In this article, we are going to discuss how binders can help improve the performance of high temperature asphalt. Asphalt binders are composed of four primary fractions known collectively as "SARA." Asphaltenes, saturates, aromatics, and resins are the constituents of these fractions. Asphaltenes, which play an important role in this process, have a significant impact on the linear viscoelastic behavior of asphalt binders. Asphaltenes are included as a separate modifier in this study to improve the operational characteristics of the asphalt binder. In a rolling thin film oven, the modified binders undergo an aging process. Following that, the binders' rheological properties are measured using a dynamic shear rheometer while they are subjected to high temperatures. Variations in the chemical makeup of the modified binders are also investigated by determining SARA fractions via precipitation and gravity-driven chromatography. Asphaltenes, according to rheological findings, make asphalt binder more rigid while increasing its elasticity. It has also been demonstrated that the addition of asphaltenes raises the asphalt binder's high Performance grade (PG) temperature. It has been demonstrated that the addition of 6% asphaltenes causes a one grade level increase in the high PG temperature grade. According to the SARA study's findings, the addition of asphaltenes increases the content of polar fractions, which increases the viscosity, stiffness, and elasticity of asphalt binders. Despite their low cost, the findings suggest that asphaltenes are a useful additive that can improve asphalt binder properties at high temperatures. Asphalt pavements are an important component of the region's infrastructure because they are the most common type of pavement found in North America. Asphalt mixture is made up of three components: asphalt binder, aggregates, and fillers. In some cases, additives or modifiers are also added to the mixture in order to improve its properties. Asphalt binder is a type of hydrocarbon produced in crude oil refineries, primarily through the fractional distillation process. The heaviest fraction of crude oil distillation, a complex mixture of high molecular weight hydrocarbons, is further processed to produce asphalt binder. 
This is done after the lighter fractions (such as liquid petroleum gas, gasoline, aviation fuel, kerosene, and so on) have been separated, and after the lighter fractions have been separated. Although asphalt binder is used as a binding agent for aggregates in the pavement industry, it also adds several characteristics to the asphalt mixture and plays an important role in determining distresses during the pavement's service life. Although asphalt binder is used as a binding agent for aggregates in the pavement industry, it also adds several characteristics to the asphalt mixture. As a result, it is critical to ensure that the asphalt binder used in the production of asphalt mixture can function admirably in a variety of environmental settings. Increasing traffic demand, severe weather conditions, and infrastructure operators' tendency to reduce maintenance costs (and, as a result, frequency) are some of the major reasons why asphalt performance improvement strategies have grown in popularity. As a result, researchers have been looking for ways to modify traditional asphalt binders in order to improve their performance and extend their service life. In this regard, polymers, one of the most commonly used materials in asphalt modification, have significantly improved the performance of asphalt mixtures. Despite the improvements that have been recorded with these modifiers, the use of polymers for the purpose of asphalt binder modification is associated with a number of disadvantages. The fact that polymer-modified asphalt is significantly more expensive than conventional asphalt binder is likely the most significant disadvantage. Furthermore, phase separation can occur during the storage and application of polymer-modified asphalt binders.
Researchers have recently become more interested in using waste materials to improve asphalt binder properties. This is due in part to growing public concern about the ability of the environment to be sustained, and in part to the high cost of certain modifiers. Asphaltenes are waste products produced during the production of oil sand asphalt binder. This waste is obtained through a process known as deasphaltation. Despite their high rate of production, asphaltenes are almost universally regarded as waste due to their low value and the limited number of industries in which they are useful. However, some recent attempts to use asphaltenes have been made, such as the development of a gasification technique to convert asphaltenes to gas fuel. However, gasification is a costly process that also contributes significantly to environmental pollution. Asphalt binders are classified chemically into saturates, aromatics, resins, and asphaltenes, which are referred to collectively as "SARA". The polarity of the asphalt binder determines this classification. The polarity of the compounds that comprise an asphalt binder, as well as the interactions that occur between those compounds, have a significant impact on the rheological properties of that binder. Asphalt binder's elastic behavior can be attributed to its polar fractions, which include asphaltenes and resins. The viscous behavior of asphalt binder, on the other hand, can be attributed to its non-polar fractions, which include saturates and aromatics. Because of differences in the polarity of the asphaltenes particles, asphaltenes particles may agglomerate and become unstable in the surrounding matrix of the remaining fractions. Two different approaches to changing the asphaltenes content of asphalt binders have been identified as general methods in the research. The first method is to use a mechanical stirrer to combine the asphalt binder with asphaltene-rich materials. The second method combines the asphaltenes extracted from the asphalt binder with n-heptane with the asphaltenes already present in the binder. The second method has the advantage of allowing the number of asphaltenes produced to be adjusted, which has contributed to the process's popularity and led to the development of the concept of artificial bitumen.
- Asphalt Temperature
Previous research has shown that increasing an asphalt binder's asphaltenes content reduces the asphalt binder's susceptibility to temperature changes. The incorporation of asphaltenes into asphalt binders, on the other hand, has the potential to improve their resistance to the effects of time. Furthermore, the asphaltenes content has been shown to be primarily responsible for the elastic component of an asphalt binder's viscoelastic response. According to the findings of the aforementioned studies, this is the case. A higher asphaltenes content causes an increase in asphalt stiffness, which causes a decrease in penetration and creep compliance, as well as an increase in binder viscosity. The abrupt change in asphalt binder properties that occurs after the addition of asphaltenes suggests that the network formed by the polar fractions (primarily asphaltenes) within the asphalt binder has been fortified. This is the process that gives the binder its elasticity. A review of the existing literature revealed that, to the best of the authors' knowledge, no research has been conducted into the effects of using asphaltenes produced as waste in crude oil refineries as a distinct modifier to improve the performance of asphalt binders. Despite the fact that asphaltenes can be used to improve the performance of asphalt binders, they are not widely used. In light of this, the current study aims to investigate the high-temperature performance of asphalt binders modified with varying degrees of asphaltenes content, with a particular emphasis on binders manufactured in oil refineries. The primary goal of this study is to examine the rheological performance of asphalt binders modified with asphaltenes derived from Alberta oil refineries at high temperatures. Furthermore, the chemical compositions of the asphalt binders will be investigated. Asphaltenes are macro-polar structures found in the oil matrix in solution. There are several methods for extracting asphaltenes from their sources; however, solvent dissolution, also known as solvent deasphalting, is the most commonly used. Asphaltene precipitation is the first step in the solvent deasphalting process. This is accomplished by employing n-alkanes as an anti-solvent. The asphaltenes used in this study were produced in northern Alberta facilities using Athabasca bitumen produced by SAGD.
This was accomplished by adding a sufficient amount of a non-polar solvent to the oil matrix (typically in the range of NC3 to NC7) to disrupt the solubility of the asphaltenes and cause them to precipitate out of the solution. Asphaltenes have traditionally been regarded as a waste due to their low value and limited range of industrial applications. The asphaltenes used in this investigation were obtained in chunk form. The solid asphaltenes were ground into a powder before being added to the asphalt binder. This was done to make the mixing process more efficient and to ensure that there was enough surface area for mixing. The asphalt binder was modified with asphaltenes particles fine enough to pass through a #100 sieve with a 150 micron opening. Each of the modified binders was created using a high shear mixer (L5M-A model, Silverson Co., East Longmeadow, MA, USA). A hot plate was used to keep the asphalt binder at 140 5 °C while it was being mixed, preventing aging at high temperatures, which would have occurred if the temperature had been higher. Following this, the desired amount of asphaltenes was added to the heated asphalt binder, and the mixture was stirred for sixty minutes at a rotation speed of 2000 rpm to achieve a consistent consistency. Asphaltenes-modified binders were made by adding 3% increments of 0% to 20% asphaltenes content (as a proportion of the weight of the asphalt binder), with the exception of the final mix, which had the asphaltenes content increased from 18% to 20%. This was done to investigate the effects of asphaltenes at various levels of asphaltene content. A rolling thin film oven (RTFO) was used to age asphalt binders in accordance with the AASHTO T240 standard [40], simulating the short-term aging that occurs in asphalt binders during mixing in asphalt plants. This was done to learn more about how short-term aging affects the asphalt binder. A study was conducted to investigate the impact of asphaltenes on the aging characteristics of asphalt binders by estimating the aging indices. These indices are defined as the ratio of a performance parameter of the aged binder to that of the unaged binder.
Tests were performed on samples using a dynamic shear rheometer (DSR) in accordance with the AASHTO T315 standard to characterize the viscoelastic behavior of asphalt binders when subjected to high temperatures (Smartpave 102 model by Anton Paar, Co., Ltd., Graz, Austria). In order to conduct DSR, samples are subjected to sinusoidal shear loadings, after which the stress and strain response is measured. Using these data, this device can calculate the complex shear modulus (G*) and phase angle () of viscoelastic materials. The phase angle is the time lag between the shear stress and the shear strain response, and the complex shear modulus is the ratio of the maximum shear stress applied to the maximum value of strain. The complex shear modulus, on the other hand, indicates how rigid the material is, whereas the phase angle indicates how elastic or viscous it is. The temperatures at which the parameter G*/sin drops below 1.0 kPa and 2.2 kPa, respectively, would be recorded as the binder's failure temperatures in terms of rutting resistance at a loading frequency of 1.59 Hz, according to the AASHTO M320 standard. For unaged and RTFO-aged binders, these temperatures would be recorded as the binder's failure temperatures in terms of rutting resistance.
- Asphalt Bindder
The effects of asphaltenes with varying levels of content on the performance of asphalt binder PG 70-22 were investigated at high temperatures. The primary conclusions that can be drawn from the analysis conducted during the course of this study are as follows: The addition of asphaltenes increases the stiffness and elasticity of the asphalt binder, resulting in a significant improvement in the material's resistance to the development of permanent deformation. On average, a 6% increase in asphaltenes content corresponds to a one-interval increase in the high PG temperature grade of the asphalt binder.
The effect of asphaltenes on high-temperature performance parameters such as shear modulus, phase angle, and rutting factor becomes more pronounced as the binder ages. As the temperature drops, the asphaltenes have a greater impact on the stiffness and elasticity of the asphalt binder. This is because asphaltenes age faster than asphalt. Given that higher stiffness and elasticity values have a negative effect on cracking resistance at lower temperatures, this implies that the possibility of cracking increases at lower temperatures as asphaltenes content increases. When asphaltenes are used to modify the asphalt binder, the viscosity of the binder increases when heated to high temperatures. When the temperature is lower and the asphaltenes content in the binder is higher, the impact of asphaltenes on the viscosity of the binder is more pronounced. When the rheological and SARA results are compared, it is possible to conclude that the addition of asphaltenes increases the polar fraction content of the asphalt binder, which in turn increases the stiffness, elasticity, and viscosity of the asphalt binder. Based on the CI values, it is possible to deduce that the addition of asphaltenes to the maltenes matrix makes the asphaltenes particles more unstable due to the differences in polarity level between asphaltenes and the other fractions of the asphalt binder. This phenomenon is primarily caused by asphaltenes having a higher polarity level than the other fractions of the asphalt binder.