Characterizing Temperature Susceptibility of Asphalt Binders Using Activation Energy for Flow (original) (raw)
Related papers
Influence of Time and Temperature on Asphalt Binders Rheological Properties
Life Science Journal
One of the major problems associated with the asphalt binders is its sensitivity towards the temperature. In Pakistan, asphalt binders have been selected for asphalt pavements on the basis of penetration grade, determined at 25oC. Temperature and loading time sensitivity of asphalt binders were never investigated before its applications. The effect of temperature and time of loading of three commonly used asphalt binders in Pakistan was investigated and compared to ascertain best performing binders under these conditions. Two neat asphalt binders of 60-70 and 40-50 penetration grade and modified 60-70 pen. grade bitumen with 1.6% elvaloy were studied at six temperatures of 18, 24,30,36,42 and 48oC and in a frequency range of 0.01Hz to 100Hz using a dynamic shear rheometer. Master curves are constructed and the shift factor curves are plotted to determine the temperature susceptibility of binders. Asphalt binder with 60-70 penetration grades showed higher temperature sensitivity in a...
Polymers
This paper investigates the viscoelastic properties of oxidized neat bitumen and three polymer-modified binders at low temperatures. The earlier proposed interrelated expressions for the relaxation modulus and for the creep compliance of bitumen binders are further developed. The results of creep testing of the binders on a bending beam rheometer at the six temperatures from −18 °C to −36 °C are presented. The results were analyzed using the equations developed for the relaxation modulus and the relaxation time spectrum. Viscosities at the low temperatures of tested binders were estimated. Approximate interrelations between the loss modulus and the relaxation spectrum were presented. The method for the determination of the glass transition temperature of a binder in terms of the relaxation time spectrum is proposed. The glass transition temperatures of tested binders were determined by the proposed method and compared with ones determined by the standard loss modulus-peak method.
Temperature Susceptibility of Modified Asphalt Binders
IOP Conference Series: Materials Science and Engineering, 2020
Temperature is considered here as an important measurement affecting the behaviour of asphalt cement. The relationships between temperature and viscosity for ten pure and modified asphalt cements were thus assessed using traditional methods (including penetration, and (R&B) softening point) and dynamic shear rheometer (DSR) and rotational viscometer (RV) tests. The temperature used for testing were (25˚C), (120 to 195 ˚C), and (4 to 70 ˚C) for traditional, RV, and DSR tests, respectively. The effects of test type, asphalt cement type, modifier type, and content, on temperaturesusceptibility were investigated. The results showed that using activation energy () for flow allowed discernment of asphalt cement's susceptibility to temperature variation, and that the addition of modifiers (SBS, BR, and BG) to asphalt cement increased the indices. Higher increment rates in E a (23.57%) were caused by the addition of BR, while reduced VTS was seen with the addition 9% BR, and 5% and 7% SBS, with reduction rate of 44.138%, 15.994% and 15.241%, respectively, due to reductions in viscosity changes with variation in temperatures, while the addition of 0.075% BG Plus increased VTS by 2.496% compared with base asphalt binder.
RANKING ASPHALT BINDERS BY ACTIVATION ENERGY FOR FLOW
The viscosity of neat and modified asphalt binders were measured at temperatures between 110 o C and 160 o C by rotational viscometry. The Arrhenius relationship was used to analyze the data and obtain the activation energy for flow of the asphalt binders. Activation energies for flow ranged from 44 kJ/mol to 90 kJ/mol. The effects of film thickness, asphalt type, aging, polymer content, and polymer type on the activation energy for flow were studied. A preliminary analysis was conducted to explain these effects. The results indicate that the activation energy for flow can be used to differentiate asphalt binders and rank their temperature susceptibility in a quantitative manner. It is suggested that this asphalt binder ranking can be used to predict the relative compaction effort for these binders in mixes.
ASPHALT BINDER FLOW ACTIVATION ENERGY AND ITS SIGNIFICANCE FOR COMPACTION EFFORT
The temperature dependence of viscosity of neat and modified asphalt binders were evaluated between 80°C and 200°C using rotational viscometry,. The activation energy for flow was determined for these asphalt binders using the Arrhenius equation. Different types of polymer and polymer contents were selected to study the effects of polymer type and concentration on the activation energy for flow. Attempts were made to use a global model to evaluate the relationship between polymer content and viscosity. The effect of aging was also discussed. The results indicate that the flow activation energy can be used to rank the temperature susceptibility of different asphalt binders. It is suggested that this ranking may be used to predict the relative compaction effort for the different asphalt binders studied. Densification curves for different asphalt binders at a compaction temperature of 138 °C are discussed in relation to their activation energy for flow.
True characterization of asphalt binders requires finding the rheological behavior at different temperature and stress levels. Asphalt binder's performance in the field mainly depends on its aging conditions that govern different rheological parameters. Five asphalt binders were tested in the laboratory at different aging conditions, using the dynamic shear Rheometer. The main objectives were to characterize the high temperature load response of asphalt binders under cyclic and static loading conditions. Two testing procedures have been adopted in the laboratory to investigate the high temperature stiffness and creep compliance of asphalt binders. Result shows that stiffness of asphalt binder increases and creep compliance decreases with aging. Creep compliance (J nr ) is temperature and stress sensitive parameter and behaves linear visco-elastic up to a stress level of 3.2 kPa. Temperature sensitivity depends upon the grade of asphalt binder.
Study of rheological properties of pure and polymer-modified Brazilian asphalt binders
Journal of Materials Science, 2004
In recent years, many authors have suggested techniques to study asphalt binders and establish structure-property correlations for these materials. Several works have shown that rheological analysis provides reliable information about the stability, elasticity, thermal susceptibility, and also that rheological behavior depends on chemical composition and structure of pure and modified binders. The objective of this work was to study the effect of the asphalt binder chemical composition and modifier polymer type on the linear viscoelastic properties and to correlate these properties to the PMB's thermal susceptibility. A set of polymer-modified asphalt binders (PMB) was prepared using two Brazilian asphalts. Both pure binders and PMB were analyzed by classical and dynamic rotational rheology tests. The rheological analysis results were also compared to storage stability data and PMB's morphology. The fitting capability of the Christensen-Anderson and Christensen-Anderson-Marasteanu rheological models was analyzed for the two pure asphalt binders. Both models presented lack of fitness in the regions of lowest and highest frequencies. When using elastomeric modifiers, it was possible to state the existence and interrelation between the width of the phase angle master curve plateau and the PMB's thermal susceptibility and stability. This interrelation was supported by PMB's storage stability data and microscopy analysis. C 2004 Kluwer Academic Publishers
Viscoelastic-based approach to evaluate low temperature performance of asphalt binders
Construction and Building Materials, 2016
h i g h l i g h t s The Schapery viscoelastic model is implemented into the FE code to model the binders. Thermally induced stress (TIS) is used to specify the neat and modified asphalt binders. Time-temperature superposition of BBR test was not valid for neat and modified binders. 0.1 wt% of sulfur improved thermal cracking resistance of polymer modified binder.