Michael P. Wistuba

• Technische Universität Braunschweig

A novel test method for measuring the Poisson’s ratio of asphalt binders using a Dynamic Shear Rheometer (DSR) equipped with a linear drive is presented. The paper describes the preparation ofhomogeneousand isotropic cylindrical binder specimens, their loading into the DSR, and the subsequent measurement of the absolute complex shear modulus |G*|,...

Three different rejuvenators are blended with a differently-aged penetration graded asphalt binder 50/70 and investigated using different rheological test methods. Characteristic temperatures T(G*=15 kPa) and T(G*=5 MPa) as well as corresponding phase angles δ(G*=15 kPa) and δ(G*=5 MPa) are used to evaluate the efficiency of the rejuvenators, to ob...

In this present study, the effects of polyacrylonitrile fibres and high content (50%) of Reclaimed Asphalt Pavement (RAP) on the mechanical properties of asphalt mixtures in binder and base layers were studied. This is the first time that the effect of high RAP content on the mechanical properties of fibre reinforced asphalt mixtures (FRAM) was eva...

In order to reduce production and compaction temperatures, as well as to increase the resistance to permanent deformation, synthetically refined waxes are commonly used as additives in asphalt pavements. This study focuses on the capability of replacing synthetically refined wax with bio-degradable wax. Ten different bio-waxes (called Biomer) with...

One predominant type of failure in under-designed asphalt pavements in cold regions is cracking due to low-temperature induced stress. The asphalt binder is the key factor that drives cracking resistance of the asphalt layer. Due to its visco-elastic behavior, the asphalt binder is basically able to relax induced stress, however relaxation capacity...

Recently, nanotechnology has been effectively used in the field of road pavement. Oxidation and aging of asphalt cause deterioration of road pavements and increase asphalt-related emissions. We propose an anti-aging strategy to interrupt the asphalt deterioration by using engineered clay/fumed silica nanocomposites. In this research, the morphologi...

A novel Three-Point Bending Beam Test (3-PBT) using a Dynamic Shear Rheometer (DSR) with linear drive motor is introduced for testing asphalt binder at low temperature conditions. This 3-PBT in DSR can be used as surrogate for Bending Beam Rheometer (BBR) tests. Advantages in comparison to BBR are that (i) 3-PBT works without harmful cooling medium...

In this article, creep properties of asphalt binders and asphalt mastics (binder filler composite) are tested in the Dynamic Shear Rheometer using a single shear creep test and considering steady-state flow conditions. These tests are performed for a set of 10 different asphalt binders and 18 corresponding asphalt mastics. The same material combina...

For designing asphalt materials resistant to permanent deformation and rutting, a low creep deformation at high temperature is the crucial performance property. Usually, creep deformation is assessed through static or cyclic compression tests at elevated temperature, both for asphalt mixtures as well as for asphalt binders. For asphalt mixtures, st...

The research was carried out to explore the effect of silica nanoparticles (NPs) on the ultraviolet aging properties of bitumen. In this study, characterization of NPs-modified Bitumen using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible spectrophotometer were investigated. In addition,...

The use of Dynamic Shear Rheometer (DSR) has become a standard tool to characterise bituminous binders, either for research or specifications purposes. Testing with the DSR enables to cover a wide range of temperature and frequency conditions in a fast way by using limited amount of materials. Depending of the test type, DSR measurements provide di...

In this paper, the effect of the combined use of re-recycled Reclaimed Asphalt Pavement (RAP) on the performance properties of Warm Mix Asphalt (WMA) was experimentally investigated at both binder and mixture scales. First, a virgin 50/70 Pen Grade binder and fresh Gabbro aggregates were used to prepare a conventional Hot Mix Asphalt (HMA) for surf...

Im Rahmen der Wiederverwendung von Asphalt ist es notwendig, das im Ausbauasphalt enthaltene, gealterte Bitumen durch Maßnahmen der Verjüngung wieder in den Zustand eines lieferfrischen Bindemittels zu versetzen. Rejuvenatoren sind geeignete Stoffe zur Verjüngung von Bitumen. Die Produktpalette an Rejuvenatoren ist riesig, doch es mangelt an einer...

Warm mix asphalt (WMA) is gaining increased attention in the asphalt paving industry as an eco-friendly and sustainable technology. WMA technologies are favorable in producing asphalt mixtures at temperatures 20–60 °C lower in comparison to conventional hot mix asphalt. This saves non-renewable fossil fuels, reduces energy consumption, and minimize...

Styrene-butadiene-styrene (SBS) modified bitumen is a widely-used civil engineering material with a variety of applications. The properties and durability of bitumen greatly depend on its chemical composition. Due to its organic nature bitumen is highly prone to oxidation. The main cause of bitumen oxidation is the interplay of sunlight (photo-oxid...

Asphalt mastic is known to play an important role when determining the fatigue performance of asphalt mixture. Time sweep test using a Dynamic Shear Rheometer can be used. However, a long testing time is a major disadvantage, and no guidelines for testing asphalt mastic are available. Therefore, this study presents an Accelerated Dynamic Shear Rheo...

No standard procedure is available for low temperature asphalt binder testing in the Dynamic Shear Rheometer. In this study, an overview is given of the necessary equipment to use the 4 mm geometry for asphalt binder testing including an explanation of shear compliance correction. Furthermore, the testing conditions of 4 mm geometry including speci...

In this study, bitumen modified by fumed silica nanoparticles was characterized through dynamic shear rheometer tests, scanning electron microscopy, and Fourier transform infrared spectroscopy. The fumed silica nanoparticles were used in three different ratios, i.e., 0.1, 0.2 and 0.3 wt.-% of bitumen. Specifically, the modified bitumen characterist...

Die Prüfung von rheologischen Eigenschaften von Bitumen und bitumenhaltigen Bindemitteln mit dem Dynamischen Scherrheometer (DSR) findet international und in Deutschland immer mehr Verbreitung. Weil das Messgerät DSR eine Vielzahl von unterschiedlichen Messverfahren ermöglicht, besteht vielerorts Unklarheit darüber, welches Messverfahren am geeigne...

In this laboratory study, combined effects of polyacronitrile fibres and reclaimed asphalt planings on performance properties of asphalt mixtures were investigated. Performance properties of six asphalt mixtures in total were comparatively analyzed, always considering a standard mix design concept for asphalt binder courses. Three asphalt mixtures...

The use of Dynamic Shear Rheometer (DSR) has become a standard tool to characterise bituminous binders, either for research or specifications purposes. Testing with the DSR enables to cover a wide range of temperature and frequency conditions in a fast way by using limited amount of materials. Depending of the test type, DSR measurements provide di...

An interlaboratory study was conducted among 20 European road asphalt laboratories, to screen current test protocols for testing low temperature properties of asphalt binders using a Dynamic Shear Rheometer (DSR) with 4 mm diameter parallel plate geometry. From the comparison of the test protocols for conducting temperature-frequency sweep tests be...

Asphalt binder ageing leads to significant changes in mechanical and physicochemical properties and often to premature cracking in asphalt pavements. A polymer-modified asphalt binder is repeatedly aged through laboratory techniques, i.e. rolling thin film oven test and pressure age-ing vessel. The resulting properties of the aged binder are analys...

In this study, surface morphology, rheological and chemical properties were investigated of bitumen, which was modified by a composite of clay and fumed silica nanoparticles, and exposed to ultraviolet (UV) aging in laboratory. The volume fraction of the nanoparticles within the binder ranged from 1 to 3%, the temperature range considered was 30 to...

Due to economic and environmental benefits, Recycled Asphalt Pavement (RAP) has been commonly used in the asphalt pavement construction. However, the in-crease in stiffness and brittleness of asphalt binder restrict the use of a high RA con-tent. In this study, the possibility of recycling a RA binder content of 80 % is exper-imentally investigated...

This paper investigates the effect of the glass transition temperature, Tg, and the use of modulus shift factors bT on the measured rheological properties of asphalt binders at low temperatures. First, temperature-frequency (T-f) sweep tests are performed with the Dynamic Shear Rheometer (DSR) on asphalt binder, and, the corresponding Tg is calcula...

The need for road (re)construction materials is constantly growing. At the same time, there is a limited quantity of new, high-quality materials available and a buildup of secondary/recycled construction materials. One possible solution may be the use of recycled concrete aggregate (RCA) in asphalt mixtures instead of natural aggregate (NA), which...

The purpose of the current review is to give an insight into various Warm Mix Asphalt (WMA) techniques in pavement engineering. The idea is to provide a comprehensive overview of this technology that may serve as a basis for engineers and practitioners to structure the entire processes, associated with the design and construction of roads, under he...

The application of additives in asphalt mixtures to enhance the performance properties of asphalt pavements has become an attractive approach in recent years. Several studies have confirmed that the incorporation of fibers into bituminous materials can improve the durability of the pavement. However, whether a single optimum fiber content can impro...

Thermal cracking is one of the most common distresses for asphalt pavement constructed in the cold regions. In order to address this issue, the combined use of fracture mechanics-based tests and simulation is a solid option. First, asphalt mixture samples are prepared based on the German standard and the low temperature strength are measured by Sem...

The use of porous asphalt (PA) mixture to build the wearing course is in some countries common practice to enhance durability and performance of asphalt pavements. Meanwhile, a number of studies have been conducted to evaluate the possibility of improving the pavement performance through the incorporation of fibers at the binder and mixtures level....

The current experimental method used in Europe to characterise asphalt binder at high temperature is based on the Ring & Ball softening point. However, for modified binders it was demonstrated that such a method is unable to correctly characterise the material. In the present work, an alternative solution to determine the high-temperature propertie...

A simple method using Dynamic Shear Rheometer is proposed for determining high temperature key parameters of asphalt binders in place of the Ring-and-Ball softening point, currently used in Germany. The test was recently introduced in the German standards under the name “Bitumen-Typisierungs-Schnell-Verfahren (BTSV)”, which translates to Binder-Fas...

In this paper, the combined use of re-recycled reclaimed asphalt pavement (RAP) and Electric Arc-Furnace Steel Slag (EAFSS) is experimentally investigated and evaluated. First, a virgin asphalt mixture for surface layers is prepared and next aged in the laboratory to reproduce artificial RAP. Then, this material is used to prepare a set of first ge...

In this study, usual asphalt mixtures are tested using known and established perfor-mance testing methods. In a second step, the asphalt mastics (mastic considered as composite of asphalt binder and aggregate filler) that correspond to the asphalt mix-tures, are investigated with regard to their rheological properties. All asphalt mixtures and corr...

One of the main tasks of asphalt reinforcement is to delay or prevent the formation of reflection cracking in asphalt structures. For large-scale tests on reinforced asphalt systems, the unbound base layers were simulated by an 8 mm thick rubber granulate mat and a 10 mm thick rubber mat resting on a low-vibration concrete plate. The asphalt struct...

The 4 mm parallel plate geometry in the DSR with a new sample installation method is proposed to evaluate low temperature rheological properties of asphalt binders. For this purpose, the influences of temperature conditioning and normal force were studied, and finally suitable test conditions were identified to run T-f-Sweep tests in oscillation mo...

As a consequence of aging, asphalt binders from reclaimed asphalt pavements (RAP) are brittle and more susceptible to cracking than virgin binders. During recycling of RAP different additives/rejuvenators are used together with different addition rates in order to restore original asphalt binder properties and to build asphalt pavements with good p...

In this paper, the effect of physical hardening and aging temperatures on the low temperature rheological properties of the asphalt binder is experimentally investigated and modeled. First, Dynamic Shear Rheometer (DSR) tests are performed from -30ºC to 80ºC on four virgin asphalt binders and the corresponding long-term aged binders, which were pre...

In this paper, the combined use of re-recycled reclaimed asphalt pavement (RAP) and Electric Arc-Furnace Steel Slag (EAFSS) is experimentally investigated and evaluated. First, a virgin asphalt mixture for surface layers is prepared and next aged in the laboratory to reproduce artifi-cial RAP. Then, this material is used to prepare a set of first g...

In this paper, the possibility of repeated recycling (re-recycling) of reclaimed asphalt pavement (RAP) is experimentally evaluated. First, a virgin asphalt mixture with asphalt binder PG 58-28 and maximum aggregate size equal to 12.5mm was prepared. Then, the virgin mixture was artificially aged to simulate the different generations of recycled ma...

In this paper, the combined effect of aging temperatures and cooling medium on the rheological properties of asphalt binder was experimentally investigated and evaluated. Two 70/100 penetration grade binders, which were part of the core materials used by the active RILEM committee CMB-252, were selected for this purpose. The materials were artifici...

The performance and durability of asphalt pavements can be estimated by using performance tests on laboratory scale. However, these tests methods are very complex and elaborate. In comparison to conventional tests (sieving curve, void content, etc.) sophisticated and expensive cyclic testing instruments are required, which prevent the implementatio...

In this paper, the combined use of reclaimed asphalt pavement (RAP) and rejuvenators for producing hot recycled asphalt mixture is investigated based on the new Bitumen Typisierungs Schnell Verfahren - BTSV method (Binder-Fast-Characterization-Test), recently proposed in Germany, and through laboratory experimentation. For this purpose, a set of th...

In this paper, the possibility of using the Dynamic Shear Rheometer (DSR) with 4 mm parallel plates and 3 mm gap is investigated as an alternative experimental method to measure the rheological properties of asphalt binders at low temperature. A special butterfly silicone mold was prepared for this purpose and the corresponding testing procedure wa...

During 1998/99, the Western European Road Directors (WERD), now called the Conference of European Directors of Roads (CEDR), asked its members for topics of interest affecting the European road network, with the aims of identifying any knowledge gaps and initiating research. Long-life pavements (LLPs) was one of the topics suggested by the UK Highw...

In Germany, Warm Mix Asphalt (WMA) is not commonly used although this technology was initially introduced to the practice between the 60s and the 80s. The current guidelines are devoted to the reduction of the mixing temperature for mastic asphalt (MA) (Gussasphalt). Due to this requirement, a number of products consisting of plain or polymer modif...

The Binder-Fast-Characterization-Test in the DSR can be used instead of conventional test methods for characterizing plain and modified asphalt binders in the high temperature range. The test is called “Bitumen-Typisierungs-Schnell-Verfahren (BTSV)” and was recently introduced to the German standards. With two rheological key parameters (TBTSV and...

Low-temperature properties of asphalt binders are fundamental for designing asphalt mixture in cold regions. This is especially true for alternative technologies such as Warm Mix Asphalt (WMA), for which a temperature reduction during production may potentially lead to substantial benefits in terms of long-term aging conditions. At low temperature,...

Rutting is one of the most severe failure mechanisms for asphalt pavements. This phenomenon is due to the accumulation of permanent deformation in consequence of traffic loading. The behavior of asphalt mixture is highly affected by the properties of the asphalt binder used in the mix design. For this reason, the Multiple Stress Creep and Recovery...

This volume contains the Proceedings of the RILEM TC 252-CMB International Symposium on the Chemo-Mechanical Characterization of Bituminous Materials. The Symposium was attended by researchers and practitioners from different fields presenting the latest findings in the chemical, mechanical, and microstructural characterization of bituminous materi...

With the Binder-Fast-Characterization-Test (BTSV, Bitumen-Typisierungs-Schnell-Verfahren, in German) plain and modified bitumen can be characterized in the high service temperature range. The method uses the Dynamic Shear Rheometer (DSR) and is based on the historical Softening Point Ring & Ball (SPR&B), which is unable to correctly characterize mo...

In this paper, the low temperature behavior of asphalt mixture containing Reclaimed Asphalt Pavement (RAP) was experimentally and numerically investigated. For this purpose, four asphalt mixtures prepared with different percentages of RAP were tested with the Bending Beam Rheometer (BBR) to determine their creep stiffness, S(t). Then, the S(t) of t...

This paper presents an experimental investigation on the combined use of high content of reclaimed asphalt pavement (RAP) and rejuvenators, for producing asphalt mixtures for wearing courses. First, the new Binder-Fast-Characterization-Test (Bitumen Typisierungs Schnell Verfahren in German) BTSV method, recently proposed in Germany, is used to dete...

In this paper, the low temperature behavior of asphalt mixture containing Reclaimed Asphalt Pavement (RAP) was experimentally and numerically investigated. For this purpose, four asphalt mixtures prepared with different percentages of RAP were tested with the Bending Beam Rheometer (BBR) to determine their creep stiffness, S(t). Then, the S(t) of t...

This paper presents a laboratory test protocol for evaluating fatigue properties of asphalt mixtures through sweep tests at multiple amplitudes and frequencies. Conventional fatigue evaluation of asphalt mixtures typically relies on a limited number of single fatigue tests, and each test is performed at constant test temperature. Moreover, in order...

This paper presents an investigation on the low-temperature properties of asphalt mixture determined with the indirect tensile (IDT) and the semi-circular bending (SCB) experimental methods. First, IDT and notched and unnotched SCB tests are performed on a set of ten different asphalt mixtures. Then, the maximum stress (strength) along the crack su...

One of the most important aspects of asphalt pavement deterioration is the ingress of water in pavement which leads to loss of the material characteristics, even material integrity with loss of aggregates. Thus the behaviour of asphalt mixture under moisture conditions is one of the key parameter for specifications. It’s a complex phenomenon which...

This chapter focuses on the three-dimensional linear viscoelastic (3D-LVE) behaviour of bituminous mixtures and in particular on the measurement and modelling of the complex Young’s modulus and Poisson’s ratio (PR). In the first part of the chapter, the LVE definition of PR is reviewed and experimental measurements of the LVE PR carried out over th...

In this paper, a new and simple approach to estimate the rheological properties of Reclaimed Asphalt Pavement (RAP) binder is proposed to overcome the limitations of the conventional extraction procedure. This method is based on Dynamic Shear Rheometer tests performed on mortars composed of RAP fine fraction and virgin binder, together with a new b...

The characterisation of asphalt binder at low temperature is of fundamental importance for selecting and designing asphalt materials with good and durable performance in regions experiencing severely cold climates. The current specification addresses this issue based on the Performance Grading (PG) system, developed during the Strategic Highway Res...

In this paper, the interface shear fatigue performance is investigated based on a new fatigue test protocol, which includes both cyclic shear and normal static compressive load. Several asphalt structure types are tested at five temperatures (from −10°C to 50°C) and three normal stress levels (from 0 to 0.50 MPa). Based on fatigue tests at three di...

In this paper, an experimental study is performed to evaluate the effect of different notch depths on the scaling law of quasibrittle fracture for asphalt mixture at low temperature. Three-point bending tests are performed on plain and notched asphalt mixture beams of different sizes. The results on unnotched specimens are analysed through the Type...

Asphalt materials used in road pavements are exposed to repeated heavy traffic loading under changing climates. These phenomena make pavements prone to fatigue deterioration as a consequence of the formation of micro-cracks, which can coalesce into a network, ultimately leading to macro cracking and structural collapse. Susceptibility of asphalt mi...

Fatigue cracking is one of the primary failure mechanisms in asphalt pavements and it predominantly occurs within the mortar phase. For this reason, in recent years, a number of studies were carried out by various researchers to better understand the fatigue mechanism in such a critical mixture phase. In the present work, time sweep tests were perf...

In this paper, the possibility of improving the global response of asphalt materials for pavement applications through the use of hydrated lime and Electric Arc-Furnace Steel Slag (EAFSS) was investigated. For this purpose, a set of asphalt mortars was prepared by mixing two different asphalt binders with fine granite aggregate together with hydrat...

Standard asphalt mixtures for road infrastructures consist of natural aggregate and bitumen. A number of research efforts have successfully investigated the possibility of replacing the conventional aggregate skeleton with industrial by-products such as slag originating from steel production process. However, little is known on the effect of steel...

In this paper the effect of the combined use of different amount of Reclaimed Asphalt Pavement (RAP) and Electric Arc Furnace Steel Slag (EAFSS) on the low temperature properties of asphalt mixture is investigated with two experimental methods: Bending Beam Rheometer (BBR) mixture creep and Semi-Circular Bending (SCB) fracture tests. Creep stiffnes...

With modern recycling technologies, Reclaimed Asphalt (RA) has been successfully used in new Hot Mix Asphalt (HMA). However, even if the conventional technical specifications on binders and asphalt mixtures are met, HMA produced with high amount of RA, 50 % and higher, may show poor performance behaviour. This is particularly true for cracking susc...

Identifying the causes of asphalt pavement distress is crucial for determining adequate management strategies and rehabilitation treatments. However, it is difficult for young engineers to determine the causes associated to the specific distress based on simple field observation. This paper presents a multi-scale approach for diagnosing the causes...

This paper presents investigation on the recovery potential of hot mix asphalt (HMA) mixture using cyclic uniaxial tension-compression test in stress-controlled mode. The recovery potential and its dependence on rest period duration were investigated taking into consideration nonlinearity and self-heating effects observed during cyclic loading. In...

Low-temperature cracking is one of the most severe distresses for asphalt pavement experiencing severely cold weather conditions. Many road authorities recognise thermal stress as a crucial parameter for evaluating the low-temperature performance of asphalt pavement. Thermal stress is conventionally computed with a two-step approach where the relax...

In this paper, the possibility of using bending beam rheometer (BBR) experimental results to determine the critical cracking temperature of an asphalt mixture is evaluated. First, thermal stress restrained specimen test (TSRST) together with BBR creep and strength tests is performed on eight asphalt mixtures designed with and without recycled mater...

In this paper, the low temperature strength of asphalt mixture is investigated based on indirect tensile (IDT) and semi-circular bending (SCB) tests and on two-dimensional numerical simulation. The values of maximum stress at crack tip in SCB simulation are obtained using commercial finite element software and cohesive zone modelling. Then, a corre...

In this paper the recovery properties of hot mix asphalt (HMA) mixture in fatigue tests are investigated based on dissipated energy approach. In order to determine the influence of material ageing, bitumen content, polymer modification and compaction energy on material ability to recover its initial characteristics, different variations of an aspha...

Rutting is one of the dominant pavement distresses, hence, the accuracy of rut depth measurements can have substantially impact on the maintenance and rehabilitation (M & R) strategies and funding allocation. Different computation algorithms such as straight-edge method and wire line method, which are based on the same raw data, may lead to rut dep...

The use of recycled materials in asphalt pavements increased significantly over the years, determining well known environmental and economic benefits. Many research agencies and road authorities evaluated the impact of Recycled Asphalt Pavement (RAP) on pavement performance. Nevertheless, the mechanism governing the interaction between virgin aspha...

The determination of the rheological properties of the aged binder in Reclaimed Asphalt Pavement (RAP) materials is a challenging problem. Conventionally, extraction and recovery are used to obtain the RAP binder for further experimental characterisation; however, this procedure is not entirely reliable and accurate. Alternative and more precise ap...

Low-temperature cracking is a serious distress for asphalt pavement built in cold regions, such as northern USA. and northern Europe. Therefore, accurate assessment of the strength and fracture properties of asphalt mixtures is fundamental for ensuring the long-term integrity of the entire pavement structure. It has been shown that asphalt mixtures...

Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) are valuable materials commonly reused in asphalt mixtures due to their economic and environmental benefits. However, the aged binder contained in these materials may negatively affect the low temperature performance of asphalt mixtures. In this paper, the effect of RAP and RAS on...