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

7 Materials and Testing BTSV G* [kpa] 1.E+04 1.E+03 δ BTSV = E+02 G* = 15 kpa 1.E+01 1.E+00 Complex shear modulus Phase angle T BTSV = 54.3 C 1.E T [ C] δ [ ] Figure 2 BTSV Schematic Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

8 Materials and Testing BTSV Figure 3 BTSV Plain Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

9 Materials and Testing Materials Table 2 Composition and properties of laboratory prepared asphalt mixtures 1 to 7 An average reduction of 13 C is achieved for the extracted RAP binder with all rejuvenators starting from the initial 71 C down to 58 C. Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

10 Materials and Testing Resistance to permanent deformations (EN ) ISBS Figure 4 Uniaxial cyclic compression test Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

11 Materials and Testing Stiffness modulus (EN ) Cylindrical indirect tensile test mode (CIDT) Table 3 Number of load cycles to determine the stiffness modulus E ΔF μ h Δu E = [Δ F ( µ )] / [ h Δ u] stiffness modulus difference between minimum and maximum load Posson s ratio specimen height and difference between minimum and maximum deformation Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

12 Materials and Testing Stiffness modulus Figure 5 Example of Stiffness modulus results (T=-10, 0, 10 and 20 C) at different frequencies. Stiffness modulus master curve: w absolute modulus z material parameter f R =a T f f is the frequency and α T is the shift factor, such as ( ) logα T = m 1/ T 1/ T 0 E = y + 0 log( fr )-x z 1+ e Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov, w 0

13 Materials and Testing Fatigue behavior (EN ) 1.5E E+04 Energy Ratio ER Stiffness modulus E 1.2E E+04 ER [MPa] 9.0E E E E+04 E [MPa] 3.0E E+03 N Macro E+04 4.E+04 6.E+04 8.E+04 1.E+05 Loading cycles N Figure 6 Schematic to obtain the N macro based on the maximum value of EN at f=10 Hz Figure 7 Example of fatigue function at T=20 C and f=10 Hz Fatigue functions N = C ε 1 C 2 Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

14 Materials and Testing Low temperature performance (EN ) Prismatic mixture specimens were subjected to Thermal Stress Restrained Specimen Tests (TSRST) for evaluating the low temperature behavior = C σ cry = 4.09MPa T f σ cry AC 32 T S σcry [MPa] T [ C] Figure 8 Example of cryogenic stress as function of temperature Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

15 Results Resistance to permanent deformations Figure 9 Strain rates at the end of the uniaxial cyclic compression test It appears that the addition of RAP + rejuvenator positively influences the deformation resistance compared to the virgin mixture with lower strain rates. Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

16 Results Stiffness modulus Figure 10 Stiffness modulus from CIDT test at T=20, 10, 0, and -10 C and f=10 Hz When using Rheofalt and Storflux with a content of 40% of RAP (mixtures 5 and 7) lower stiffness values are observed. Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

17 Results Stiffness modulus Table 4 Regression parameters of the mixtures master curves Figure 11 Master curves of stiffness moduli obtained from CIDT tests at f=10 Hz for an AC 11 with a content of 40 M.-% RAP Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

18 Results Fatigue Figure 12 Loading cycles to fatigue failure N macro ; initial strain level ε el f=10 Hz, T = 20 C and 20 M.-% RAP Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

19 Results Fatigue Table 5 Fatigue functions and R 2 for wearing course mixtures at 20 C All mixtures prepared with rejuvenators show better fatigue properties than the control material, except for mixture 6 (Storflux and 20% RAP) which presents fatigue behavior similar to mixture 1. Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

20 Results Low Temperature Performance Table 6. TSRST fracture temperature and corresponding cryogenic stress Fracture temperature Fracture stress Mixture Rejuvenator RAP [%] [ C] [MPa] / Rheofalt Storflux nature Figure 13 Fracture temperature and corresponding cryogenic stress from TSRST Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

21 Summary and Conclusions The use of rejuvenators in combination with high reclaimed asphalt pavement (RAP) was investigated based on the analysis method recently introduced in Germany and known as Bitumen Typisierungs Schnell Verfahren - BTSV (Binder- Fast-Characterization-Test), and then experimentally evaluated. The following conclusion can be drawn: Rejuvenators and high amounts of RAP have a negligible impact on stiffness properties, improve the fatigue response result in comparable low temperature performance, except for a specific rejuvenator. Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

22 Acknoledgements Laboratory Team Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

23 Important Dates RILEM-CMB-SYMPOSIUM BRAUNSCHWEIG, GERMANY SEPTEMBER 17 18, 2018 CHEMO MECHANICAL CHARACTERIZATION OF BITUMINOUS MATERIALS Nov. 27 th, 2017 Submission of paper open Apr. 10 th, 2018 Submission of paper due Jun. 1 st, 2018 Notification of papers acceptance Sept th, 2018 RILEM 252-CMB Symposium Sept th, 2018 RILEM Annual Meeting Secretariat Nina Eßmann, Technische Universität Braunschweig, n.essmann@tu-bs.de Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,

24 Thank you! Augusto Experimental investigation of wearing course mixtures prepared with reclaimed asphalt pavement and rejuvenators based on the BTSV method Nov,