Rheology of Asphalt Binders in Pakistan (original) (raw)
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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...
Asphalt mixtures are the one of the most popular building materials in Hungary, because of the highway programme of the government. In spite of this large popularity, some of the mechanical properties of asphalts have not been discovered enough till today. In particularly, there is no mechanical model usable to understand and explain the rheological behaviours of asphalt mixtures with different composition of bitumen and mineral raw materials. The present used in industry rheological model of Burgers is not reliable enough to understand mechanical properties of asphalt mixtures, because of the included Maxwell element. This means that under any kind of mechanical forces the asphalt surfaces of roads must be continuously deformed, in spite of these forces are as small as possible. The rheological model of Burgers suggests, the lifetime cycle of asphalt roads and highway must be very-very short, which is inconsistent with the real lifetime cycle of asphalt roads. On the basis of Rheo-...
This paper aims to study the rheological properties of the binder taken from four years old flexible pavement stretch. The stretch was divided into six different sections based on the thickness of the surface course. Originally, 60/70 grade asphalt binder was used throughout the pavement stretch. The binder was obtained from the process of extraction and recovery. Dynamic shear rheometer (DSR) test was conducted on the recovered asphalt binder to determine the various parameters viz., Complex modulus G * , Elastic and viscous modulus, Complex viscosity and the phase angle δ. The major pavement distress modes namely, rutting and fatigue cracking were addressed by these output parameters of DSR. Rutting is caused by permanent deformation of paving mix while fatigue is related to the energy absorbed during repeated load application to pavement. The test results indicated that the 60/70 binder extracted from the selected stretches were stiff enough to resist rutting and fatigue failure.
The Effect of Temperature and Composition to the Rheological Properties of Asphalt Pavements
Materials Science Forum, 2008
Ceramics, concretes and asphalt-mixtures are the most popular building materials in Hungary, because of the highway programme of the government. In spite of their large popularity, some of the mechanical properties of ceramics, concretes and asphalts are not investigated enough till today. Particularly, there is no mechanical model usable to understand and explain the rheological behaviours of these materials with different compositions of mineral raw materials. It is well known, that the viscosity of viscous materials, viscoelastic materials, and viscoplastic materials dynamically decreases, as the temperature increases. The decrease of viscosity by leaps and bounds could be extremely dangerous in case of asphalt pavements in the range of 55 – 75 °C, due to the crossing of cars on the low viscosity pavements which suffer inelastic deformation, as a result. Using a Rheo-tribometer instrument developed by L. A. Gömze and others, the authors have investigated and tested asphalt mixtur...
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.
Rheological Properties of Asphalt Binder Modified with Chemical Warm Asphalt Additive
Advanced Materials Research, 2013
Going towards sustainable pavement construction, asphalt industries constantly give their effort to implement Warm Mix Asphalt (WMA) by adding the chemical warm asphalt additive (CWAA). This can lower its energy consumption and pollution by reducing the mixing and compaction temperatures of the asphalt mixture without affecting its properties. Several studies have been conducted evaluating the properties of the WMA, however, little documented research on the rheology of the binders containing CWAA is available especially when dealing the sources of binders. In this paper, the tests for rheology characteristics of the Malaysian asphalt binder containing CWAA were conducted with rotational viscosity and for dynamic mechanical analysis with dynamic shear rheometer (DSR). The results of the investigation indicated that the CWAA had a significant reduction of required heat for mixing and compaction effort and also shows lower permanent deformation when compared to the control binder.
Science Progress
Major distresses such as rutting, fatigue, and thermal cracking are facing asphalt pavement structures due to continuous heavy traffic loading and climate change. The modification of asphalt binders (one of the main components of the asphalt paving mix) has the potential to mitigate distresses through using different additives. Polymer modified asphalt (PMA) binders showed a noticeable resistance to pavement distresses as reported in previous studies. The present study aims to evaluate the effect of polymer modification on the rheological properties of asphalt binders through laboratory tests. The polymers included styrene-butadiene-styrene (SBS) and epolene emulsifiable (EE2) types. The 60/70 binder was used as a control for comparison. The Mechanistic-Empirical Pavement Design Guide (MEPDG) was also utilized to simulate the effect of PMA binders on the rheological properties under different climatic conditions and structural capacities. Additionally, the MEPDG was further utilized...
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