Fatigue Behavior Of Asphalt Binders Research Articles

Characterization of the fatigue behavior of asphalt binders, FAMs, and AC mixtures based on multiscale approaches and the S-VECD model

Although investigations on upscaling methodologies across binder, Fine Aggregate Matrix (FAM), and Asphalt Concrete (AC) have been reported in the literature, additional evaluations should be performed considering the characteristics of the materials. This study investigates the relationship between the fatigue damage behavior of asphaltic material constituents based on a correlational assessment, as well as on experimental and analytical approaches. For that, rheological properties of asphalt binders were determined and AC and FAM were characterized by uniaxial tests. The fatigue parameters presented strong correlations across the scales and upscaling experimental equations were obtained from experimental data with good and promising results.

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

Estimating asphalt binder fatigue at multiple temperatures using a simplified pseudo-strain energy analysis approach in the LAS test

The linear amplitude sweep (LAS) test is considered an effective tool for evaluating the fatigue behavior of asphalt binders. However, because of the inherent viscoelastic nature of binders their fatigue life varies with temperatures. This leads to a challenge of selecting the LAS testing temperature for screening binders. Recently, an idea of incorporating the time–temperature superposition into the simplified viscoelastic continuum damage (S-VECD) model based on the pseudo-strain energy (PSE) concept is suggested as an opportunity for predicting the fatigue behavior at other temperatures of interest. This study investigates the temperature dependency of the material integrity-damage intensity (C-Damage Intensity) curves derived from the PSE analysis. The results show that the time–temperature superposition is not always applicable for the C-Damage Intensity curves in the PSE analysis. It is however found that those curves at various temperatures have their inherent correlation, allowing the prediction of fatigue behavior at other temperatures. A simplified approach is introduced in this study in which the shift factors measured from frequency sweep portion of LAS tests are used to predict the C-Damage Intensity curves and calculate the fatigue life at other temperatures. The results from this approach is found to correlate very well with the measured fatigue life of asphalt binders.

The effect of different aging conditions and strain levels on relationship between fatigue life of asphalt binders and mixtures

Hardening, the most important cause of aging, can lead to different pavement failures. The first goal of the present research was to appraise the impact of different aging conditions and strain levels on fatigue behavior of asphalt binders and mixtures using frequency sweep, linear amplitude sweep (LAS), and four-point bending (4PB) fatigue tests. The second aim of this study was to assess the impact of aging on the correlation between fatigue life of asphalt binders and mixtures. The outcomes of the LAS test demonstrated that increasing the aging severity at low strain levels improved the asphalt binder fatigue life. However, aging reduced binders fatigue life when subjected under higher strain levels. The rheological master curves showed that aging had a remarkable influence on the viscoelastic characteristics of the binders at low-frequency ranges, and the aging influence on rheological characteristics of the binders decreased at high-frequency ranges. The polymer modified binders (PMB) performed better in terms of fatigue performance under higher loading frequencies and lower strain. However, by reducing the loading frequency and increasing the strain level, the degradation of the polymeric network led to a reduction in the fatigue performance of the PMB. The outcomes of the 4PB fatigue test indicated that aging reduced the fatigue life of neat and modified mixtures at high strain levels, while it had not any remarkable impact on the fatigue behavior of modified mixtures at low strains. The ANOVA analysis showed that aging and strain levels had a substantial influence on the fatigue life of asphalt mixtures with a significance level of 0.05. The correlation between the fatigue life of binders and mixtures demonstrated that applying aging on mixtures increases the accuracy and correlation coefficient between the fatigue life of binders and mixtures.

Evaluation of fatigue behavior of asphalt binders containing reclaimed asphalt binder using simplified viscoelastic continuum damage approach

Several fatigue damage analysis approaches have been introduced for asphalt binders and mixtures. In this study, using three modifiers including softer bitumen, a rejuvenator and waste polymer modified bitumen, fatigue behavior of RAB-containing binder mixes was evaluated based on the simplified viscoelastic continuum damage mechanics (S-VECD). In addition, correlations between the S-VECD parameters and the other fatigue failure criteria were investigated. For this purpose, the time sweep test was used to evaluate fatigue behavior of various asphalt binders in controlled-strain mode. Results showed that the rejuvenator and softer bitumen had the greatest effect in terms of prioritization on the improvement of the fatigue resistance of the RAB-containing binder mixes. Moreover, the results showed that good unique relationships between plateau value (PV) and Nf50 and between rate of change of total released pseudo strain energy (GR) and Nf50 were established in the RAB-containing binder mixes. Furthermore, there was a good relationship between the two concepts of the dissipated energy approach used for determination of the PV and the dissipated pseudo strain energy approach which used for calculation of the GR values.

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.

Evaluation of fatigue behavior of high reclaimed asphalt binder mixes modified with rejuvenator and softer bitumen

Reclaimed asphalt binder (RAB) is aged bitumen extracted from milling of deteriorated asphalt pavement materials. The objective of this study was to analyze the effect of a new rejuvenator as well as softer bitumen on regenerating fatigue characteristics of the RAB-containing binder mixes as compared to the virgin (control) binder. In this study, firstly fatigue resistance of binder mixes containing different percentages of RAB was evaluated by temperature sweep, linear amplitude sweep (LAS) and time sweep tests. Secondly, correlations between different fatigue test methods were established. Results showed that use of rejuvenating agent improved fatigue performance of binder mixes containing up to 100% RAB to the level of that of the control binder. On the other hand, the softer bitumen improved fatigue behavior of asphalt binders containing up to 50% RAB in comparison with the control binder. Based on the obtained results, the current fatigue Superpave criteria (G∗.sinδ) correlated well with parameter B (LAS parameter). In addition, the fatigue lives obtained from the LAS test have good correlation with strains at peak stress in stress-strain curve. Furthermore, Results indicated that there was a fair agreement between fatigue lives obtained using the LAS and the time sweep tests.

Rutting and fatigue performance of asphalt mixtures containing amorphous carbon as filler and binder modifier

In this research amorphous carbon (AC) powder, a waste by-product from paraffin production, was used as a bitumen additive and filler material in asphalt mixtures to investigate its influence on rutting and fatigue behavior of asphalt binder and mixtures. For this purpose, multiple stress creep recovery and time sweep tests were conducted on asphalt binders; dynamic creep, Hamburg wheel track and four point bending beam fatigue tests were carried out as asphalt mixture tests to evaluate fatigue and rutting behavior of asphalt binders and mixtures. Results revealed that replacing up to 50% of filler material by AC powder improved the rutting performance and did not have substantial negative effect on fatigue resistance of asphalt mixtures. Using AC powder as bitumen modifier enhanced rutting resistance of both asphalt binders and their corresponding mixtures substantially. However, in spite of enhancing the rutting resistance and fatigue life at low strain levels, the use of more than 5% AC powder as a bitumen additive impaired the fatigue resistance of asphalt mixtures when exposed to high strain levels. From the results of this study to enhance rutting and fatigue performance of asphalt mixtures incorporation of 50% AC powder as filler material by weight of total filler, and 5% AC powder as bitumen additive is recommended.

EVALUATING FATIGUE BEHAVIOR OF ASPHALT BINDERS AND MIXES CONTAINING DATE SEED ASH

Fatigue is one of the most occurring distresses in asphalt pavements. Asphalt binder plays a critical role in fa­tigue behavior of asphalt mixes. Modelling and predicting fatigue behavior of binders will result in more fatigue resistant mixes. In this research, possibility of using Date Seed Ash alongside two commonly used additives (namely, a siliceous and a limestone) as bitumen modifier were investigated. Then, the influence of these additives on fatigue behavior of asphalt binders and mixes was investigated. Linear Amplitude Sweep (LAS) test was carried out and Viscoelastic Con­tinuum Damage (VECD) parameter was determined. In addition, Indirect Tensile Fatigue Test (ITFT) was performed on mixes containing these additives. Correlation equations were developed to link fatigue behavior of binders to those of mixes. The results showed acceptable agreement between binders and mixes fatigue testing results. In addition, with predicted models it was able to obtain the asphalt binders contribution to mixes fatigue resistance. However, in the case of ash modified samples, no good correlation was observed between fatigue behavior of binders and that of mixes.

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.

Analysis of the thixotropic behavior and the deterioration process of bitumen in fatigue tests

The characterization of fatigue damage on bituminous materials under cyclic loading has been classically studied using tests and procedures previously developed for the characterization of metallic materials. However, these materials present important differences in their behavior in cyclic testing. For instance, the significant loss of modulus the bitumen exhibits at early stages of the test or its total recovery when loading is removed.Comparison between two types of cyclic testing applied to bitumens, time and strain sweep tests has proven that this phenomenon is related with the nonlinear behavior of the bitumen, thixotropy and viscoelasticity, and that the amount of modulus loss during the initial part of cyclic testing is directly related to the strain applied.Using the framework of the work potential theory, a new expression has been found for the damage law that describes the loss of modulus of bitumens during the linear phase of the fatigue tests. Additionally, a procedure is proposed to estimate the fatigue relation between the strain applied and the number of cycles to failure using only the data obtained in strain sweep tests. These relations fit reasonably well the experimental data obtained in more time consuming time sweep tests.Applying this estimation procedure implies a great time savings in the characterization of the fatigue behavior of asphalt binders and the determination of their fatigue laws.

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.

Desenvolvimentos recentes em ensaios de fadiga em ligantes asfálticos

The resistance to fatigue cracking affects directly the lifespan of asphaltic pavements. In order to improve the fatigue performance of HMA mixes, additives have been incorporated into the asphalt binder. The hardening of the asphalt binder induced by additives, as a rule, increases the rutting resistance, but, on the other hand, it is not clearly known which are their effects on the resistance of asphalt binders to fatigue and thermal cracking. One of the main actual challenges for researchers is the development of a rapid test procedure to determine the fatigue resistance of asphalt binder in the laboratory. In the time line of the development of fatigue tests, Bahia et al. (2001) proposed the time-sweep test. Afterward, Johnson (2010) developed the LAS test (Linear Amplitude Sweep), in which a model that correlates the fatigue life of asphalt binders to the load applied is adjusted. More recently, Hintz (2012) proposed some changes in the LAS test procedure, establishing the modified LAS and a new method to analyze the results. Based on these recent developments, this work aims to introduce the most recent procedures (time sweep, original LAS and modified LAS) to evaluate the fatigue behavior of asphalt binders, exemplifying its applicability in the characterization of modified asphalt binders.

Application of a strain sweep test to assess fatigue behavior of asphalt binders

Fatigue cracking is the most common failure mechanism of bituminous pavements. Asphalt binders gives cohesion to the mixture, and are therefore particularly prone to fatigue. The Road Research Laboratory of the Technical University of Catalonia is developing a uniaxial tension–compression test to characterize the fatigue behavior of asphalt binders by performing fatigue strain sweep tests. This paper describes the efforts to calibrate the test procedure by evaluating its repeatability and sensitivity to test temperature/frequency and binder type. The test procedure presented a reasonably good repeatability in all parameters computed, and was sensitive to both the test frequency and the binder type.

Modeling the Effects of Temperature and Loading Rate on Fatigue Property of Asphalt Binder

Abstract Fatigue cracking is one of three major distresses for asphalt pavement. Asphalt binder is a very important component of asphaltic mixture. The fatigue performance of asphalt binder also greatly affects that of asphaltic mixture. Asphalt binder’s fatigue characteristics are affected by external conditions, such as temperature and loading rate. It is warranted to study the effects of these external conditions on fatigue of asphalt binder and take them into account. New fatigue tests and properties have been proposed to characterize the fatigue behavior of asphalt binders, such as monotonic constant shear-rate tests. This study investigated the effects of temperature and shear rate on fatigue properties of asphalt binder. Two asphalt binders were tested with a range of temperature and shear rates. It was found that time-temperature superposition principle also applies to critical strain energy density and shear strength of asphalt binders. The values of shift factors for building the master curves of critical strain energy and shear strength are comparable.