Investigation of Rheological Properties of Asphalt Binders Containing Conductive Fillers

2008 ◽  
Vol 385-387 ◽  
pp. 753-756 ◽  
Author(s):  
Shao Peng Wu ◽  
Bo Li ◽  
Jun Feng Huang ◽  
Zhi Fei Liu

It is currently interesting to use thermal or electrical conductive asphalt mixtures for snow-melting and maintenance of asphalt pavements in winter or strain-sensing application. Graphite is the principal conductive filler for asphalt mixtures. The addition of Graphite not only makes asphalts conductive but also has effects on other properties. Considering the visco-elastic property of asphalt, the effects of graphite on rheological properties of asphalt binders were investigated by Viscosity Test(VT) and Dynamic Shear Rheometer(DSR). The results of Viscosity Test indicate that viscosity of asphalt binder increases with an increasing amount of graphite. And the effect is more prominent at higher amount and lower temperature. It means that graphite makes asphalt binders stiffer. The results from DSR tests present that the values of complex modulus increase while phase angles decrease under a proper amount of graphite. It infers that proper amount of graphite can make asphalt a more elastic like material. And the results of rutting parameter point out that graphite can improve the rutting resistance of asphalts.

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7727
Author(s):  
Xiaorui Zhang ◽  
Chao Han ◽  
Jun Yang ◽  
Xinquan Xu ◽  
Fan Zhang

With the increasing traffic loading and changing climatic conditions, there is a need to use novel superior performing pavement materials such as high-modulus asphalt binders and asphalt mixtures to mitigate field distress such as rutting, cracking, etc. This laboratory study was thus conducted to explore and substantiate the usage of Rubber Polymer Composite Modifier (RPCM) for high-modulus asphalt binder modification. The base asphalt binder used in the study comprised A-70# Petroleum asphalt binder with RPCM dosages of 0.25%, 0.30%, 0.35%, 0.40% and 0.45%, separately. The laboratory tests conducted for characterizing the asphalt binder rheological and morphological properties included the dynamic mechanical analysis (DM), temperature-frequency sweep in the dynamic shear rheometer (DSR) device, bending beam rheometer (BBR), and florescence microscopic (FM) imaging. The corresponding test results exhibited satisfactory compatibility and potential for using RPCM as a high-modulus asphalt binder modifier to enhance the base asphalt binder’s rheological properties, both with respect to high- and low-temperature performance improvements. For the A-70# Petroleum asphalt binder that was evaluated, the optimum RPCM dosage was found to be 0.30–0.35%. In comparison to styrene–butadiene–styrene (SBS), asphalt binder modification with RPCM exhibited superior high-temperature rutting resistance properties (as measured in terms of the complex modulus and phase angle) and vice versa for the low-temperature cracking properties. Overall, the study beneficially contributes to the literature through provision of a reference datum toward the exploratory usage of RPCM for high-modulus asphalt binder modification and performance enhancements.


2020 ◽  
Vol 103 (4) ◽  
pp. 003685042095987
Author(s):  
Ghazi G Al-Khateeb ◽  
Waleed Zeiada ◽  
Mohammed Ismail ◽  
Ahmad Shabib ◽  
Adel Tayara

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 to compare the effect of asphalt binders on rheological properties using four different binder input levels. Findings of the study showed that laboratory tests experienced varying outcomes regarding the most efficient asphalt binder by means of distresses resistance. However, the MEPDG evaluation showed that the overall ranking of asphalt binders positively impacting the rheological properties was as following: (1) 4.5% EE2 PMA, (2) 4% EE2 PMA, (3) 60/70 binder, (4) 5% SBS PMA, and (5) 4% SBS PMA binders. Furthermore, statistical analysis illustrated that the effect of using different binder input levels on the performance of pavement varied relatively to the evaluated distresses. The analysis showed that using different binder input levels would affect, to a certain extent, the asphalt binder influence on rheological properties only when evaluating rutting and fatigue distresses. Therefore, it is recommended that precise asphalt binder inputs, that is, shear complex modulus (G*) and phase angle (δ) are used when designing pavement structures in regions with hot and mild climate conditions.


2021 ◽  
Vol 902 ◽  
pp. 135-143
Author(s):  
Mohammad Ali Khasawneh ◽  
Khalid Ghuzlan ◽  
Nada Bani Melhem

Rutting, fatigue cracking and low temperature cracking are the most important distresses in asphalt pavements as a result of changes in rheological properties of asphalt binder. Many types of modifiers were used to enhance asphalt behavior at both low and high temperatures. In this study, carbon nanotubes (CNT) were used as one of many nanomaterials that take a large attention in the latest research related to asphalt modification against different types of distresses. Effect of CNT on rheological properties of asphalt binder was investigated by testing unmodified and CNT modified asphalt binders using two of Superpave devices: Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR). Penetration, softening point, flash point and rotational viscosity (RV) tests were carried out as well. CNT was added in 0.1%, 0.5% and 1% by weight of asphalt binder. It was found that adding CNT in 0.5% and 1% increase stiffness of asphalt and consequently asphalt pavement rutting resistance. On the other hand, this increase in stiffness affected pavement behavior adversely which is not desirable for fatigue and low temperature cracking. However, Superpave specifications were still satisfied and asphalt binder’s relaxation properties were improved upon CNT modification. It was eventually found that 0.5% of CNT is the optimum percentage for the best performance.


2019 ◽  
Vol 10 (1) ◽  
pp. 82-92
Author(s):  
Khlifa Saad El atrash ◽  
Gabriel J. Assaf

The complex modulus test is dependent on temperature and loading frequency. Thus, the results produced from this test will give a more accurate representation of traffic load effects on asphalt pavement. Laboratory experiments were conducted on two different asphalt mixtures for road research projects (Libya/Roads). All specimens had the same mixtures of aggregate gradation GB-20 incorporated with two different asphalt binders PG70-10 and B (60/70). To obtain the master curve, there were some errors at low temperatures (-25, -10 ºC) and high temperature (54 ºC), so these values were discarded. In addition, 2-complex modulus (CM) and phase angles (Phi) in the test were measured at temperatures of -25, -10, -5, 10, 25, 35, and 54ºC, as well as frequencies of 25, 10, 5, 1, 0.5 and 0.1 Hz. The results displayed the influence of the type of binder on the rheology of the mixtures and gradation on the intensity. Hence, using binder PG 70-10 in Libyan asphalt roads may reduce the binder content, increase the mixture workability, and decrease the thermal cracking. The intrinsic characteristics related to binder properties and weather temperature exhibited the most significant impact on the predicted dynamic modulus. Keywords: complex modulus, frequencies, temperatures, sinusoidal, phase angles


2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Okan Sirin ◽  
Dalim K. Paul ◽  
Emad Kassem

The detrimental effects of hardening in asphalt pavements were first recognized by pioneering pavement engineers in the 1900s and have been studied extensively during the last 70 years. This hardening process, referred to as asphalt aging, is generally defined as change in the rheological properties of asphalt binders/mixtures due to changes in chemical composition during construction and its service life period. Aging causes the asphalt material to stiffen and embrittle, which affects the durability and leads to a high potential for cracking. This paper presents the state of the art on asphalt and asphalt mixture aging and use of antioxidant additives to retard the aging. A picture of complex molecular structure of asphalt and its changes due to atmospheric condition and various protocols used to simulate aging in laboratory environment are also discussed. Emphasis is given on recent studies on simulation of aging of asphalt mixtures as there has been limited research on mixtures compared to the asphalt binder. Finally, this paper presents the application of antiaging techniques and its mechanism, use of various types of antioxidant additives to retard aging of asphalt and, hence, improve the performance of asphalt pavements.


2009 ◽  
Vol 620-622 ◽  
pp. 497-500 ◽  
Author(s):  
Shao Peng Wu ◽  
Jin Gang Wang ◽  
Yuan Zhang

After a preliminary investigation on the binary asphalt/clay binder, the ternary binder was prepared by adding the nanoclay and TAFPACK-SUPER (TPS) to the original asphalt. The previous research shows that exfoliated/intercalated layers homogeneously are dispersed in the asphalt matrix and the nanocomposite has formed. Rotation Thin Film Oven Test (RTFOT) and Pressure Age Vessel Test (PAV) results indicate that the modified asphalt with 3% organic nano-montmorillonite (OMMT) present better performance of aging resistance. The purpose of this research is to attain ternary asphalt binder with better rheological performance and aging resistance. The ternary modified asphalt binder containing 4% OMMT and 12% TPS by weight were prepared at the laboratory scale using high speed shearing mixer. The rheological properties of OMMT/TPS modified asphalt binders were evaluated before and after aging in present paper. Temperature sweep tests and frequency sweep tests were conducted to characterize the rheological properties of modified asphalt using Dynamic Shear Rheometer (DSR). According to the frequency sweep tests, complex modulus master curves were plotted to analysis the rheological properties. The results indicate that nanoclay/TPS/asphalt ternary binders have more excellent performance of rheological and aging resistance at both high and low temperatures, compared with the virginal bitumen and TPS modified asphalt.


2021 ◽  
Vol 13 (12) ◽  
pp. 6634
Author(s):  
Hayder Al Hawesah ◽  
Monower Sadique ◽  
Clare Harris ◽  
Hassan Al Nageim ◽  
Karl Stopp ◽  
...  

Hot mix asphalt has various benefits such as good workability and durability. It is one of the most general materials used as asphalt mixtures in road pavements. Asphalt mixtures and binders can be improved by modifying them with various additives. Gilsonite is a natural asphalt hydrocarbon which may be used as an additive to hot mix asphalt. It is used as an asphalt binder modifier (wet process) and an asphalt mixture modifier (dry process) to improve the properties of the mix. It provides the option of improved rheological properties, stability, strength rutting resistance and moisture sensitivity. This paper examines the current research relating to the use of gilsonite to improve the asphalt properties (binder and mixture). The rheological properties of the modified asphalt binders and mechanical properties of the modified asphalt mixtures will be reviewed. The influence of adding gilsonite individually or combined with other additives will be discussed. Furthermore, assessment of the environmental and economic perspectives of the studied asphalt along with some suggestions to improve the asphalt binders and mixtures will be explored.


2022 ◽  
Vol 13 (1) ◽  
pp. 140-152
Author(s):  
Eslam Deef-Allah ◽  
Magdy Abdelrahman

The use of reclaimed asphalt pavement (RAP) and/or recycled asphalt shingles (RAS) in the asphalt mixtures is a common practice in the U.S.A. However, there is a controversy to date on how RAP/RAS interact with virgin asphalt binders (VABs) in asphalt mixtures. For mixtures containing RAP/RAS, the aged asphalt binders in RAP and air-blown asphalt binders in RAS alter the performances of the extracted asphalt binders (EABs). Thus, the rheological properties of EABs from these mixtures require more investigation. The focus of this paper was relating the high-temperature properties of EABs from field cores to the corresponding rolling thin film oven aged virgin asphalt binders (RTFO AVABs). Furthermore, a comparison of the effect of RAP and RAS on the high-temperature rheological properties of EABs was another objective. Different asphalt cores were collected from the field within two weeks after the pavement construction process in 2016. These cores represented eight asphalt mixtures with different asphalt binder replacement percentages by RAP, RAS, or both. The asphalt binders were extracted from these mixtures and considered as RTFO AVABs. The high-temperature rheological properties included the temperature sweep and frequency sweep testing and the multiple stress creep recovery testing. The EABs had higher stiffnesses and elasticates than the corresponding RTFO AVABs because of the aged binders in RAP/RAS. The binders in RAP interacted more readily with VABs than RAS binders.


2012 ◽  
Vol 598 ◽  
pp. 473-476 ◽  
Author(s):  
Yong Mei Guo ◽  
Wei Chen

Five SBS modified asphalts and one base asphalt were selected to carry out frequency sweeps over a wider frequency range using the dynamic shear rheometer (DSR). Six asphalt binders were subjected to sinusoidal loading at 30°C-90°C within the linear viscoelastic limits, and master curves of complex modulus (G*) and phase angle (δ) could be constructed by means of the time-temperature superposition principle (TTSP). The results show that the G* values of SBS modified asphalts are significantly greater than those of base asphalt at low frequencies, but are slightly smaller at high frequencies. Compared with the base asphalt, SBS modified asphalts have narrower master curves of complex modulus, and their phase angles are much smaller within the whole frequency range. This indicates that various properties of SBS modified asphalts, such as high-temperature property, low-temperature property, temperature susceptibility and elastic recoverability, are superior to those of the base asphalt. The G* values of the rolling thin-film oven (RTFO) aged asphalt are larger than those of the unaged asphalt in the whole range of frequencies, demonstrating that the anti-rutting performance of asphalt binder is improved after short-term aging.


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