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Natural asphalt is a highly valuable material with diverse uses that humans have been utilizing for centuries. Its beneficial qualities, environmental friendliness compared to synthetic alternatives, versatility, and cost-effectiveness contribute to its overall importance as a valuable natural material. It emphasizes the abundance and significance of Iran’s natural asphalt, which is known to be one of the largest producers globally. The investigations of the characteristics and analysis methods provide valuable information for further research and utilization in various industries, particularly in road construction and maintenance. The chapter utilizes several analysis methods, including Fourier Transform Infrared (FT-IR), elemental analysis, X-ray fluorescence, thermogravimetric analysis (TGA), and scanning electron microscope (SEM) analysis, to investigate the characteristics of Iranian natural asphalt. These techniques help understand its composition, thermal stability, and properties relevant to its application as a filler and bitumen modifier in asphalt mixtures and it explains how it improves various properties of traditional bitumen, enhancing stability, durability, rutting resistance, and water resistance. This is due to its exceptional traits such as high viscosity, thermoplastic behavior, and robust adhesive properties, making it a valuable modifier and filler in the industry.
Department of Chemistry, Faculty of Basic Sciences, Ilam University, Ilam, Iran
Homa Kohzadi
Department of Chemistry, Faculty of Basic Sciences, Ilam University, Ilam, Iran
Saeed Toolabi
Department of Civil Engineering, Master of Engineering, Ilam University, Ilam, Iran
*Address all correspondence to: soleimanbeigi@yahoo.com, m.soleimanbeigi@ilam.ac.ir
1. Introduction
Bitumen modifiers and fillers play crucial roles in enhancing the performance of bitumen, which is a key component in road construction and pavement materials. These additives improve the durability, stability, and flexibility of asphalt mixtures, making them resistant to various environmental factors, such as heavy traffic, temperature fluctuations, moisture, and aging. The economic significance of bitumen modifiers and fillers lies in their ability to extend the lifespan of roads and pavements. By enhancing the performance of bitumen, these additives reduce the frequency of maintenance and repair works, leading to significant cost savings over the life cycle of a road. When bitumen is properly modified, it reduces the occurrence of cracks, rutting, and other forms of distress, which are common issues in traditional asphalt pavements. These results in longer-lasting roads and decreased maintenance expenses. Moreover, bitumen modifiers and fillers can enhance the performance of bituminous mixtures, allowing for thinner road surfaces. This reduces the overall material required for construction, resulting in direct cost savings in terms of reduced quantities of bitumen, aggregates, and other raw materials. Additionally, these additives improve the workability of bitumen during the construction process. They enhance the mixing and compaction properties of asphalt mixtures, making them easier to handle and place. This leads to reduced construction time and labor costs. Furthermore, bitumen modifiers and fillers can help in the use of recycled materials. By properly modifying bitumen, it becomes possible to incorporate reclaimed asphalt pavement (RAP) and other recycled materials into the asphalt mixtures. These promote sustainable practices by reducing the consumption of virgin materials and decreasing the overall construction costs. In recent years, there has been increasing interest in utilizing natural asphalt as a modifier or filler in various industries [1, 2, 3, 4].
One of the primary applications is in road construction. Natural asphalt helps to lower the overall cost of road construction by reducing the need for other costly additives. Natural asphalt is used as a filler and modifier in various applications due to its exceptional binding properties. When mixed with other materials, it helps improve strength, durability, and flexibility, making it ideal for road construction, roofing, and waterproofing projects. For example, Little et al., in 2018, summarized the impact of fillers on the rheological properties of asphalt binders. They describe how active fillers, such as hydrated lime, can improve the asphalt-aggregate bond and magnify the volume filler effect. The chapter further explains how polymer additives interact with asphalt binders and how relatively low additive amounts of polymer by weight of asphalt binder can result in an inverted matrix [5]. Another study conducted by Gupta et al. in 2021 explored the impact of incorporating waste glass powder as new asphalt filler. Their findings indicated that the inclusion of glass powder enhanced the stiffness and rutting resistance of asphalt mixtures, thereby encouraging sustainable practices in the construction sector [6]. Furthermore, a significant study by Rubio-Gamez et al. in 2022 investigated the effects of filler type and bitumen on the mechanical properties of asphalt mortar. The research concluded that the filler type primarily influences the stiffness and ductility of the asphalt material, while bitumen plays a more significant role in the fatigue life of asphalt mortar [7].
The current chapter presents a comprehensive overview of natural asphalt as a valuable material, from its introduction and historical discovery to its global sources and analytical methods. Understanding its unique characteristics and properties is crucial for optimizing its usage and exploring its potential applications. The criteria for the research include The criteria for this research on natural asphalt include introduction and historical discovery of natural asphalt, global sources of natural asphalt, analytical methods used to study its characteristics and properties, applications of natural asphalt in the bitumen industry, understanding the significance and historical development of natural asphalt, current research trends and future prospects, highlighting the sustainable nature, versatility, durability, and environmental benefits of natural asphalt. The chapter aims to deepen our understanding of the historical significance, sustainability, versatility, durability, environmental benefits, and cost-effectiveness. The chapter explores its unique characteristics and properties, emphasizing its preferred usage in the preparation of bitumen and asphalt mixtures and by shedding light on the current research trends and promising future prospects, serves as a detailed exploration of the intriguing world of natural asphalt. In the subsequent, we will discuss the types of bitumen and solid natural asphalt. Also, we will explore its history and sources, investigate the characteristics of Iranian natural asphalt, and finally, examine its use as both a filler and modifier.
The word bitumen is taken from asphaltic and related to the language of the ancient Akkad civilization. Ancient Iranians called bitumen mummy. The term asphalt has different meanings in Europe and South America. In Europe, the word asphalt means a mixture of bitumen and gravel. In South America, the word asphalt has been known to mean bitumen [8, 9].
2.1 Types of bitumen
Bitumen is a petroleum-based material that has various types and grades. Bituminous materials or heavy petroleum materials are prepared by a reaction with underground water and bacteria at relatively shallow depths. In such environments, oxygenated underground water dissolves and oxidizes part of the oil in the washing process. The bacteria in the water also break down less-weight molecules. During the phenomenon, which is called bacterial erosion, hydrogen is eliminated, and as a result, hydrocarbons and heavy oil molecules remain [10].
Bitumen is a heavy hydrocarbon material divided into different groups based on their physical properties, solubility in carbon tetrachloride, and chemical composition. Also, based on its resources, bitumen is classified into petroleum (refined) bitumen and natural bitumen.
2.1.1 Petroleum bitumen
Petroleum bitumen, also known as petroleum asphalt or refinery bitumen, is derived from the refining of crude oil. Crude oil is a complex mixture of hydrocarbons obtained from underground oil reserves. During the refining process, various fractions such as gasoline, diesel, kerosene, and bitumen are separated based on their boiling points.
Petroleum bitumen is a byproduct of the distillation of crude oil and is obtained as a residue from the atmospheric distillation process or vacuum distillation. It is composed of a mixture of heavy hydrocarbons and other impurities like sulfur, nitrogen, and trace metals. To improve its quality and remove impurities, petroleum bitumen undergoes further processing, such as air blowing, in which air is passed through the bitumen under controlled conditions. Petroleum bitumen is the most commonly used type of bitumen worldwide due to its abundance, ease of extraction, and standardized properties. It is used extensively in road construction, where it is mixed with aggregates to form asphalt concrete.
Tar also is a bitumen’s material but it is different in origin and resource with bitumen. Tar is a black, high-viscosity liquid that is produced through the destructive distillation of organic materials such as coal or wood. It is composed of various organic substances and is sensitive to temperature changes, becoming hard and brittle in low temperatures and soft and liquefied in high temperatures. Due to its sensitivity to temperature, it is not ideal for areas with frequent temperature changes [11, 12, 13].
2.1.2 Natural bitumen (asphalt)
Natural bitumen, also known as asphaltite or natural asphalt, is referred to in this chapter by the same name. It originates from crude oil, which undergoes a process of gradual migration to the surface layers. Over time, low-weight materials evaporate, and under the influence of factors like heat, pressure, and various processes like oxidation, sulfurization, polymerization, and condensation, bitumen is formed (Figure 1) [11, 12, 13].
Figure 1.
Natura asphalt: Lump (a) lake (b).
The results in the classification of bitumen into various grades with different applications. Natural bitumen based on physical properties is classified as tree types, as shown in Figure 2 [11, 12, 13].
Figure 2.
Classification of natural bitumens (asphalts).
Bitumen can reach higher horizons and, in some cases, to the earth’s surface under the pressure of the layers from inside the seams and cracks until it hardens completely. Coal and natural bitumen are both naturally occurring substances, but they have different properties and origins. The main difference between coal and natural bitumen is their physical form and composition. Coal is a solid fossil fuel composed mainly of carbon, while natural bitumen is a viscous liquid or semi-solid that is primarily composed of hydrocarbons.
In 1981, according to Abraham’s theory, Jacob and Wenner classified natural asphalt with a degree of concentration based on the parameters of reflection, fluorescence, solubility, and softening temperature. The results are presented in Table 1 [14].
Classification of natural asphalt based on reflectance, fluorescence, solubility, and softening temperature.
Mean random reflectance oil immersion may be calculated from values obtained using water immersion.
Fluorescence intensity at 546 nm where a masked uranyl glass standard (10 um diameter, Wild Leitz Co.) equals 1.00 intensity units.
Observed solubility in immersion oil (or when cleaning specimen with petroleum ether).
Observed hot-stage softening temperature (degree C).
Notes:
2.1.2.1 Lake natural asphalt
Liquid natural bitumen, often referred to as crude bitumen or lake bitumen, is a highly viscous and sticky form of bitumen in its natural state. It is a thick, black, and tar-like substance with a lower melting point compared to its solid counterpart. It is typically stored and transported at high temperatures, around 150°C, as it becomes liquid and flows more easily at elevated temperatures. Liquid natural bitumen is usually found trapped in sand or sandstone reservoirs and can be extracted through various methods, including oil sand mining or in situ extraction techniques.
While solid natural bitumen is commonly used in asphalt applications and is solid at room temperature, liquid natural bitumen requires additional processing to transform it into a usable form, such as the production of synthetic crude oil or upgrading into lighter petroleum products. The viscosity and physical characteristics of solid and liquid natural bitumen differ significantly due to their distinct molecular structures and states [11, 12, 13]. Trinidad bitumen lake is an example of liquid bitumen with a relatively high viscosity, which means it is thick and sticky at normal temperatures. Its viscosity is highly temperature-dependent, becomes more fluid with increasing temperature, and solidifies at lower temperatures.
2.1.2.2 Solid natural asphalt
Solid natural bitumens, also known as asphaltites, are divided into three groups: gilsonite (uintaite), grahamite, and glanspit, which is one of the best and most famous groups of bitumen. It is very brittle and soft and turns into powder easily [15].
Solid natural asphalt is a solid mineral substance with scaly schists with shell fractures similar to volcanic glass or obsidian, which is black during extraction but turns brown after crushing and turning into powder Figure 3. The mineral has a hydrogen content of about 9% and contains polar molecules whose ability to spread makes solid natural asphalt soft at a temperature of more than 177°C. There are several analysis methods to determine the type or quality of natural asphalt [15].
Figure 3.
Solid natural asphalt veins.
2.1.2.3 Gilsonite
Gilsonite or uintaite is a brand name for a type of asphaltites that is black and shiny, which is found in a limited number of countries, such as Iran. Gilsonite is a naturally occurring, sticky hydrocarbon and natural asphalt, similar to hard petroleum asphalt, often referred to as natural asphalt. Gilsonite can dissolve in oily solvents as well as petroleum asphalt. Due to the compatibility of gilsonite, it is generally used to harden soft petroleum products. In bulk, gilsonite is a shiny black substance similar to the mineral obsidian. Gilsonite is fragile and can be crushed easily, and it turns into a brown powder [16]. The chemical analysis of gilsonite shows that in terms of elemental composition, it is composed of approximately 89.35% carbon, 191.9% hydrogen, 26.9% nitrogen, 27.1% sulfur, and 1.98% oxygen. Figure 3 shows natural asphalt veins [17].
2.1.2.4 Pitch
Glance pitch, which is also called Manjak, has properties between gasolineite and grahamite, which means that it is heavier and has a higher melting point than gasoline, but the same properties of glance pitch are less than grahamite, and it has been found in Argentina, Cuba, America, Mexico, and Russia. Glance pitch is used in glazing and polishing as a kind of varnish, thermal plastic, coloring, and purification [18, 19, 20].
Petroleum pitch is a byproduct of the petroleum refining process and is primarily composed of aromatic hydrocarbons, including compounds like benzene, toluene, and xylene. It is obtained through the distillation and cracking of crude oil. The composition of petroleum pitch can vary based on the source of the crude oil and the refining methods used. It also contains impurities such as sulfur, nitrogen, and trace metals [18, 19, 20].
2.1.2.5 Grahamite
Grahamite was first discovered in a state of America and was later found in parts of Cuba, Trinidad, Colorado, and Oklahoma. Grahamite may have been obtained as a result of gasoline metamorphism. Graham is blacker than gasoline and has a shell fracture surface and many fractures. Grahamites are used as cement mortar, covering roofs and floors of buildings [21]. Grahamite has a Softening temperature of 104–287°C.
Although determining the structure of natural asphalt is difficult, data analyses suggest natural asphalt comprises 70–80% of carbon and 15% of hydrogen, along with traces of nitrogen, sulfur, oxygen, and metals. Hydrocarbons can consist of polycyclic aromatic structures with different numbers of aromatic rings. Saturated hydrocarbon chains with different chain lengths and substitution patterns constitute the core of all these structures. Natural asphalt is generally characterized by aromatic fused rings, i.e., poly-nuclear aromatic, aliphatic side chains, and functional groups containing polar heteroatoms, e.g., amide, hydroxy, sulfide and sulfoxide, phenols, pyrroles, furanes, and pyridines (Figure 4) [22, 23, 24, 25].
Figure 4.
A part of natural asphalt molecular structure.
The different compounds of petroleum bitumen are not well known so far, but these compounds, which are separated from bitumen by means of different solvents, are divided into four general categories: saturated compounds, aromatic compounds, resins, and asphaltenes. Saturated compounds have saturated hydrocarbons, and aromatic compounds have simple rings. Resins and asphaltenes have similar chemical properties, and in the meantime, resins become asphaltene monomers, and asphaltene monomers together form asphaltene clusters [26, 27].
3.1 Saturated compounds
Chemically saturated compounds have linear, branched, and even cyclic hydrocarbon chains without any double bond or aromatic structure. Saturated compounds are mainly composed of carbon and hydrogen and have an H/C ratio of 1.8. Saturated compounds make up 5–20% of asphalt structure. From the physical point of view, tares are white to pale yellow viscous oils, and their molecular weight is around 800 g/mol [28].
3.2 Aromatic compounds
Aromatic compounds have unsaturated chemical structures and aromatic nuclei or rings. Aromatics account for 40–65% of asphalt structure. The molecular weight of these compounds is between 300 and 2000 g/mol, and the H:C ratio is equal to 1:5. Aromatics are created by connecting aromatic rings with non-polar and saturated carbon chains and act as solvents for heavy compounds in bitumen [29].
3.3 Resins
Resins are compounds soluble in n-heptane and have a chemical structure similar to asphaltenes. Resins have a lower molecular weight than asphaltenes, and their H:C ratio is 4:1, higher than asphaltenes. Resins also contain oxygen and nitrogen compounds. Resins are dark brown compounds, solid to semi-solid, polar, and very viscous. Due to the structural similarity of resins to asphaltenes, they can also act as a dispersing agent for asphaltenes [30].
3.4 Asphaltenes
Asphaltenes are compounds made of aromatic rings welded together. Aliphatic bridges connect these planar polycyclic structures. With the advancement of chemical structure identification methods, serious differences have arisen regarding the molecular weight of asphaltenes. In the past, the molecular weight of asphaltenes was estimated in the range of 1000 to 10,000 g/mol, but nowadays, its value has decreased to 1000 to 2000 g/mol [30]. An example of saturated compounds (a), aromatic compounds(b), resins (c) and asphaltenes in structures of asphalt are shown in Figure 5.
Natural asphalt has been utilized throughout history for various purposes. It was used by ancient civilizations such as the Sumerians, Persians, Egyptians, and Romans for waterproofing structures like roofs and walls. It was also mixed with aggregates to create durable roads, as seen in the road networks of the Romans, Incas, and Persians. Natural asphalt served as a sealant for ships, canoes, and containers, preventing leaks, and preserving contents. It was used in mummification in ancient Egypt to protect the body from decomposition. Additionally, bitumen was used in medicine, cosmetics, and artistic applications, acting as an ointment, base for cosmetics and perfumes, and a binder for pigments in paint. Natural bitumen’s durability and adhesive properties made it a versatile material for ancient societies [31, 32, 33, 34, 35, 36]. The natural leakage of ancient bitumen has been observed in various regions of the world specifically the Mesopotamian region (modern-day Iraq and Iran), is known for its natural seeps of bitumen (Figure 6). These regions were the first areas where natural bitumen leaks were discovered. Later, other new areas were discovered and expanded [37].
Figure 6.
The map of ancient natural asphalt and its applications.
Most reserves of natural bitumen mines are located in the United States, Canada, Iran, Iraq, Russia, Venezuela, China, Australia, Mexico, Albania, and the Philippines, respectively. Canada, Venezuela, and Russia have the most natural bitumen reserves. However, significant reserves are also concentrated in the United States, Mexico, Kuwait and Indonesia [33]. In the United States of America, the largest gilsonite reserves have been found in Utah and Colorado, estimated to have 45 million tons [38].
In Canada, technological advances have led to the recovery of bitumen in the remote areas of Northeastern Alberta [39].
There are many reserves and resources of heavy crude oil and natural bitumen, especially in Eastern Europe (Russia) and Siberia, where there are at least 700 billion barrels. Unlike the rest of the earth, most of the Russian Federation’s reserves and resources are Mesozoic, Paleozoic, and Proterozoic. One hundred billion barrels of natural bitumen resources are located in China and Mongolia [40, 41].
Nigeria is a country in West Africa with many natural bitumen reserves. The Nigerian bitumen belt is found in the southwest of Nigeria and is located in the coastal areas of the eastern Dahomey basin, one of the prominent cities in Agababu, where natural bitumen was discovered for the first time in 1900. While the commercial exploitation of its materials has not yet begun, scientific research on it is steadily increasing [42].
Iran is one of the world’s largest producers and exporters of solid natural bitumen. Iran holds significant reserves of natural bitumen, mainly found in the southwest region of the country, particularly in the provinces of Kermanshah and Ilam, western Iran. In Kermanshah, there are several natural asphalt sources scattered throughout the province. Overall, the Kermanshah and Ilam provinces in Iran are rich in natural asphalt sources. These deposits contribute to the local economy and are utilized in various industries. The natural asphalt from these regions is of high quality and has gained recognition both domestically and internationally.
The natural bitumen deposits in Iran are classified into two types: lake bitumen and rock bitumen (solid natural asphalt). Rock bitumen or solid natural asphalt, on the other hand, is a major source of Iran’s natural bitumen and is found in sedimentary carbonate rocks in various parts of Iran. These deposits are usually mined underground, and the bitumen is extracted using conventional mining techniques. The rock bitumen typically contains impurities such as sand, limestone, and shale, which are separated during the refining process. Lakes bitumen contains highly pure bitumen and is a minor source of Iran’s natural bitumen production.
Iran has invested significantly in the extraction, processing, and marketing of natural bitumen. Iran’s natural bitumen is known for its quality and diverse range of characteristics. Figure 7 shows Iran’s natural asphalt mine.
Various physical parameters such as ash content, carbon, hydrogen, nitrogen, and sulfur content, solubility, softening point, specific gravity and humidity are crucial in determining the quality of natural bitumen for different purposes [43]. The ash content in natural bitumen consists of inorganic materials and waste materials like clays, sulfides, sulfates, carbonams, etc. These materials remain as ash after combustion and are divided into inherent ash and secondary ash. The main elements in ash are aluminum, calcium, iron, sulfur, silicon, potassium, magnesium, sodium, phosphorus, and titanium [44].
Sulfur in natural bitumen, like coal, can exist in organic and inorganic forms. Inorganic sulfur includes sulfide minerals like pyrite, asphaltite, galena, and arsenopyrite, as well as sulfate minerals like barite, geysers, dendrite, and some iron sulfates. Pyrite sulfur is typically the dominant mineral sulfur in natural bitumen, existing as crystals among the bitumen structure. Organic sulfur in natural bitumen is covalently attached to its complex structure and is more difficult to remove compared to pyrite or mineral sulfur. It can exist as aromatic or aliphatic thiols, sulfides, disulfides, and hetero- and cyclic compounds [44].
Natural bitumen contains two types of moisture: outward moisture, which may be added during the extraction process, and analytical moisture, which is the intermolecular moisture present in natural asphalt [44]. Another important parameter is solubility. Solubility of natural bitumen depends on its large amount of asphaltene. It is soluble in aromatic hydrocarbons such as benzene, toluene, carbon disulfide, chloroform, and solvents containing chlorine. Natural bitumen has low solubility in alcohols and ketones. Solubility percentage in carbon disulfide (CS2) can be used to determine the type and quality of mineral compounds present in natural bitumen. Carbon disulfide, trichloroethylene, and carbon tetrachloride are three commonly used solvents to assess the solubility percentage and quality of natural bitumen [44].
The softening point and specific gravity are important properties used to characterize and classify natural asphalt. The softening point of natural asphalt refers to the temperature at which it starts to soften and flow under the application of heat. It is a measure of the asphalt’s resistance to deformation at elevated temperatures. The softening point is essential in determining the appropriate application temperature range for natural asphalt. It helps assess the material’s ability to withstand temperature variations during storage, transportation, and use. Different grades of natural asphalt have different softening points, enabling them to be used in a wide range of applications, from road construction to roofing.
Specific gravity is the ratio of the density of a substance to the density of a reference substance, typically water. The specific gravity of natural asphalt provides information about its density and helps assess its quality. It is an important parameter in determining the asphalt’s suitability for specific applications. As specific gravity is influenced by the composition and impurities in the asphalt, it can vary depending on the source and processing techniques. A high specific gravity indicates that the asphalt is denser, which makes it more durable and resistant to deformation. Low-specific gravity may indicate the presence of lighter hydrocarbons, which can lead to a less stable and weaker material. Overall, the softening point and specific gravity of natural asphalt are essential properties used to determine its performance and characteristics. These parameters assist in selecting the appropriate grade of asphalt for various applications, ensuring the material’s optimal use and longevity [44].
Natural asphalt is chemically composed of complex organic compounds along with resins, oils, and waxes. The high hydrocarbon content in natural asphalt gives it its sticky and black characteristics. When heated, it undergoes molecular changes and can be used in various industrial processes. It softens when heated and hardens upon cooling. While generally chemically stable in its solid form, natural asphalt may experience oxidative degradation over time when exposed to air and sunlight, resulting in changes to its physical properties.
When studying natural asphalt, factors such as material characterization, cost, availability, challenges, and limitations must be considered. Material characterization involves studying its physical, chemical, and rheological properties. The cost of natural asphalt varies depending on extraction methods, refining processes, transportation, and market demand, which can be influenced by geological, economic, and political factors. Challenges and limitations include environmental impact and climate sensitivity due to extraction processes and weather conditions affecting its performance.
6.1 Characteristics of Iran’s solid natural asphalt
Natural asphalt in Iran stands out from other types of asphalt due to its unique qualities. Composed primarily of hydrocarbon bitumen, it contains a high concentration of volatile components like naphthalene, toluene, and other aromatic compounds. The composition gives it advantageous properties, including a high melting point, low viscosity, and exceptional resistance to weathering. Renowned for its hardness and durability. Iran’s solid natural asphalt is one of the hardest natural bitumen available. It can resist deformation under heavy traffic loads and withstand extreme weather conditions. In comparison, other types of asphalt often have lower hardness and require additives or modifiers to improve durability. Iran’s natural asphalt also has a higher melting point, typically ranging from 180 to 245°C. This quality makes it suitable for applications in hot climates and areas with high-temperature variations. Other types of asphalt may have lower melting points, necessitating additional measures to prevent premature softening or melting. Additionally, Iran’s natural asphalt exhibits excellent annular strength, which refers to its ability to adhere to aggregates or other materials used in asphalt mixtures. This property ensures good bonding and improved resistance to stripping or rutting. In contrast, other types of asphalt might require adhesion agents or chemical additives to achieve similar strength. Furthermore, Iran’s natural asphalt possesses high chemical resistance due to its aromatic composition. It is less susceptible to chemical attack and degradation from fuel spillage, acidic substances, or saline water compared to other asphalts, making it a preferred choice for applications where exposure to corrosive substances is common. The solubility of Iran’s natural asphalt may be slightly different than regular natural asphalt. Some studies have shown that Iran’s natural asphalt has high solubility in organic solvents such as toluene, xylene, and carbon disulfide (Figure 8).
Figure 8.
Solid natural asphalt lumps (a) and a depot (b).
6.1.1 Mechanical analysis and structure study of natural asphalt of Iran
FT-IR (Fourier Transform Infrared) spectra of Iran’s natural asphalt and petroleum bitumen have been studied. In the spectrum of Iran’s natural asphalt, the broadband of 3200 cm−1 to 3600 cm−1 is related to NH and OH groups. The absorptions of 2920 cm−1 and 2850 cm−1 are, respectively, associated with the asymmetric and symmetric stretching vibration of the C-H bond of aliphatic compounds. The absorption of the 1600 cm−1 region is related to the stretching vibration of the C=C bond, which is another characteristic of asphaltene aromatic compounds. Absorptions in the regions of 1450 cm-1 and 1375 cm−1 are the vibrations of methyl groups (CH3), which have been observed for both samples of Iran’s natural bitumen and petroleum bitumen (Figure 9).
Figure 9.
FT-IR spectrum of petroleum bitumen (a) and solid natural asphalt (b).
In another study, proton and carbon nuclear magnetic resonance (1H and 13C-NMR) samples of Iran’s natural and petroleum bitumen were investigated. Natural bitumen is richer in terms of aliphatic (saturated) hydrogens and on the other hand, it has a small amount of aromatic hydrogens (Figure 10).
Figure 10.
1H NMR and 13C NMR spectrums of Iran’s natural asphalt (400 MHz, CDCl3).
Also, elemental analysis and X-ray fluorescence of Iran’s natural asphalt sample have been done. The results of these analyses are presented in Tables 2 and 3.
Element
C
H
S
N
%
75
12.5
2.5
2.3
Table 2.
The results of elemental analysis of Iran’s natural asphalt.
Element
C
H
S
N
CaO
TiO2
MnO
Al2O3
Fe3O4
K2O
Na2O
P2O5
MgO
SO3
SiO2
%
81.08
11.31
0.63
—
0.41
0.014
0.001
0.082
0.102
0.007
0.005
0.008
0.011
4.467
0.774
Table 3.
The results of X-ray fluorescence analysis of Iran’s natural asphalt.
Thermogravimetric analysis (TGA) of Iran’s natural asphalt shows that in the temperature range of 0–160°C, the sample did not lose weight. But in the 160°C and later can be considered as the beginning of the first step of decomposition of organic substances, which can be seen at 160–400°C, 10% of the organic substances in the sample have been decomposed. This step is called the first decomposition step. The graph below shows that the highest percentage of weight loss is assigned to the second step of decomposition, which is in the temperature range of 400–490°C, where 44% of the organic compound in the sample is decomposed. The third step of decomposition, in which a minimal amount of Iran’s sample is decomposed, belongs to the temperature range of 490–810°C, during which another 7% of the compounds in the sample are decomposed. Finally, in a general conclusion, 61% of the organic substances in the sample have been destroyed in the temperature range of 0 to 810°C, and it is noteworthy that 39% of the organic compounds in the sample remain. The amount includes organic compounds with strong chemical bonds, as well as a percentage of ash. Figure 11 shows the TGA analysis of Iran’s natural asphalt. According to the TGA analysis results, Iran’s asphalt has good thermal stability and is suitable for use as a filler and bitumen modifier.
Figure 11.
TGA analysis of Iran’s natural asphalt.
Iran’s natural asphalt sample has been investigated using the scanning electron microscope (SEM) analysis method. The scanning electron microscope image of Iran’s natural asphalt has shown the existence of multifaceted particles with smooth and flat surfaces (Figure 12) [44].
Natural asphalt has been reported to have many valuable uses in various industries. Due to the fact that natural asphalt is a natural and non-toxic material, its use is increasing. The main applications of natural asphalt include the production of asphalt, paints and postings, isolation, preparation of emulsion bitumen, coke production, application in drilling mud, natural asphalt consumption as fuel, usage of natural asphalt in casting industries and usage of natural asphalt in the chemical industry. Most of the research carried out regarding the use of gilsonite in bitumen and asphalt was done by the American gilsonite company, which we will explain and mention in the following.
8.1 Natural asphalt (gilsonite), as a petroleum bitumen modifier
In the late 1970s, European contractors showed great interest in using bitumen modifiers because they believed in reducing the overall cost of using these modified bitumen compared to the high prices of raw materials. In the mid-1980s, more bitumen modifiers were investigated and known, attracting the special attention of American contractors. The use of modifiers gradually spread to different parts of the world [45]. Natural asphalt (gilsonite), can be used as a modifier in different forms, for example, gilsonite powder, granules, flakes, modified gilsonite, and blended gilsonite. Blended gilsonite is a mixture of natural asphalt and other additives or modifiers specifically formulated to achieve desired performance when added to petroleum bitumen.
The history of using bituminous modifiers dates back to 1943, when they were used for the first time. Natural asphalt can be used as a modifier in asphalt mixtures to enhance their performance characteristics. It is a performance-enhancing agent for asphalt mixes, achieving higher performance grades and easily blending into the asphalt without the need for high-shear milling. It also provides higher stability, reduced deformation, reduced temperature susceptibility, and increased resistance to water stripping compared to non-modified asphalt. Gilsonite can also be used to make pavement sealers with superior appearance and weathering. Its use in asphalt mix allows for a highly solid material without the need for additional balancing materials. Gilsonite can replace styrene-butadiene-styrene(SBS) polymers in asphalt modifiers, providing higher stability, lower shape changes, and increased resistance to water. It is commonly used due to its cost-effectiveness compared to other alternatives. When used as an asphalt binder modifier, gilsonite reduces susceptibility to high temperature and deformation performance issues and increases the use of recycled asphalt materials. Additionally, gilsonite-modified asphalt binder can produce a stronger road that is thinner compared to other pavements (Figure 13) [46].
Figure 13.
Influence of gilsonite on the strength of asphalt.
On the other hand, when polymer-modified binders are used, they form large molecules that interconnect or cross-link with each other to create a matrix. This matrix is not compatible with the recycled binder, meaning it cannot effectively bond with it. As a consequence, the pavement made with recycled asphalt and polymer-modified binders becomes more vulnerable to breaking down or deteriorating over time Figure 14 [46].
Figure 14.
Effect of gilsonite as a bitumen modifier.
So many studies have been performed in order to investigate the properties of modified bitumen using natural asphalt and (especially gilsonite). The below study shows the influence of different percentages of gilsonite in different weather conditions (temperature − 22 to +76) and also determines the performance grade (PG) of modified bitumen with gilsonite according to Superpio standards. The base bitumen used in the current project was PG 52–28 functional bitumen, which was modified in the presence of different percentages of gilsonite (0%, 3%, 6%, 9%, 12%) and was comprehensively investigated (Table 4) [47].
Gilsonite content
Flashpoint, oC
Mass loss, %
Viscosity @ 135°C
Grade Temp. at Which specified criterion is satisfied, oC
PG grade
DSR origin.
DSR RTFO
DSR PAV
BBR S
BBR m-value
DTT strain
High
Low
0
310
0.59
0.2168
52
52
16
−18
−18
—
52
−28
3
316
0.61
0.2555
58
58
19
−18
−18
—
58
−28
6
310
0.21
0.3400
58
58
22
−12
−12
—
58
−22
9
316
0.24
0.3842
64
64
25
−12
−12
—
64
−22
12
316
0.23
0.5208
70
70
25
−12
−12
—
70
−22
Table 4.
Summary of superpave binder test results.
Considering that PG refers to the primary performance factors of asphalt, namely rutting, low temperature cracks, and aging cracks, it is highly regarded nowadays.
Some general properties and qualities of natural asphalt that make it suitable for modification include:
Natural asphalt has several properties that make it suitable for modification. It has a high softening point, enabling it to enhance stiffness and resistance at high temperatures. It exhibits thermoplastic behavior, softening when heated and hardening when cooled, making it a useful binding agent. Its elasticity and flexibility contribute to improved durability and crack resistance. Natural asphalt’s chemical composition allows for effective modification and compatibility with other materials. It has strong adhesion and cohesion properties, enhancing strength and stability. It demonstrates high resistance to aging and weathering, ensuring long-term performance. Incorporating natural asphalt into asphalt mixtures increases flexibility and durability and enhances resistance to rutting and water infiltration. It can be modified through physical blending, chemical modification, oxidation, polymerization, and the use of additives [48].
8.2 Solid natural asphalt, as a petroleum bitumen filler
Some chemical specifications make it suitable as a filler material. These specifications are primarily related to its composition and physical properties. Solid natural asphalt primarily consists of hydrocarbons, including aromatic and aliphatic compounds. The presence of these hydrocarbons provides desirable adhesive and binding properties, making it an effective filler material. Also, natural asphalt has a high molecular weight, which contributes to its viscosity and solid-like behavior. This characteristic ensures that it remains in place and fills gaps effectively when used as filler. Another important factor is the chemical stability of natural asphalt. Natural asphalt is resistant to many chemicals, including acids, alkalis, and salts, which enhances its durability and resistance to degradation when used as a filler.
These chemical specifications and other physical and mechanical properties contribute to the effectiveness of natural asphalt as a filler material.
Physical specifications that make it suitable as a filler material. These physical properties contribute to its ability to fill gaps effectively and provide long-lasting performance. Here are the key physical specs of natural asphalt as filler:
Viscosity: Natural asphalt exhibits a suitable viscosity that allows it to flow and fill voids efficiently. Its viscosity can be adjusted by controlling the temperature during application, ensuring optimal workability as a filler.
Cohesion: Asphalt has inherent cohesive properties that enable it to bond together when used as an aggregate and maintain structural integrity. Additionally, it helps prevent the aggregate from separating or shifting over time.
Plasticity: Natural asphalt demonstrates plastic behavior, meaning it can be molded or shaped under pressure without breaking. The plasticity is advantageous for filling irregular cracks or voids, as it enables the filler to conform to the surrounding surfaces.
Thermal Stability: Bitumen possesses excellent thermal stability, allowing it to withstand a wide range of temperatures without significant degradation.
Waterproofing Capability: Natural asphalt is impervious to water, making it an effective filler for sealing cracks and preventing moisture intrusion. It acts as a barrier, enhancing the durability and lifespan of structures.
Low Solubility: Bitumen exhibits low solubility in water and other common solvents. This characteristic contributes to the longevity of the filler material, as it resists dissolution or leaching out over time.
Durability: Asphalt is known for its exceptional durability, resistance to aging, and ability to withstand weathering effects such as UV radiation and oxidation. These properties ensure the filler maintains its performance and structural integrity over an extended period.
It is important to note that the physical specifications of natural asphalt may vary depending on the specific grade or source of the material. Additionally, the requirements for a filler material can vary based on the application and intended use [3].
Natural asphalt is used as a filler in various applications. As a filler, natural asphalt offers several benefits due to its unique properties. Here are some common uses of natural asphalt as filler:
In the construction industry: Natural asphalt is often used as a filler in paving mixtures. It helps improve the durability, stability, and resistance of asphalt pavements. The addition of natural asphalt increases the viscosity and stiffness of the asphalt binder, leading to better performance in rutting resistance and fatigue cracking.
In the production of adhesives and sealants: Natural asphalt is utilized as a filler in the formulation of adhesives and sealants. Its excellent adhesive properties and compatibility with various polymer systems make it an effective choice for enhancing the performance of these products. Natural asphalt helps improve the cohesion, tensile strength, and aging resistance of adhesives and sealants.
In manufacturing inks and coatings: Natural asphalt is widely employed as a filler in the production of printing inks and coatings. It provides desirable properties like improved flow, pigment dispersion, and resistance to wear and tear. Natural asphalt acts as a rheological modifier, enhancing the handling and application characteristics of inks and coatings.
In the rubber and tire industry: Natural asphalt is utilized as a filler and reinforcing agent in rubber compounds and tire manufacturing. Its incorporation improves the mechanical properties of rubber, such as tensile strength, abrasion resistance, and elasticity. Natural asphalt also enhances the processability and extrudability of rubber compounds [49, 50].
8.3 The effect of Gilsonite-modified asphalt on hot mix asphalt concert mixes
8.3.1 Study case: Texas
The District 12 laboratory conducted tests on different asphalt mix designs to assess the effects of gilsonite. In the current plan, gilsonite is added to the bitumen in percentages of 0%, 4%, 6%, and 8%. Modified bitumen is mixed with stone materials according to patterns 1 and 2. The stability, specific gravity, indirect elasticity and moisture sensitivity of the resulting asphalt mixture have been investigated (Table 5) [51]. The results of the laboratory tests showed that the gilsonite-modified asphalt mixes increased both dry and wet tensile strength. As there is not sufficient evidence to prove that gilsonite alone is effective as an anti-stripping agent (preventing the separation of asphalt and aggregate due to moisture), it is recommended to use it in conjunction with an anti-stripping agent to mitigate the risk of stripping and rutting.
Group
Average stability
Dry (psi)
Wet (psi)
Ratio wet/dry
Control 1
37
124.10
40.53
033
4% gilsonite
41
171.78
62.36
0.36
6% gilsonate
36
178.30
51.50
0.29
8% gilsonate
41
169.10
50.50
0.3
Design 2:
Control 1
40
74.50
47.90
0.64
4% gilsonite
38
103.70
87..60
0.84
6% gilsonate
39
121.30
80.60
0.66
8% gilsonate
33
153.30
138.00
0.90
Table 5.
Results from mix design 1.
Also, it was found that gilsonite did not have a significant impact on Hveem stability, which is a measure of the resistance to deformation under loading (Figure 15). To determine Hveem stability, a cylindrical specimen of the asphalt mixture is subjected to a vertical load in a controlled testing apparatus. The load is gradually applied, and the specimen’s resistance to deformation is measured. During the test, the stability value represents the maximum load sustained by the specimen without causing excessive deformations or failure. A higher stability value indicates better resistance to deformation and is desirable for durable asphalt pavements. Hveem stability is influenced by various factors, including the type and amount of aggregate used, the proportion of asphalt binder, the level of compaction, and the presence of additives, such as gilsonite in this case. In the current project, it was found that the addition of gilsonite did not significantly increase the Hveem stability of the asphalt mixes. This suggests that gilsonite may not have a substantial impact on the resistance of the asphalt mixture to deformation under loading.
Figure 15.
Stability vs. percent gilsonite in asphalt mix design 1.
9. Comparing the use of asphalt as filler and modifier
As a clarification, natural asphalt is typically used as a filler rather than a modifier in various applications. It is more commonly utilized for its physical properties and benefits as a filler material rather than as a modifier to alter the characteristics of a material. However, suppose you are specifically interested in the drawbacks of using natural asphalt as a modifier. Natural asphalt may not have the desired properties to modify materials effectively. It may have limited abilities compared to synthetic modifiers in achieving specific performance enhancements. Natural asphalt can vary in composition and properties, making it challenging to achieve consistent results. Compatibility issues may arise with certain materials or chemical additives, potentially reducing effectiveness or causing negative interactions.
9.1 Methods of modification of petroleum bitumen with natural asphalt (gilsonite)
Mixing method refers to the process of combining different materials in an asphalt plant to produce asphalt mixture. One of the key components in asphalt mixture is bitumen and is the binding agent that holds the asphalt together. In an asphalt plant, the process of mixing bitumen with other materials (such as aggregate, filler, and additives) takes place in the asphalt mixer. Different mixing methods can be employed, depending on the type of asphalt plant and the desired properties of the asphalt mixture. One common mixing method used in asphalt plants is the batch mixing method. In this method, the different materials, including bitumen, are weighed and then added to the mixer. The mixer ensures that all the materials are thoroughly mixed together to form a consistent and uniform mixture. The process is repeated for each batch of asphalt mixture produced.
Another mixing method commonly used in asphalt plants is the continuous mixing method. The materials are continuously fed into the mixer, including the bitumen. The mixer has rotating paddles or blades that mix and blend the materials together as they pass through the mixer. This ensures a continuous flow of asphalt mixture output.
The choice of mixing method depends on various factors, such as the plant capacity, the type of asphalt mixture being produced, and the construction project requirements. Both batch and continuous mixing methods have their advantages and disadvantages. For example, batch mixing allows for more control and flexibility in batch size and mixture composition, while continuous mixing offers higher production rates. For example, in the following method, 200 mesh micronized powder is added to the flask of molten refinery bitumen at 170°C and stirred for 2 hours by a regular stirrer. The method is for percentages less than 12% Figure 16 [52].
Figure 16.
Method of modification of petroleum bitumen by gilsonite.
9.2 Preparation of modified asphalt using natural asphalt powder (Gilsonite)
In this method, gilsonite is stored in a silo that is part of the plant, and stone materials and natural asphalt powder (gilsonite) enter the mixer of the asphalt plant at the same time; therefore, the time of injection or spraying of natural asphalt powder (gilsonite) into the mixer is adjusted at the same time as the stone materials enter the mixer. The temperature of stone materials in the batch mixer should be between 160 and 174°C, so the temperature in that range should be adjusted and fixed (Figure 17) [52].
Natural asphalt has been primarily used in various applications such as road construction, roofing materials, waterproofing, and industrial compounds. However, it is important to note that industries and technologies are constantly evolving, and the future of natural asphalt applications may involve new developments and trends. Here are a few potential directions for the future of natural asphalt applications:
Sustainable Infrastructure: With increasing global emphasis on sustainability, there may be a growing demand for eco-friendly alternatives in infrastructure development. Natural asphalt, a naturally occurring material, could gain popularity as a renewable and sustainable option for road pavements and other construction projects. Efforts to enhance the durability and performance of natural asphalt through research and innovation could further drive its adoption.
Advanced Manufacturing Techniques: Advancements in manufacturing techniques, such as nanotechnology and polymer modification, could offer new possibilities for natural asphalt applications. These techniques can help enhance the strength, flexibility, and overall performance of natural asphalt, making it suitable for a wider range of applications.
Green Roofing: As green building practices gain momentum, natural asphalt could find increased use in green or vegetated roofing systems. Natural asphalt can provide an effective waterproofing layer while complementing the overall sustainability goals of green roofs.
Alternative Energy Storage: Natural asphalt’s thermal properties make it a potential candidate for energy storage applications. It can absorb and release heat effectively, presenting opportunities for using natural asphalt in thermal energy storage systems or solar heating applications.
It is worth noting that these projections are speculative, and the actual future of natural asphalt applications may depend on several factors, such as market demand, technological advancements, environmental regulations, and availability of alternative materials.
11. Conclusion
In conclusion, the chapter on introducing natural asphalt provides valuable information on its characteristics, sources, analysis methods, and applications. Natural asphalt, also known as gilsonite and asphaltite, is a unique geological material with diverse properties and applications. The chapter highlights the various sources of natural asphalt around the world, emphasizing the abundance and significance of Iran’s natural asphalt. Iran is known as one of the largest producers of natural asphalt, with vast reserves and a long history of utilization in various industries. The characteristics of Iranian natural asphalt were investigated using FT-IR, elemental analysis, X-ray fluorescence, TGA, and SEM analysis. According to the elemental analysis and X-ray fluorescence of Iran’s natural asphalt, it has a high percentage of carbon. Additionally, the TGA analysis results have shown that Iran’s asphalt has good thermal stability and is suitable for use as a filler and bitumen modifier. Asphalt modifiers can enhance the performance of asphalt by improving its stiffness, durability, and resistance to aging. The addition of asphalt fillers can improve the volumetric properties of asphalt mixtures, such as stability and void content. The effectiveness can vary depending on factors like climate, traffic conditions, and mix design.
Various types of modifiers, such as polymers, crumb rubber, and natural fibers, have been studied and shown to have positive effects on asphalt performance. The use of certain modifiers, such as crumb rubber from scrap tires, raises environmental and sustainability concerns. The use of bitumen modifiers and asphalt fillers holds promise for improving the performance of asphalt mixtures. However, further research is required to determine the optimal materials and dosage for specific conditions. Considerations regarding environmental impact and sustainability are important in the selection of modifiers and fillers.
Natural asphalt has proven to be an effective additive in enhancing the properties of traditional bitumen, such as improving stability, durability, and rutting resistance in asphalt mixtures. It has also been utilized as an alternative to bitumen in road construction and maintenance, offering economic and environmental advantages. Natural bitumen has several characteristics that make it suitable for modifiers and fillers. Natural asphalt has a high viscosity, making it an effective modifier for materials like asphalt, rubber, and polymers. It exhibits thermoplastic behavior, softening when heated and hardening when cooled, enhancing flexibility and durability. Bitumen is highly resistant to water penetration, improving water resistance in materials. Additionally, it has excellent adhesive properties, enhancing bonding strength and improving material performance. However, there are a few disadvantages of using bitumen and asphalt as a modifier and filler. Over time, bitumen and asphalt can undergo aging and weathering, causing them to become brittle and prone to cracking. That can result in the deterioration of road surfaces and the need for frequent repairs. Also, bitumen and asphalt surfaces can contribute to increased noise levels and vibration, particularly in urban areas with high traffic volumes, and it have adverse effects on nearby residents and sensitive structures.
Overall, the chapter underscores the importance of natural asphalt as a valuable resource with unique characteristics and wide-ranging applications. Its abundance in Iran and the analysis methods discussed pave the way for further research and utilization of natural asphalt in various industries, particularly in the field of road construction and maintenance.
References
1.Luo J, Li Q , Ali MA, Alizadeh AA, Raise A, Alali AF, et al. Experimental investigation of the rheological behaviors of bitumen and stone matrix asphalt mixtures using waste material. Construction and Building Materials. 2023;15(365):130003. DOI: 10.1016/j.conbuildmat.2022.130003
2.Wen Y, Wang Y, Zhao K, Sumalee A. The use of natural rubber latex as a renewable and sustainable modifier of asphalt binder. International Journal of Pavement Engineering. 2017;18:547-559. DOI: 10.1080/10298436.2015.1095913
3.Wu W, Jiang W, Yuan D, Lu R, Shan J, Xiao J, et al. A review of asphalt-filler interaction: Mechanisms, evaluation methods, and influencing factors. Construction and Building Materials. 2021;299:124279. DOI: 10.1016/j.conbuildmat.2021.124279
4.Liu N, Liu L, Li M, Sun L. Effects of zeolite on rheological properties of asphalt materials and asphalt-filler interaction ability. Construction and Building Materials. 2023;382:131300. DOI: 10.1016/j.conbuildmat.2021.124279
5.Sun M, Wang J, Sun H, Hong B. Feasibility analysis of polyurethane-Prepolymer-modified bitumen used for fully reclaimed asphalt pavement (FRAP). Materials. 2023;16:5686. DOI: 10.3390/ma16165686
6.Choudhary J, Kumar B, Gupta A. Utilization of waste glass powder and glass composite fillers in asphalt pavements. Advances in Civil Engineering. 2021;13:1-7. DOI: 10.1155/2021/3235223
7.Tauste-Martínez R, Hidalgo AE, García-Travé G, Moreno-Navarro F, Rubio-Gámez MD. Influence of type of filler and bitumen on the mechanical performance of asphalt mortars. Materials. 2022;15:3307. DOI: 10.3390/ma15093307
8.Asphalt Institute, The Asphalt Handbook MS-4, Asphalt Institute. 7th ed, Lexington, KY (Kentucky). 2007. ISBN-10: 193415427X 2007
9.Read J, Whiteoak D. The Shell Bitumen Handbook. 5th ed. London: Thomas Telford Publishing; 2003. p. 2553
10.Delano WH. Twenty Years' Practical Experience of Natural Asphalt and Mineral Bitumen. Whitefish, MT: Kissinger Publishing; 2007 (original 1893)
11.Wen CS, Chilingarian GV, Yen TF. Properties and structure of bitumens. Bitumens, asphalts and tar sands. 1978;7:155. DOI: 10.1016/S0376-7361(08)70066-9
12.Bitumen [Internet]. Wikipedia. 2023. Available from: https://en.wikipedia.org/wiki/Bitume
13.Tar pit [Internet]. Wikipedia. 2023. Available from: https://en.wikipedia.org/wiki/Tar_pit
14.Abraham H. Asphalts and Allied Substances, sixth edition, volume 1, Van Nostrand, Princeton. 1960. 370 p
15.Erdman JG, Ramsey VG. Rates of oxidation of petroleum asphaltenes and other bitumens by alkaline permanganate. Geochimica et Cosmochimica Acta. 1961;25:175. DOI: 10.1016/0016-7037(61)90075-8
16.Ameri M, Mansourian A, Ashani SS, Yadollahi G. Technical study on the Iran’s Gilsonite as an additive for modification of asphalt binders used in pavement construction. Construction and Building Materials. 2011;25:1379. DOI: 10.1016/j.conbuildmat.2010.09.005
17.Kohzadi H, Soleiman-Beigi M. A recyclable heterogeneous nanocatalyst of copper-grafted natural asphalt sulfonate (NAS@ Cu): Characterization, synthesis and application in the Suzuki–Miyaura coupling reaction. New Journal of Chemistry. 2020;44:12134. DOI: 10.1039/D0NJ01883J
18.Aureal T, Cross D, Gordon D. Palynology and petrography of solid Bitumens of the Uinta Basin, Utah. Brigham Young University Geology Studies. 1976;22:157-173
19.Chockalingam K, Saravanan U, Krishnan JM. Characterization of petroleum pitch using steady shear experiments. International Journal of Engineering Science. 2010;48:1092-1109. DOI: 10.1016/j.ijengsci.2010.08.008
20.Han SH, Park EJ. Characterization and application of petroleum pitch. Materials. 2014;7:816-826. DOI: 10.1039/C8RA04679D
21.Jacob H. Classification, structure, genesis and practical importance of natural solid oil bitumen (“migrabitumen”). International Journal of coal geology. 1989;11:65. DOI: 10.1016/0166-5162(89)90113-4
22.Kohzadi H, Soleiman-Beigi M. Immobilization of PdCl2 on a natural asphalt sulfonic acid network for C−N and C−O bonds formation. ChemistrySelect. 2022;7:e202200799. DOI: 10.1002/slct.202200799
23.Kohzadi H, Soleiman-Beigi M. Progress on the natural asphalt applications as a new class of carbonious heterogeneous support; synthesis of Na [Pd-NAS] and study of its catalytic activity in the formation of carbon–carbon bonds. Molecular Diversity. 2022;26:1957. DOI: 10.1007/s11030-021-10306-3
24.Kohzadi H, Soleiman-Beigi M. XPS and structural studies of Fe3O4-PTMS-NAS@ Cu as a novel magnetic natural asphalt base network and recoverable nanocatalyst for the synthesis of biaryl compounds. Scientific Reports. 2021;30(11):24508. DOI: 10.1038/s41598-021-04111
25.Falah S, Soleiman-Beigi M, Kohzadi H. Potassium natural asphalt sulfonate (K-NAS): Synthesis and characterization as a new recyclable solid basic nanocatalyst and its application in the formation of carbon–carbon bonds. Applied Organometallic Chemistry. 2020;34:e5840. DOI: 10.1002/aoc.5840
27.Mukhametshin RZ, Punanova SA. Composition of natural bitumens from the Ural-Volga region. Solid Fuel Chemistry. 2014;48:58-70. DOI: 10.3103/S0361521914010078
28.Speight JG. The Chemistry and Technology of Petroleum. 4th. ed. Boca Raton: CRC Press; 2006. DOI: 10.1201/9781420008388
29.Read J, Whiteoak D, Hunter RN. The Shell Bitumen Handbook. Fifth ed. London, UK: Thomas Telford; 2003
30.Krchma LC, Gagle DW. A USA history of asphalt refined from crude oil and its distribution. In: Association of Asphalt Paving Technologists Proc. University of Minnesota. Vol. 43. 1974 Accession Number: 00127522
31.Chen JS, Huang LS. Developing an aging model to evaluate engineering properties of asphalt paving binders. Materials and Structures. 2000;33:559-565. DOI: 10.1007/BF02480536
32.Krishnan M, J, Rajagopal KR. Review of the uses and modeling of bitumen from ancient to modern times. Applied Mechanics Reviews. 2003;56:149-214. DOI: 10.1115/1.1529658
33.Clark KA, Ikram S, Evershed RP. The significance of petroleum bitumen in ancient Egyptian mummies. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 2016;374:20160229. DOI: 10.1098/rsta.2016.0229
34.Edwards DS, Vinall DR, Corrick AJ, McKirdy DM. Natural bitumen stranding on the ocean beaches of southern Australia: A historical and geospatial review. Transactions of the Royal Society of South Australia. 2016;140:152. DOI: 10.1080/03721426.2016.1203532
35.Roberts JD. Performance of Cement-Modified Soils: A Follow-Up Report. Oklahoma City: Transportation Research Board. 1986. pp. 81-86. DOI: worldcat.org/isbn/0309041090
36.Crawford AL. Gilsonite-its Discovery and the Early History of the Industry. The United States: Eighth Annual Field Conference; 1957
37.Connan J. Use and trade of bitumen in antiquity and prehistory: Molecular archaeology reveals secrets of past civilizations. Philosophical transactions of the Royal Society of London. Series B: Biological Sciences. 1999;354:33-50. DOI: 10.1098/rstb.1999.0358
38.Rahimi E, Shekarian Y, Farahani S, Asgari G, Nakini A. New approach in application of the AHP–fuzzy TOPSIS method in mineral potential mapping of the natural bitumen (Gilsonite): A case study from the Gilan-e-Gharb block, the Kermanshah, west of Iran. American Journal of Engineering and Applied Sciences. 2020;13:96. DOI: 10.3844/ajeassp.2020.96.110
39.Ameri M, Mirzaiyan M, Amini A. Rutting resistance and fatigue behavior of gilsonite-modified asphalt binders. Journal of Materials in Civil Engineering. 2018;30:04018292. DOI: 10.1061/(ASCE)MT.1943-5533.0002468
40.Abraham H. Asphalts and Allied Substances: Their Occurrence, Modes of Production, Uses in the Arts and Methods of Testing. New York, USA: David Van Nostrand; 1918
41.Helms JR, Kong X, Salmon E, Hatcher PG, Schmidt-Rohr K, Mao J. Structural characterization of gilsonite bitumen by advanced nuclear magnetic resonance spectroscopy and ultrahigh resolution mass spectrometry revealing pyrrolic and aromatic rings substituted with aliphatic chains. Organic Geochemistry. 2012;44:21. DOI: 10.1016/j.orggeochem.2011.12.001
42.Sugihara JM, McCullough TF. Analysis of hydrocarbon fraction of Gilsonite. Analytical Chemistry. 1956;28:370. DOI: 10.1021/ac60111a022
43.Sugihara JM, Sorensen DP. Some pyrroles, phenols and pyridines contained in a Gilsonite distillate. Journal of the American Chemical Society. 1955;77:963. DOI: 10.1021/ja01609a049
44.Soleiman-Beigi M, Noroozian Z, Sarai R, Kohzadi H, Naghipour A. Palladium and zirconium nanoparticles immobilized on functionalized natural asphalt sulfonate as magnetically and recoverable nanocatalysts for the synthesis of symmetrical and unsymmetrical disulfides. Reaction Kinetics, Mechanisms and Catalysis. 2023;136:2465-2480. DOI: 10.1007/s11144-023-02487-9
45.Bahia BU, Anderson AD. Strategic highway research program binder rheological parameters: Background and comparison with conventional properties. Transportation research record. 2005;1488:32-39. DOI: worldcat.org/issn/03611981
46.Cost-effective and adds a new dimension of strength to asphalt. Americangilsonite company. Available from: https://www.americangilsonite.com
47.Liu J. Screening Test of Gilsonite Application. Fairbanks, Alaska, USA: Alaska University Transportation Center; 2007
48.Hawesah AL, Sadique H, Harris M, Al Nageim C, Stopp H, Pearl K, et al. A review on improving asphalt pavement service life using gilsonite-modified bitumen. Sustainability. 2021;13:6634. DOI: 10.3390/su13126634
49.Lv S, Fan X, Yao H, You L, You Z, Fan Z. GAnalysis of performance and mechanism of Buton rock asphalt modified asphalt. Journal of Applied Polymer Science. 2019;136:46903. DOI: 10.1002/app.46903
50.Coleman SR. Structural fat grafts: The ideal filler? Clinics in plastic surgery. 2001;28:111-119. DOI: 10.1016/S0094-1298(20)32343-9
51.Wong C, Ho MK. Effect of Gilsonite-Modified Asphalt on Hot-Mix Asphaltic Concrete Mixes Used in District 12, Houston, Texas. Austin, TX (USA): Texas Dept. of Highways and Public Transportation; 1990
52.Mixing gilsonite in to bitumen or asphalt mix. Hillinton international group. 2015. Available from: www.gilsonitesuppliers.co.uk
Written By
Mohammad Soleiman-Beigi, Homa Kohzadi and Saeed Toolabi
Submitted: 23 August 2023Reviewed: 17 October 2023Published: 07 March 2024
Open access peer-reviewed chapter - ONLINE FIRST
