SBS-modified Binder Research Articles

Investigation of the oxidation ageing of RAP asphalt blend binders and mixtures

ABSTRACT This study evaluates the oxidation ageing properties of asphalt blends and mixtures combined with various percentages of RAP and SBS-modified binder, rejuvenator and neat binder. Four ageing methods were conducted in the laboratory on the asphalt blends and mixtures. The results showed that the G-R parameter, the ICO and the flexibility index increased, while the ΔTcr decreased with the RAP content and the ageing level. The SBS-modified binder and rejuvenator improved the cracking resistance of the RAP binder and mixture. After PAV 20 h ageing, the asphalt blends containing a low amount of RAP were equivalent to their virgin binder after PAV 40 h ageing. The asphalt blends containing a low amount of RAP after PAV 40 h ageing were equivalent to their virgin binder after PAV 60 h ageing. It was found that binders subjected to RTFO, PAV 20 h ageing, PAV 40 h ageing, and PAV 60 h ageing had rheological and chemical properties equivalent to those of loose mixtures subjected to the STOA protocol for 4 h at 135°C, the LTOA protocol for 8 h at 135°C, the LTOA protocol for 12 h at 135°C, and the LTOA protocol for 24 h at 135°C, respectively.

Effect of kaolinite clay/SBS on rheological performance of asphalt binder

The main aim of the present study was to investigate the impact of kaolinite clay/styrene–butadiene–styrene (KC/SBS) on the viscosity, rheology and storage stability of the asphalt binder. This research work was carried out to develop KC/SBS-modified asphalt binder by evaluating the optimum KC and SBS content with proper mixing time and mixing temperature. The quantity of KC and SBS was varied by the weight of the control binder from 0 to 5%. The addition of KC in an appropriate amount can dramatically enhance the compatibility between SBS and base asphalt. The Superpave rutting parameter (G*/Sinδ) showed that with the addition of 2% of KC and 4% of SBS, the binder exhibits better rutting strength performance. It was also observed that there was marginal increment in the fatigue parameter at a certain percentage of KC and SBS. Storage stability test shows that modified asphalt binder does not exhibit phase separation under elevated temperatures. Thus, it can be concluded that when a small amount of KC was added to the SBS-modified binder, its physical properties were successfully enhanced on a condition that the clay scatters into the binder at the nanoscopic level.

Fatigue and Rutting Performance of Airfield SBS-Modified Binders Containing High Modulus and Antirutting Additives

AbstractPermanent deformation and fatigue cracking are two main distresses on airfield pavement. To enhance material performances, the researchers introduced three additives in this study: namely, ...

Characterizing the Temperature Effects on Rutting and Fatigue Properties of Asphalt Binders Based on Time-Temperature Superposition Principle

Abstract The objective of this article is to investigate the effects of temperature on rutting and fatigue cracking resistance of asphalt binders based on the time-temperature superposition principle (TTSP). In this study, the TTSP approach was employed to interpret the results of multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests for both neat and styrene-butadiene-styrene (SBS)–modified asphalt binders. The higher stress level of 3.2 kPa in the standard MSCR test procedure was extended to 10 and 15 kPa to verify the stress sensitivity of the nonrecoverable compliance (Jnr). A loading duration of 5 minutes in the standard LAS test was extended to 10 and 15 minutes to develop the fatigue failure criterion at different conditions. The results demonstrate that the time-strain curves of the neat binder during the MSCR tests under different temperatures can be unified into a single strain master curve using the TTSP shift factors, based on which the predictive Jnr showed good agreement with the measured values. This TTSP-based analysis approach does not work well for the MSCR results of the SBS-modified binder at high temperatures. However, the fatigue failure criterion determined from the LAS tests under different temperatures was verified to be successfully constructed into a single failure criterion according to the TTSP approach for both the neat and SBS-modified binders. Therefore, only an additional caution is raised for the TTS-based analysis on rutting resistance of the modified binder in a high temperature range.

Fatigue resistance of asphalt binders and the correlation with asphalt mixture behaviour

The prediction of asphalt pavements performance in relation to the main distresses has been proposed by different researchers, by means of laboratory characterisation and field evaluation. With respect to fatigue, there are different approaches to determine what failure criterion to be considered, what testing conditions to be used and which specimens’ geometry to be produced. Tests performed in asphalt binders and mixtures have been recommended to characterise the fatigue resistance, and correlations among the several scales are proposed in order to make it more practical and more precise to predict the performance of asphalt layers. In terms of laboratory fatigue characterisation of asphalt mixtures, some of the most common tests are the four-point bending beam, diametral compression, the push-pull tests, among others. The characterisation of asphalt binders is also relevant, since fatigue is dependent on their rheological characteristics. Linear viscoelastic parameters of the binders, time sweep and amplitude sweep tests were used to rank three asphalt binders (one neat 30/45 penetration grade binder; one SBS-modified binder; and one highly modified asphalt, HiMA) in terms of fatigue behaviour. HiMA showed the highest fatigue resistance. One dense hot mix asphalt (HMA) mixture (prepared with the AC 30/45 neat binder) was characterised in terms of different fatigue test methods and correlated with binder tests, comparing the two scales approaches. The fatigue life of the asphalt mixture followed in agreement with results from the asphalt binder.

Effect of filler in asphalt mastic on rheological behaviour and susceptibility to rutting

ABSTRACT Mastic, a compound consisting of an asphalt binder and a mineral filler, is an important ingredient in asphalt mixtures, as it is responsible for critical adhesion and viscoelasticity. The rheological properties of mastic are strongly correlated with the rutting potential of asphalt pavement. To explore the impact of filler on the rheological response, three types of asphalt binders and eight types of filler contents were used to fabricate the mastic samples. A modified version of multiple stress creep recovery (MSCR) test selected in this study was regarded as a superior protocol by which to test the rutting potential of asphalt binder and mastic. Based on the rheological behaviour, the 1.0 mm parallel plate gap height was recommended for use in the dynamic shear rheometer (DSR) to evaluate mastic in the MSCR test. The test yielded excellent results with regard to modifier contents, filler contents and stress levels. The regression analysis proved that percent recovery (%R) was a better index for estimating the rheological ability of mastic. Based on the results for %R, the linear viscoelastic region of modified mastic could be expanded by increasing the filler content, while neat mastic demonstrated poor recovery under high stress regardless of filler content. Based on the rheological response, the recommended filler contents were 100%, 120% and 50% for the mastics with 4.0% SBS-modified binder, 3.5% SBS-modified binder and neat binder, respectively.

Low- and intermediate-temperature behaviour of polymer-modified asphalt binders, mastics, fine aggregate matrices, and mixtures with Reclaimed Asphalt Pavement material

The long-term effects of SBS-modified binders and rejuvenators on the properties of high-RAP mixtures, especially the cracking resistance, have not been resolved. Therefore, this paper evaluates the cracking resistance of polymer-modified asphalt binders, mastics, fine aggregate matrices (FAMs) and mixtures containing RAP material and a rejuvenator. A series of laboratory tests is performed on different asphalt material scales, including a frequency sweep test; a BBR test for asphalt binders, mastics and FAM mixes; and a dynamic modulus test and the Illinois flexibility index test for asphalt mixtures. Short-term ageing and long-term ageing are also considered for different asphalt material scales. The results show that the asphalt binders and mixes containing RAP materials have similar Glover-Rowe (G-R) values and flexibility index (FI) values to those of the virgin binders and mixtures that are only subjected to short-term ageing. These results indicate that a rejuvenator can partially decrease the stiffness of the RAP material before long-term ageing; however, the cracking resistance of asphalt materials obviously decreases after long-term ageing. Asphalt materials containing RAP are more susceptible than virgin asphalt material to thermal cracking, and the rejuvenator does not improve the long-term cracking resistance of high-RAP material. The correlations between different laboratory ageing conditions for the asphalt binder, mastic, FAM and mixture are analysed. Binders subjected to PAV 20 h ageing present rheological properties equivalent to those of mixes subjected to the long-term oven ageing (LTOA) protocol for 5 d at 85°C. Binders subjected to PAV 40 h ageing present rheological properties equivalent to those of loose mixtures subjected to the LTOA protocol for 12 h at 135°C. The cracking resistance parameters of the binders, mastics and FAMs are also compared with the cracking resistance parameters of the mixture, and the results illustrate that the G-R parameters of asphalt binder, mastic and FAM are well correlated with the G-R parameter and FI parameter of the mixture. Moreover, the G-R parameter can predict the cracking performance of the asphalt mixture.

Rutting and fatigue cracking performance of SBS-RAP blended binders with a rejuvenator

The reclaimed asphalt pavement (RAP) content in surface course construction in China is low due to the poor cracking performance of aged binder. The use of a rejuvenator is considered when using a higher RAP content. However, the undesirable softening effect of the rejuvenator makes the pavement susceptible to rutting. Thus, RAP binders with a balanced rutting and fatigue cracking performance is needed. This paper evaluated the rutting and fatigue cracking performance of SBS-RAP blended binders using multiple stress creep recovery (MSCR) and linear amplitude sweep test (LAS). Two different superpave performance grade (PG) SBS-modified binders, four RAP contents and two rejuvenator dosages were considered. The test results indicated that RAP binders improved the rutting performance of SBS-modified binders but degraded their recovery behaviour. The rejuvenator was detrimental to the rutting performance of SBS-RAP blended binders and did not improve the binders’ recovery behaviour. The RAP binder reduced the fatigue life of the SBS-RAP blended binders compared with the virgin SBS binder, whereas the rejuvenator improved the fatigue life. However, the fatigue life of the SBS-RAP blended binders was still lower than that of virgin SBS binder. In summary, there are significant differences between the rutting and fatigue cracking behaviours of SBS-RAP blended binders. To achieve a balance between the rutting and fatigue cracking performances of SBS-RAP blended binders, a suitable virgin SBS binder type, rejuvenator dosage and RAP content should be used, and advanced performance tests are needed rather than PG test.

Nanoscale Quantification of Moisture Susceptibility of Paving Asphalts

Moisture-induced damage due to stripping is one of the major concerns to the highway agencies in recent years. In this study, nanoscopic investigations were carried out to examine the effects of moisture in asphalt binders. An Atomic Force Microscope (AFM) was used to estimate the asphalt binder’s modulus and adhesion values, which were believed to be indicators of binder’s resistance to moisture damage. To this end, two Performance Grade (PG) binders and their modified counterparts using polyphosphoric acid (PPA), styrene-butadiene-styrene (SBS), and SBS plus PPA were tested in this study. Test results show significant reductions of adhesion and modulus values after water immersion of the asphalt binders. AFM data also reveals that SBS-modified binders exhibit better moisture resistance compared to the base binder. Findings of this study are expected to help transportation professionals to achieve a better understanding of moisture damage of asphalt binders at a molecular level and their suitability in pavements.

Evaluation of rheological performance and moisture susceptibility of polyphosphoric acid modified asphalt binders

The effects of modification of asphalt binders with polyphosphoric acid (PPA) were evaluated in this study. Mechanistic performance was evaluated by examining the stiffness, rutting, and fatigue properties of two selected binders modified with different dosages of PPA. A surface science approach, namely the surface free energy (SFE) technique as employed to evaluate moisture susceptibility of different PPA-modified asphalt binder and aggregate systems. Since PPA is a hydrophilic material, two different crude oil originated PPA modified binders with selected liquid antistripping agents (LAAs) were evaluated. Binders modified with PPA and Styrene–Butadiene-Styrene (SBS) were also included in the test plan to observe their performance with a simultaneous presence of acid and polymer. Laboratory test results reveal that SBS-modified binders are more rutting resistant than the corresponding PPA-modified binders. The effects of LAA are contingent upon the crude origin of the asphalt binder. Furthermore, PPA did not show any negative effects on fatigue behaviour of long-term aged asphalt binders. From the SFE analysis it was concurred that PPA-modified binders could be more susceptible to moisture damage than the corresponding SBS-modified binders. Higher amount of PPA made asphalt binders more susceptible to moisture damage than lower amounts. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) spectra revealed no changes in the functional groups due to the addition of PPA. The outcome of this study is expected to help Arkansas Department of Transportation (ArDOT) and other agencies in revising their quality control guidelines for possible inclusion of PPA as an approved modifier for asphalt binders.

Prediction of Dynamic Modulus for Elastomer-Modified Asphalt Concrete Mixes at Desert Environment

Two types of elastomeric polymers commonly used in gulf area are selected to modify the asphalt concrete mixtures produced from local materials that can serve at high temperatures and very heavy traffic loads. These polymers are styrene/butadiene/styrene (SBS), crumb rubber (CR). Because of significant contribution of asphalt binder on the performance of the mix at high temperatures, the objective of the study is to predict the dynamic moduli of asphalt concrete mixtures having polymer-modified binders satisfying the latest performance grading $$\hbox {(PG}^{+})$$ . Results showed that 5–10% of CR-modified binders and 2% of SBS-modified binders have elastomeric properties only at temperatures lower than $$58\,{}^{^{\circ }}\hbox {C}$$ . While 6% SBS-modified binder have shown elastomeric behavior at any temperature between 58 and $$76\,{}^{^{\circ }}\hbox {C}$$ . In the case of 4% of SBS-modified sample; the elastomeric properties are affected when testing temperature is above $$67\,{}^{^{\circ }}\hbox {C}$$ . It is concluded that PG 70(V) grade can be obtained by adding at least 3.9% of SBS, while 5.2% of SBS is required to reach PG 76(V) grade. In case of CR-modified binders, adding a minimum amount of 12.1 and 12.9% of CR is required to achieve the $$\hbox {PG}^{+}$$ grade of PG 70(V) and PG 76(H), respectively. The measurement of dynamic modulus $${\vert }E^*{\vert }$$ values of modified asphalt concrete samples was conducted utilizing the asphalt mixtures performance tester (AMPT) then the results were used to create master curves using symmetrical sigmoidal model at any given performance grade of the asphalt binder in terms of polymer type and content.

Evaluation of cracking properties of SBS-modified binders containing organic montmorillonite

In recent years, organic montmorillonite (OMMT) has become a popular additive for the Styrene–Butadiene–Styrene (SBS) modified binder to improve its storage stability. Though many studies have examined the effect of OMMT additive on asphalt performance, little research has focused on the cracking properties of SBS/OMMT-modified binders. In this study, SBS/OMMT-modified binders for asphalt were first produced using five SBS contents of 1%, 2%, 3%, 4%, and 5% and then blended with 3% OMMT additives. First, FTIR and XRD tests were performed to verify the structure of the asphalt/SBS/OMMT. Then, the intermediate-temperature fatigue cracking property was determined by the G∗sinδ of pressure aging vessel (PAV) specimen through a dynamic shear rheometer (DSR) test, while the low-temperature cracking performance was characterized by the creep stiffness and m-value for the unaged, short-term aged, and long-term aged specimens through bending beam rheometer (BBR) tests. The results show that the OMMT/SBS modified asphalt has formed an intercalated structure and a nanocomposite. The compound modification of OMMT and SBS generally exhibited more intermediate-temperature cracking resistance than that of the single SBS-modified bitumen, but the influence of SBS and OMMT is statistically insignificant. Both SBS and OMMT play key roles in determining the m-value, and higher SBS contents lead to a lower stiffness under three aging conditions at low temperatures.

Research on properties of bio-asphalt binders based on time and frequency sweep test

Bio-asphalt is a binding agent that is made of bio-oil and petroleum asphalt, or bio-oil modified with incorporations of some other additives under certain conditions. This study was carried out to evaluate the properties of bio-asphalt binder-based in terms of the value of complex shear modulus (G∗) and the phase angle (δ) tested by dynamic shear rheometer (DSR). Four bio-oil dosages of 5, 10, 15, and 20% based on the weight of asphalt (S100) were used to alter the SBS-modified binder. Whereby, the SBS content is approximately 1% of the weight of the virgin asphalt. The complex shear modulus and frequencies of virgin and short-term aged binders were tested. The master curves of rutting factor (G∗/sinδ) of different bio-asphalt were then generated to survey its rheological properties in a broad range of frequencies and temperatures. Based on the results, it was found that the addition of bio-oil extracted from sawdust has significantly increased the complex shear modulus of asphalt binder at the same frequency conditions after going through rolling thin film oven (RTFO), which is desirable for rutting prevention of asphalt mixtures. The rheological properties of bio-binders are more susceptible to the RTFO aging condition compared to the reference binder. The master curve of rutting factor of bio-binder indicated that the rutting factor of bio-asphalt increased with the increase of frequency before and after RTFO. Additionally, incorporations of bio-oil into the SBS modified asphalt, has greatly increased the rutting factor (G∗/sinδ) after RTFO, regardless of the loading frequency. However, the degree of enhancement was dominated by the percentage of bio-oil and aging condition.

Stress-dependent behavior and rutting resistance of modified asphalt binders: An MSCR approach

In this paper, the stress-dependent behavior of modified asphalt binders was studied using multiple stress creep recovery (MSCR) tests. A neat binder was modified with different amounts of styrene–butadienestyrene (SBS), ground tire rubber (GTR) or polyphosphoric acid (PPA) to investigate the effects of these modifiers on the stress-dependent behavior of asphalt binders. Two non-standard MSCR testing regimes, each representing different stress levels and varying numbers of cycles, were applied at 64°C to each of the modified binders. The nonrecoverable creep compliance (Jnr) and the percentage recovery (R) values were calculated at each cycle. In addition, the average Jnr and the average R values were also calculated at each stress level. All of the modified binders studied in this research showed that a higher degree of non-linear behavior is associated to the higher stress levels. Likewise, all of the binders (except those modified with SBS) showed a decreasing trend of average percent recovery as the stress level increased. In the case of the SBS-modified binders exposed to cumulative incremental stress testing conditions, the initially increasing trend in the average percent recovery was followed by a decreasing trend. This might be due to the fact that, initially, the polymer network in the modified binder got stretched until it reached its highest extension capacity. After reaching this point, the polymer network likely started to rearrange itself while still remaining stronger than neat asphalt.

Aging Behaviour and Mechanism of SBS-Modified Asphalt

Abstract The aging behaviour and mechanism of styrene-butadiene-styrene (SBS)-modified asphalt has been investigated based on laboratory tests in this study. Rolling thin-film oven (RTFO) test and pressure-aging-vessel (PAV) test were conducted to prepare aged SBS-modified asphalt. Conventional property tests, including penetration, soften point, and ductility, as well as elastic recovery and SHRP property tests, including viscosity, dynamic shear rheometor (DSR) and bending-beam rheometer (BBR) tests, were mainly used to analyse the aging behaviour of SBS-modified asphalt. Then Fourier transform infrared spectroscopy (FTIR) and gel-permeation chromatography (GPC) tests were conducted to capture the aging mechanism of SBS-modified asphalt. The testing results indicated that SBS-modified asphalt has similar aging behaviour as base asphalt but better performance and anti-aging ability because of the existence of the SBS modifier. However, it is still inevitable that SBS-modified asphalt becomes aged because of thermal oxidation. The aging of SBS-modified binder consists of two parts: (i) the oxidative aging of the asphalt components, and (ii) the degradation of the SBS modifier. Because of the protective effect between asphalt and SBS polymer, the aging degrees of asphalt and SBS polymer were lower than those aged independently.

Ignitability and thermal stability of asphalt binders and mastics for flexible pavements in highway tunnels

Due to their chemical composition, asphalt binders and mixtures are quite flammable and tend to produce smoke and poisonous gases while burning. Therefore, fire reaction of asphalt pavements is a topic of increasingly interest to improve fire safety in highway tunnels. Different asphalt binders and mastics containing aluminium hydroxide and magnesium hydroxide as inorganic flame retardants (FRs) were analysed through Thermo-Gravimetric Analysis (TGA) and Limiting Oxygen Index (LOI) test. Due to the lack of technical specifications for LOI measurements of asphaltic materials, a specific sample geometry and preparation as well as a testing procedure were developed and applied. The comparison between the two techniques indicated that both thermal stability and flammability are strictly related to asphalt composition. Moreover, the Thermo-Gravimetric test can be preventively used to select the most appropriate FR filler, whose decomposition temperature (together with particle size) is a factor of primary importance. Among the different flame retardants tested, the aluminium hydroxide showed the most important increase in LOI with respect to the unmodified binders. On the contrary, the SBS-modified binder, probably due to the unsaturated nature of the polymeric modifier, showed an increased flammability when compared with the base asphalt binders.

Relaxation of stresses in polystyrene–carbon microcomposite resistive layers

Abstract This paper presents the investigation results on thermoresistive elements made with a styrene–butadiene–styrene (SBS) modified polystyrene binder and carbon filler. Resistive layers were deposited by screen-printing method onto a polyethylene terephthalate (PET) foil. The temperature–resistance dependence of the examined layers was observed. The carbon filler content was precisely selected to obtain high values of TCR, such as 70,000 ppm/°C, for resistive layers with a SBS-modified polystyrene binder in the temperature range from 24 to 100 °C. Because of high TCR the influence of mechanical stresses, which is unfavorable feature of the examined layers, may be omitted. The highest TCR value and stability of electrical parameters during operation were observed for layers containing 42.9% of carbon filler by mass content. The measurements were carried out with the aid of an infrared camera and an oscilloscope because of very fast changes of resistive elements parameters. The analysis of the obtained results allows to draw conclusions about the carbon layer properties and to determine the stress–relaxation rate of the polymer structures.

The effects of compaction temperature on CRM mixtures made with the SGC and the Marshall compactor

The compaction temperature of crumb rubber modifier (CRM) asphalt mixes needs to be determined cautiously because the viscosity and the amount of the CRM binder affects the compactability of the mixtures. In this study, a laboratory investigation was carried out on the volumetric properties of CRM mixtures fabricated using the Superpave gyratory compactor (SGC) and the Marshall compactor as a function of compaction temperature. Two CRM binders were incorporated into HMA mixtures. Two other mixtures were produced with the control binder (PG 64-22) and SBS-modified binder (PG 76-22) and used for comparison purposes. The CRM binders were produced using one base binder (PG 64-22) with 10% or 15% ambient CRM (−40 mesh) by weight of the binder. For this research, the Superpave and the Marshall mix designs for four different asphalt binders were conducted to determine the optimum asphalt contents (OAC). A total of 128 specimens were manufactured using the SGC and the Marshall compactor at various compaction temperatures (116, 135, 154, and 173°C). The volumetric properties were obtained and analyzed using the statistical methods. The results from this study indicated that (1) the compaction temperatures used in this study significantly affected the volumetric properties of the CRM mixtures, regardless of the compaction methods (the SGC and the Marshall compactor); (2) the CRM mixtures in both the SGC and the Marshall compactor showed the higher VMA values than the control and SBS-modified mixtures; (3) a general trend of the volumetric properties as a function of compaction temperature and compaction method was found for the CRM mixtures used in this study.

Rutting response of hot-mix asphalt to generalized dynamic shear moduli of asphalt binder

In this paper, a stiffness indicator of Generalized Dynamic Shear Modulus (GDSM) of asphalt binders is introduced to study the rutting resistance of unmodified and polymer-modified asphalt binders. Seven binders of two unmodified and five SBS-modified binders are tested. At 60 °C, the data of peak shear stress and corresponding peak shear strain are obtained for each binder by the Dynamic Shear Rheometer (DSR). In the linear viscoelastic region of binders, the GDSM is calculated on the basis of the constitutive shear stress–strain equation that is obtained by fitting the Box–Lucas model to experimental data. Two kinds of bituminous mixtures classified by the type of aggregate gradation are used to evaluate the rutting potential. For each gradation, the aggregate is blended with the seven binders. For each mixture, single binder content is employed so that differences in rutting depth can be investigated, depending on various GDMS values of the binders. The rutting depth of mixes is tested with the Asphalt Pavement Analyzer (APA) at 60 °C and the correlation between the average rutting depth and the GDSM is established. Results indicate that for two kinds of mixtures, there exists a good correlation between the GDSM and the average rutting depth. It is confirmed that GDSM is useful as a stiffness indicator for the evaluation of rutting resistance of binders. The constitutive equation of shear stress–strain can be obtained by fitting the Box–Lucas model up to the peak shear stress, which represents an explicit mechanistic implication.

Practical test methods for measuring the zero shear viscosity of bituminous binders

When the zero shear ciscosity (ZSV) is derived from a creep test, the creep time should be sufficiently long to obtain a steady state with a constant shear rate. The creep test works well for most conventional binders. Unfortunately, for polymer modified binders (PmBs), the long waiting times required to obtain a steady state are not always acceptable from a practical point of view and three are problems concerning the repeatability. This paper compares the steady state creep test to alternative test methods for the determination of the ZSV. One method is a short time creep/recovery test, with a short creep period and a longer recovery period, where the ZSV is derived from the recovery part. The other method is an oscillation test at low frequencies, where the complex viscosity is extrapolated to zero frequency to obtain the ZSV. Measurements are presented on a pure 70/100 binder and on a highly SBS-modified binder. While all methods give comparable and repeatable results for the case of the pure binder, complications occur for the highly modified binder. The oscillation method seems to be the most promising, method.