Thermal Cracking Research Articles

Influence of high temperature treatment on tensile strength and fracture evolution of coarse-grained granite under Brazilian splitting

ABSTRACT High temperature induces thermal damage of granite and deteriorates its bearing capacity. To investigate the deteriorating characteristics and mechanism of granite subjected to high temperature, a series of Brazilian splitting tests were conducted on granite discs after thermal treatment with various temperatures and cycles. The results indicate that high temperature is the crucial factor that decreases the mass, longitudinal wave velocity (V P) and tensile strength of granite. Thermal damage based on V P can better reflect the generation of thermally induced cracks and the expansion of granite structure. Temperature and thermal cycling number significantly impact the number, type, magnitude, and distribution of the cracks throughout the splitting process. Specifically, tensile cracks dominate the fracture process, while shear cracks increase rapidly near the peak load, coalescing into large-scale fractures. The spatial distribution of acoustic emission (AE) events becomes more dispersed as temperature elevates, while the number of AE events decreases with increasing thermal cycles, due to the enlargement of the porous structure in rock. This enlargement further reduces both the occurrence areas and propagation paths of AE signals. Elevated high temperature alters the redistribution of the equivalent stress within the granite disc and leads to the shift of strain concentration zone from two ends to the centre of the disc, expanding into a strip-like shape and penetrating the disc. Temperature prominently influences the fracture characteristics of granite. Elevated temperature induces numerous thermal cracks within the rock, and alternating thermal stress caused by thermal cycling also stimulates the propagation and connectivity of micro-cracks and further results in the expansion of porous structure of granite, promoting transition of fracture properties from brittleness to ductility. These findings help in understanding how thermal cycling at high temperatures deteriorates the physical and tensile fracture behaviour of rocks, providing valuable insights for associated thermal engineering problems.

Structural Control on Fluid Circulation and Alteration Patterns in the Lavas-Dikes Transition Zone of the Superfast- and Intermediate-Spreading Oceanic Crust, Equatorial Pacific Ocean

The lavas-dikes transition in oceanic crust represents a critical boundary between two crustal portions with different lithology, structure, porosity, permeability, and other physical properties. We refined the structural features of the lavas-dikes transition in ODP/IODP Hole 1256D and DSDP/ODP Hole 504B drilled in in situ oceanic crust created at superfast- and intermediate-spreading rate in the Pacific Ocean. Both holes, although showing some differences in the thickness of lithological sections, have a comparable lavas-dikes transition zone characterized by a wide diffusion of veins, breccias, vein network and cataclasites, possibly with development of pseudotachylytes. Fracturing have started with fissuring of basalt already in the ridge axis domain due to thermal contraction of lavas. Fissures have triggered the circulation of seawater from above and hydrothermal fluids from below enhancing the crust alteration and the mechanical response of the basaltic crust near the lavas-dikes boundary. The high concentration of permeable structures including cataclasites in the lavas-dikes transition in the two holes are in favour for interpreting this crustal interval as a (large scale?) mechanically weak zone, possibly a fault zone at least for intermediate-spreading ridge of Hole 504B. The lack of clear kinematic indicators prevents a conclusive interpretation. Other processes that may concur to fracturing is fluid overpressure, and diking. These processes are not mutually exclusive: the intense fluid circulation concentrated in the transition zone is responsible of alteration inducing a dramatic weakening of the rock; conversely, rock fissuring due to thermal cracks, diking, and eventually faulting developed permeable structure that may channelize the circulation of fluids. Our finding of cataclasites at a shallower depth in Hole 1256D and at deeper depth in Hole 504B with respect to what described so far, suggests that the extension of the lavas-dike boundary should be revised by taking into consideration not only the change in lithology but also the structural features. As well, our finding of chlorite and amphibole at shallower depths with respect to those described so far suggests that the alteration boundary across the lavas-dikes transition is thicker than previously thought allowing the upflow of high-temperature hydrothermal fluids towards shallower levels.

Assessment of Asphalt Mixtures Enhanced with Styrene–Butadiene–Styrene and Polyvinyl Chloride Through Rheological, Physical, Microscopic, and Workability Analyses

This study investigates the performance improvement of asphalt binders through the incorporation of two polymers, polyvinyl chloride (PVC) and styrene–butadiene–styrene (SBS), with asphalt grade (60–70), to address the growing demand for durable and climate-resilient pavement materials, particularly in areas exposed to high temperatures like Iraq. The main objective is to improve the mechanical characteristics, thermal stability, and workability of typical asphalt mixtures to extend pavement lifespan and lessen maintenance costs. A thorough set of rheological, physical, morphological, and workability tests was performed on asphalt binders modified with varying content of PVC (3%, 5%, 7%, and 9%) and SBS (3%, 4%, and 5%). The significance of this research lies in optimizing binder formulations to enhance resistance to deformation and failure modes such as rutting and thermal cracking, which are common in extreme climates. The results indicate that PVC enhances performance grade (PG), softening point, and viscosity, although higher contents (7% and 9%) exceeded penetration grade specifications. SBS-modified binders demonstrated marked improvements in softening point, viscosity, and rutting resistance, with PG values increasing from PG64-x (unmodified) to PG82-x at 5% SBS. Fluorescence microscopy confirmed optimal polymer dispersion at 5% concentration for both SBS and PVC, ensuring compatibility with the base asphalt. Workability testing revealed that SBS-modified mixtures exhibited higher torque requirements, indicating reduced workability compared to both PVC-modified and unmodified binders. These findings offer valuable insights for the design of high-performance asphalt mixtures suitable for hot-climate applications and contribute to the development of more durable and cost-effective road infrastructure.

Using mechanical and thermodynamic methods to evaluate the effects of nanomaterials on thermal cracking mechanisms of asphalt mixtures under the influence of different moisture conditions

Using mechanical and thermodynamic methods to evaluate the effects of nanomaterials on thermal cracking mechanisms of asphalt mixtures under the influence of different moisture conditions

Effect of glass sheet restraint on the development of thermal cracks

Effect of glass sheet restraint on the development of thermal cracks

An improved micromechanical model for multiscale fiber reinforced ultra-high performance concrete: From hydration, dehydration to thermal damage

Multiscale fiber-reinforced ultra-high performance concrete (MSFUHPC) was recently developed to obtain the desired thermal and mechanical properties for engineering structures suffering from fire accidents. Quantitative methods to characterize the evolution of its thermal damage are necessary to design MSFUHPC and remain to be presented. This study presents an improved micromechanical model focusing on the material's stiffness from hydration through dehydration to thermal damage. MSFUHPC is renowned for its exceptional mechanical properties and durability; however, its susceptibility to thermal degradation poses significant challenges, particularly in fire scenarios. The integration of multiscale fibers—comprising steel, polyethylene, and carbon fibers and carbon nanotubes—alongside lightweight aggregates such as fly ash cenospheres, enhances the material's performance subjected to elevated temperatures. The proposed micromechanical model captures the complex interactions between the fibers, sand and cement matrix at various scales. By considering the effects of hydration and dehydration, the model offers valuable insights into the mechanisms leading to thermal damage during thermal exposure. Moreover, two Weibull probabilistic models are introduced to characterize the evolution of thermal cracking and sand debonding. Experimental studies are carried out to estimate the thermal and mechanical properties of MSFUHPC, thereby validating the model's feasibility. The results indicate that the multiscale fiber reinforcement significantly mitigates thermal damage. These findings underscore the importance of optimizing fiber and aggregate combinations to achieve superior fire resistance. Moreover, the proposed micromechanical model can serve as input parameters for thermomechanically coupled analysis of structures and components.

Data-Driven Prediction of Binder Rheological Performance in RAP/RAS-Containing Asphalt Mixtures

Asphalt recycling technologies have advanced considerably over the last few decades with the utilization of reclaimed asphalt pavements (RAP) and recycled asphalt shingles (RAS). Characterizing aged and heterogeneous binders in these mixtures is challenging, particularly with limited extracted binders. This study suggests a data-driven framework that considers the rheological, chemical, and thermal characteristics to predict the binders’ performance. Ninety-seven mixtures with 0–35% of the asphalt binder replaced with RAP/RAS binders were included as cores from the field, plant-produced mixtures, and laboratory-fabricated mixtures. The binders were chemically quantified using aging, aromatic, and aliphatic indices. Thermal analyses of the binders involved the percentage of the thermal residue. The framework predicted the rheological resistance of the binders to rutting and cracking using linear and nonlinear machine learning models. The nonlinear models outperformed the linear models for the three rheological parameters. The nonlinear models achieved a 69% reduction in the root mean square error (RMSE) for rutting, a 37% reduction in the RMSE for fatigue cracking, and a 21% reduction in the RMSE for thermal cracking. However, the nonlinear models overfitted for block cracking and had an RMSE 41% higher than the linear models, despite a perfect correlation (R = 1.00). The feature importance demonstrated the strong effects of the chemical and thermal parameters on rheological prediction. The data-driven framework can successfully support efforts to better manage asphalt recycling by predicting the binder performance.

The study on crack evolution mechanism of TiAlN‐coated tool in milling TC4 titanium alloy

Abstract This study aims to investigate the effects of thermo‐mechanical coupled stresses on crack initiation and propagation in coated cutting tools during milling processes. TiAlN‐coated tools machined TC4 workpieces, and a comprehensive analysis of cutting forces, cutting temperatures, and tool stresses was carried out through finite element simulation. By decoupling thermal and mechanical stresses, the study aimed to identify the different forms and effects of both types of stresses on the coated tools. Experimental results revealed that an increase in cutting speed resulted in higher tool surface temperatures, leading to elevated thermal stresses that facilitated the propagation of “comb‐like” thermal cracks. Additionally, mechanical stresses induced by impacts during milling operations were found to initiate and propagate mechanical cracks in tools. The research observed that mechanical cracks, running parallel to the cutting edge, and thermal cracks, propagating perpendicular to the cutting edge, eventually result in coating spalling. The primary modes of tool failure identified were the propagation of micro‐cracks and coating spalling, with the direction of crack propagation closely linked to the stress state distribution within the tool. The research highlights the intricate interplay between thermal and mechanical stresses in the evolution of cracks in coated cutting tools during milling processes.

Effect of acid washing and torrefaction combined pretreatment on the properties of waste tobacco stem biomass and the quality of pyrolysis bio-oil.

Aiming at the issues of low yield and poor quality of bio-oil obtained from direct pyrolysis of biomass, in this study, waste tobacco stems (TS) were used as raw materials, and the pretreatment methods of torrefaction and acid washing were adopted to study the effects of different torrefaction temperatures and pretreatment sequences on the quality of TS biomass and bio-oil. Results showed that combined pretreatment synergistically integrated deoxygenation from torrefaction and deashing from acid washing. High-temperature torrefaction-based combined pretreatment reduced TS oxygen content from 54.83% to 20.14%. Acid washing pretreatment achieved more than 90% removal of inorganic elements (K, Cl and Mg). The order of combined pretreatment also had an important influence on biomass pyrolysis. Torrefaction-acid washing pretreatment decreased ash content of TS, increased the relative content of sugars and aromatic compounds in bio-oil, reduced alcohols and ketones relative contents, and improved bio-oil higher heating value (HHV) and pH. Acid washing-torrefaction pretreatment enhanced bio-oil productivity, increased nitrogen-containing compounds and phenols relative content, reduced acids and aldehydes contents, and lowered bio-oil water and ash contents. Additionally, with the increase in torrefaction temperature, the O/C molar ratio of TS decreased, the HHV of TS increased, and the thermal cracking of nicotine in bio-oil to generate pyridine compounds was promoted. This study demonstrates a viable pathway to convert TS into high-quality fuels and bio-oil via combined pretreatment, offering new insights for optimizing biomass pyrolysis technology and enhancing resource utilization efficiency.

Zero-energy solution for thermal cracking to concrete: High-altitude anti-cracking coating based on radiative cooling

Zero-energy solution for thermal cracking to concrete: High-altitude anti-cracking coating based on radiative cooling

Performance prediction models for flexible and rigid pavements – state-of-the-practice review for implementation in North America

ABSTRACT The durability of pavement infrastructure depends on accurate distress and service life predictions. Empirical, mechanistic, and neural network models have been extensively developed to predict pavement distresses considering structural, traffic, and environmental factors, yet their accuracy varies due to inherent assumptions and diverse failure mechanisms. This paper presents a comprehensive review of pavement distress prediction models with an emphasis on selecting suitable mechanistic-empirical (M-E) models for integration into the Joint Evaluation and Design Integrated 2D (JEDI2D) pavement analysis platform developed by the U.S. Army Engineer Research and Development Center. The review critically evaluated existing predictive models for primary pavement distresses, including fatigue cracking, rutting, thermal cracking, roughness in flexible pavements, and transverse cracking, faulting, and roughness in rigid pavements, considering stabilised layers. Each model was assessed in terms of practical implementability, credibility, and complexity of required input parameters to identify the most suitable models associated with each distress type, such as the AASHTOWare Pavement ME models, which demonstrate robust validation, straightforward implementation, and established credibility. Furthermore, key research gaps were highlighted to guide future enhancements, emphasising the necessity of local calibration and advanced modelling techniques to improve accuracy and applicability for pavement management systems.

Effect of nano carbonate calcium on the low temperature performance of bitumen and asphalt mixtures in acidic and alkaline moisture

Moisture damage becomes more problematic when accompanied by changes in water acidity caused by surface contaminants. Due to the hydrophobicity and unique mechanical properties of nano-carbonate calcium (NCC), this study evaluated the effect of NCC on improving the low-temperature performance of asphalt mixtures under acidic (pH = 5 and pH = 6), alkaline (pH = 9 and pH = 8), and neutral (pH = 7) wet conditions using mechanical and surface free energy (SFE) tests. Two types of performance grade bitumen (PG 58–22 and PG 64–16), NCC at two weight percentages of bitumen (0.3% and 0.6%), and two types of aggregates (limestone and siliceous) were used. Low-temperature mechanical tests of bitumen and asphalt mixtures were performed using the bending beam rheometer (BBR) and semi-circular bending (SCB) tests, respectively. In addition to mechanical tests, SFE, including the Wilhelm Plate (WP) and Universal Sorption Device (USD), were utilized to determine the SFE components of bitumen, aggregates, and aqueous solutions with different pH values. Applying environmental conditions decreased the debonding energy, which reduced bitumen-aggregate adhesion and increased the likelihood of cracking at low temperatures. Acidic and alkaline conditions increased the creep stiffness and reduced the m-value of bitumen, heightening the risk of low-temperature cracking. These environments also resulted in higher fracture energy and toughness, which reduced the asphalt mixture’s stress absorption capacity and resistance to crack growth, with acidic conditions having the most severe impact. Based on the test results and statistical analysis, NCC as a bitumen additive significantly increased the bitumen-aggregate debonding energy. NCC also significantly increased the fracture energy and fracture toughness parameters in acidic and alkaline environmental conditions, reducing the likelihood of thermal cracking.

INFLUENCE OF THERMAL CRACKING CONDITIONS OF PLASTIC WASTE ON THE COMPOSITION AND YIELD OF PRODUCTS

In this study, the composition of the products resulting from the thermal cracking of a mixture of plastic waste was investigated. The mixture included polyethylene (low and high density), polypropylene, polystyrene, and polyethylene terephthalate. The study was conducted under specific process conditions, with temperatures ranging from 450 to 525 °C and durations ranging from 1 to 60 min. It has been ascertained that during the process of cracking (at a temperature of 450 °C and for a duration of 15 min) of the studied mixture of plastic waste, a considerable amount of fractions with boiling points above 360 °C and solid n-alkanes are formed. It has been demonstrated that increasing the duration of the process to 60 min leads to the active destruction of solid n-alkanes, with the concomitant formation of more than 24% wt. of gaseous products. Conversely, increasing the process temperature to 475 ºC allows for the reduction of the cracking duration from 60 to 5 min, thereby facilitating the active destruction of plastic waste and the formation of almost 36% of gasoline and 34% of diesel fractions by weight. The analysis of a mixture of plastic waste subjected to a temperature of 500 °C for a duration of 5 min results in the production of a liquid product that exhibits a content of light fractions analogous to that obtained at 475 °C. However, a predominance of diesel is observed in the liquid product. It has been established that during the process of plastic waste cracking at temperatures ranging from 450 to 500 ºС, destructive processes predominate. At a temperature of 525 °C, condensation reactions occur with the formation of fractions of 200-360 °C and >360 °C from gasoline. As demonstrated in the extant research, the during cracking of plastic waste produces a variety of gaseous by products, including carbon monoxide and dioxide, methane, ethane, propane, n-butane, and n-pentane. It has been established that, in order to obtain a large number of light fractions with minimal yields of by-products, the following conditions must be met: 475 °C and 5 min. For citation: Sviridenko N.N., Frolova U.A., Urazov Kh.Kh., Sergeyev N.S. Influence of thermal cracking conditions of plastic waste on the composition and yield of products. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 8. P. 112-118. DOI: 10.6060/ivkkt.20256808.13t.

ASPHALTENE TRANSFORMATION DURING THERMAL CRACKING OF HEAVY OILS

The present study examines the composition of thermal cracking products derived from four distinct heavy crude oils sourced from the Russian Federation. The experiments were conducted at a temperature of 450 °C for a duration of 60 to 120 min. The optimal cracking duration for each oil was determined. It was found that during thermal cracking of Ashalchinskaya and Karmalskaya crude oils (oils with a high resin to asphaltene ratio) in relation to Zyuzeevskaya and Usinskaya crude oils (oils with a low resin to asphaltene ratio), the component destruction reactions proceed slowly, while condensation reactions are more pronounced. The data indicate that the yield of by-products for Ashalchinskaya and Karmalskaya oils is 3-4 times less than that for Zyuzeevskaya and Usinskaya oils. The cracking of Zyuzeevskaya and Usinskaya oils results in a more profound destruction of resinous-asphaltene components, leading to an increase in the yield of light fractions by over 20% by weight. It has been demonstrated that the thermal cracking of oils from the Ashalchinskoye and Karmalskoye fields results in an increase in biaromatic hydrocarbons and a decrease in mono- and polyaromatic hydrocarbons. Additionally, the formation of saturated and triaromatic hydrocarbons exhibits a notable distinction between these two oil types. The results demonstrate that following the cracking of Zyuzeevskaya oil, there is a notable decline in the saturated and biarylic hydrocarbon content, while the polyarylic hydrocarbon content exhibits an increase. Conversely, inverse dependencies are observed in the oil composition of Usinskaya oil for these groups of hydrocarbons. It has been established that during thermal cracking of Ashalchinskaya and Karmalskaya oil, the blockiness of asphaltene molecules increases, and the destruction of aliphatic substituents proceeds slowly. It has been shown that various heteroaromatic fragments participate in the formation of secondary asphaltenes. Additionally, various heteroaromatic fragments are involved in the formation of these substituents. The structural-group analysis method revealed that the destruction of asphaltenes occurs more intensively in Zyuzeevskaya and Usinskaya oils, resulting in smaller average molecules and a twofold reduction in the number of structural blocks. The reactions of aromatization and dealkylation contribute to greater condensation of molecules. For citation: Sviridenko N.N., Urazov Kh.Kh., Korneev D.S. Asphaltene transformation during thermal cracking of heavy oils. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 8. P. 75-83. DOI: 10.6060/ivkkt.20256808.12t.

Hydrocarbon Composition of the Products of Thermal and Catalytic Cracking of Asphaltenes Obtained in Supercritical Water

Hydrocarbon Composition of the Products of Thermal and Catalytic Cracking of Asphaltenes Obtained in Supercritical Water

Crack growth life assessment of the deep-sea manned cabin based on eddy current thermal imaging detection.

Most of the deep-sea pressure-resistant structures are made of high-strength materials. The pressure-resistant structures are made with large-thickness welding technology, which can easily result in stress concentration and cracks. In this paper, a method for crack identification and life evaluation of pressure-resistant structures based on the crack is proposed. On the one hand, the principle of eddy current thermal imaging detection is used to identify cracks. The experimental platform is built to detect cracks in pressure-resistant structures. The titanium alloy samples with micro-cracks are detected to analyze the temperature distribution and heat conduction mechanisms of surface cracks. In addition, the correlation between transient temperature changes and crack damage is investigated. On the other hand, based on the detection of micro-cracks, a fatigue crack growth model is proposed to compute the fatigue crack growth life of the pressure hull. The rationality of the eddy current thermal imaging crack detection method and life evaluation of pressure-resistant structures is verified.

Performance Evaluation of the Thermal Cracking Resistance of Asphalt Mixtures Prepared with High RAP Content and Rejuvenators

Performance Evaluation of the Thermal Cracking Resistance of Asphalt Mixtures Prepared with High RAP Content and Rejuvenators

Experimental Study for Development of Thermal Cracking Reaction Model of exo-THDCPD under Supercritical Condition

Experimental Study for Development of Thermal Cracking Reaction Model of exo-THDCPD under Supercritical Condition

Composition characteristics of the soluble component and fast pyrolysis products distribution of the insoluble part from coal tar residue

ABSTRACT Petroleum ether (PE) was used as the solvent to extract organic matter in coal tar residue (CTR) to obtain the easily soluble fraction (CTR-E) and the insoluble residue (CTR-R). Comparative analysis of the composition characteristics and thermal cracking behavior of CTR, CTR-E, and CTR-R using characterization methods such as FTIR and TG-DTG. Results showed that, CTR-R has a reduced content of benzene ring-like functional groups (FTIR) and better thermal stability (TG-DTG). CTR-E contains abundant condensed aromatic compounds (GC/MS), among which 98.6% of polycyclic aromatic hydrocarbons are 2–4 rings, providing valuable chemical materials for further separation of high value-added organic matter in CTR. Compared with CTR, the content of alkanes in the pyrolysis products from CTR-R at 300 °C is reduced, which is attributed to the selective disruption of the entanglement between alkanes and alkyl groups by PE. The pyrolysis products from CTR-R at 450 °C are dominated by alkanes and acid compounds, accounting for 41.5% and 19.3%, respectively. At 700 °C, the aromatic hydrocarbons in the pyrolysis products of CTR-R were mainly benzofluorene and benzanthracene as well as other polycyclic hydrocarbons with carbon number ≥16, indicating that condensation reactions between aromatic rings might occur during the pyrolysis of CTR-R at this temperature.

Temperature-induced microstructural evolution and fractal characteristics of high-enthalpy Chumathang granite for enhanced geothermal energy

Micro-structural attributes of Chumathang granite from Leh, India, were experimentally determined in the temperature range from 25 to 600 °C for enhanced geothermal systems (EGS). P-wave velocity, thermal crack generation, and pore attributes were analyzed using a combination of pulse ultrasonic velocity study, 3D X-ray tomography and low-pressure gas adsorption experiments, respectively. Results indicate that thermal crack development is driven by mineral composition and differential thermal expansion, with a significant increase in the thermal damage factor between 450 ∘C and 600 ∘C, accompanied by visible cracks at 600 ∘C. Surface area and pore volume decreased up to 300 ∘C due to mineral dissolution, then slightly increased up to 600 ∘C due to microfracture formation. Pore size distribution showed a dominance of coarser mesopores, and fractal dimensions decreased with temperature, reflecting simpler pore geometries. These findings enhance the understanding of granite’s microstructural changes under thermal stress, informing the optimization of EGS heat extraction efficiency.