Natural Asphalt Research Articles

The influence of fine recycled asphalt pavement aggregates on the properties of self-compacting mortar in fresh and hardened state

Sustainable development is a contemporary concern in the field of asphalt pavements, as road construction consumes a significant amount of new aggregates. Furthermore, road maintenance necessitates the milling of old pavement layers, which generates a substantial quantity of bituminous material waste. This study explores the use of recycled sand from asphalt waste as a substitute for 0, 25, 50, 75, and 100% of natural sand in self-compacting mortar, aiming to achieve both sustainable and economical asphalt production. The differences in physical properties between natural sand (NS) and fine recycled asphalt pavement (FRAP) aggregates are analyzed and compared. The characteristics of the various self-compacting mortars are measured, including spread, flow time, as well as compressive and tensile strength, shrinkage and sorptivity. Compared to the control mortar, the mortars containing RPAS exhibit a rougher surface, additional pores, and more complex pore structures. The need for superplasticizers increases with the substitution rate, as do the rheological parameters. The results indicate that recycled mortar can be an alternative to natural sand, although this comes with negative impacts on the mechanical properties of the mortar. Nonetheless, these effects can be mitigated when considering their economic and environmental implications.

Rapid and efficient removal of water-soluble dyes via natural asphalt oxide as a new carbonaceous super adsorbent; NA-oxide synthesis and characterization

In this study, natural asphalt was oxidized to synthesize a new nano-structure adsorbent for dye removal. The functionalization of natural asphalt by oxidation introduced new properties that influenced its activity. The process of oxidizing natural asphalt with potassium permanganate resulted in a low-cost adsorbent, which can potentially be a more affordable option compared with synthetic alternatives. Characterization analysis confirmed the enhanced surface area, improving dye interaction and adsorption. The interconnected channels and capillaries of the oxidized natural asphalt facilitated the capillary action drawing in liquids, including dyes. The distinctive porosity of natural asphalt oxide (NA-oxide) was noted, and the experimental results showed that the NA–oxide nanoadsorbent efficiently adsorbed cationic and anionic dyes in water, with maximum capacities of 14.68 mg.g−1, 17.81 mg.g−1 and 16.47 mg.g−1 for methyl orange, methylene blue and Rhodamine B, respectively. The study investigated various parameters, such as concentration, adsorption dose, pH, contact time, and temperature, affecting the dye removal process. Langmuir, Freundlich, and Temkin isotherms along with pseudo-first and pseudo-second-order kinetic equations were applied to assess the adsorption process, indicating that dyes adhered to the pseudo-first-order model and Langmuir isotherm. Analysis of MO, MB, and RhB dyes revealed conformity to Langmuir isotherm and first-order kinetics. Thermodynamic evaluations like ΔH°, ΔS°, and ∆G° displayed the exothermic and spontaneous nature of dye adsorption on the NA-oxide adsorbent. Furthermore, the absorbent displayed remarkable stability with a recovery rate of 98.45% after ten cycles, signifying its potential for enduring effectiveness in dye removal processes.

Performance of natural asphalt as a paving material: A laboratory and field evaluation

The ever-growing need to build roads to meet the necessary transportation demands is challenging, especially for developing countries. Low-volume roads (LVRs) are usually the backbone of catalyzing economic growth in these countries. With impediments surrounding Petroleum bitumen (price fluctuations) and environmental concerns, scientists are putting their effort into finding an alternative. The presented research is an attempt to check if Natural asphalt can be used as a full or partial replacement of the Petroleum bitumen. To the best of the authors' knowledge, only limited studies have focused on characterizing and understanding the engineering properties of Natural asphalt. The available techniques do not provide reliable information to the road authorities and hence they are discouraged from using it in practice. Particularly for countries, where the Natural asphalt source is available, the overall dependence on importing the Bitumen could be substantially reduced. Empirical and experience-based design criteria may not be sufficient as the standards were never developed for such materials, hence, a scientific approach is required before bringing it into practice. In this research, Natural asphalt sourced from different locations in Nigeria was assessed. Before performing the mixture level tests using Marshall and Cantabro design methods, the rheological and fatigue properties of the extracted Natural bitumen were examined in the laboratory. In the design of the experiment, various percentages of Natural asphalt were added between 0 % and 20 % by total mix weight; implying that the remaining required fraction of binder was fulfilled by the addition of petroleum bitumen. By using a ranking system (supported by statistics), an optimal design of mixture was obtained which was used in the field (exposed to normal traffic) at 30 different sections. Overall, results showed a good correlation between laboratory and field performance as compared to the petroleum-based mixture which was used as a reference mixture

Identifying the effect of adding coconut coir on the characteristics of the top layer of pure natural buton asphalt concrete wearing course (AC-WC)

Buton Asphalt is natural asphalt originating from Buton Island (Indonesia), with the potential deposit amount reaching up to 662 million tons. This substantial domestic mining potential must be utilized for domestic road needs and to boost the country's economy. However, Buton asphalt's utilization is minimal compared with imported oil asphalt, which reached a usage rate of up to 94 % in 2022. Therefore, as a form of a solution-oriented policy, Buton asphalt is included as one of the 21 commodities in the Strategic Roadmap for Downstream Investment in Indonesia, followed by various supportive regulations for developing this Buton asphalt product. One of the leading products the government targets is natural pure Buton asphalt. This product consists of >99 % bitumen content after extraction, also called Pure Buton Asphalt. The idea was to modify pure Buton asphalt with coconut coir to increase the Marshall Stability and Dynamic Stability values to make the asphalt mixture more resistant to vehicle loads and rutting. The tests were conducted to determine the optimum asphalt content (OAC) of the mixtures, Marshall's Stability comparison, and the dynamic stability test using a Wheel Tracking Machine to identify the comparison of permanent deformation. This study analyzed the Marshall characteristics and dynamic stability characteristics with variations in coconut coir content of 0.5 %, 0.75 %, and 1 % by weight of asphalt and variations in coconut coir length of 0.5 cm, 1 cm, and 1.5 cm. Based on the results of this study, the optimum asphalt content in this study is 6.76 %, where pure Buton Asphalt modified with coconut coir has an increase in Marshall's stability value and dynamic stability value compared to pure Buton asphalt without additional coconut coir

Mechanical performance of an asphalt stabilized base with natural asphalt, hydrated lime and Portland cement

This study aimed to evaluate the mechanical performance of an asphalt stabilized base with natural asphalt mix (ASB-NA) with added contents of 1.0 %, 2.0 %, and 3.0 % of Hydrated Lime (HL) and Portland Cement (PC). Tests were employed under dry and wet conditions to analyze the response to monotonic loading in compression and indirect traction and evaluate the susceptibility to water. Additional tests were conducted to analyze the resistance to cyclic dynamic loading, employing resilient modulus, permanent deformation, and fatigue resistance testing. The results reported that adding HL and PC in ASB-NA significantly increased the mechanical performance under monotonic and dynamic loading. These increases were evidenced by higher compressive strength, indirect tensile strength, resilient modulus, fatigue resistance and permanent deformation. Regarding water susceptibility (durability), higher resistance values to moisture damage were presented for the samples with 2 % HL and PC contents. This paper presents new materials for pavement asphalt base courses, which would reduce asphalt consumption, save energy, cut costs, and protect the environment.

Modified Asphalt Using Buton Natural Rock Asphalt

he characteristics of asphalt mostly determine how well asphalt pavements work. High temperatures can cause stress on the asphalt surface layer. At high temperatures, irreversible alteration or bubbling occurs and leads to spalling as it travels. This is due to the slow movement of the asphalt components in the pavement mixture, which resists the strain caused by traffic. This is because the pavement mix's viscous asphalt matrix flow resists stresses brought on by vehicles. As a result, the rheological characteristics of asphalt, which may be altered, have a significant impact on pavement performance. In this study, Pen. 60/70 asphalt was modified by using Buton Natural Rock Asphalt (BNRA). A total of 10 to 25% of fine BNRA passing sieve #200 was added to the asphalt. Four mixtures of asphalt and BNRA were then tested for penetration and softening point. From the Penetration and Softening Point test results, thePenetration Index (PI) was determined. The PI results obtained were 0; 0.2; 0.1; 0.1; and 0.4 for BNRA content of 0, 10, 15, 20, and 25%. The higher the PI value of asphalt, the lower its temperature susceptibility. It can be seen that with the addition of BNRA, the asphalt is more resistant to temperature changes. While it is evident that BNRA affects the resistance of asphalt to temperature changes, it is also evident that its strength.

Physical, rheological and micro characteristics of ARA/Nano-TiO2 composite modified asphalt before and after short-term aging

This paper aims to investigate the composite application of nanomaterials and natural asphalt in order to enhance the road performance of asphalt pavement. The objective is to develop high-performance modified asphalt that improves the durability, reliability, and load resistance of asphalt roads while reducing resource waste and environmental pollution. The composite modified asphalt was prepared by adding different blends of Albanian natural rock asphalt (ARA) and 1% of nano titanium dioxide (Nano-TiO2), and the basic properties and rheological properties of the asphalt before and after aging were tested by using basic performance tests and temperature scanning tests. Subsequently, the microscopic morphological characteristics of the asphalt were observed by scanning electron microscope and atomic force microscope, and the number of bee structures, the area share of bee structures, root mean square roughness Rq, and arithmetic mean roughness Ra were used as microscopic quantitative indexes. The results indicate that the complex modulus and rutting coefficient of ARA/Nano-TiO2 composite-modified asphalt increase with an increase in ARA dosage when the dosage of Nano-TiO2 is 1%. The asphalt modified with Nano-TiO2 composite blended with 15% ARA exhibits higher residual needle penetration, composite modulus ratio, rutting coefficient ratio and lower softening point increment compared to 70# asphalt. The bitumen modified with titanium dioxide nanocomposite blended with 15% ARA exhibits higher Rq and Ra and a more stable phase structure before and after aging. 15% of ARA/Nano-TiO2 composite-modified asphalt has higher Rq and Ra before and after aging, and its phase structure is more stable. The results show that ARA/Nano-TiO2 composite-modified asphalt has better high-temperature deformation resistance and aging resistance than 70# and that 15% ARA is recommended as the optimum amount of composite-modified asphalt.

Effect of vulcanisation on the properties of natural rubber-modified asphalt

Natural rubber (NR), a bio-based polymer, has significant potential for economic and environmental sustainability when used as an asphalt modifier in flexible pavements. In this study, natural rubber-modified asphalt (NRMA) was produced and the effects of vulcanisation on NRMA were investigated. The results showed that vulcanisation can improve the stiffness and elasticity of NRMA, thereby strengthening its resistance to deformation at high loads and temperatures. Specifically, vulcanisation increased the rutting factor of NRMA by 1.5, increased the elastic recovery by 60%, and decreased the temperature-sensitivity factor by 6.75%. In addition, the softening-point difference (SPD) of vulcanised natural rubber-modified asphalt (VNRMA) was significantly reduced by 36.8%, and the thermal-storage stability was improved. The micromorphology and changes in chemical bonds that occurred in VNRMA revealed that vulcanisation not only deepened the level of crosslinking between NR and asphalt, but also refined the NR particles, making NR more uniformly dispersed within the asphalt phase. By creating new chemical bonds, vulcanisation reinforced the NR network structure and change the main modification method for asphalt using NR from physical to chemical modification. This improved the rheological and mechanical properties of NRMA. The results of this study provide new solutions for NRMA applications and help improve its performance and application scope.

Synthesis and application of natural asphalt sulfonic acid (NA-SO3H) as a novel and reusable carbonaceous super adsorbent for rapid decolorization of aqueous dye solutions

This research involves functionalizing solid natural asphalt through sulfonation in the presence of H2SO4. The resulting product, known as mildly sulfonated natural asphalt sulfonic acid (ms-NA-SO3H), was investigated and confirmed by SEM, DRS, EDX, BET, CHNOS, and FT-IR analyses. The FT-IR spectrum of ms-NA-SO3H displays distinctive absorption peaks related to the presence of asymmetric and symmetric stretching modes of SO2, which are associated with SO vibrations. These findings confirm the successful sulfonation of natural asphalt. The SEM images illustrated that the surface of natural asphalt appears relatively smooth, with minimal porosity except for occasional cracks. Conversely, the external surface of the ms-NA-SO3H adsorbent exhibits irregular pores, compared to natural asphalt. In the next step, the porous heterogeneous bituminous has been used for the decolorization of methylene blue, and methyl orange solutions. Variation of removal percent versus dye concentration showed functionalization surface groups of natural asphalt with SO3H groups have provided high activated sites for color removal from the aqueous environment. Various parameters such as solution pH, contact time, adsorbent dosage, and initial dye concentration, were examined. The results of surface adsorption analysis at different concentrations revealed that the adsorption behavior on the adsorbent could be accurately described by the Langmuir isotherm and the pseudo-second-order kinetic model. The rapid removal and high adsorption capacity of the modified asphalt indicate its efficiency in the surface adsorption processes. The reusability of the ms-NA-SO3H adsorbent was studied via a physical adsorption mechanism, using ethanol or dimethyl formamide. Obtained results showed the prepared modified asphalt is a simple, efficient, cost-effective, and environmentally friendly candidate for different pollution removal.

A new application of natural asphalt (mineral bitumen) in chemistry as a novel class of carbonaceous compound: Synthesis and characterization of NA-SO3H@Oxalic Acid@ CuI as a heterogeneous and reusable catalyst for the synthesis of symmetric diaryl guanidine

Natural asphalt, containing more than 70 % carbon in molecular structure, is one of the newest and most promising sources for producing large quantities of different carbonaceous compounds. In this article, we report a systematic study of the synthesis of a new network from solid natural asphalt via coating natural asphalt sulfonic acid with oxalic acid. Then, CuI was doped on the NA@oxalic acid network and in fallow that ability as an effective, new, thermal and air-stable, heterogeneous, and reusable catalyst for CN bond formations via cross-coupling reactions of guanidine nitrate with aryl halides was investigated. The shape and size of the heterogeneous NA-SO3H@Oxalic Acid-Cu were characterized by SEM, FT-IR, BET,EDX and TGA techniques. In addition, the ability of NA-SO3H@oxalic acid@CuI to catalyze cross-coupling reactions was compared to MOF-199. NA-SO3H@oxalic acid@Cu, as well as MOF-199, catalyzed coupling reaction of guanidine and aryl halides in short reaction times, high yields, and mild conditions.

Assessment of Traditional Asphalt Mixture Performance Using Natural Asphalt from Sulfur Springs

This research utilized natural asphalt (NA) deposits from sulfur springs in western Iraq. Laboratory tests were conducted to evaluate the performance of an asphalt mixture incorporating NA and verify its suitability for local pavement applications. To achieve this, a combination of two types of NA, namely soft SNA and hard HNA, was blended to create a binder known as Type HSNA. The resulting HSNA exhibited a penetration grade that adhered to Iraqi specifications. Various percentages of NA (20%, 40%, 60%, and 80%) were added to petroleum asphalt. The findings revealed enhanced physical properties of HSNA, which also satisfied the requirements outlined in the Iraqi specifications for asphalt cement. Consequently, HSNA can serve as an asphalt binder to produce asphalt mixtures for flexible paving construction. Notably, HSNA mixtures exhibited greater Marshall stability and stiffness index when compared to traditional mixtures. The results from indirect tensile strength (ITS) and tensile strength ratio (TSR) tests indicated that the 80NA mixture displayed the highest ITS values and a TSR of 81.36%, surpassing the TSR of the mixture incorporating petroleum asphalt by 0.57%.

Synthesis of new-type, cost-effective and insensitive energetic materials via nitration of solid bituminous hydrocarbons.

A global trend for the development of energetic materials using various sources is promoted by researchers annually. Solid bituminous hydrocarbons can play a key role in carbon science as abundant, low-cost, and mineral carbonaceous substrates. This study focuses on the design and synthesis of a series of new energetic materials from natural asphalt (NA), petroleum pitch (PP) and petroleum bitumen (PB) as industrial and available solid bituminous hydrocarbons. Energetic materials NA-NO2, PP-NO2 and PB-NO2 were synthesized through the nitrification reaction. The heat of combustion, thermal behaviors and FTIR, elemental, BET, UV-vis, SEM, EDX-map, AFM, GC-MS and TG-DSC analyses were applied to identify and confirm that all were prepared successfully. Further, the physicochemical and energy properties of NA-NO2, PP-NO2 and PB-NO2 were calculated using EMDB V 1.0 software. Thermal analysis showed thermal stability and insensitivity of NA-NO2, PP-NO2 and PB-NO2 toward mechanical stimuli. The combustion heats of NA-NO2, PP-NO2 and PB-NO2 were measured using a calorimeter bomb via the ASTM D240 method and evolved high amounts of energy of 23 500, 23 450 and 23 360 kJ kg-1, respectively. The density of NA-NO2 was measured using the ASTM-D8176 test and confirmed to be 0.5 g cm-3, which can be considered the lightest energetic material. Based on the conducted studies and analyses, new energetic materials synthesized based on solid bituminous hydrocarbons are classified as first-generation energetic materials.

Performance of asphaltic concreate binder course (AC-BC) using gilsonite modified asphalt

The road pavement structure is the most important part of the design and manufacture of highways, so there is a need for innovation in designing pavement to get a type of pavement that has good quality and is efficient in its design. At this time, many road pavements have suffered damage caused by poor quality. Gilsonite is a natural asphalt that has a relatively high asphalt content compared to other additives, which is 70.9%. In addition, Gilsonite has a maltene content of 27% and 2% oil, then has a nitrogen content of 3.2%. After that, to carry out this test, a test object was made with the addition of Gilsonite Resin using 3 variations of the addition, namely 6%, 7%, and 8%, and compared to the mixture without Gilsonite. The mixture using the addition of Gilsonite (6%, 7%, 8%) an increase in the stability value of the mixture using the addition of Gilsonite, but the flow becomes increased so the properties of the mixture have large deformations. From all the tests that have been carried out, the optimum Gilsonite content is 8%

Comparison of the moisture resistance of a steel-slag stone mastic asphalt mixture modified with Ca(OH)2

Stone mastic asphalt is a type of hot mix asphalt that requires much coarse aggregate, so substitution waste aggregate, such as steel slag, will be an economic reason. The problem is that there are still many things that have not been consistent in various studies related to the moisture resistance of steel slag. The study aimed to compare the effect of Ca(OH)2 on the moisture resistance of the steel-slag stone mastic asphalt mixture and to determine the optimal Ca(OH)2 dosage for improving the mixture resistance. This study employs basalt aggregate, steel slag from Krakatau Steel Company, 60/70 penetration asphalt, a stabilizing substance made of bamboo fiber, and Ca(OH)2. The Texas boiling and the static immersed methods are used to test the adhesion on a loose mixture. The retained Marshall stability and indirect tensile strength are used to test the adhesion on the compacted mix. Testing result of Krakatau steel slag shows that steel slag has a much higher Fe2O3 content than steel slag in general and has low water absorption; a poor affinity for asphalt results from this. The result of the Texas boiling method showed a decrease in the percentage adhesion value between steel slag and asphalt compared to natural basalt aggregates and asphalt. Marshall Stability Ratio and Tensile Strength Ratio increased after mixing the asphalt with Ca(OH)2. Marshall test results show decreased stability in mixtures with steel slag substitution. Adding Ca(OH)2 increased stability and resistance to moisture significantly. This indicated that Ca(OH)2 enhances moisture resistance on stone mastic asphalt with modified steel slag. Stability, Marshall stability ratio, indirect tensile strength ratio, particle loss, and Texas boiling test significantly improved with adding Ca(OH)2

History of St. Petersburg’s Pavements

Within the article, the author examines the history of everyday life of St. Petersburg through analyzing documents that have recorded the history of the city’s pavement replacement with various materials over a period of more than three hundred years. The study was mainly carried out on the basis of archival materials from the funds of the Central State Historical Archive of St. Petersburg and the Russian State Historical Archive. It is evident that this work is the first comprehensive study of the history of the pavements of the Russian Empire capital as a theme, a topic which has not yet been adequately reflected in either domestic or foreign historiography. It has been established that it took the city authorities a considerable time to pave the capital's roads during the imperial period. The paving of the city roads developed from the use of raw stone to natural asphalt. In the end, it took almost a century to bring the streets of the main part of the city to the proper condition; they have been previously been covered with mainly stone. Whereas in the XVIII century the main task of the central and city authorities was to pave as many streets as possible, then in the XIX - early XX centuries the city government instead concentrated on a way find an inexpensive but durable material for this purpose.

Natural asphalt on Late Neolithic (5000–4500 BCE) potsherds from southeastern Albania: A geochemical study

Nine archaeological bituminous potsherds from the Neolithic of Maliq and Kamnik (5000–4500 BCE) in Albania were geochemically compared for the first time to four natural asphalts from the famous present-day mine of Selenicë. The bitumen on potsherds originates from Selenicë, a unique source in Albania and the southern Balkans. Carbon isotopes on the asphaltene chromatographic fraction confirm that the bitumen on the potsherds came from Selenicë. Carbon and hydrogen isotopes on saturates, aromatics, NSO, and asphaltenes show changes that may be due to biodegradation-oxidation effects and also the occurrence of organic remains from the content of the vessels mixed with bitumens. Steranes, terpanes, and aromatics confirm the increased biodegradation of bitumen on potsherds when compared to natural asphalts references.

Effect of Natural Bitumen on the Performance of Hot Asphalt Mixture‏

Globally, for more than a century, large quantities of asphalt binder have been consumed in the production of asphalt mixtures. There are two types of natural asphalt (NA) deposits in the Heet region: rock asphalt and sulphur spring asphalt. NA from sulphur springs was used in this study to assess NA performance and determine the suitability of using NA in local asphalt mixtures. The NA was treated by heating it to 163 °C for several hours. NA was subjected to laboratory testing after industrial treatments, and it was found that the physical properties of NA can conform to Iraqi specifications by heating it for 20 hours. The results showed that treated NA is better suited to hot climates because it is less temperature sensitive than traditional petroleum asphalt. NA was discovered to be highly effective in improving mechanical properties. In addition, the NA mixture had the highest indirect tensile strength values and a tensile strength ratio of 81.2%, which was 0.37% higher than the TSR of the conventional mix. NA will play an important role in the production of flexible pavements and provide a significant economic benefit without compromising the overall performance of the mixture because it is less expensive than conventional asphalt and is available in large quantities in Iraq.

The effect of carbon dioxide absorption using buton asphalt residue through carbonation on calcium carbonate precipitated efficiency

The study investigated the efficiency of generating precipitated calcium carbonate (PCC) by chemical dissolution and carbonation from extracted natural asphalt solid waste residue. This residue was then further transformed into calcium carbonate through a series of steps involving calcination at a temperature of 900 °C for 5 hours and ammonium salt dissolution. Subsequently, the calcined residue is dissolved in ammonium salt solutions (2M - NH4Cl, and NH4NO3) under a temperature condition of 60°C. Next, CO2 was injected into the solution contained a high concentration of calcium sources under a predetermined pressure. Additionally, the solution’s initial pH changed to 12 to be the ideal degree of alkalinity. A flow rate of 1 L/min of acetic acid as the extracting agent would result in the highest level of carbonation efficiency. This process yielded vaterite calcium carbonate with a purity of 99.4%, as verified through X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) tests. The vaterite of polymorphic calcium carbonate has a spherical morphology, according to studies utilizing scanning electron microscopy (SEM), confirming the morphological structure of calcium carbonate. The study could add knowledge on preparing the wastes into the high value of vaterite with low processing procedures.

Hard carbon-based electrode boosts the performance of a solid-state symmetric supercapacitor

Hard carbon materials have gained extensive utilization in energy storage systems because of their stable chemical properties, unique lamellar arrangement, and significant interlayer spacing. In this study, we present a novel porous carbon electrode based on hard carbon to enhance the performance of a solid-state symmetric supercapacitor. This electrode was fabricated through an efficient and straightforward synthetic approach using natural asphalt as the precursor. The resulting carbon electrode exhibits remarkable features including a large surface area (2334.48 m2 g−1), a well-distributed pore size (mesopore ratio of 16.04 %), an appropriate oxygen content (18.11 %), and a lamellar structure. As a result, the as-prepared carbon electrode demonstrates a high specific capacitance of 325.82 F g−1 at 0.5 A g−1, along with excellent rate capability, with coulombic efficiency ranging from 99.89 % at 0.5 A g−1 to 98.92 % at 10 A g−1. Moreover, the assembled symmetrical all-solid-state supercapacitor utilizing this electrode achieves an energy density of 18.91 Wh Kg−1, an equivalent series resistance of 0.820 Ω, a relaxation time of 9.0 s, and self-discharge performance lasting up to 72 h. Notably, owing to its large layer spacing (0.391 nm), the electric double layer capacitor contributes as much as 94 %, indicating favorable electrical double layer characteristics. Our work not only showcases a high-performance electrode material but also contributes to the expanded application of hard carbon.

Influence of Multiple Modifications on the Fatigue Behavior of Bitumen and Asphalt Mixtures

Abstract The study included six bitumens, one unmodified and five modified, and their corresponding asphalt mixtures. The first bitumen was the base bitumen and further five variants were made by the authors using the same base bitumen and different combinations of modifiers which included styrene-butadiene-styrene (SBS), Fischer–Tropsch wax (FTW), ethylene vinyl acetate (EVA), reactive elastomeric terpolymer (RET), and natural asphalt (NA). The influence on the fatigue life of bitumen and asphalt due to modification, bitumen rheology, preload, water storage, and aging was studied. A new temperature range was developed—the fatigue-relevant temperature range (FRTR) for specifying fatigue test temperatures for bitumen and asphalt. A new methodology that includes preload and water storage was also done to study the active adhesion behavior between bitumen and aggregates and its influence on fatigue life. Overall, modifications showed positive influence on the fatigue behavior of bitumen and asphalt. Variants E (SBS and RET) and F (SBS and NA) showed the greatest positive influence with an increase in the fatigue life by 500% and 210% for bitumen and 200% and 375% for asphalt respectively. With water storage, the fatigue life reduced by 500% for unmodified asphalt and in the range of 333–1350% for modified ones. Due to aging, the fatigue life reduced from 700% for unmodified and between 700% and 2500% for modified asphalt mixtures.