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Mr. Georgios Pipintakos
University of Antwerp, EMIB, RERS

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0 Asphalt
0 Bitumen
0 Mechanisms
0 Modifiers
0 Spectroscopy

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Asphalt
Bitumen
Spectroscopy
Ageing
Mechanisms

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Journal article
Published: 17 July 2021 in Fuel
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Asphaltenes and maltenes of bitumen before and after aging are investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), time of flight - secondary ion mass spectrometry (TOF-SIMS), and gel permeation chromatography (GPC). It has been shown that bitumen differs in terms of wax. After fractionation, more wax is found in the maltenes compared to the bitumen, and this is even more evident when bitumen is aged. For one bitumen, asphaltenes from the virgin binder do not contain carbonyls, which all fall into the maltenes. After bitumen aging, a large part of the carbonyl and sulfoxide signals is shifted to the asphaltenes. Differences in aromaticity are also evidenced as asphaltenes > bitumen > maltenes. TOF-SIMS shows that maltenes are close to the bitumen, but asphaltenes are more different. Also, maltenes are relatively unaffected by aging while larger differences are found in the asphaltenes between the virgin and aged binders. By GPC, a large molecular weight fraction of bitumen is shown as main part of the asphaltenes. However, asphaltenes also contain low molecular weight molecules that overlap with maltenes. Upon bitumen aging, some low molecular weight compounds may become part of asphaltenes, making the average molecular weight of the asphaltenes lower.

ACS Style

Xiaohu Lu; Hilde Soenen; Peter Sjövall; Georgios Pipintakos. Analysis of asphaltenes and maltenes before and after long-term aging of bitumen. Fuel 2021, 304, 121426 .

AMA Style

Xiaohu Lu, Hilde Soenen, Peter Sjövall, Georgios Pipintakos. Analysis of asphaltenes and maltenes before and after long-term aging of bitumen. Fuel. 2021; 304 ():121426.

Chicago/Turabian Style

Xiaohu Lu; Hilde Soenen; Peter Sjövall; Georgios Pipintakos. 2021. "Analysis of asphaltenes and maltenes before and after long-term aging of bitumen." Fuel 304, no. : 121426.

Review
Published: 21 May 2021 in Micron
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Undoubtedly bitumen’s viscoelastic performance has received much attention in the literature. Especially, the oxidative ageing phenomenon of bitumen has been studied by several scholars from different physicochemical and mechanical perspectives due to its direct impact on asphalt performance. The microstructural patterns observed with ageing utilising different microscopic techniques have not remained unexplored, and an increasing interest has been expressed to understand the bitumen’s architecture by coupling it with different theories. This review aims to provide a useful guide for the road engineer by collecting all the existing microstructural trends that have been reported upon ageing by utilising some of the most promising microscopic techniques. The study demonstrates the changes being observed for the size of the so-called bee structures via Atomic Force Microscopy (AFM). The apparent fibril microstructure captured with Environmental Scanning Electron Microscopy (ESEM) consistently reported in the literature to become denser and coarser with ageing. The existing findings of Confocal Laser Scanning Microscopy (CLSM) revealed the conflicting observations that exist for the fluorescent centres of bitumen upon oxidation, concerning their size and number. Finally, this paper provides a comparative analysis of the three techniques for bitumen applications and recommends a systematic sample preparation protocol to move towards more consistent observations between the different research groups.

ACS Style

Georgios Pipintakos; Navid Hasheminejad; Caitlin Lommaert; Anastassiya Bocharova; Johan Blom. Application of Atomic Force (AFM), Environmental Scanning Electron (ESEM) and Confocal Laser Scanning Microscopy (CLSM) in bitumen: A review of the ageing effect. Micron 2021, 147 .

AMA Style

Georgios Pipintakos, Navid Hasheminejad, Caitlin Lommaert, Anastassiya Bocharova, Johan Blom. Application of Atomic Force (AFM), Environmental Scanning Electron (ESEM) and Confocal Laser Scanning Microscopy (CLSM) in bitumen: A review of the ageing effect. Micron. 2021; 147 ():.

Chicago/Turabian Style

Georgios Pipintakos; Navid Hasheminejad; Caitlin Lommaert; Anastassiya Bocharova; Johan Blom. 2021. "Application of Atomic Force (AFM), Environmental Scanning Electron (ESEM) and Confocal Laser Scanning Microscopy (CLSM) in bitumen: A review of the ageing effect." Micron 147, no. : .

Research article
Published: 26 April 2021 in Road Materials and Pavement Design
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Incorporating reclaimed asphalt (RA) in surface layer mixtures is still limited due to performance concerns, and it becomes even more challenging when combining aged polymer-modified bitumen (PMB) with virgin PMB. This study aims to evaluate, from a binder perspective, the feasibility of incorporating reclaimed polymer-modified binder (RPMB) in new surface layer mixtures. To address this challenge, blends of RPMB and virgin PMB were investigated at three replacement rates (20%, 40% and 60%) with and without a tall oil-based rejuvenator. First, the viscoelastic behaviour of the blends was assessed using a dynamic shear rheometer. Moreover, physicochemical changes were tracked using infrared spectroscopy and fluorescence microscopy. The experimental investigation revealed that, due to polymer degradation of the RMPB, only the blends with 20% RMPB exhibited polymer activity. Finally, the use of the rejuvenator compensated for the rheological properties of the aged RPMB and reduced the susceptibility to non-load-associated cracking.

ACS Style

Alexandros Margaritis; Georgios Pipintakos; Geert Jacobs; David Hernando; Mats Bruynen; Jeroen Bruurs; Wim Van Den Bergh. Evaluating the role of recycling rate and rejuvenator on the chemo-rheological properties of reclaimed polymer-modified binders. Road Materials and Pavement Design 2021, 22, S83 -S98.

AMA Style

Alexandros Margaritis, Georgios Pipintakos, Geert Jacobs, David Hernando, Mats Bruynen, Jeroen Bruurs, Wim Van Den Bergh. Evaluating the role of recycling rate and rejuvenator on the chemo-rheological properties of reclaimed polymer-modified binders. Road Materials and Pavement Design. 2021; 22 (sup1):S83-S98.

Chicago/Turabian Style

Alexandros Margaritis; Georgios Pipintakos; Geert Jacobs; David Hernando; Mats Bruynen; Jeroen Bruurs; Wim Van Den Bergh. 2021. "Evaluating the role of recycling rate and rejuvenator on the chemo-rheological properties of reclaimed polymer-modified binders." Road Materials and Pavement Design 22, no. sup1: S83-S98.

Journal article
Published: 10 April 2021 in Construction and Building Materials
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Understanding the fundamental mechanisms of oxidative ageing in bitumen is considered of paramount importance in order to take steps towards durable binders able to tackle distresses related to this phenomenon which deteriorates the asphalt performance. This paper focuses on the identification of the intermediate and final oxygenated products after short- and long-term laboratory ageing simulated with rolling thin-film oven testing (RTFOT) and pressurised ageing vessel (PAV) respectively. Three binders were investigated in this study, two originated from the same wax-free crude source, while the third was obtained from a different source, containing natural wax, and followed a different manufacturing process. Fourier-Transform Infrared (FTIR) spectroscopy demonstrated a clear increase of the sulfoxide and carbonyl functional groups upon ageing for all the binders independently of origin, manufacturing or performance. Electron Paramagnetic Resonance (EPR) spectroscopy showed an increase of the organic carbon-centred radicals after short-term ageing (RTFOT), whereas after PAV these radicals remained constant in the two wax-free binders originating from the same crude source, and even decreased for the third, waxy binder. Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy reported differences in the relative distribution of protons between the binders in the unaged state, and similar minor changes after both ageing steps regardless of the binder’s crude source and distillation. The results of Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) revealed that SOx- and (OH)x-containing compounds are produced after the sequentially occurring short- and long-term ageing in both wax-free bitumens, whereas an almost constant behaviour of aliphatics after PAV ageing can be seen for the same bitumens. Finally, the strengths and weaknesses of each of these experimental techniques were reviewed and compared versus the obtained results and possible ageing mechanisms.

ACS Style

Georgios Pipintakos; Hilde Soenen; H.Y. Vincent Ching; Christophe Vande Velde; Sabine Van Doorslaer; Filip Lemière; Aikaterini Varveri; Wim Van Den Bergh. Exploring the oxidative mechanisms of bitumen after laboratory short- and long-term ageing. Construction and Building Materials 2021, 289, 123182 .

AMA Style

Georgios Pipintakos, Hilde Soenen, H.Y. Vincent Ching, Christophe Vande Velde, Sabine Van Doorslaer, Filip Lemière, Aikaterini Varveri, Wim Van Den Bergh. Exploring the oxidative mechanisms of bitumen after laboratory short- and long-term ageing. Construction and Building Materials. 2021; 289 ():123182.

Chicago/Turabian Style

Georgios Pipintakos; Hilde Soenen; H.Y. Vincent Ching; Christophe Vande Velde; Sabine Van Doorslaer; Filip Lemière; Aikaterini Varveri; Wim Van Den Bergh. 2021. "Exploring the oxidative mechanisms of bitumen after laboratory short- and long-term ageing." Construction and Building Materials 289, no. : 123182.

Journal article
Published: 12 December 2020 in Materials
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With the increased use of reclaimed asphalt (RA), the ability of bituminous materials to resist fatigue cracking may face a decline mainly due to the aged reclaimed asphalt binder (RAB), especially when RA is used at higher rates and not sufficiently treated. In this study, the bulk scale (asphalt) and its subscale (mortar) were employed to evaluate the effect on fatigue resistance when a RAB is added, by considering three replacement rates: 0%, 40%, and 70% RAB. The fatigue testing of asphalt mixtures was carried out using a four-point bending (4PB) setup, while the mortars were tested using a new column-like geometry utilising a dynamic shear rheometer (DSR). The fatigue properties were further analysed using dissipated energy concepts. The aim of this study was, first, to assess whether the inclusion of a RAB can provide at least similar fatigue properties compared to an all-virgin mix, and second, to evaluate whether the proposed treatment is beneficial for the mixtures with a RAB. The asphalt tests revealed that the inclusion of a 40% RAB led to increased fatigue resistance, whereas the mortar tests showed that the inclusion of RAB has an inverse effect on fatigue life.

ACS Style

Alexandros Margaritis; Geert Jacobs; Georgios Pipintakos; Johan Blom; Wim Van Den Van Den Bergh. Fatigue Resistance of Bituminous Mixtures and Mortars Containing High Reclaimed Asphalt Content. Materials 2020, 13, 5680 .

AMA Style

Alexandros Margaritis, Geert Jacobs, Georgios Pipintakos, Johan Blom, Wim Van Den Van Den Bergh. Fatigue Resistance of Bituminous Mixtures and Mortars Containing High Reclaimed Asphalt Content. Materials. 2020; 13 (24):5680.

Chicago/Turabian Style

Alexandros Margaritis; Geert Jacobs; Georgios Pipintakos; Johan Blom; Wim Van Den Van Den Bergh. 2020. "Fatigue Resistance of Bituminous Mixtures and Mortars Containing High Reclaimed Asphalt Content." Materials 13, no. 24: 5680.

Journal article
Published: 19 November 2020 in Construction and Building Materials
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The fatigue resistance, as a performance indicator, is of paramount importance for the selection and benchmarking of bituminous materials. The bituminous mortar can be considered as the medium that connects and envelopes the coarse aggregate skeleton, and hence will significantly influence the fatigue resistance at bulk-scale. Therefore this study presents the steps and challenges of a new testing framework to evaluate the fatigue resistance of bituminous mortars. To do so, first, a new test geometry is introduced, which will ensure cohesive failure in a predefined area. The integrity of this sample geometry is assessed theoretically through finite element simulations and by computer tomography scans. Secondly, specimens of the new geometry are evaluated experimentally using a dynamic shear rheometer, where time-sweep tests are performed on two control mortar types under various test conditions. The control mortar types are fabricated using two commercial bituminous binders, one modified and one neat binder, to evaluate the effect of binder type. The test results are comprehensively analysed using fundamental dissipated energy-based concepts but also empirical and phenomenological failure criteria, providing insights into the failure evolution. For the tested mortar types, the analysis shows good convergence with the considered fatigue models. Finally, using dissipated energy concepts led to the most consisted fatigue model, which is independent of binder type and test conditions.

ACS Style

Alexandros Margaritis; Georgios Pipintakos; Aikaterini Varveri; Geert Jacobs; Navid Hasheminejad; Johan Blom; Wim Van Den Bergh. Towards an enhanced fatigue evaluation of bituminous mortars. Construction and Building Materials 2020, 275, 121578 .

AMA Style

Alexandros Margaritis, Georgios Pipintakos, Aikaterini Varveri, Geert Jacobs, Navid Hasheminejad, Johan Blom, Wim Van Den Bergh. Towards an enhanced fatigue evaluation of bituminous mortars. Construction and Building Materials. 2020; 275 ():121578.

Chicago/Turabian Style

Alexandros Margaritis; Georgios Pipintakos; Aikaterini Varveri; Geert Jacobs; Navid Hasheminejad; Johan Blom; Wim Van Den Bergh. 2020. "Towards an enhanced fatigue evaluation of bituminous mortars." Construction and Building Materials 275, no. : 121578.

Journal article
Published: 28 October 2020 in Nanomaterials
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Transparent binder is used to substitute conventional black asphalt binder and to provide light-colored pavements, whereas nano-TiO2 has the potential to promote photocatalytic and self-cleaning properties. Together, these materials provide multifunction effects and benefits when the pavement is submitted to high solar irradiation. This paper analyzes the physicochemical and rheological properties of a transparent binder modified with 0.5%, 3.0%, 6.0%, and 10.0% nano-TiO2 and compares it to the transparent base binder and conventional and polymer modified binders (PMB) without nano-TiO2. Their penetration, softening point, dynamic viscosity, master curve, black diagram, Linear Amplitude Sweep (LAS), Multiple Stress Creep Recovery (MSCR), and Fourier Transform Infrared Spectroscopy (FTIR) were obtained. The transparent binders (base and modified) seem to be workable considering their viscosity, and exhibited values between the conventional binder and PMB with respect to rutting resistance, penetration, and softening point. They showed similar behavior to the PMB, demonstrating signs of polymer modification. The addition of TiO2 seemed to reduce fatigue life, except for the 0.5% content. Nevertheless, its addition in high contents increased the rutting resistance. The TiO2 modification seems to have little effect on the chemical functional indices. The best percentage of TiO2 was 0.5%, with respect to fatigue, and 10.0% with respect to permanent deformation.

ACS Style

Iran Segundo; Salmon Landi; Alexandros Margaritis; Georgios Pipintakos; Elisabete Freitas; Cedric Vuye; Johan Blom; Tom Tytgat; Siegfried Denys; Joaquim Carneiro. Physicochemical and Rheological Properties of a Transparent Asphalt Binder Modified with Nano-TiO2. Nanomaterials 2020, 10, 2152 .

AMA Style

Iran Segundo, Salmon Landi, Alexandros Margaritis, Georgios Pipintakos, Elisabete Freitas, Cedric Vuye, Johan Blom, Tom Tytgat, Siegfried Denys, Joaquim Carneiro. Physicochemical and Rheological Properties of a Transparent Asphalt Binder Modified with Nano-TiO2. Nanomaterials. 2020; 10 (11):2152.

Chicago/Turabian Style

Iran Segundo; Salmon Landi; Alexandros Margaritis; Georgios Pipintakos; Elisabete Freitas; Cedric Vuye; Johan Blom; Tom Tytgat; Siegfried Denys; Joaquim Carneiro. 2020. "Physicochemical and Rheological Properties of a Transparent Asphalt Binder Modified with Nano-TiO2." Nanomaterials 10, no. 11: 2152.

Journal article
Published: 10 October 2020 in Construction and Building Materials
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Diffusion-reaction models derived within the frame of continuum thermodynamics of irreversible processes for reacting mixtures enjoy a number of advantages over purely phenomenological models. This paper explores the potential and challenges of this approach by means of a particular model for spurt oxidation in bitumen. Film ageing experiments are simulated considering different bitumen compositions in terms of SARA fractions. The predicted spurt completion times are contrasted with parameters characterizing the initial composition. The results demonstrate the consistency of the model. Furthermore, the trend regarding spurt completion time predicted by the model is in line with experimental results from the Strategic Highway Research Program (SHRP). In addition, the change in diffusivity due to oxidation is discussed for different compositions. The model consistently predicts a significant decrease in diffusivity due to oxidation in the absence of out-diffusion of reaction products.

ACS Style

Uwe Mühlich; Georgios Pipintakos; Christos Tsakalidis. Mechanism based diffusion-reaction modelling for predicting the influence of SARA composition and ageing stage on spurt completion time and diffusivity in bitumen. Construction and Building Materials 2020, 267, 120592 .

AMA Style

Uwe Mühlich, Georgios Pipintakos, Christos Tsakalidis. Mechanism based diffusion-reaction modelling for predicting the influence of SARA composition and ageing stage on spurt completion time and diffusivity in bitumen. Construction and Building Materials. 2020; 267 ():120592.

Chicago/Turabian Style

Uwe Mühlich; Georgios Pipintakos; Christos Tsakalidis. 2020. "Mechanism based diffusion-reaction modelling for predicting the influence of SARA composition and ageing stage on spurt completion time and diffusivity in bitumen." Construction and Building Materials 267, no. : 120592.

Preprint
Published: 17 September 2020
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Transparent binder is used to substitute conventional black asphalt binder and to provide light-colored pavements, whereas nano-TiO2 has the potential to promote photocatalytic and self-cleaning properties. Together, these materials provide multifunction effects and benefits when the pavement is submitted to high solar irradiation. This paper analyses the physicochemical and rheological properties of a transparent binder modified with 0.5%, 3.0%, 6.0%, and 10.0% of nano-TiO2 and compares it to the transparent base binder, and conventional and polymer modified binders (PMB) without nano-TiO2. Their penetration, softening point, dynamic viscosity, master curve, black diagram, Linear Amplitude Sweep (LAS), Multiple Stress Creep Recovery (MSCR), and Fourier-Transform Infrared Spectroscopy (FTIR) were obtained. The transparent binders (base and modified) seem to be workable considering their viscosity and exhibited values between the conventional binder and PMB regarding rutting resistance, penetration, and softening point. They showed similar behavior as the PMB, demonstrating signs of polymer-modification. The addition of TiO2 seems to reduce fatigue life, except for the 0.5% content. Nevertheless, its addition in high contents increases the rutting resistance. The TiO2 modification seems to have little effect on the chemical functional indices. The best percentage of TiO2 was 0.5%, considering fatigue and 10.0% concerning permanent deformation.

ACS Style

Iran Rocha Segundo; Salmon Landi Jr.; Alexandros Margaritis; Georgios Pipintakos; Elisabete Freitas; Cedric Vuye; Johan Blom; Tom Tytgat; Siegfried Denys; Joaquim Carneiro. Physicochemical and Rheological Properties of A Transparent Asphalt Binder Modified with Nano-TiO2. 2020, 1 .

AMA Style

Iran Rocha Segundo, Salmon Landi Jr., Alexandros Margaritis, Georgios Pipintakos, Elisabete Freitas, Cedric Vuye, Johan Blom, Tom Tytgat, Siegfried Denys, Joaquim Carneiro. Physicochemical and Rheological Properties of A Transparent Asphalt Binder Modified with Nano-TiO2. . 2020; ():1.

Chicago/Turabian Style

Iran Rocha Segundo; Salmon Landi Jr.; Alexandros Margaritis; Georgios Pipintakos; Elisabete Freitas; Cedric Vuye; Johan Blom; Tom Tytgat; Siegfried Denys; Joaquim Carneiro. 2020. "Physicochemical and Rheological Properties of A Transparent Asphalt Binder Modified with Nano-TiO2." , no. : 1.

Journal article
Published: 31 July 2020 in Sustainability
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Several factors affect asphalt binder and mixture characteristics. This makes pavement performance assessment a mounting task. This paper evaluates the effects of short-term aging on compactibility and volumetric properties of asphalt mixtures using the Response Surface Method (RSM). Three different binders were utilized to produce mixtures (type AC-14). Aging temperature, aging duration, and duration in a climate chamber with increased humidity and ultraviolet lighting were considered as independent variables (IV), while compactibility and volumetric properties were regarded as dependent variables (DV). The findings revealed significant impacts of aging temperature and duration on compactibility, air voids, voids in mineral aggregate, and voids filled with asphalt, while duration in the climate chamber exhibited no significant influence on the DVs. The effects of IVs on DVs varied by binder type. This was achieved through an elaborate statistical analysis. The study, finally, demonstrates the RSM’s potential to predict changes in responses from mathematical equations—converging with the experimental observation—with excellent accuracy. Potentially, pavement contractors can use this method by replacing haulage duration and mixtures’ temperatures during paving in the developed models. It enables them to predict the pavement density and adjust pressure as well as the number of roller passes to achieve the desired requirements.

ACS Style

Seyed Omranian; Meor Hamzah; Georgios Pipintakos; Wim Van Den Bergh; Cedric Vuye; Mohd Hasan. Effects of Short-Term Aging on the Compactibility and Volumetric Properties of Asphalt Mixtures Using the Response Surface Method. Sustainability 2020, 12, 6181 .

AMA Style

Seyed Omranian, Meor Hamzah, Georgios Pipintakos, Wim Van Den Bergh, Cedric Vuye, Mohd Hasan. Effects of Short-Term Aging on the Compactibility and Volumetric Properties of Asphalt Mixtures Using the Response Surface Method. Sustainability. 2020; 12 (15):6181.

Chicago/Turabian Style

Seyed Omranian; Meor Hamzah; Georgios Pipintakos; Wim Van Den Bergh; Cedric Vuye; Mohd Hasan. 2020. "Effects of Short-Term Aging on the Compactibility and Volumetric Properties of Asphalt Mixtures Using the Response Surface Method." Sustainability 12, no. 15: 6181.

Journal article
Published: 28 June 2020 in Construction and Building Materials
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Oxidative ageing in bituminous materials is considered one of the most important factors for distress types in road applications. This paper aims to offer insights into the validity of commonly held beliefs regarding the oxidation phases of ageing in bitumen, the fast- and the slow-rate phase, and explore the main oxidation products formed upon ageing. In order to evaluate possible differences between bitumen types, the penetration grade as well as the bitumen production process was varied. Thus, the ageing of three different binders was first studied by Fourier-Transform Infrared (FTIR) and Electron Paramagnetic Resonance (EPR) spectroscopy. The formation of oxygen-containing molecular structures on the bitumen surface during ageing was studied with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The results of FTIR reveal a gradual increase of sulfoxides upon ageing, while the EPR results show an increase of organic carbon-centred radicals. In parallel, TOF-SIMS results provide evidence for an increase of oxygenated compounds, such as SOx--, HOx-- and NOx--containing compounds. It appears also that paramagnetic metal species, such as vanadyl-porphyrins, are insusceptible during ageing. Overall, the findings of this study are in agreement with a mechanism comprising two rate-determining phases and support the formation of different oxygenated products. It is believed that the experimental approach used in this work may contribute further to an improved understanding of the ageing mechanisms in bitumen.

ACS Style

Georgios Pipintakos; H.Y. Vincent Ching; Hilde Soenen; Peter Sjövall; Uwe Muehlich; Sabine Van Doorslaer; Aikaterini Varveri; Wim Van Den Bergh; Xiaohu Lu. Experimental investigation of the oxidative ageing mechanisms in bitumen. Construction and Building Materials 2020, 260, 119702 .

AMA Style

Georgios Pipintakos, H.Y. Vincent Ching, Hilde Soenen, Peter Sjövall, Uwe Muehlich, Sabine Van Doorslaer, Aikaterini Varveri, Wim Van Den Bergh, Xiaohu Lu. Experimental investigation of the oxidative ageing mechanisms in bitumen. Construction and Building Materials. 2020; 260 ():119702.

Chicago/Turabian Style

Georgios Pipintakos; H.Y. Vincent Ching; Hilde Soenen; Peter Sjövall; Uwe Muehlich; Sabine Van Doorslaer; Aikaterini Varveri; Wim Van Den Bergh; Xiaohu Lu. 2020. "Experimental investigation of the oxidative ageing mechanisms in bitumen." Construction and Building Materials 260, no. : 119702.

Journal article
Published: 08 February 2020 in Construction and Building Materials
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Nowadays, Reclaimed Asphalt (RA) is widely used in pavement applications as part of new asphalt mixtures. To design high-quality asphalt mixes, the RA material and especially the RA binder must be systematically characterised with the purpose to explore its ageing state, especially when RA is added in high rates (above 20%). In this research, chemical (SARA and FTIR ageing indexes) and rheological properties (master curve parameters, Glower-Rowe parameter and ΔΤc) of a large selection of RA binders (19 samples) were determined to reveal their ageing level. The results of this experimental validation were further analysed statistically to discover clusters of similar chemorheological properties, reflecting in this way their ageing state. The exploratory techniques PCA and HCA were able to detect five clusters of RA binders with different ageing states. The five clusters clearly distinguish the RA binders in groups with statistically different properties, assessed using one-way ANOVA. The method proposed here is a potential tool to “fingerprint” RA binders with similar ageing states, particularly for decision-making strategies, to optimise the use and treatment of RA.

ACS Style

Alexandros Margaritis; Hilde Soenen; Erik Fransen; Georgios Pipintakos; Geert Jacobs; Johan Blom; Wim Van Den Bergh. Identification of ageing state clusters of reclaimed asphalt binders using principal component analysis (PCA) and hierarchical cluster analysis (HCA) based on chemo-rheological parameters. Construction and Building Materials 2020, 244, 118276 .

AMA Style

Alexandros Margaritis, Hilde Soenen, Erik Fransen, Georgios Pipintakos, Geert Jacobs, Johan Blom, Wim Van Den Bergh. Identification of ageing state clusters of reclaimed asphalt binders using principal component analysis (PCA) and hierarchical cluster analysis (HCA) based on chemo-rheological parameters. Construction and Building Materials. 2020; 244 ():118276.

Chicago/Turabian Style

Alexandros Margaritis; Hilde Soenen; Erik Fransen; Georgios Pipintakos; Geert Jacobs; Johan Blom; Wim Van Den Bergh. 2020. "Identification of ageing state clusters of reclaimed asphalt binders using principal component analysis (PCA) and hierarchical cluster analysis (HCA) based on chemo-rheological parameters." Construction and Building Materials 244, no. : 118276.

Journal article
Published: 17 August 2018 in Transportation Research Record: Journal of the Transportation Research Board
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The chemical irreversible hardening of epoxy modified bitumen is affected by various physical factors and the successful application of this technology is directly linked with full understanding of chemo-rheological material characteristics. This study proposes a model to describe the material viscosity evolution during hardening of epoxy modified bitumen. The findings from numerical analyses performed to assess the mechanical response of epoxy modified bituminous binders are presented. Information of the chemical interaction of epoxy within a bituminous matrix was collected and all the influential factors have been determined. The proposed chemo-rheological model accounting for the polymerization of the epoxy in the bitumen was formulated and the sensitivity of material parameters, such as activation energy, reaction order and extent of hardening reaction until the gel point of epoxy modified binders, was demonstrated. Results of the analyses suggest that lower levels of activation energy increase the degree of hardening and the rate of viscosity development. By decreasing the hardening reaction until the gel point the achieved viscosity of epoxy modified bitumen was increased showing the importance of gel reaction extent on material viscosity evolution. The numerical studies have shown also that the polymerization rate in the epoxy modified bitumen is highly dependent on the temperature under various (non-) isothermal conditions. Also, the polymerization rate should be considered through all the material curing processes to avoid unwanted variations in the mechanical properties.

ACS Style

P. Apostolidis; X. Liu; C. Kasbergen; M.F.C. Van De Ven; Georgios Pipintakos; A. Scarpas. Chemo-Rheological Study of Hardening of Epoxy Modified Bituminous Binders with the Finite Element Method. Transportation Research Record: Journal of the Transportation Research Board 2018, 2672, 190 -199.

AMA Style

P. Apostolidis, X. Liu, C. Kasbergen, M.F.C. Van De Ven, Georgios Pipintakos, A. Scarpas. Chemo-Rheological Study of Hardening of Epoxy Modified Bituminous Binders with the Finite Element Method. Transportation Research Record: Journal of the Transportation Research Board. 2018; 2672 (28):190-199.

Chicago/Turabian Style

P. Apostolidis; X. Liu; C. Kasbergen; M.F.C. Van De Ven; Georgios Pipintakos; A. Scarpas. 2018. "Chemo-Rheological Study of Hardening of Epoxy Modified Bituminous Binders with the Finite Element Method." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 28: 190-199.

Website
Published: 16 July 2018 in Advances in Materials and Pavement Performance Prediction
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Lateral restraint is considered to be a primary mechanism of geogrid base stabilization, and the geogrid-aggregate interlocking establishes the stiffness enhancement around the geogrid. This paper introduces an innovative application of bender elements in an aggregate base as shear wave transducers to quantify local stiffness increase in the vicinity of a geogrid. Several triaxial test specimens of granite aggregate compacted at optimum moisture content were prepared for resilient modulus testing. For the geogrid-stabilized specimens, a triangular aperture punched and drawn geogrid was placed at mid-height of specimen. To measure shear wave velocities across the specimen at different locations above the geogrid, three bender element pairs were installed on the membrane at three different heights above the mid-specimen. Shear wave velocities and axial resilient strains were recorded under the applied stress states. The shear moduli obtained from the geogrid-stabilized specimen were always greater than those obtained from the unstabilized specimen thereby presenting a local stiffness improvement due to geogrid-aggregate interlocking. Further, in the stabilized specimens, the shear moduli obtained near the geogrid were always greater than those obtained far from the geogrid. Therefore, through the successful shear wave velocity measurements and shear modulus estimation, bender element pairs can be effectively used for the quantification of local stiffness improvement due to geogrid-stabilized aggregate.

ACS Style

P. Apostolidis; Georgios Pipintakos; X. Liu; M.F.C. Van De Ven; S. Erkens; A. Scarpas. Epoxy modified bitumen: Chemical hardening and its interpretation. Advances in Materials and Pavement Performance Prediction 2018, 415 -418.

AMA Style

P. Apostolidis, Georgios Pipintakos, X. Liu, M.F.C. Van De Ven, S. Erkens, A. Scarpas. Epoxy modified bitumen: Chemical hardening and its interpretation. Advances in Materials and Pavement Performance Prediction. 2018; ():415-418.

Chicago/Turabian Style

P. Apostolidis; Georgios Pipintakos; X. Liu; M.F.C. Van De Ven; S. Erkens; A. Scarpas. 2018. "Epoxy modified bitumen: Chemical hardening and its interpretation." Advances in Materials and Pavement Performance Prediction , no. : 415-418.