It is well documented that most bituminous binders contain crystallisable material. This crystall... more It is well documented that most bituminous binders contain crystallisable material. This crystallisable fraction, often referred to as paraffinic or natural wax, is associated with the bitumen’s origin and has an influence on its rheological performance. In the literature, Differential Scanning Calorimetry (DSC) is the primary technique used to determine the melting and crystallisation behaviour of this waxy fraction. However, in bitumen, thermal transitions in DSC are typically very broad and can be combined with recrystallisation effects upon reheating. This work explores the potential crystallisation and melting process of a waxy and a wax-free bitumen via three different approaches: DSC, Wide-Angle X-ray Diffraction (WAXD) and Confocal Laser Scanning Microscopy (CLSM). The findings reveal that the DSC transitions of the waxy bitumen are in good agreement with the corresponding occurrence of WAXD signals and to some extent with the formation and disappearance of the surface micro...
In this study, the suitability of a natural peat fiber, as a modifier for bitumen was investigate... more In this study, the suitability of a natural peat fiber, as a modifier for bitumen was investigated. Peat fibers were dried, ground, and fractionated into a fiber and a granular fraction. Rheological data on peat modified binders indicated that the granular fraction is acting as a filler mainly stiffening the bituminous binders whilst the fiber fraction mainly increases the elastic behavior, which became especially visible at higher service temperatures. It was observed that by changing the ratio of fibers versus granular particles, the rheological behavior can be regulated. In addition, drainage tests were carried out on stone mastic asphalt (SMA) mixes. The data indicated that peat fibers can effectively reduce drainage, and can be used as an alternative for the currently used cellulose fibers.
Microstructures of bitumen were investigated using atomic force microscopy (AFM) and environmenta... more Microstructures of bitumen were investigated using atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM), and a chemical characterization was successfully carried out using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The bee structures were observed by AFM, for which a chemical explanation by wax was confirmed by the TOF-SIMS analysis. A tube pattern or worm structures were generated and visualized by ESEM on bitumen surfaces. Chemical differences between the structured and unstructured areas, as well as between different areas of the structure, were observed. A mechanism for the structure formation on bitumen surface during ESEM analysis is suggested.
This recommendation is based on the results of an inter-laboratory study organised by the RILEM t... more This recommendation is based on the results of an inter-laboratory study organised by the RILEM technical committee TC 264-RAP "Asphalt Pavement Recycling"—Task Group 3 (TG3) focusing on Asphalt Binder for Recycled Asphalt Mixture. The TG3 aimed to evaluate the effect of a specific family of materials known as asphalt recycling agent (ARA) on the aged binder under different configurations. Even though ageing is an irreversible phenomenon, effective ARA must have the capability to improve the flexibility of the bituminous materials and their resistance against cracking susceptibility with no adverse effect on the rutting resistance of pavements containing reclaimed asphalt. A total of 17 participating laboratories analysed the properties of binder blends composed of aged binder from reclaimed asphalt in three different contents (60, 80, 100%), ARA and virgin binder. The physical properties of the blends were thoroughly evaluated through traditional and rheological binder te...
Additional file of Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network ... more Additional file of Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network hydrogel utilized for the cleaning of works of art
Tout comme dans le cas des specifications Superpave, le module complexe des liants bitumineux con... more Tout comme dans le cas des specifications Superpave, le module complexe des liants bitumineux constituera certainement un element cle des futures normes europeennes basees sur les performances. Afin de mieux cerner la fidelite des procedures d'essai actuellement disponibles, le groupe miroir francais du WG1 du CEN/TC 336 (liants bitumineux) a organise un essai circulaire portant sur deux bitumes purs (classes 10/20 et 50/70) et trois bitumes modifies (plastomere, elastomere et elastomere reticule). Les dix laboratoires participants ont travaille avec deux types d'appareillage, essentiellement des rheometres a plateaux paralleles (DSR) mais aussi des rheometres a sollicitation lineaire (traction-compression ou cisaillement annulaire). Les mesures ont porte sur une large gamme de temperatures et de frequences afin de tester la reproductibilite (phase 1) et la repetabilite (phase 2). L'article presente une synthese du traitement statistique realise et des premieres conclusi...
Rheological properties such as stiffness, elasticity, and viscosity are crucial parameters for th... more Rheological properties such as stiffness, elasticity, and viscosity are crucial parameters for the use of bitumen as a construction material. In bitumen oxidation studies, the increased viscosity has often been related to an increase in polar interactions from oxygen-containing compounds, like carbonyl groups. In this study, bitumen was subjected to two oxidation processes, aging and air blowing. Aging was performed using the rolling thin film oven test (RTFOT) and the pressure aging vessel (PAV), whereas air blowing was conducted in a laboratory unit. This investigation gives more insights in the changes observed during oxidation and highlights the differences between aging and air blowing. Moreover, the oxidation tests provide bitumen samples of increasing viscosity, which are used to evaluate relations between molecular and viscoelastic characteristics. As a comparison, the changes observed in harder bitumen samples prepared by a continued distillation are also included. As expected, the evolution of rheological properties with oxidation time is very similar in the PAV and in the air-blowing unit, although the timescales are very different. Fourier transform infrared spectroscopy (FT-IR) and acidity measurements reveal clear differences in the formation of oxygen-containing functional groups depending on the oxidation process. UV–visible spectroscopy shows that during aging as well as during air blowing, larger conjugated aromatic compounds are formed. These findings suggest that the formation of polyaromatic compounds may be the main contributor to the increase in elasticity and viscosity during oxidation.
The linear viscoelastic properties of a poly(styrene)-poly(ethylene, butylene) triblock copolymer... more The linear viscoelastic properties of a poly(styrene)-poly(ethylene, butylene) triblock copolymer in the presence of a hydrocarbon oil have been investigated. The samples were followed rheologically, during annealing at different temperatures. In a relatively small temperature ...
It is well established that the mechanical properties of bitumen can change isothermally at moder... more It is well established that the mechanical properties of bitumen can change isothermally at moderate and low temperatures, because of physical changes occurring in the binder. However, evidence of an impact of isothermal hardening on the mechanical properties of asphalt mixtures is very limited. The main focus of this paper is to investigate the importance of isothermal hardening on the characteristics of an asphalt mix, in particular on its low temperature fracture resistance. The objective was to investigate whether the phenomenon of isothermal hardening should be taken into consideration when evaluating binders for their low temperature performance. In a first part, binder properties were investigated, using a bending beam (BBR) and a dynamic shear rheometer (DSR). A study of hardening effects at different temperatures (from - 25 to +25 degrees C) was performed including the reversibility of this phenomenon and the influence of high strain levels applied during isothermal storage...
Initial results are presented of a common research project of Nynas and BRRC, in which three tech... more Initial results are presented of a common research project of Nynas and BRRC, in which three techniques for reducing asphalt production temperatures are considered: the addition of waxes as viscosity reducers, the addition of zeolites as foaming agent and the use of foamed bitumen. The first phase of the project aims at developing laboratory procedures for assessing the potential of each technique to reduce the production temperature. If the mix undergoes curing after compaction, procedures to simulate and possibly accelerate the curing process also need to be developed. Small field trials are planned to validate the outcome of the laboratory work. In a second phase, the performance of the mixes produced at reduced temperature will be evaluated and compared to standard hot mix asphalt, since requirements on asphalt performance (including stiffness, durability, resistance to permanent deformation and cracking) have to be fulfilled. Test sections are planned in a third phase, to extra...
In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPé/P04/GE1) of... more In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPé/P04/GE1) of the CEN/TC336 – WG1 committee (bituminous binder) has reported the results of a round robin test on DSR complex modulus measurements involving two paving grade bitumen (10/20 and 50/70 classes) and three modified binders (plastomer, elastomer and cross-linked elastomer). This paper presents the outcome of the follow-up studies which had been decided at the time. In a first step, a number of dedicated investigations have been made to identify the potential contribution of different factors to the variation in measurement results. In particular, the impact of waiting time after test sample preparation, gap setting procedure, bonding temperature, conditioning times and temperature sweep procedure have been investigated. How to establish the limits of the linear domain of visco-elasticity is another issue which has been dealt with. This has allowed to define more stringent operating conditi...
In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPe/P04/GE1) of... more In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPe/P04/GE1) of the CEN/TC336 – WG1 committee (bituminous binder) has reported the results of a round robin test on DSR complex modulus measurements involving two paving grade bitumen (10/20 and 50/70 classes) and three modified binders (plastomer, elastomer and cross-linked elastomer). This paper presents the outcome of the follow-up studies which had been decided at the time. In a first step, a number of dedicated investigations have been made to identify the potential contribution of different factors to the variation in measurement results. In particular, the impact of waiting time after test sample preparation, gap setting procedure, bonding temperature, conditioning times and temperature sweep procedure have been investigated. How to establish the limits of the linear domain of visco-elasticity is another issue which has been dealt with. This has allowed to define more stringent operating conditi...
There is a need for true performance indicators for bituminous binders, which are equally applica... more There is a need for true performance indicators for bituminous binders, which are equally applicable independent of whether the binder is modified or not. The purpose of this research is to evaluate performance indicators for permanent deformation both for modified and unmodified binders, and to select those indicators that relate best to permanent deformation in laboratory asphalt mix tests. The binder indicators considered are mainly rheological parameters, including the SHRP rutting parameter, the zero shear viscosity and the recently proposed repeated creep test. To evaluate the permanent deformation or rutting susceptibility of the corresponding mixes two devices were used: the French rut tester (large size device, according to EN12697-22) and the cyclic triaxial compression test, according to EN12697-25, part B. This study shows that rheological and even conventional properties of modified binders can be extremely dependent on the thermal history and preparation conditions pri...
It is well documented that most bituminous binders contain crystallisable material. This crystall... more It is well documented that most bituminous binders contain crystallisable material. This crystallisable fraction, often referred to as paraffinic or natural wax, is associated with the bitumen’s origin and has an influence on its rheological performance. In the literature, Differential Scanning Calorimetry (DSC) is the primary technique used to determine the melting and crystallisation behaviour of this waxy fraction. However, in bitumen, thermal transitions in DSC are typically very broad and can be combined with recrystallisation effects upon reheating. This work explores the potential crystallisation and melting process of a waxy and a wax-free bitumen via three different approaches: DSC, Wide-Angle X-ray Diffraction (WAXD) and Confocal Laser Scanning Microscopy (CLSM). The findings reveal that the DSC transitions of the waxy bitumen are in good agreement with the corresponding occurrence of WAXD signals and to some extent with the formation and disappearance of the surface micro...
In this study, the suitability of a natural peat fiber, as a modifier for bitumen was investigate... more In this study, the suitability of a natural peat fiber, as a modifier for bitumen was investigated. Peat fibers were dried, ground, and fractionated into a fiber and a granular fraction. Rheological data on peat modified binders indicated that the granular fraction is acting as a filler mainly stiffening the bituminous binders whilst the fiber fraction mainly increases the elastic behavior, which became especially visible at higher service temperatures. It was observed that by changing the ratio of fibers versus granular particles, the rheological behavior can be regulated. In addition, drainage tests were carried out on stone mastic asphalt (SMA) mixes. The data indicated that peat fibers can effectively reduce drainage, and can be used as an alternative for the currently used cellulose fibers.
Microstructures of bitumen were investigated using atomic force microscopy (AFM) and environmenta... more Microstructures of bitumen were investigated using atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM), and a chemical characterization was successfully carried out using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The bee structures were observed by AFM, for which a chemical explanation by wax was confirmed by the TOF-SIMS analysis. A tube pattern or worm structures were generated and visualized by ESEM on bitumen surfaces. Chemical differences between the structured and unstructured areas, as well as between different areas of the structure, were observed. A mechanism for the structure formation on bitumen surface during ESEM analysis is suggested.
This recommendation is based on the results of an inter-laboratory study organised by the RILEM t... more This recommendation is based on the results of an inter-laboratory study organised by the RILEM technical committee TC 264-RAP "Asphalt Pavement Recycling"—Task Group 3 (TG3) focusing on Asphalt Binder for Recycled Asphalt Mixture. The TG3 aimed to evaluate the effect of a specific family of materials known as asphalt recycling agent (ARA) on the aged binder under different configurations. Even though ageing is an irreversible phenomenon, effective ARA must have the capability to improve the flexibility of the bituminous materials and their resistance against cracking susceptibility with no adverse effect on the rutting resistance of pavements containing reclaimed asphalt. A total of 17 participating laboratories analysed the properties of binder blends composed of aged binder from reclaimed asphalt in three different contents (60, 80, 100%), ARA and virgin binder. The physical properties of the blends were thoroughly evaluated through traditional and rheological binder te...
Additional file of Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network ... more Additional file of Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network hydrogel utilized for the cleaning of works of art
Tout comme dans le cas des specifications Superpave, le module complexe des liants bitumineux con... more Tout comme dans le cas des specifications Superpave, le module complexe des liants bitumineux constituera certainement un element cle des futures normes europeennes basees sur les performances. Afin de mieux cerner la fidelite des procedures d'essai actuellement disponibles, le groupe miroir francais du WG1 du CEN/TC 336 (liants bitumineux) a organise un essai circulaire portant sur deux bitumes purs (classes 10/20 et 50/70) et trois bitumes modifies (plastomere, elastomere et elastomere reticule). Les dix laboratoires participants ont travaille avec deux types d'appareillage, essentiellement des rheometres a plateaux paralleles (DSR) mais aussi des rheometres a sollicitation lineaire (traction-compression ou cisaillement annulaire). Les mesures ont porte sur une large gamme de temperatures et de frequences afin de tester la reproductibilite (phase 1) et la repetabilite (phase 2). L'article presente une synthese du traitement statistique realise et des premieres conclusi...
Rheological properties such as stiffness, elasticity, and viscosity are crucial parameters for th... more Rheological properties such as stiffness, elasticity, and viscosity are crucial parameters for the use of bitumen as a construction material. In bitumen oxidation studies, the increased viscosity has often been related to an increase in polar interactions from oxygen-containing compounds, like carbonyl groups. In this study, bitumen was subjected to two oxidation processes, aging and air blowing. Aging was performed using the rolling thin film oven test (RTFOT) and the pressure aging vessel (PAV), whereas air blowing was conducted in a laboratory unit. This investigation gives more insights in the changes observed during oxidation and highlights the differences between aging and air blowing. Moreover, the oxidation tests provide bitumen samples of increasing viscosity, which are used to evaluate relations between molecular and viscoelastic characteristics. As a comparison, the changes observed in harder bitumen samples prepared by a continued distillation are also included. As expected, the evolution of rheological properties with oxidation time is very similar in the PAV and in the air-blowing unit, although the timescales are very different. Fourier transform infrared spectroscopy (FT-IR) and acidity measurements reveal clear differences in the formation of oxygen-containing functional groups depending on the oxidation process. UV–visible spectroscopy shows that during aging as well as during air blowing, larger conjugated aromatic compounds are formed. These findings suggest that the formation of polyaromatic compounds may be the main contributor to the increase in elasticity and viscosity during oxidation.
The linear viscoelastic properties of a poly(styrene)-poly(ethylene, butylene) triblock copolymer... more The linear viscoelastic properties of a poly(styrene)-poly(ethylene, butylene) triblock copolymer in the presence of a hydrocarbon oil have been investigated. The samples were followed rheologically, during annealing at different temperatures. In a relatively small temperature ...
It is well established that the mechanical properties of bitumen can change isothermally at moder... more It is well established that the mechanical properties of bitumen can change isothermally at moderate and low temperatures, because of physical changes occurring in the binder. However, evidence of an impact of isothermal hardening on the mechanical properties of asphalt mixtures is very limited. The main focus of this paper is to investigate the importance of isothermal hardening on the characteristics of an asphalt mix, in particular on its low temperature fracture resistance. The objective was to investigate whether the phenomenon of isothermal hardening should be taken into consideration when evaluating binders for their low temperature performance. In a first part, binder properties were investigated, using a bending beam (BBR) and a dynamic shear rheometer (DSR). A study of hardening effects at different temperatures (from - 25 to +25 degrees C) was performed including the reversibility of this phenomenon and the influence of high strain levels applied during isothermal storage...
Initial results are presented of a common research project of Nynas and BRRC, in which three tech... more Initial results are presented of a common research project of Nynas and BRRC, in which three techniques for reducing asphalt production temperatures are considered: the addition of waxes as viscosity reducers, the addition of zeolites as foaming agent and the use of foamed bitumen. The first phase of the project aims at developing laboratory procedures for assessing the potential of each technique to reduce the production temperature. If the mix undergoes curing after compaction, procedures to simulate and possibly accelerate the curing process also need to be developed. Small field trials are planned to validate the outcome of the laboratory work. In a second phase, the performance of the mixes produced at reduced temperature will be evaluated and compared to standard hot mix asphalt, since requirements on asphalt performance (including stiffness, durability, resistance to permanent deformation and cracking) have to be fulfilled. Test sections are planned in a third phase, to extra...
In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPé/P04/GE1) of... more In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPé/P04/GE1) of the CEN/TC336 – WG1 committee (bituminous binder) has reported the results of a round robin test on DSR complex modulus measurements involving two paving grade bitumen (10/20 and 50/70 classes) and three modified binders (plastomer, elastomer and cross-linked elastomer). This paper presents the outcome of the follow-up studies which had been decided at the time. In a first step, a number of dedicated investigations have been made to identify the potential contribution of different factors to the variation in measurement results. In particular, the impact of waiting time after test sample preparation, gap setting procedure, bonding temperature, conditioning times and temperature sweep procedure have been investigated. How to establish the limits of the linear domain of visco-elasticity is another issue which has been dealt with. This has allowed to define more stringent operating conditi...
In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPe/P04/GE1) of... more In a previous paper presented at the 2008 E&E Congress, the French mirror group (BNPe/P04/GE1) of the CEN/TC336 – WG1 committee (bituminous binder) has reported the results of a round robin test on DSR complex modulus measurements involving two paving grade bitumen (10/20 and 50/70 classes) and three modified binders (plastomer, elastomer and cross-linked elastomer). This paper presents the outcome of the follow-up studies which had been decided at the time. In a first step, a number of dedicated investigations have been made to identify the potential contribution of different factors to the variation in measurement results. In particular, the impact of waiting time after test sample preparation, gap setting procedure, bonding temperature, conditioning times and temperature sweep procedure have been investigated. How to establish the limits of the linear domain of visco-elasticity is another issue which has been dealt with. This has allowed to define more stringent operating conditi...
There is a need for true performance indicators for bituminous binders, which are equally applica... more There is a need for true performance indicators for bituminous binders, which are equally applicable independent of whether the binder is modified or not. The purpose of this research is to evaluate performance indicators for permanent deformation both for modified and unmodified binders, and to select those indicators that relate best to permanent deformation in laboratory asphalt mix tests. The binder indicators considered are mainly rheological parameters, including the SHRP rutting parameter, the zero shear viscosity and the recently proposed repeated creep test. To evaluate the permanent deformation or rutting susceptibility of the corresponding mixes two devices were used: the French rut tester (large size device, according to EN12697-22) and the cyclic triaxial compression test, according to EN12697-25, part B. This study shows that rheological and even conventional properties of modified binders can be extremely dependent on the thermal history and preparation conditions pri...
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