Behavior Of Asphalt Binders Research Articles

Evaluating the Ageing Sensitivity of the Asphalt Binder via Distinct Ageing Methods

Asphalt binder is a crucial component of asphalt pavements that undergoes ageing over time, which can result in the reduced performance and deterioration of pavements. Consequently, artificial ageing methods play a significant role in providing valuable insights into the ageing behaviour and long-term performance of asphalt binders. However, a consensus on the most effective method for simulating ageing behaviour remains elusive, leading to disparities in the outcomes across different research studies. To address this issue, the study utilises two thermo-oxidative ageing approaches, one focusing on the binder itself and another on the loose asphalt mixture. The study investigates the effect of these ageing methods on the behaviour of asphalt binder using physical, rheological, and chemical characterisation. For the binder ageing method, a rolling thin film oven (RTFO) and a pressure ageing vessel (PAV) were utilised, whereas the loose asphalt mixture ageing was performed in an oven at 95 °C for various durations. The results indicated that the ageing trend differed between the two oxidative ageing approaches as the ageing duration increased. However, by employing an ageing sensitivity index, comparable rheological properties were observed between the binders aged using the PAV for 20 h and the loose asphalt mixture for 5 days. The Fourier Transform Infrared (FTIR) spectroscopy analysis revealed that the ageing methods influenced the functional groups associated with ageing in distinct ways, even though they exhibited similar rheological behaviour. Overall, this study provides a comprehensive understanding of different thermo-oxidative ageing approaches, their correlation, and their relevance to the studied field-aged binders.

Investigation of the Effect of Combined Nanosilica and Iranian Natural Binder on the Rheological Behavior of Mastics and Performance of Asphalt Mixtures

The aim of this study was to evaluate the impact of nanosilica (NS) and gilsonite on the behavior of asphalt binders and stone matrix asphalt (SMA) samples. An asphalt binder with 60/70 penetration grade, 0%, 3%, 5%, and 7% gilsonite, and 0%, 2%, 4%, and 6% NS by the weight of the asphalt binder were used. The rotational viscosity (RV), linear amplitude sweep (LAS), bending beam rheometer (BBR), multiple stress creep recovery (MSCR), and dynamic shear rheometer (DSR) tests were applied to evaluate the physical and rheological behaviors of modified asphalt binders. Also, the wheel track, dynamic creep, indirect tensile strength (ITS), resilient modulus (Mr), and four-point bending (FPB) fatigue tests were utilized to examine the performance characteristics of mixtures. Moreover, a two-factor analysis of variance (ANOVA) was used to analyze the data. The rheological test results showed that gilsonite and NS enhanced the rutting and fatigue resistances of asphalt binders. Gilsonite also reduced the low-temperature resistance of asphalt binders, while NS improved that. The storage stability test showed that gilsonite enhanced the storage stability of asphalt binders. Also, adding NS led to an improvement in phase separation. MSCR test indicated an improvement in the high-temperature performance of base asphalt binder at different stress levels by the addition of gilsonite and NS. Based on the LAS test, gilsonite and NS enhanced the fatigue characteristics of asphalt binders. The sample test results also showed that gilsonite and NS improved the permanent deformation resistance, MR, ITS, fracture energy, and intermediate-temperature properties of samples.

Effect of Modifier on Low-Temperature Reversible Hardening Behavior of Asphalt Binder and its Morphology Analysis

Effect of Modifier on Low-Temperature Reversible Hardening Behavior of Asphalt Binder and its Morphology Analysis

Characterization of the Fatigue Behavior of Asphalt Binders, Fams, and Ac Mixtures Based on Multiscale Approaches and on the S-Vecd Model

Characterization of the Fatigue Behavior of Asphalt Binders, Fams, and Ac Mixtures Based on Multiscale Approaches and on the S-Vecd Model

Assessment and Modeling of Aging Effect on Asphalt Material Dynamic-Mechanical Properties

Abstract In this study, the effects of progressive aging on the dynamic-mechanical characteristics of asphalt and asphalt concrete were assessed and evaluated. Field-collected asphalt-aggregate mixture was used to prepare asphalt concrete test specimens. These specimens were then subjected to five aging levels and tested for dynamic-mechanical properties in the laboratory. Results showed that the dynamic-mechanical characteristics of asphalt concrete are significantly affected by progressive aging. In addition, aged asphalt binders that corresponded to the asphalt concrete samples aged at various aging levels were tested for complex shear modulus using a dynamic shear rheometer. A significant effect of progressive aging on the complex shear modulus and viscosity of the binder was observed. A detailed assessment showed that even though the mechanical behavior of asphalt binder significantly changes because of aging, the corresponding asphalt concrete sample does not necessarily show similar change in its behaviors. Finally, this study developed an approach to estimate the dynamic-mechanical characteristics of the aged asphaltic materials. Using this approach, it may be possible to predict the mechanical behaviors of aged asphalt concrete and binder. It is hoped that the developed approach can be useful for advanced modeling of asphalt pavements.

Low Temperature Behavior of Asphalt Binders, Mortars, and Mixtures with High Recycled Materials Content

With the increased usage of recycled materials and various evaluation techniques being utilized to evaluate them, it is becoming increasingly important to be able to obtain consistency between the various techniques. Given the wide range of recycled materials as well as treatments or additive materials being used and the complex interactions resulting between them, it is becoming increasingly important to continually verify the field performance related to the findings of the various evaluation techniques. Therefore, this effort utilized binder blending, mortar procedure, and the uniaxial thermal stress and strain test (UTSST) to examine several mixtures containing recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) along with example recycling agents. The methodologies were compared to each other to seek similarity in findings as well as preliminary comparisons to relevant field performance. The results indicated general agreement between certain parameters of each methodology, while the UTSST showed promising relationships to measured longitudinal and transverse cracking in the observed field test sections.

Laboratory evaluation of the effect of SBS and Lucobite on performance properties of bitumen

In this research, the effects of two additives namely SBS (3, 5%) and Lucobite (3, 5%) on the performance properties of binder were evaluated. The binder fatigue and rutting performance was evaluated through linear amplitude sweep (LAS) and multiple stress creep and recovery (MSCR) test, respectively. Results indicated that 3% SBS modified binder has the highest percent recovery value and the lowest Jnr value, but had the highest sensitivity to a sudden increase in the stress level inside the asphalt mixture. The LAS test results demonstrated that the fatigue behavior of asphalt binders modified with 3% Lucobite, is the highest one.

Review of experimental characterisation and modelling of asphalt binders at low temperature

Asphalt binder represents the main constituent of asphalt paving mixtures. The functional performance and durability of asphalt pavements strongly depend on the rheological and mechanical properties of the binder. Asphalt binder is a highly temperature susceptible material that becomes brittle and more prone to failure at low temperature, which may ultimately result in thermal cracking at the mixture level. Significant effort was devoted over the years to reduce the occurrence of this distress. For this purpose, a number of experimental methods were developed to characterise asphalt binders at low temperature. At the same time, different models were formulated to better understand and predict the material behaviour while extrapolating more information from the testing measurements. In this paper, a comprehensive review on the behaviour of asphalt binders at low temperature is presented. First, a synthetic introduction and background on the development of the criteria for asphalt binder low-temperature behaviour are provided. Then, the current testing procedures for characterising asphalt binders are presented and the validity of the current PG specification is discussed. Finally, the most significant modelling developments are reviewed.

Effective Technique to Estimate Cross Model Parameters

AbstractThe Cross model has been successfully used for modeling the shear thinning behavior of asphalt binders. Usually minimization of least squares/absolute error is used for obtaining model para...

Linear and nonlinear viscoelastic and viscoplastic analysis of asphalt binders with warm mix asphalt additives

ABSTRACTWarm-Mix Asphalt (WMA) is a widely used product, which proved a contribution to the reduction in asphalt mixing and compaction temperatures. This reduction leads to lower fuel consumption and smoke emission in asphalt plants. Most of the characterisation of binders used in WMA has focused in the past on measuring linear viscoelastic properties and associated Superpave parameters. Several studies have shown that the average stresses and strains of the asphalt mixture remain mostly within the linear viscoelastic response. However, localised strains in the binder phase of the mixture could reach values high enough to induce nonlinear viscoelastic and viscoplastic deformations. Therefore, this study focuses on an experimental and analytical evaluation of linear, nonlinear viscoelastic and viscoplastic responses of selected binders modified for use in WMA. The first part of the paper analyses the linear viscoelastic material properties and their ability to evaluate permanent deformation resistance. Then, the non-recoverable creep compliance parameter obtained from the Multiple Stress Creep Recovery (MSCR) test is analysed to assess the nonlinear response and permanent deformation of asphalt binders. The paper utilises a nonlinear plasto-viscoelastic (NPVE) approach to assess and quantify the nonlinear plasto-viscoelastic response of binders by separating the recoverable and irrecoverable strains measured in the MSCR test. Two WMA additives were included in this study by mixing them with polymer-modified and unmodified asphalt binders. Analysis of results showed that the NPVE approach captured a higher percentage of recovery than the NLVE approach. However, binder’s performance evaluation and ranking did not change by adopting the NPVE approach. The nonlinear viscoelastic parameters provided insight on the behaviour of asphalt binders mixed with WMA additives during loading cycles. Sasobit showed higher influence than Advera on binders in resisting permanent deformation by increasing the recoverable strain during the unloading phase.

Mechanical behaviour of asphalt binders at high temperatures and specification for rutting

This is a study of the temperature dependence of the mechanical behaviour of asphalt binders. Creep-recovery and steady-shear experiments were conducted on selected modified and unmodified binders at 60, 70 and 80 C, and the results were used to characterise the binders using a nonlinear viscoelastic model. Experimental and model parameters obtained in this manner were all found to follow Arrhenius relationship with temperature. Rutting parameters such as zero shear viscosity, non-recoverable creep compliance, Superpave criterion and apparent viscosity were predicted using the model, and were also found to follow an Arrhenius relationship with temperature. However, it was found that the temperature sensitivity of the binders can vary considerably. Issues with ‘failure temperature’-based grading systems, such as the Superpave high temperature specification, were analysed in the light of the Arrhenius-like temperature dependence and varying temperature sensitivities. Possible ways to consider varying temperature sensitivities in the high temperature specification are proposed.

The Evaluation of Rheofalt as a Warm Mix Asphalt Additive on the Properties of Asphalt Binder

In this research study, Rheofalt as warm additive was used to modify original binder (60–70 penetration grade). The binder fatigue and rutting performance was evaluated through Linear Amplitude Sweep (LAS) and multiple stress creep and recovery (MSCR) test, respectively. Results indicated that the binder modified with 2% rheofalt has the highest Jnr value which lead the pure binder more susceptible to rutting. The LAS test results demonstrated that the fatigue behavior of asphalt binders modified with 2% rheofalt is the highest one.

An extension of the fractional model for construction of asphalt binder master curve

Knowledge and prediction of viscoelastic behaviour of asphalt binder is of great interest in order to design asphalt mixtures for civil construction of road and airports with good performances. The capability of a fractional model – requiring a very limited number of parameters – to describe and predict the linear viscoelastic behaviour of asphalt binder subjected to sinusoidal oscillations is investigated. Experimental data of complex modulus, |G*|, and phase angle, δ, are used to validate the proposed constitutive model. Based on the proposed extension of a fractional model, complex modulus isotherms for a range of frequencies can be created simply starting from isochronals at frequency value of 1 Hz. Furthermore, a mathematical procedure derived from the same model is proposed in order to compute the shift factors and automatically create the master curve, thus avoiding further errors due to manual adjustments. This shifting procedure requires only a few isotherms to create a smooth master curve able to describe asphalt binder behaviour under a wide range of temperature and loading conditions. When the fractional model is adopted and the mathematical shifting procedure is applied, only a temperature sweep test at 1 Hz is needed in order to create complex modulus and phase angle master curves.

Evaluation of Fatigue and Rutting Behavior of Asphalt Binder Containing Warm Additive

In this research study, Sasobit as warm additive was used to modify original binder (60/70 penetration grade). The binder fatigue and rutting performance was evaluated through linear amplitude sweep (LAS) and multiple stress creep and recovery test, respectively. Results indicated that 3% Sasobit modified binder has the highest percent recovery value and the lowest Jnr value, but had the highest sensitivity to a sudden increase in the stress level inside the asphalt mixture. The LAS test results demonstrated that the fatigue behavior of asphalt binders modified with 1% Sasobit is the highest one.

Comparative evaluation of laboratory and field ageing of asphalt binder using a non-linear differential model

Aging of asphalt binders leads to evolution of pavements’ mechanical performances. To study the ageing process and ageing behaviour of asphalt binder, a rolling thin film oven test (RTFOT) and a self-designed ventilation oven test at 60°C (VOT) were conducted on five regular asphalt samples in the laboratory, and aged asphalt was extracted from six pavement sections of different service lives. Viscosity of asphalt samples was fitted with a non-linear differential dynamic model by numerical analysis software, and two parameters of L and r for different ageing approaches are obtained. With the two parameters, the ageing process of these asphalts under different ageing conditions was discussed, and the relationship between simulation ageing and field ageing was investigated. The results indicate that the non-linear differential dynamic model can effectively evaluate the asphalt ageing process in the laboratory and in the field. The model parameters (L and r) can be used to quantify the ageing state and ageing rate. Asphalt has its ultimate ageing state corresponding with different ageing temperatures. The ultimate ageing degree of RTFOT and field ageing is about 4–5 times that of VOT. The ageing effect shift factor is approximately 60 min of extended RTFOT ageing to represent 1 year of field ageing. Thus time-extending RTFOT can simulate the long-term ageing of pavement asphalt. And the parameter L or r may be used to predict the extent of ageing in lab-aged materials.

Study on Nonlinear Viscoelastic Properties of Asphalt Mixture Based on Stress Relaxation Test

Development of normal stress in the direction perpendicular to the asphalt mixture is an important feature of the nonlinear viscoelastic behavior of asphalt binders. In this paper, this phenomenon was studied with the help of stress-relaxation experiments in torsion. Results indicate that stress relaxation test by controlling strain could be used to evaluate the stress relaxation ability of asphalt mixture. With the aging degree of asphalt mixtures increased, the low temperature cracking resistance got worse; the higher the temperature is, the faster the stress relaxed; the smaller the initial strain, the worse the stress relaxation ability also. The viscoelasticity of asphalt mixture could be simulated by exponential model fractional and the experiments well supported the modeling results.

Effect of Thermal Cycles on Creep Behavior of Bituminous Binder in Hot Regions

This research is devoted on the study of creep behavior of asphalt binder in hot region. This binder was subjected to thermal cycles due to the variation of temperature from day to night. These cycles produce a heating-cooling phenomenon. To evaluate the effect of climate change in laboratory, it was used the rheometer DSR, and compare the results found with the nine sample. These thermal cycles led to aging and therefore hardening of the binder. Thus, the proposal of a rheological model that can represent the curves obtained experimentally, where it is able to describe the creep behavior of binders tested. It is proposed a new model that correlates well with the experimental curves, it is called A+2K.

Emerging Methods in Asphalt Binder Rheological Characterization

ABSTRACT One of the most significant achievements in the area of paving asphalt materials characterization was the development of the Strategic Highway Research Program Specifications at the beginning of the 1990's. The PG tests and analyses, detailed in a number of AASHTO specifications, are used to specify the asphalt binders used in pavement applications and also serve as primary tools to investigate the behavior of asphalt binders in many research studies. In this paper the limitations of the current PG system are discussed and emerging methods developed to address these limitations and to improve the selection of good performing asphalt binders are described.

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.