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Ethylene-Octene-Copolymer as an alternative to Styrene-Butadiene-Styrene bitumen modifier
Published in Inge Hoff, Helge Mork, Rabbira Saba, Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1, 2021
A. Riekstins, V. Haritonovs, R. Merijs-Meri, J. Zicāns
Stiffness and fatigue test results are illustrated in Figure 9 and Figure 10. Contrary to the results of the previous physical properties (rutting and thermal cracking) difference between asphalt mixtures produced by laboratory and industrially manufactured bitumen are much higher. SBS fact shows significantly higher fatigue strength then SBS lab and EOC lab (see Figure 10). What’s more SBS fact also showed a better ability to withstand higher strain amplitudes. The main reason for that might be a more elastic and less stiff binder. SBS fact in comparison to EOC lab and SBS lab is less stiff (9762 MPa versus 10212 MPa and 11043 MPa). Other important factors that may influence fatigue behaviour are 1) possible concentration differences of polymer modifier within bitumen matrix, 2) presence of specific additives in the commercially produced bitumen 3) as well as the grade of the neat bitumen (before modification). It is known that the content of light fractions (maltenes) can significantly impact the properties of asphalt (Hofko et al., 2016). As it can be seen in Figure 2 and Figure 3 there exist important differences between the equipment used for the production of bituminous binders at industrial and laboratory scales, which results in a lower mixing degree in the case of laboratory-produced bitumen formulations.
Bitumen
Published in A. Bahurudeen, P.V.P. Moorthi, Testing of Construction Materials, 2020
The quality of the pavement is widely influenced by bitumen. The chemical composition of bitumen consists mostly of hydrocarbons (hydrogen and carbon) along with a small trace of heterocyclic compounds such as sulphur, nitrogen and oxygen. Bitumen can be further sub-divided into two types as asphaltenes and maltenes based on its complex chemical composition. Maltenes can be further sub-divided into saturated hydrocarbons, aromatic hydrocarbons and resins. This separation can be carried out by the following methods. Solvent extractionChromatographyAdsorption by finely divided solid and removal of un-adsorbed solids by the filtrationMolecular distillation used in conjunction with one of the other techniques
Instability and Incompatibility
Published in James G. Speight, Refinery Feedstocks, 2020
The resin constituents are closely related to the asphaltene constituents and for the purposes of this text, the term resin generally implies material that has been eluted from various solid adsorbents (Koots and Speight, 1975; Speight, 2014, 2015). Thus, after the asphaltene constituents are precipitated, adsorbents are added to the n-pentane or n-heptane solutions of the resin constituents and oils, by which process the resin constituents are adsorbed and subsequently recovered by the use of a more polar solvent and the oils remain in solution. The term maltenes (sometimes called petrolenes) indicates a mixture of the resin constituents and oil constituents obtained in the filtrates from the asphaltene precipitation (Speight, 2014a,b, 2015, 2017).
Performance evaluation of rejuvenated recycled asphalt blends at high and intermediate pavement temperatures
Published in International Journal of Pavement Engineering, 2022
Mohd Tahir Ansari, Khailesh Khatri, R. Vishnu, Venkaiah Chowdary
Table 5 presents the results of MSCR test carried out on different binder blends at 60°C. It can be found that all recycled blends had higher Jnr when compared with control binder (BH) at both the stress levels. The blends synthesised using approach 1 had lower Jnr than those synthesised using approach 2. Higher percentage of rejuvenator oil dosage in the blends synthesised in approach 2 (see Table 3) would have resulted in a lower asphaltene to maltene ratio. It can be found that with an increase in oil dosage, the blends synthesised using approach 2 exhibited higher Jnr, whereas in the case of blends synthesised using approach 1, with an increase in rejuvenator oil dosage in the blend, the Jnr value decreased. Bitumen is a colloidal system, where asphaltenes are suspended in the volatile maltene fraction. The volatile maltene fraction evaporates during ageing, and thus increasing the asphaltene to maltene ratio. The rejuvenator oil in the first approach was added to the RAP binder (which is expected to have a higher asphaltene to maltene ratio than that of its un-aged condition), whereas in approach 2, the rejuvenator oil was added to the virgin binder BH in its un-aged condition. Addition of high dosage of oil (as in approach 2) to un-aged BH binder results in a poor colloidal system with a low asphaltene to maltene ratio (Behnood 2019). Hence, in approach 1, when the rejuvenated RAP binder is mixed with the soft virgin binder, the resulting blend would be stiffer than blends synthesised using approach2 .
Properties of bitumen modified by polyethylene and polyethylene glycol with different molecular weights
Published in International Journal of Pavement Engineering, 2022
Tian Xia, Xiang Chen, Jianhui Xu, Wenqiang Chen, Xinyue Huang, Youbing Li
Bitumen is widely used in pavement and road construction. Approximately 95% of 100Mt of bitumen produced worldwide every year is utilised as pavement material in the twenty-first century (Lesueur 2009). Bitumen is a complex mixture of mostly hydrocarbons whose structure is well described by the colloidal model: solid particles (the asphaltenes) with a radius of a few nanometres dispersed in an oily liquid matrix (the maltenes) (Lesueur 2009). The maltenes consist of resin, aromatics and saturates whose molecular weight and aromaticity decrease successively (Claudy et al. 1991). Bitumen has a low molecular weight and a wide distribution of molecular weight, which make it sensitive to temperature, exhibiting brittleness at low temperature and viscosity at high temperature. To enhance the performance of base bitumen, modification should be done prior to use. The most common one is to blend it with polymer, such as styrene–butadiene–styrene (SBS), ethyl vinyl acetate (EVA), polyethylene (PE), to produce polymer-modified bitumen (PMB) (Vasiljevic-Shikaleska et al. 2010, Zhu et al. 2014, Rossi et al. 2015, Padhan and Sreeram 2018).
Effect of long-term ageing on the rheological properties of rejuvenated asphalt binder
Published in Road Materials and Pavement Design, 2021
Heena Dhasmana, Kamal Hossain, Ahmet S. Karakas
Asphalt molecules are subdivided into two groups based on polarity; asphaltene (solid fractionate) and maltene (liquid phase). Maltene molecular group consists of saturates, aromatics and resins. These molecular groups are alerted by ageing. They are also influenced by the rejuvenation of aged asphalt binder (Dony, Colin, Bruneau, Drouadaine, & Navaro, 2013; Lu & Isacsson, 2002). Some benefits of using rejuvenating agents include cheap storage, simple techniques of addition to the mix, ease of adding the precise dosage based on RAP/RAS asphalt properties and level of ageing, flexibility of adding RAP from 0% to 100% with the same product, and low costs (Zaumanis, Mallick, & Frank, 2015). Change in fundamental properties of asphalt due to addition of rejuvenators lead to variations in the rheological and engineering properties of asphalt including cracking, rutting and fatigue resistance, and low or high temperature properties (Mogawer, Booshehrian, Vahidi, & Austerman, 2013; Shen, Amirkhanian, & Tang, 2007; Tran, Taylor, & Willis, 2012). Some studies found that the rheological performance of asphalt characterised by rutting and fatigue resistance improved with rejuvenation (Ali & Grzybowski, 2012; Dony et al., 2013; Shen, Amirkhanian, & Xiao, 2006).