Rheological Behavior Of Asphalt Binders Research Articles

Influence of Basalt Fiber Morphology on the Properties of Asphalt Binders and Mixtures.

Basalt fiber (BF) has been proven to be an effective additive for improving the properties of asphalt mixtures. However, the influence of basalt fiber morphology on the properties of asphalt binders and mixtures remains inadequately explored. In this study, chopped basalt fiber (CBF) and flocculent basalt fiber (FBF) were selected to make samples for testing the influence of the two types of basalt fibers on asphalt materials. Fluorescence microscopy was used to obtain the dispersion of fiber in asphalt binders. Then, a temperature sweep test and a multiple stress creep recovery (MSCR) test were carried out to appraise the rheological characteristics of the binder. Moreover, the performance of the fiber-reinforced asphalt mixture was evaluated by a wheel tracking test, a uniaxial penetration test, an indirect tensile asphalt cracking test (IDEAL-CT), a low-temperature bending test, a water-immersion stability test, and a freeze-thaw splitting test. The results indicate that the rheological behavior of asphalt binders could be enhanced by both types of fibers. Notably, FBFs exhibit a larger contact area with asphalt mortar compared to CBFs, resulting in improved resistance to deformation under identical shear conditions. Meanwhile, the performance of the asphalt mixture underwent different levels of enhancement with the incorporation of two morphologies of basalt fiber. Specifically, as for the road property indices with FBFs, the enhancement extent of DS in the wheel tracking test, that of RT in the uniaxial penetration test, that of the CTindex in the IDEAL-CT test, and that of εB in the low-temperature trabecular bending test was 3.1%, 6.8%, 15.1%, and 6.5%, respectively, when compared to the CBF-reinforced mixtures. Compared with CBFs, FBFs significantly enhanced the elasticity and deformation recovery ability of asphalt mixtures, demonstrating greater resistance to high-temperature deformation and a more pronounced effect in delaying the onset of middle- and low-temperature cracking. Additionally, the volume of the air void for asphalt mixtures containing FBFs was lower than that containing CBFs, thereby reducing the likelihood of water damage due to excessive voids. Consequently, the moisture susceptibility enhancement of CBFs to asphalt mixture was not obvious, while FBFs could improve moisture susceptibility by more than 20%. Overall, the impact of basalt fibers with different morphologies on the properties of asphalt pavement materials varies significantly, and the research results may provide reference values for the choice of engineering fibers.

Evaluation the Rheological Behavior of Asphalt Binder, Fracture Resistance and Moisture Susceptibility of Asphalt Mixtures: Before and After Adding Nano Fe2O3

Evaluation the Rheological Behavior of Asphalt Binder, Fracture Resistance and Moisture Susceptibility of Asphalt Mixtures: Before and After Adding Nano Fe2O3

Practical Methods to Construct Asphalt Binder Master Curves and Calculate Christensen–Anderson Model Parameters

Asphalt binder master curves are applied to describe the rheological behavior of asphalt binders. A standard for constructing asphalt binder master curves and fitting a model to the results does not presently exist. In this study, a pairwise interpolation is established for free shifting of isotherms. The pairwise interpolation method yields time–temperature shift factors that are in good agreement with the Gordon and Shaw method and can be more easily implemented without sophisticated software. Subsequently, practical methods to calculate the Christensen–Anderson (CA) model crossover frequency and R parameters are compared. The relationship between reduced frequency and the tangent of the phase angle in logarithmic space is generally linear over the tangent of phase angle values spanning from 0.2 to 0.5 and can be used to determine the crossover frequency. Two approaches that generally yielded acceptable model accuracy were identified for calculating the CA model R value: (1) least squares optimization to minimize the sum of squared errors for storage and loss moduli; and (2) fitting a line to log (log dynamic shear modulus) versus the tangent of the phase angle over the tangent of the phase angle values spanning between 0.5 and 2. Based on the asphalt binders evaluated in this study, the CA model can accurately reflect asphalt binder rheological behavior when the dynamic shear modulus exceeds 105 Pa and the phase angle is less than 70° for unmodified asphalts or less than 60° for polymer-modified asphalts.

Effect of Nano-Cobalt Oxide on the Rheological Behavior of Asphalt Binder and Mechanical Characteristics of Hot Mix Asphalt

In this study, the effects of nano-cobalt oxide (nano-CoO) (1 and 2% by asphalt binder weight) on the rheological behavior of the asphalt binder and mechanical characteristics of asphalt mixtures were examined. To evaluate the behavior of the asphalt binder at moderate and high temperatures, the dynamic shear rheometer (DSR) test was used. Besides, to study asphalt mixtures’ rutting potential and fatigue cracking, the repeated load axial (RLA) test and the indirect tensile fatigue test (ITFT) were conducted, respectively. Based on the rheological tests, adding 1 and 2% of nano-CoO to asphalt binder increases the complex modulus (G∗) and reduces the phase angle (δ) at high temperatures and significantly improves the modified asphalt binder’s rutting parameter. Also, at moderate temperatures, the addition of nano-CoO reduced the fatigue parameter of the modified asphalt binder compared to the control asphalt binder. It was demonstrated that the permanent strain of the modified specimens was decreased by about 35% compared to that of the control specimens. The fatigue tests at two temperatures and five stress levels also showed that incorporating nano-CoO significantly increased (about 90%) the fatigue life of modified samples compared to controlled samples.

RETRACTED: Rheological behavior of asphalt binder and performances of asphalt mixtures modified by waste soybean oil and lignin

Effort has been made in this study to examine how the rheological behaviors of asphalt binder and performances of Stone Matrix Asphalt (SMA) mixture are affected using lignin and soybean oil. In current research lignin (3%, 5%, 7% by weight of asphalt binder) and soybean oil (5% by weight of asphalt binder) were added to modify-two types of virgin binders (AC 60–70 and AC 85/100). To assess different binders’ performance by checking their physical and rheological behavior, penetration grade, ductility, linear amplitude sweep, multiple stress creep recovery, Dynamic Shear Rheometer, rotational viscosity and softening point tests, and to evaluate asphalt mixtures’ performance, fatigue, rutting, indirect tensile strength and resilient modulus performances were evaluated. ANOVA is applied for statistically analyzing data. Rheological behaviors’ results showed the use of lignin additive increases the softening point and decrease the penetration grade. Using lignin decreases low temperature resistances of binder, whereas oil improves the bitumen’s low-temperature resistance. Multiple Stress Creep Recovery (MSCR) experiment result demonstrated an enhance in high performance temperature of the virgin binder at different stress levels by the addition of lignin. While, the utilization of oil decreases the rutting strength of sample. According to Linear Amplitude Sweep (LAS) outcomes, the use of lignin additive decreases fatigue property of the binders. While, soybean oil enhanced it. The mixtures experiment outcomes reveal the use of lignin increased the lasting deformation resistances, resilient modulus (MR), Indirect tensile strength (ITS), fracture energies. While, addition of oil has negative effect. Fatigue test results indicated that addition of lignin decreases the fatigue life of specimens, while soybean oil increases it. The Mr of the oil modified mixture is 7% lower than original mixture. While addition of 3%, 5%, and 7% lignin leads to increase the Mr by 3%, 18%, and 25%, respectively. Through the outcomes, addition of oil to 3% lignin modified mixture lead to decrease the FE by 1% which has the same value like original binder. Adding oil to mixtures comprising 3%, 5%, and 7% lignin leads to increase the rut depth amounts about 5%, 10%, 12%, respectively.

Characterization and rheological behavior of asphalt binder modified by a novel cyclic borate ester additive

• Asphalt binder was modified novel boron-containing additive named cyclic borate ester (CBE). • CBE additive was used into an asphalt binder in the ratios of 1%, 2%, 4% and 6% (w/w). • 1 H NMR, FTIR, SEM, TG/TDG and DSR tests were applied. • CBE additive interacted with asphalt’s chemical structure electro-statically. • CBE enhanced the elastic property of asphalt binder. In the current study, the synthesis of a novel additive containing boron and its inclusion in asphalt binder was completely achieved under chemical laboratory conditions. Following this objective, the structural analyses of the additive containing boron, namely Cyclic Borate Ester (CBE), and the modified asphalt binders were examined. The asphalt binders were blended with CBE additive in 1%, 2%, 4%, and 6% (w/w) ratios at each stage of the experiment. The elemental analyses of CBE were performed using the Fourier transform infrared (FTIR) spectroscopy test, the thermogravimetry (TG), and the proton nuclear magnetic resonance ( 1 H NMR) spectroscopy test. The mechanisms of the modification in the modified asphalt binders were researched using FTIR while their microstructures and thermal degradation behaviors were analyzed via scanning electron microscopy (SEM) and TG tests. In the analyses the rheological behaviors of the blends were investigated by the temperature-frequency-amplitude sweeps in dynamic shear rheometer (DSR) test. According to the experimental results, it was seen that there was no phase separation between CBE and the asphalt matrix. There was an electrostatic interaction between asphalt and CBE’s hydrocarbon chain. Accordingly, it was observed that the rutting resistance and elastic characteristics of the base asphalt binder investigated in the study were increased by including CBE.

Evaluation of rheological behavior of asphalt binder modified by recycled polyethylene wax and crumb rubber

As in recent years the disposal of waste tire rubbers in landfills are increased because of increase in population, the environmental population are increased. The recycle and reuse of these material to modify bitumen can be environmentally and economically beneficial. In current research the polyethylene wax and Crumb Rubber are used to modify original binder. Several bitumen tests were used to evaluate the rheological properties of binder such as; Multiple Stress and Creep Recovery (MSCR) and Linear Amplitude Sweep (LAS), dynamic shear rheometer (DSR), bending beam rheometer (BBR), rotational viscosity. Results revealed that samples modified by 18% crumb rubber and 5% polyethylene wax have better performance to save energy and reduce air pollution. Results indicated that addition of polyethylene wax led to decrease in the performance of binder in low temperature, while CR enhance it. Fatigue test results indicated that addition of CR increased the fatigue life of binder, while as the polyethylene wax content increased, the fatigue lives decreased. MSCR test results indicated that CR improves the recovery potential of binder which lead to enhance the rutting properties of binder. Based on results in 15% CR modified binders, addition of 3% polyethylene wax improves the resistance against permanent deformation while addition of 5% and 7% polyethylene wax reduces the rutting resistance of binder. While in binder modified by 18% and 21% CR, addition of 3% and 5% polyethylene wax enhance the permanent deformation resistance of binder and addition of 7% polyethylene wax decreases the rutting performance.

Rheological evaluation of asphalt binder modified by amorphous poly alpha olefin (APAO)

This study examined the effect of amorphous poly alpha olefin (APAO) on the rheological behavior of asphalt binder. In order to modify asphalt binder, several percentages of APAO (0, 2, 4, 6, 8%, and 10% by the weight of asphalt binder) were used. The penetration grade, softening point, ductility, and viscosity tests were performed. Also, the multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests were conducted to evaluate the rutting and fatigue behavior of asphalt binder. The storage stability test was implemented to measure the ability of modified asphalt binder against separation. Based on the results, using APAO reduced the penetration grade and increased the softening point due, maybe, to the asphalt binder stiffening. The PI values increased with the addition of APAO, which indicated that the temperature susceptibility of all modified asphalt samples was reduced compared to the base asphalt binder. The increase in the viscosity of virgin asphalt binder due to APAO addition caused the mixture placement/compaction operations to become harder. The G*/sinδ parameter for all types of pre-post-aging RTFO asphalt binders was improved for APAO-modified asphalt binder, meaning that the latter stiffened and thus increased the respective rutting resistance of mixtures. The low-temperature performance of asphalt binder indicated that the stiffness of asphalt sample increased with an increase in the APAO percentage, which indicates that the addition of APAO improved the cracking potential of modified asphalt binders and had negative effects on the asphalt binders. The storage stability test results indicated that the phase separation of asphalt binder was related to the APAO content. Results revealed, ignoring the levels of stress, that using APAO reduced the non-recoverable creep compliance (Jnr) value of virgin asphalt binder, indicating the production of an asphalt binder benefitting higher rutting resistance with APAO modification. APAO increased the %R of asphalt binder. Based on the LAS test results, the addition of APAO led to an increase in the fatigue life of asphalt binders, and by increasing the additive content, the fatigue life increased. The FTIR analysis indicated that no chemical interaction was observed between asphalt binder and APAO.

Rheological behavior of asphalt binders and fatigue resistance of SMA mixtures modified with nano-silica containing RAP materials under the effect of mixture conditioning

Due to the environmentally associated issues regarding the construction or rehabilitation of asphalt pavements with merely virgin materials, researchers have proposed the re-utilization of the reclaimed asphalt pavement (RAP) materials. However, their adoption in asphalt pavements is detrimental to the fatigue performance of asphalt pavements. For this, modifying asphalt binders with nanoparticles has been one of the successful choices among researchers. In this study, different compounds of asphalt binders and stone matrix asphalt (SMA) mixtures containing 20%, 30%, 40%, and 50% RAP materials modified with 2%, 4%, and 6% nano-silica were prepared. Moreover, the rheological behavior of each mix was evaluated using several tests, including rotational viscosity (RV) considering the flow activation energy (FAE) method, frequency sweep, Multiple Stress Creep Recovery (MSCR), Linear Amplitude Sweep (LAS), and Bending Beam Rheometer (BBR). Besides, the fatigue performance of aged SMA mixtures was investigated using the four-point beam fatigue (4 PB) test. The results indicated that the temperature susceptibility of binders was decreased by the addition of nano-silica and RAP binder. Also, according to the MSCR and frequency sweep tests results, the rutting resistance of modified binders with the RAP binder was superior to that of the base binder. Besides, due to the establishment of a network by nano-silica within the structure of the asphalt binder in which the functional groups of asphalt binder interact with nanoparticles, the modified binders with RAP binder outperformed their unmodified counterparts regarding the fatigue life. Also, aging had a less detrimental impact on the fatigue life of the RAP contained SMA mixtures. However, the low-temperature performance of binders was degraded by the addition of nano-silica.

Investigating the rheological properties of asphalt binder incorporating different crumb rubber contents based on a response surface methodology

The effects of different crumb rubber (CR) contents and their interactions with high temperature ranges on the rheological behavior of asphalt binder were investigated in this study using the response surface methodology (RSM). A temperature sweep test was performed using a dynamic shear rheometer (DSR) on modified binders with 5%, 7%, 10%, 12%, and 15% crumb rubber content at temperatures ranging from 46 °C to 82 °C. RSM statistical analysis was conducted based on central composite design (CCD) and assuming the rheological parameters complex modulus (G*) and phase angle (δ°) as response variables. Results from analysis of variance (ANOVA) test indicated that temperature and rubber content affect rheological parameters significantly (p < 0.05). A value of p < 0.0001 indicated a good agreement between the predictions of quadratic models and experimental results with a mean error <5% for all responses. The separate effects of temperature and rubber contents were analyzed, and the results revealed that all responses were influenced by the interaction of both independent variables but were more strongly influenced by rubber content than temperature. Consequently, it can be concluded that RSM is an effective approach for investigating rheological properties.

The effects of UHMWPE/nanoclay on rheological properties of modified asphalt binder

This study is aimed to investigate the effect of polymer nanocomposite of Ultra-high-molecular-weight polyethylene and Nanoclay on rheological behavior of asphalt binder. Therefore, the dynamic shear rheometer and bending beam rheometer were used to determine the characteristics of control and modified asphalt binder at moderate, high and low temperatures. The results indicate that the use of nanocomposite, especially in the amount of 4% (by weight of asphalt binder), increases the resistance to rutting fatigue cracking. Also, Modified asphalt binder at low temperatures based on the two creep stiffness parameter and m-value has a better performance than control asphalt binder.

Effect of styrene-butadiene-styrene (SBS) on the rheological behavior of asphalt binders

The binders in pavement could support the loading in either linear or nonlinear regime. The linear viscoelasticity of asphalt binders was well established, however, a few of researches focused on the nonlinear viscoelasticity of asphalt binders. Here, this paper deals with the effects that SBS exerts on the linear and nonlinear rheological behavior of asphalt binders. The nonlinear rheological behavior of one kind of neat asphalt binder and the corresponding SBS modified asphalt binders under large amplitude oscillatory shear stress (LAOS stress) is analyzed by Fourier Transform (FT)-rheology and strain decomposition methods. The linear viscoelastic measurements show that the elastic proportion and the complexity of rheological behavior of the asphalt binder increases with increase in SBS content. The nonlinear viscoelastic measurements reveal that the relative nonlinearity of asphalt binders increases with increase in stress and decrease in frequency; the relationship between I3/I1 and stress amplitude can obey the sigmoidal function; the intrinsic nonlinearity Q0 decreases with increase in frequency and increases with the increase of SBS content. Both the FT analysis and decomposition results show that the nonlinearity of SBS modified asphalt binder is more obvious than neat asphalt binder and increases with the increase of SBS content. SBS could increase the nonlinearity and the elastic proportion of asphalt binder and decrease its fluidity. All the studied binders exhibit stress softening and stress thinning under all the studied test conditions.

Investigations on viscosity and flow behavior of polyphosphoric acid (PPA) modified asphalt at high temperatures

The rheological behavior of asphalt binders is composed of the deformation behavior at medium-low temperature and the flow behavior at high temperature, however, few researchers pay attention to the latter for polyphosphoric acid (PPA) modified asphalt. To analyze viscosity characteristics and flow behavior of PPA modified asphalt, six kinds of PPA modified asphalts with different mass fractions were prepared, and the effects of PPA dosage, test temperature and shear rate on the Brookfield rotary viscosity were discussed. The rheological parameters, viscous activation energy Eη, flow index n and consistency coefficient k were obtained based on Arrhenius law and the power law model, and the flow master curve was established by the time-temperature superposition principle. The results show that viscosity is positively correlated with PPA dosage, approximately, conforms to the exponential growth model. Meanwhile, viscosity is negatively correlated with test temperature and shear rate, respectively, in accordance with Arrhenius equation and power law equation. Under the test conditions, the flow index n of six kinds of asphalts goes up with the increase of PPA dosage or the decrease of temperature. However, all the n values are less than 1, indicating asphalts are pseudo-plastic fluid. The consistency coefficient k is consistent with the viscosity with the change of PPA dosage and test temperature, and may represent viscosity to a certain extent. The flow master curve with three parameters established can describe the effects of test temperature and shear rate on viscous flow characteristics. In this investigation, the non-Newtonian flow behavior of PPA modified asphalt was analyzed from the perspective of viscosity, proposing a method to estimate the dependence of viscosity on test conditions in a wider range through limited experimental data. This method is not only applicable to PPA modified asphalt, but also can provide references for the study of viscous flow characteristics of other asphalt binders.

The Effect of Zinc Stearate Modification on Aging Characteristics of Asphalt Binder

Different types of modifiers have been investigated to improve aging characteristics of asphalt binders. In this research, the effect of zinc stearate modification has been studied on aging resistance of asphalt binder. For this purpose, viscous flow properties and other rheological characteristics of neat and modified asphalt binders have been evaluated by using conventional experimental tests and superpave protocol test. In order to evaluate rheological behavior of asphalt binder in presence of zinc stearate, a neat asphalt binder sample with three modified samples containing 0.5, 1 and 2 wt% of zinc stearate were aged by means of the Rolling Thin Film Oven Test (RTFOT). The Brookfield rotational viscosity (RV) was implemented at six different temperatures from 100 to 200 degree of centigrade. Furthermore, the dynamic shear rheometer (DSR) was used for evaluating complex modulus (G*) and phase angle (δ) of all neat and modified samples at 10, 20, 30, 40, 50 and 60°C in frequency sweep mode. To evaluate effect of adding zinc stearate by using viscosity results, proportion of asphalt binder’s viscosity after aging to its viscosity before aging was defined as viscosity aging index (VAI). Results showed that adding zinc stearate to neat asphalt binder reduces the viscosity aging index. Results of frequency sweep test indicated that zinc stearate causes the values of complex shear modulus in aging asphalt binder approach to neat state which means the effect of zinc stearate modification is positive for improving aging resistance of asphalt binder.

Modification of thermal and rheological behavior of asphalt binder by the addition of an ethylene-methyl acrylate-glycidyl methacrylate terpolymer and polyphosphoric acid

Abstract This study evaluated the modification effects of adding ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMGMA) in the presence of polyphosphoric acid (PPA) to an asphalt binder graded as 50/70 (0.1mm) in the Brazilian penetration grade specification (AC 50/70). The EMGMA terpolymer has been presented as a new alternative to modify asphalt binders properties, as scientific literature is scarce on its usage in this context and also on the role of PPA when used in combination with reactive polymers. The characteristics of the modified binder were analyzed by standard and rheological testing, including Multiple Stress Creep Recovery test (MSCR) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The MSCR test showed that the modified binder presented lower values of non-recoverable compliances (Jnr) and a higher percent recovery, when compared to the conventional binder. This behavior indicates that addition of EMGMA and PPA in asphalt binders could enhance the resistance to rutting of asphalt mixtures. The statistical evaluation showed that EMGMA had greater influence on the studied properties of Jnr (0.1kPa), MSCR recovery, softening point and elastic recovery at 25°C and that the PPA had also significant influence on these properties. FTIR analysis showed that chemical reactions occurred between the asphalt binder and EMGMA, forming a three-dimensional polymeric network, which promotes improved characteristics.

Characterizing rheological behavior of asphalt binder over a complete range of pavement service loading frequency and temperature

The present study presented a new procedure for characterizing the rheological properties of asphalt binders over the complete range of pavement service frequency and temperature. The proposed procedure involved two primary steps. In the first step, a modified windowing method (MWM) with a pre-smoothing operation and a modified windowing inter-conversion method (MWIM) with an accurate distribution of the time constants were developed to convert the flexural creep compliance observations from the bending beam rheometer (BBR) test into the corresponding complex shear moduli, so that these measurements could be well combined with the DSR test results. In the second step, the 2S2P1D model was adopted to construct the full master curves of the asphalt binders in frequency domain. To extend the application of the procedure for simulating the master curves in time domain, an existing continuous relaxation spectrum model and a derived continuous retardation spectrum model for the 2S2P1D model were employed. The results showed that the combination of the BBR and DSR data substantially expanded the scale of the complex shear modulus. The corresponding linear viscoelastic (LVE) master curves could be incorporated into the existing asphalt concrete complex modulus predictive equations for better pavement response analysis and performance assessment.

Effect of Film Thickness on Rheological Behavior of Asphalt Binders

In the current Superpave® binder tests, the rheological properties of asphalt binders are determined by the dynamic shear rheometer. The asphalt binders are tested using a gap size of either 1 or 2 mm. In the asphalt mixture, the thickness of the asphalt film between aggregates can vary between a few microns and a few millimeters. Because of the interaction between the asphalt and the aggregate, rheological behavior in thin films can differ from the behavior determined at large gap sizes. In this study the rheological properties of asphalt binders were measured at different gap sizes that simulate the range in film thickness of a typical mixture. Significant changes in rheological properties were observed as the gap size changed. The results indicate that different modified binders show different trends as the gap size changes. A review of the literature was conducted for an explanation of this behavior. Four mechanisms were offered to explain similar gap effects observed for other materials. Using the data collected in this study, the disentanglement mechanism caused by adhesion to testing plates appears to fit the observations for asphalt binders. The results suggest that the current gap settings in the binder tests might not be sufficient to determine the performance of the binder in the mixture. The findings also suggest that more work is required to understand the effect on the rheological behavior of asphalt binders of physical and chemical interactions with aggregates.

Damping of Shear Vibrations in Asphalt Modified with Styrene-Butadiene-Styrene Polymer

Shear vibrations in conventional and polymer-modified asphalt binders are examined. Using dynamic compliances instead of moduli, viscous deformation effects can be separated from total deformation and the modified dynamic loss compliance and modified loss tangent functions can be defined. These two material functions appear to be more sensitive than viscoelastic moduli to the rheological behavior of asphalt binders and to changes caused by polymer addition. The characteristic temperature of the transition from the viscoelastic to viscous behavior of asphalt binder ( Tv) can be identified by using the viscous asymptote J”. The damping of shear vibrations that likely relates to the internal structure of asphalt material can be described by the modified loss tangent. The rheological behavior of the base asphalt 200/300 penetration grade and its blends with different amounts of radial styrene-butadiene-styrene rubber is investigated. Using master curves of dynamic functions and the Williams-Landel-Ferry form of the shift factor, isochrones of the original and modified dynamic material functions are constructed. Characteristic temperatures of the viscous transition ( Tv) and the glass transition ( Tg) are determined. Damping behaviors of the base and modified asphalts are studied.