Base Binder Research Articles

Combined effect of gilsonite, sasobit, and soft binder on performance characterization of high RAP binder

The purpose of this research is focused on the performance evaluation of Gilsonite-modified binders (GMBs) and high-aged binder (HAB) content (more than 40 %) with and without the use of WMA additive. Accordingly, GMBs and GMB-WMA samples were prepared by combining PG52–28 softer binders and 4 %, 8 %, 12 %, and 16 % of Gilsonite with and without Sasobit. The results indicated that increasing the Gilsonite increases the viscosity, improves the rheological behavior, reduces the rutting, and increases the fatigue life Although higher Gilsonite content has performance advantages, it also has negative effects in terms of performance and low temperature/fatigue resistance. While the use of a composite-modified binder showed an effective way to overcome these limitations and optimize the overall performance characteristics of HAB. Adding 4, 8, 12, and 16 Gilsonite combined with Sasobit increased the rutting resistance by 46 %, 64 %, 80 %, and 87 % respectively, compared to the base binder. Combining Sasobit with 8 and 12 Gilsonite upgraded the performance of the base binder from PG58–22 to PG70–16 and PG76–10. The fatigue life of the AB/G+WMA containing 4, 8, 12, and 16 Gilsonite was 2.11, 2.25, 2.52, and 2.38 times greater than the base binder, respectively. Based on optimization results, Gilsonite/Sasobit combinations were recommended for different traffic conditions: G15.3+S1.8 for heavy traffic areas, G11.6+S1.9 for tropical regions, and G6+S2 for cold climates. The goal was to optimize the blends to leverage the benefits of Gilsonite while mitigating any drawbacks, depending on the specific climate and traffic conditions. The study demonstrates that the synergistic use of Gilsonite and Sasobit can significantly enhance the performance characteristics of asphalt binders, enabling tailored solutions for different applications and environmental conditions.

Mechanical and economical feasibility of LDPE Waste-modified asphalt mixtures: pathway to sustainable road construction

This research study evaluates the impact of low-density polyethylene (LDPE) modified asphalt binder on the mechanical performance and economical feasibility of asphalt concrete (AC) mixtures. LDPE-modified mixtures were compared with conventional mixes prepared with various binders commonly used in India, i.e., VG 30, VG 40, Polymer-Modified Binder (PMB), and Crumb Rubber Modified Binder (CRMB). LDPE-modified mixtures exhibit superior mechanical performance, increasing the stiffness of AC mixtures by 171% and 125% at 25 °C and 35 °C, respectively, compared to VG 30 base binder. Additionally, the indirect tensile strength (ITS) improved by 51% over VG 30. LDPE-modified mixtures also showed improved resistance to permanent deformation, with RTIndex values up to 133.46% higher than VG 30, and higher fatigue resistance, as indicated by increased CTIndex values compared to VG 30 and CRMB. However, the CTIndex values for LDPE-modified mixtures were 26.32% and 56% lower than those for VG 40 and PMB, respectively. Pavement analysis using 3D-Move showed lesser deflections at pavement layer interfaces, resulting in higher rutting and fatigue life for LDPE-modified pavements. Furthermore, LDPE-modified pavements showed up to 57% higher fatigue life (Nf) and up to 42.33% higher rutting life (Nr) than other pavements. The economic analysis showed that the cost of LDPE-modified pavements is comparable to VG 40 and around 10% more economical than pavements containing PMB. Using LDPE also offers environmental benefits by repurposing up to 750 kg for every kilometer of single-lane pavement section having 50mm thick surface course. Overall, LDPE-modified asphalt mixtures present a sustainable and high-performance solution for asphalt pavement construction.

Aging behaviour and mechanical characterisation of maltenes and asphaltenes

The analysis of bitumen is challenging due to its complex and ever-changing chemical composition. Fractionation techniques based on solubility and polarity properties facilitate the examination process, shedding more light on composition, structure and aging behaviour. However, these separation experiments are often performed post-aging, making it difficult to understand the behaviour and mechanical properties of individual subfractions. Hence, the focus of this study was to separate maltenes and asphaltenes in large quantities and age them at various temperatures (80, 130 and 180°C), followed by analysis with chemical and mechanical methods. Results showed that both maltenes and asphaltenes display viscoelastic properties: maltenes are more viscous, while asphaltenes are more elastic compared to the base binder. Maltenes aged at 180°C became extremely stiff with a nearly temperature-independent phase angle, while asphaltenes aged at 130°C exhibited the stiffest and most elastic behaviour. Decomposition of sulfoxides at high temperatures was observed for both fractions, while additional decarboxylation occurred in the asphaltenes. During the aging of the maltenes, a significant amount of asphaltenes were formed, which most likely originated from both the aromatics and resins fraction. Furthermore, no major discrepancies between oxidation products in bitumen and in the maltenes were detected, indicating that asphaltenes might not crucially influence the qualitative aging process. This study demonstrated a possible approach for obtaining bituminous subfractions in large quantities, allowing for a detailed analysis of their mechanical and aging properties.

Effects of antioxidants on chemical and rheological properties of asphalt binders from different crude oil sources

Antioxidants can effectively mitigate or delay the oxidative aging degradation of asphalt binder, thereby improving pavement durability. While research has largely concentrated on the application of antioxidants to asphalt binders from a single source, limited studies have explored their effects on binders derived from different crude oil sources. Moreover, the relationship between the chemical and rheological properties of antioxidant-modified asphalt binders remains insufficiently understood. In this study, three antioxidants - zinc diethyldithiocarbamate (ZDC), Irganox 1010 and kraft lignin - were utilized and blended with base binders sourced from three distinct regions globally. Fourier transform infrared spectroscopy (FTIR) was utilized to analyze the impact of these antioxidants on the chemical composition of aged binders. Additionally, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were conducted to assess the high- and low-temperature performance of the antioxidant-modified binders, identifying the most effective antioxidant. The linear amplitude sweep (LAS) test further evaluated the performance of ZDC across binders from different crude oil sources. The results revealed three key findings: first, chemical functional group changes due to antioxidants are not always reflected in rheological performance; second, ZDC demonstrated superior performance across different base binders, as evidenced by improved aging indices, high-temperature rutting resistance, and enhanced fatigue and low-temperature cracking resistance; and third, asphalt binders from different crude oil sources exhibit varying sensitivities to antioxidant type and dosage. This study underscores the necessity of determining optimal antioxidant dosages for different asphalt binders, as the relationship between antioxidant dosage and effectiveness is not straightforward.

Low-Temperature Mixed Mode (I/II) Fracture Characterization of Polymerized Sulfur Modified AC Mixtures

In this study, asphalt concrete (AC) mixtures were modified with polymerized sulfur, using PG58-22 bitumen, and crushed siliceous aggregate. Modifications involved replacing the base binder with 20%, 30%, and 50% polymerized sulfur, compared to a control mix with no replacement. The mixtures were subjected to Single Edge Notched-Beam (SE(B)) fracture tests under mixed mode (I/II) conditions with notch offset value of 48 mm, with temperatures ranging from 0 °C to -20 °C. These tests, focusing on the mixtures' response to mixed mode loading, provided load-displacement curves, enabling the determination of fracture energy. Results indicated an increase in fracture energy for 20% and 30% sulfur-modified mixtures. However, a trend towards increased embrittlement was also observed, as fractures occurred at lower displacements. Significantly, higher sulfur content correlated with similar or decreased mixed-mode (I/II) fracture energy, suggesting an improved resistance to low-temperature cracking for lower replacement percentages.

Modification of the Crumb Rubber Asphalt by Eucommia Ulmoides Gum under a High-Temperature Mixing Process

The crumb rubber (CR) asphalt has some defects of high viscosity and poor storage stability, which brings great challenge to the high-quality construction of the CR asphalt pavement. To improve the interaction between the CR and base binder, the Eucommia ulmoides gum (EUG) with double-bond structure similar to trans-polyoctenamer rubber (TOR) was used to modify the CR asphalt. However, the original EUG double bond is basically inactive at room temperature and cannot form the effect of TOR. Open double bonds of EUG with asphalt and rubber powder form a network structure similar to TOR-modified rubber asphalt by high-temperature mixing with EUG in a torque rheometer. The effects of modified CR on rubber asphalt were analyzed by macro- and micro-experiments such as rotational viscosity tests, segregation tests, FTIR tests, and PG tests. It was found that the high-temperature mixing process works in both physical and chemical ways to mix the CR and EUG into an inseparable substance. The modified CR has higher chemical activity after desulfurization and degradation, which allows it to form a more effective chemical connection with asphalt. EUG can build a stable spatial crosslinking structure in CR asphalt due to the sulfurization reaction, which significantly improves the construction workability and system stability of the CR asphalt.

Assessment of aging behaviour of reclaimed asphalt binders: multi-scale mechanical and microstructural characterisation

This study provides a comprehensive multi-scale characterization of the aging resistance of reclaimed asphalt pavement (RAP) binder blends. The analysed samples included different dosages of a RAP binder and a recycling agent (REC). At low strain levels (2.5% and 5%), the use of up to 40% RAP did not adversely affect the Nf value; however, the effect of RAP was clear at 10% strain in the macro scale. At the microscopic scale, the AFM analysis showed that among all samples, the 100% RAP binder was affected the least by laboratory aging. However, the aging susceptibility increased as the RAP content increased from 0 to 40%. A plausible explanation is that the effects of laboratory aging (temperature and/or pressure) became more concentrated on the base binder when its quantity decreased in the blends. The use of REC reduced the stiffness of the unaged blends, but its effect diminished upon further aging of the blends.

Comprehensive rheological and mechanistic evaluation of an asphalt binder and mixture modified with warm mix additives.

Though warm mix asphalt (WMA) technology has been introduced for a long time, there is still reluctance in the industry to utilize it in practice. In regions like India, where WMA incorporation into road construction has been limited over the past two decades, building confidence in local binders is imperative for widespread adoption. Thus, the present study appraises the effect of three commonly used WMA additives in India, namely Sasobit®, Evotherm®, and Zycotherm®, with base binder VG-30 on the rheological and mixture performance parameters. Three dosages of each WMA additive were blended with the control binder to give ten binder combinations. Different binder evaluations such as Superpave grading and parameters, frequency sweep testing, multiple stress creep recovery test, and linear amplitude sweep test were conducted for comparative dynamic mechanical analysis. Based on the binder testing results, suitable dosages of WMA additives were established, and mixture testing was carried out using these specific additive dosages. Binder evaluations showed improvement in high-temperature characteristics with Sasobit® and better fatigue performance with Evotherm®, while Zycotherm® did not alter binder properties significantly. The asphalt mixture testing results indicated satisfactory performance with the three additives based on Marshall stability and flow testing. The WMA additives also showed enhancement in moisture susceptibility based on the modified Lottman test with Zycotherm® demonstrating the best performance. Overall, the study underscores promising effects of the three WMA additives across different parameters, signaling their potential for widespread application in real-world scenarios.

Assessment of Ground Tyre Rubber Impact on Stiffness Modulus and Cracking Resistance of Bituminous Mixtures

Abstract The objective of this study was to evaluate and characterize the performance of ground tire rubber (GTR) modified dense graded asphalt mixtures to recommend a suitable GTR content to produce a mix that provides superior pavement performance characteristics. The research effort encompassed investigation of stiffness and cracking resistance of six dense graded asphalt mixtures, including one conventional and five modified mixes covering 42 samples. Addition of GTR using wet process showed decrease in stiffness during loading. Cracking resistance of GTR modified mixtures increased with higher levels of dosages regardless of the base binder. An increase in the GTR dosage from 0 to 10% did not result in a significant change in fracture energy but a further increment to 25% increased the fracture energy. The laboratory Results indicated that 10% GTR was showed as the optimal content for the stiffness modulus and 25 % GTR as better content that provides better cracking resistance.

Effects of Waste Lubricant Oil on Rheological Properties of Asphalt Binders: Implications for Sustainable Asphalt Mixture Production

Reusing waste lubricant oil as an environmentally-friendly alternative for disposal and transforming it into a value-added product is a promising solution. This study aimed to evaluate the rheological properties of asphalt binder (PG 64-XX) modified with waste hydraulic oil. Two levels of oil content, 3% and 5% by weight of the base binder, were added. Physical and rheological tests, including penetration, softening point, rotational viscosity, and performance grade (PG) tests, were conducted before and after subjecting the samples to the Rolling Thin Film Oven (RTFO), multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and master curve procedures. Results showed that the addition of oil decreased the stiffness of the base binder, makingit more susceptible to premature cracking and instability. However, the mixture and compaction temperatures decreased with the oil addition. Overall, considering the investigated oil contents, the asphalt binders modified with waste hydraulic oil did not exhibit satisfactory performance. It is hypothesized that incorporating residual hydraulic oil in recovered asphalt binders may yield more favorable results.

Evaluation of the laboratory aging of field-blended crumb rubber modified binder

Field-blending approach is widely employed by the industry to introduce crumb rubber into asphalt binder. Rubber-modified binder provides satisfactory performance and benefits the environment by consuming recycled rubber manufactured from scrap tires. This work investigated the aging mechanism and post-aging performance of rubber-modified binders using laboratory aging protocols. Four rubber-modified binders containing two rubber contents (5 and 10 percent) and two particle sizes (passing 1.18 mm and 2.36 mm, respectively) were evaluated in this study. After multiple laboratory aging protocols, chemical components in aged binders were measured with Fourier transform infrared spectroscopy. Chemical analysis revealed that rubber-modified binders accumulated fewer oxidative aging products (carbonyl and sulfoxide components) than their unmodified base binder after long-term aging. Increasing rubber content and particle size increased the complex shear modulus while decreasing the phase angle of the binder. Binder viscosities were back-calculated from complex moduli and phase angles. A linear correlation between logarithmic viscosity and carbonyl area index exists for the long-term aged rubber-modified binders. This linearity can be used to predict the age-hardening of rubber-modified binders. These binders were also tested in dynamic shear rheometer to determine performance grades. Multiple stress creep recovery tests evaluated the rutting resistance of short-term aged binders. Bending beam rheometer was used to evaluate the low-temperature cracking resistance of long-term aged binders. These test results showed that rubber-modified binders provided better rutting and cracking resistance than their base binder. Statistical analysis indicated that carbonyl components correlated to the binder performance at various aging statuses.

Evaluation of the rheological properties and molecular distributions of asphalt binder under multiple aging and rejuvenating cycles (MARC)

Because of the widespread use of reclaimed asphalt pavement (RAP), various recycling agents (RAs) are developed and used in pavement engineering nowadays to restore the properties of RAP in asphalt mixes. Whereas there are many RA products available, it remains unclear on the fundamental rejuvenation mechanisms behind different RAs and the selection method of proper RA product to restore these recycled materials properties. In addition, there are important questions on hold in terms of RAP repeated recycling and the continuity of restoration capacity from these RAs. Therefore, this study is designed to track the properties changes of the asphalt binders in the context of multiple aging and rejuvenating cycles (MARC). Three different types of RA products are selected and evaluated using rheological characterization and chromatography (molecular distribution) analysis. Results show that the beneficial effects from RAs degrade over time with increase of aging/rejuvenating cycles. Two oils with their molecules that are mainly distributed in the medium molecular size (MMS) range, which compensate the loss of the MMS molecules of the base binder due to aging, show the good effectiveness in restoring not only the complex modulus but also the phase angle of the aged asphalt. And the good correlations between phase angle and MMS as well as LMS proportion indicate the fundamental relationship between binder’s molecular distribution and its rheological properties.

Chemical and Rheological Properties of Bitumen Partially Substituted with Rice-Straw-Based Lignin from Bio-Ethanol Industry Residue

The objective of this study is to evaluate the changes in the chemical and rheological properties of bitumen when partially substituted, up to 15%, with rice-straw-based lignin materials, namely isolated lignin (IL) and fermentation residue lignin (FRL), obtained from second-generation bio-ethanol industry residues. Attenuated total reflectance-Fourier transform infrared spectroscopy was used to evaluate the alterations in chemical properties. The rheological properties that were assessed include Superpave upper performance grade (PG), rutting resistance using the multiple stress creep recovery test, and fatigue resistance using the linear amplitude sweep test. The results indicated that the addition of IL and FRL materials to the base bitumen is a physical process. Furthermore, IL and FRL substituted bitumen blends exhibited distinct trends for carbonyl (C=O) and sulfoxide (S=O) functional groups with ageing, depending on the chemical structure of the additive. Specifically, the IL materials showed a reduction in the rate of increase of ageing products and a decrease in the combined ageing index, up to 10% IL dosage, suggesting some antioxidant effect within the group. The addition of IL up to 15% dosage and FRL up to 10% dosage also led to an increase in the base binder high-temperature grade from PG70-XX to PG76-XX. Moreover, both IL and FRL materials enhanced rutting resistance and reduced fatigue resistance with an increase in dosage. It is worth noting that bitumen blends with different additives showed varying trends between chemical and rheological properties.

Cementitious Composites with Cellulose Nanomaterials and Basalt Fiber Pellets: Experimental and Statistical Modeling

The production of high-performance fiber-reinforced cementitious composites (HPFRCCs) as a durable construction material using different types of fibers and nanomaterials critically relies on the synergic effects of the two materials as well as the cementitious composite mixes. In this study, novel HPFRCCs were developed, which comprised high content (50%) slag by mass of the base binder as well as nano-silica (NS) or nano-crystalline cellulose (NCC). In addition, nano-fibrillated cellulose (NFC), and basalt fiber pellets (BFP), representing nano-/micro- and macro-fibers, respectively, were incorporated into the composites. The response surface method was used in this study’s statistical modeling part to evaluate the impact of key factors (NS, NCC, NFC, BFP) on the performance of 15 mixtures. The composites were assessed in terms of setting times, early- and late-age compressive strength, flexural performance, and resistance to freezing-thawing cycles, and the bulk trends were corroborated by fluid absorption, thermogravimetry, and microscopy tests. Incorporating NS/NCC in the slag-based binders catalyzed the reactivity of cement and slag with time, thus maintaining the setting times within an acceptable range (maximum 9 h), achieving high early- (above 33 MPa at 3 days) and later-age (above 70 MPa at 28 days) strength, and resistance to fluid absorption (less than 2.5%) and frost action (DF above 90%) of the composites. In addition, all nano-modified composites with multi-scale fibers showed notable improvement in terms of post-cracking flexural performance (Residual Strength Index above 40%), which qualify them for multiple infrastructure applications (i.e., shear key bridge joints) requiring a balance between high-strength properties, ductility, and durability.

Exploring the low-temperature performance of MPP-modified asphalt binders and mixtures using wet method

Thermal cracking significantly impacts the structural integrity of flexible pavements, particularly in colder regions like Canada. Limited studies investigated the impact of plastic modification of asphalt binders and mixtures using the wet method on the low-temperature performance of asphalt materials. The plastic material utilized in this project is multilayer plastic packaging (MPP). This study aims to determine whether MPP can be integrated to enhance the performance of the MPP-modified binder and MPP-modified mixtures, especially considering that MPP accounts for just over 40% of total plastic usage, making it the largest end-use market segment. This research evaluates the impact on rheological and mechanical behaviour when introducing MPP additives to conventional hot mix asphalt. This study used the wet method to test MPP-modified asphalt materials at 2%, 4%, and 8% (by weight of the asphalt binder). Test results demonstrate that the MPP modification percentage should ideally not exceed 2% as blends with 4% MPP or higher exhibited lower performance at low temperatures. The use of a softer binder as a base binder would help increase the MPP modification rates, but this hypothesis needs to be validated experimentally.

The Combined Effects of Additives on the Conventional and High-Temperature Performance Properties of Warm Mix Asphalt Binders.

The present study investigates the effects of the simultaneous use of two additives, an organosilane warm mix asphalt (WMA) agent and a grade-bumping polyolefin compound, on the conventional and high-temperature performance properties of a paving grade 50/70 bitumen and a polymer-modified 45/80-55 bitumen. The WMA agent and polyolefin additive were introduced to the binders at rates of up to 0.3% and 2%, respectively. The base asphalt binders and their blends with the additives were tested before and after aging in a rolling thin film oven test at a temperature of 143 °C. The effects of the investigated additives were found to be dependent on the type of base binder and its aging state. It was generally observed that the WMA additive decreased the performance of the asphalt binders and limited the effects of the other additive, which increased the high-temperature stiffness and non-recoverable compliance of the blends. This interaction amounted to as much as an approx. 20% decrease in high-temperature stiffness and non-recoverable compliance of the binders. The additives caused a small increase in the elasticity of the binders and improved their creep performance when measured in multiple stress creep recovery tests.

How infrared and fluorescence spectroscopy can shed new light on the characterization of bitumen and its ageing processes

A combination of chromatography and spectroscopy was applied to characterize the chemical peculiarities of bitumen and analyse thermally induced ageing processes. Therefore, a bitumen sample was short-term and long-term aged followed by a polarity-based fractionation. Subsequently, the fractions and the base binder were analysed by infrared (IR) and fluorescence spectroscopy. IR provided the possibility to track the fate of carboxylic acids and quinolones and the evolution of ketones and sulfoxides during oxidative ageing. Information on abundant aromatic structures and the effect of ageing on certain molecular classes was obtained with fluorescence spectroscopy. It was shown that shifts to higher emission wavelengths correlate to the polarity of the fractions and the ageing state. Solid-state measurements of the resins revealed characteristic signals of porphyrins and how they are affected during ageing. Here we evaluate the impact of different ageing conditions with the perspective to improve the understanding of complex chemical ageing in bitumen.

Investigation on bonding between aggregates and asphalt binder containing warm mix additives

Increased moisture susceptibility has been identified as one of the potential failures for warm-mix asphalt (WMA). In order to critically understand the moisture damage mechanism, the evaluation of bond strength between aggregate and asphalt binder holds significant importance. The bonding mechanism can be easily explained by Pneumatic Adhesion Test (PAT). This study evaluated the bond between various aggregates and warm mix (WM) modified asphalt binders using PAT. Five aggregates, two base binders, and four WM additives with varying dosages have been selected for the present experimental study. The objective is to identify the relative contribution of these factors towards the development of bond strength and their consequence against moisture damage. Bond strength was evaluated in terms of the pull-off tensile strength (POTS), whereas moisture susceptibility was determined using the bond strength ratio (BSR) parameter. Results showed that the bonding between aggregate and asphalt binder relies on the aggregate type, base binder, WM additives and their dosages. Since PAT was carried out on both wet and dry-conditioned samples, it was found that the conditioning state (wet and dry) also affects the interfacial bonding of the asphalt-aggregate matrix. Wet-conditioned samples tend to exhibit lower POTS values than dry-conditioned samples. The BSR values were found to be different for various aggregate-asphalt binder combinations. The minimum BSR was found to be 0.82 for a moisture-resistant asphalt mixture.

Suitability of warm mix asphalt (WMA) technologies based on performance and energy consumption

Studying the effects of material variability on the performance of warm mix asphalt (WMA) is important to understand the benefits of reduced production temperatures. This study compares the performance of five different WMA mixtures prepared with two varying base binders and two different aggregate sources. The rutting, fatigue, and moisture sensitivity of asphalt mixtures were evaluated using cyclic compression test, indirect tensile cracking test, and modified Lottman test, respectively. Additionally, a theoretical analysis was used to compare the energy consumption during the production process. The results indicated that the performance of WMA is a function of the type of the base binder, aggregate source, and the type of WMA technology. Nonetheless, all the WMA mixtures contributed to higher energy savings in comparison to hot mix asphalt (HMA). Based on the ranking framework used in this study, the use of Rediset is recommended to achieve adequate performance and lower energy consumption.

Full range of mode I and II cracking performance of asphalt mixtures containing low to high reclaimed asphalt pavement (RAP) contents; modified by recycling agent and substituting of a softer binder

Reclaimed asphalt pavement (RAP) is a recycled material that can decrease the consumption of virgin materials; however, it increases stiffness and brittleness, resulting in cracking. In this regard adding recycling agents and using soft binders can be a solution. In this study, base binder (PG 64–22) with recycling agent and softer binder (PG 58–22) are used to enhance the fracture behavior of asphalt mixtures containing low to high RAP contents (20%, 40%, and 60%). The fracture test was performed using a semi-circular bending (SCB) specimen under pure mode I, two mixed mode I and II, and pure mode II loading. Also, the effect of air voids content is reviewed. Results show that the addition of RAP in mixtures prepared with PG 64–22 binder and recycling agent increases the fracture toughness from 1.22 to 1.25, 1.27, and 130 MPa√m, and reduces the fracture energy from 3.46 to 3.44, 3.36, and 3.24 KJ/m2 (respectively for of 20%, 40% and 60% substitution). By comparing the effect of binder types, although the fracture toughness of mixtures prepared with PG 58–22 binder was lower than mixtures prepared with PG 64–22 binder and recycling agent (at most 11% lower), but the fracture energy of mixtures prepared with PG 58–22 binder was superior (6–19% higher). Based on the data, regression equations of linear trends were extracted, and the relationship between fracture toughness and fracture energy data was clustered and formalized.