Effect of blending time and crumb rubber content on properties of crumb rubber modified asphalt binder (original) (raw)
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Construction and Building Materials, 2008
The application of crumb rubber modifier (CRM) in asphalt mixtures is intended to improve the properties of binder by reducing the binder's inherent temperature susceptibility. During the interaction with asphalt binder, the CRM particles absorb a portion of the oils in asphalt binder and the particles swell; therefore increasing the viscosity and stiffness of the CRM binder. Still, the performance properties of CRM binders in hot mix asphalt (HMA) pavement are considered to be unclear due to the various interaction effects of CRM with asphalt binders, depending on the CRM percentage, source and size. In this study, a laboratory investigation was conducted on the properties of CRM binders as a function of CRM processing method and percentages. A total of twenty-four CRM binders (3 binder sources * 2 CRM processing methods * 4 CRM percentages) were produced and artificially aged through an accelerated aging process. Evaluation of the CRM binders included the following testing procedures: Viscosity at high temperature, performance properties at high and intermediate temperatures, and cracking properties at low temperature. The results from this study indicated that the higher CRM percentages for CRM binders seemed to lead to a higher viscosity, a better rutting resistance and a less chance for low temperature cracking. In general, the ambient CRM was found to be more effective on producing the CRM binders that are more viscous and less susceptible to rutting and cracking.
Properties of Asphalt-Rubber Binders Related to Characteristics of the Incorporated Crumb Rubber
civil.uminho.pt
The behavior of asphalt binders modified with recycled crumb rubber depends on several factors, such as: rubber contents and type, temperature and time employed during the digestion process. This paper shows the results of a series of tests performed on asphaltrubber produced via the wet process. The tests included standard penetration, softening point, Brookfield viscosity and resilience. The results show that the limiting variable in the digestion process is the Brookfield viscosity. The influence of rubber type occurred especially in terms of Brookfield viscosity and softening point. There was a decrease in these properties for the asphalt-rubber binders produced with crumb rubber obtained by cryogenic process. Besides, the results show improvements in the modified binders properties, in terms of softening and resilience, when higher rubber content, temperature and digestion time are used.
Rheology investigation of crumb rubber modified asphalt binders
KSCE Journal of Civil Engineering, 2010
The incorporation of crumb rubber into asphalt pavement mixes is designed to enhance binder properties through reducing the binder's inherent temperature susceptibility. During the interaction process, crumb rubber particles swell after absorbing a portion of the oils in the binder, resulting in the increase of binder viscosity. In this study, the Crumb Rubber Modified (CRM) asphalt binders were produced using virgin binder of Performance Grade (PG) 64-22 and ambient rubber with various concentrations (10%, 15%, and 20% by weight of virgin binder) in the laboratory. Rheological analyses (flow behavior, elasticity, loading dependence, and temperature dependence) of the control virgin binder and the CRM binders were conducted using a Bohlin Dynamic Shear Rheometer (DSR) II. The results indicated that (1) the use of crumb rubber as a modifier seemed to improve the penetration resistance of the asphalt binder because of the increased viscosity at 60 o C, (2) its advantage was more apparent at lower frequencies of loading, and (3) the asphalt binder with higher crumb rubber contents was observed to have better resistance to permanent deformation at higher temperatures and elasticity at lower temperatures.
Effect of Crumb Rubber Modifiers (CRM) on Characteristics of Asphalt Binders in Sudan
The use of Crumb Rubber Modifiers (CRM) in flexible pavements to improve characteristics of asphalt binders has become a technique of great potential in recent years. In this regard an experimental program was undertaken to study the influence of CRM on the physical properties of asphalt binder. Asphalt cement modified with varying percentages of CRM, 0, 5, 10, 15, 20, and 30 percent were studied. Penetration, ductility, viscosity, softening point, flash and fire points, and specific gravity tests were performed on base and modified asphalts. The tests results show that addition of CRM to base asphalt has significant influence on its properties. Comparing the tests results, the viscosity, softening point, flash and fire points of the modified asphalts increased significantly, coupled with reduction in penetration and ductility as the CRM content increased. Addition of 15% CRM resulted in 200% and 15% increment in viscosity and softening point of base asphalt respectively, while the reduction in ductility and penetration were almost 75% and 25% respectively. It could be concluded that modification of asphalt binders by crumb rubber is successful and more beneficial technique.
2020
This research study evaluated the characteristics of crumb rubber modified (CRM) asphalt binders produced with neat bitumen. Two different percentages of crumb rubber (CR); 10 and 15% and one bitumen type with penetration (Pen) grade 60/70 were evaluated. The evaluated characteristics included viscosity, ductility, Penetration, and softening point of the produced asphalt binders. Additionally, images obtained by Scanning Electron Microscopy (SEM) were used to investigate the surface topographies and compositions of the neat and produced CRM binders. SEM images were used to check for separation between the crumb rubber and the bitumen. Furthermore, the Multiple Stress Creep Recovery (MSCR) test was conducted in order to evaluate the rheological properties of the produced CRM asphalt binders. MSCR results showed that the addition of CR to the neat bitumen significantly improved the performance grade (PG) of the produced binder as per AASHTO M332 standards. The traffic loading level fo...
2021
Asphalt cement usually practices physical and chemical ageing process through the service life of the flexible pavement. Such ageing may be controlled by the addition of polymeric additives. An attempt has been made in the present investigation to assess the influence of implementing crumb rubber powder into three types of asphalt binder having the same penetration grade of (40-50) and obtained from three refineries. Samples of control and rubberized binders were subjected to short-term ageing process with the aid of thin film oven test apparatus. Specimens were subjected to physical and rheological properties determination before and after the ageing process. The rheological indices (penetration ageing index, ductility ageing index, creep stiffness, and softening point) were evaluated. It was concluded that penetration and the ductility ageing index increases after implementing 16 % crumb rubber by (2.7, 20, and 12.8) % and (13, 9.9, and 12.8) % for Dourah, Erbil, and Nasiriyah bin...
Influence of Tire Crumb Rubber on Properties of Asphalt Binders
IOP Conference Series: Materials Science and Engineering, 2019
For many years, the asphalt binder has been used as the elemental material for pavement engineering. The increase in axle loads, heavy traffic, severe climate conditions and construction failures has led many researchers to seek some methods to enhance the bitumen properties. There is a wide range of applications of modifiers for bitumen in road construction. Although various kinds of modifiers have been used widely in reinforcing asphalt concrete, crumb rubber has attracted the most attention due to its high and desirable characteristics. It is realized that the well-distributed modifier can create a strong network in the internal structure of the composite, resulting in asphalt mastic that is more coherent. In the present paper, a laboratory investigation of the physical and rheological properties of various grades of asphalt binder (60-70 penetration grade, 80-100 penetration grade and PG-76 grade) modified with tire crumb rubber. The results showed improvement in physical proper...
An overview of crumb rubber modified asphalt
Roadways are considered one of the most important elements of infrastructure and they play an essential role in our daily lives. In road pavement construction, the use of crumb rubber in the modification of bitumen binder is considered as a smart solution for sustainable development by reusing waste materials. It is believed that crumb rubber modifier (CRM) could be one of the alternative polymer materials in improving bitumen binder performance properties of hot mix asphalt. This study aims to present and discuss the findings from some of the studies, on the use of crumb rubber in asphalt pavement.
Properties of Crumb Rubber and Latex Modified Asphalt Binders using Superpave Tests
MATEC Web of Conferences, 2018
Polymer modified binders have been used for long time to improve the quality of asphalt pavement. This study investigates the effect of crumb rubber and latex on the properties of bitumen binders. Crumb rubber and latex were added to the control 60/70 pen grade bitumen. Four different proportions of crumb rubber and latex were considered in this study: 0%, 4%, 6% and 8% by weight of bitumen binder. The effect of crumb rubber and latex were evaluated through standard penetration and softening point tests as well as dynamic shear rheometer (DSR) test. Temperature ranges of 20 o C-40 o C were used for the DSR rheological testing. The results showed that the addition of crumb rubber and latex leads to a promising improvement on the binder properties. A reduction in penetration and an increase in softening point temperature were observed with the addition of either crumb rubber or latex, this indicates improvement in stiffness and rutting resistance. The analysis on DSR results also show that the modified binders have good rutting resistance.
Characterization of Crumb Rubber Modifiers after Dispersion in Asphalt Binders
Energy & Fuels, 2018
Blending ground crumb rubber (CR) with asphalt binder is an economical and 12 sustainable method of binder modification. The objective of this paper was to evaluate the 13 interaction between asphalt binder and the three crumb rubber types at 170 and 190°C. The three 14 crumb rubber types are ambiently ground, cryogenically ground, and Ecorphalt (E-rubber), were 15 blended with a Louisiana conventional PG 67-22 asphalt at two temperatures, 170°C and 190°C. 16 The composition of the crumb rubber before and after treatment with asphalt was studied using 17 thermogravimetric analysis (TGA). Gel permeation chromatography (GPC) was used to study 18 the molecular weight changes to the asphalt before and after rubber treatment. Fourier Transform 19 Infrared (FTIR) Spectroscopy was used to study the aging characteristics of the CR modified 20 asphalt binder prepared at the two temperatures. Scanning Electron microscopy (SEM) shows the 21 morphology of the rubbers before and after dispersion in asphalt binder. Performance grade tests 22 of the CR/asphalt binder blends was used to characterize the rheological properties. E-rubber