Coatings

18 pages, 2698 KiB

Open AccessArticle

Predicting Dynamic Properties and Fatigue Performance of Aged and Regenerated Asphalt Using Time–Temperature–Aging and Time–Temperature–Regenerator Superposition Principles

by Zhaoli Wang, Hongli Ding, Xiaoyan Ma, Wanhong Yang and Xiaojun Ma

Coatings 2024, 14(12), 1486; https://doi.org/10.3390/coatings14121486 - 25 Nov 2024

Abstract

Reclaimed asphalt pavement (RAP) reduces energy consumption and enhances economic benefits by recycling road materials, making it an effective approach for the sustainable use of solid waste resources. The performance of reclaimed asphalt pavement is significantly affected not only by the degradation of [...] Read more.

Reclaimed asphalt pavement (RAP) reduces energy consumption and enhances economic benefits by recycling road materials, making it an effective approach for the sustainable use of solid waste resources. The performance of reclaimed asphalt pavement is significantly affected not only by the degradation of asphalt binders due to aging but also by the dosage of the rejuvenator used. The master curve of the complex shear modulus is widely recognized as a valuable tool for characterizing the rheological properties of asphalt binders. First, a virgin asphalt binder with a grade of SK70 was subjected to varying degrees of aging, followed by the rejuvenation of the aged asphalt using different dosages of the rejuvenator. Second, frequency sweeps were conducted on the aged and rejuvenated asphalt binders at various temperatures. Complex modulus master curves were constructed, and the CAM model was applied to fit these curves. The viscoelastic properties of asphalt at different aging levels and rejuvenator dosages were then analyzed based on the CAM parameters. Next, by applying a curve-shifting technique based on the least squares method to a reference state, both the time–temperature–aging (TTA) and time–temperature–regenerator (TTR) master curves of the complex modulus were constructed. The relationships between aging shift factors and aging times, as well as between regenerator shift factors and dosages, were established to predict the complex moduli of both aged and rejuvenated asphalt. Finally, the shear stress–strain relationships and material integrity of aged and rejuvenated asphalt were evaluated to assess their fatigue performance. The results indicated that aging significantly increases the complex modulus of asphalt, with TFOT (Thin Film Oven Test) aging having a more pronounced impact than PAV (Pressurized Aging Vessel) aging, resulting in reduced viscous deformation and an increased risk of cracking. Rejuvenator dosage reduces the complex modulus, with a 6% dosage effectively restoring mechanical properties and enhancing low-temperature performance. The TTA master curve demonstrates a strong linear correlation between aging shift factors and time, allowing for accurate predictions of the complex modulus of aged asphalt. Similarly, the TTR master curve reveals a linear relationship between regenerator dosage and shift factor, offering high predictive accuracy for optimizing regenerator dosages in engineering applications. The study further explores how varying levels of aging and rejuvenator dosage affect fatigue life under different strain conditions, uncovering complex behaviors influenced by these aging and regeneration processes. Full article

(This article belongs to the Special Issue Green Asphalt Materials—Surface Engineering and Applications)

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17 pages, 6277 KiB

Open AccessArticle

Refinement Properties and Refinement Mechanism of a New Master Alloy Al-5Ti-1B-1RE Refiner

by Zhengjun Wang, Shanmin Wang, Quanquan Yang, Xinyang Liu, Chen Dong and Lianxiang Liu

Coatings 2024, 14(12), 1485; https://doi.org/10.3390/coatings14121485 - 25 Nov 2024

Abstract

To obtain high-quality grain refiner, a new Al-5Ti-1B-1RE master alloy grain refiner was synthesized by the melt-matching method. Its microstructure and refining effect, refining properties, and refining mechanism were analyzed. The experimental results show that the second-phase particles of Al-5Ti-1B-1RE master alloy are [...] Read more.

To obtain high-quality grain refiner, a new Al-5Ti-1B-1RE master alloy grain refiner was synthesized by the melt-matching method. Its microstructure and refining effect, refining properties, and refining mechanism were analyzed. The experimental results show that the second-phase particles of Al-5Ti-1B-1RE master alloy are mainly TiB₂, Al₃Ti, Ti₂Al₂₀RE, etc. The magnitude of the free energy ΔG of the synthesis reaction is calculated to be ΔG_TiB2 < ΔG_Al3Ti < ΔG_Ti2Al20RE. The nucleation rate N mainly depends on the kinetic atomic diffusion activation energy Q and the thermodynamic nucleation work. The microstructure of commercial pure aluminum refined by the new grain refiner has almost transformed from coarse columnar crystals to fine equiaxed crystals, with an average grain size of 70.2 μm, which was 36.18% and 20.66% smaller than that refined by domestic and imported Al-Ti-B wire master alloy grain refiner, its mechanical properties of tensile strength σ_b were increased by 11.94% and 8.29%, and elongation δ was improved by 31.79% and 17.41%, respectively. The main refinement mechanism is the formation of TiAl₃ on TiB₂ particles and the release of RE atoms from the Ti₂Al₂₀RE phase, which in turn is partially transformed into the TiAl₃ phase, which promotes dual nucleation refinement. Full article

(This article belongs to the Special Issue Recent Studies of Metal and Metal Compound Coatings: Microstructure, Properties, and Applications)

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16 pages, 18498 KiB

Open AccessArticle

Study on Microstructure and Corrosion Fatigue Resistance of 14Cr12Ni3Mo2VN Materials Based on the Composite Technology of High-Frequency Induction Quenching and Laser Shock Peening

by Jiashun Gao, Zhilong Xu, Huiting Lv, Zhiling Yang, Guang Yang and Liehua Liu

Coatings 2024, 14(12), 1484; https://doi.org/10.3390/coatings14121484 - 25 Nov 2024

Viewed by 158

Abstract

This study investigated the microstructure, microhardness, and residual compressive stress of 14Cr12Ni3Mo2VN martensitic stainless steel treated with high-frequency induction quenching (HFIQ) and laser shock peening (LSP). Using rotating bending corrosion fatigue testing, the corrosion fatigue performance was analyzed. Results show that a microstructural [...] Read more.

This study investigated the microstructure, microhardness, and residual compressive stress of 14Cr12Ni3Mo2VN martensitic stainless steel treated with high-frequency induction quenching (HFIQ) and laser shock peening (LSP). Using rotating bending corrosion fatigue testing, the corrosion fatigue performance was analyzed. Results show that a microstructural gradient formed after HFIQ and LSP: the surface layer consisted of nanocrystals, the subsurface layer of short lath martensite, and the core of thick lath martensite. A hardness gradient was introduced, with surface hardness reaching 524 Hv_0.1, 163 Hv_0.1 higher than the core hardness. A residual compressive stress field was introduced near the surface, with a maximum residual compressive stress of approximately −575 MPa at a depth of 0.1 mm. Corrosion fatigue results indicate that cycle loading times of samples treated with HFIQ and LSP were 2.88, 2.04, and 1.45 times higher than untreated, HFIQ-only, and LSP-only samples, respectively. Transmission electron microscopy (TEM) characterization showed that HFIQ reduced the lath martensite size, while the ultra-high strain rate induced by LSP likely caused dynamic recrystallization, forming numerous sub-boundaries and refining grains, which increased surface hardness. The plastic strain induced by LSP introduced residual compressive stress, counteracting tensile stress and hindering the initiation and propagation of corrosion fatigue cracks. Full article

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16 pages, 7946 KiB

Open AccessArticle

Design and Experimental Characterization of a Microfluidic Piezoelectric Pump Utilizing P(VDF-TrFE) Film

by Bei Zhao, Xiaomeng Li, Jing Shi and Huiling Liu

Coatings 2024, 14(12), 1483; https://doi.org/10.3390/coatings14121483 - 24 Nov 2024

Viewed by 231

Abstract

Advancements in wearable technology and lab-on-chip devices necessitate improved integrated microflow pumps with lower driving voltages. This study examines a piezoelectric pump using a flexible β-phase copolymer poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) film. Six samples (S1–S6) were fabricated and subjected to a three-step annealing process [...] Read more.

Advancements in wearable technology and lab-on-chip devices necessitate improved integrated microflow pumps with lower driving voltages. This study examines a piezoelectric pump using a flexible β-phase copolymer poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) film. Six samples (S1–S6) were fabricated and subjected to a three-step annealing process to optimize their properties. Characterization was conducted via atomic force microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, impedance analysis, and polarization hysteresis loop measurements. The results show that annealing at approximately 135 degrees Celsius produces a β-phase structure with uniform “rice grain”-like crystallites. A microfluidic pump with a nozzle/diffuser structure, using S4 film as the drive layer, was designed and manufactured. Diaphragm deformation and pump performance were assessed, showing a maximum water flow rate of 25 µL/min at 60 Hz with a peak-to-peak voltage (V_pp) of 60 V. The flow rate could be precisely controlled within 0–25 µL/min by adjusting the V_pp and frequency. This study effectively reduced the driving voltage of the piezoelectric pump, showing that it has significant implications for smart wearable devices. Full article

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17 pages, 2899 KiB

Open AccessArticle

A Study on the Mechanism by Which Graphene Oxide Affects the Macroscopic Properties and Microstructure of Abrasion-Resistant Ultra-High-Performance Concrete (UHPC)

by Tusheng He, Wei Xie, Feng Wang, Zi Yu, Fang Xu, Jinhui Li, Yitong Deng, Qingjun Ding, Yan Hao, Wei Xu and Haibin Yu

Coatings 2024, 14(12), 1482; https://doi.org/10.3390/coatings14121482 - 23 Nov 2024

Viewed by 224

Abstract

To further enhance the abrasion resistance of UHPC in demanding abrasion environments, this study investigated the effects of graphene oxide (GO) on the workability, mechanical properties, and abrasion resistance of UHPC. Utilizing 27Al Nuclear Magnetic Resonance (NMR), 29Si NMR, microhardness, and BET analysis, [...] Read more.

To further enhance the abrasion resistance of UHPC in demanding abrasion environments, this study investigated the effects of graphene oxide (GO) on the workability, mechanical properties, and abrasion resistance of UHPC. Utilizing 27Al Nuclear Magnetic Resonance (NMR), 29Si NMR, microhardness, and BET analysis, the study analyzed the mechanisms through which GO influences UHPC’s microstructure in terms of abrasion resistance. Additionally, molecular dynamics simulations were employed to examine the mechanisms by which GO enhances UHPC’s abrasion resistance at the nano and micron scale. The findings show that an optimal amount of GO can improve the mechanical properties and abrasion resistance of UHPC. When 0.03% of GO (by cementitious material mass) was incorporated, the impact on workability was minimal, yet compressive strength increased by approximately 1.80%, flexural strength by 3.02%, impact wear resistance by 1.78%, the abrasion loss rate decreased by 10.01%, ultimate impact energy increased by 1.76%, and the toughness index improved by 10.10%. GO enhances abrasion-resistant UHPC primarily by increasing hydration, refining pore structure, and improving the microstructure of the interfacial transition zone. While GO increases the hydration degree of the UHPC matrix, it does not alter the silicate chain in C-A-S-H gels within the paste. Additionally, the incorporation of graphene oxide can refine the pore structure of the UHPC cement paste and improve the microstructure of the interfacial transition zone (ITZ) between the aggregate and the cement paste. The molecular dynamics simulation reveals that, under abrasive forces, GO forms strong, stable chemical bonds with the C-A-S-H base atoms, significantly enhancing the abrasion resistance of C-A-S-H. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings, 2nd Edition)

18 pages, 2482 KiB

Open AccessArticle

Investigation of the Microhardness, Morphology, and Wear Resistance of A7075 Subjected to Machine Hammer Peening

by Yu Liu, Yefu Wang, Lu Yu, Ying Yang, Ning Nie, Xingxing Wang and Yifu Shen

Coatings 2024, 14(12), 1481; https://doi.org/10.3390/coatings14121481 - 22 Nov 2024

Viewed by 317

Abstract

In industrial production, 7075 aluminum alloy (A7075) is prized for its strength and light weight. However, heat treatment can reduce its hardness and wear resistance. Therefore, proper surface treatments are often necessary to optimize its mechanical properties. In this work, a hammering tool [...] Read more.

In industrial production, 7075 aluminum alloy (A7075) is prized for its strength and light weight. However, heat treatment can reduce its hardness and wear resistance. Therefore, proper surface treatments are often necessary to optimize its mechanical properties. In this work, a hammering tool attached to a robotic arm was employed to impact the surface of A7075 using different impact energies, and the surface hardness, morphology, roughness, and frictional characteristics of samples subjected to machine hammer peening (MHP) treatment were analyzed to explore the strengthening mechanism of MHP. The results indicate that the hardness increased to a maximum value of 235 HV with rising impact energy, whereas the depth of influence (2 mm) was almost unaffected by the impact energy. Microstructural analysis revealed significant grain refinement, especially at 2.7 J. The surface roughness increased significantly to about 7.2 μm, then dropped to around 3.7 μm when the impact energy increased to 2.7 J. Finally, the roughness decreased to ~6.8 μm. In addition, the samples that were strengthened by MHP demonstrated low friction coefficients (about 0.27) and wear volume (minimum value of 7.67/10⁻⁴ mm³), implying that MHP can effectively improve the wear resistance of A7075. Observation by SEM revealed that the corresponding wear mechanism is mainly attributable to mild oxidative wear and three-body wear. Full article

19 pages, 6947 KiB

Open AccessArticle

Surface Functionalization of CaCO₃ Whiskers for Improved Asphalt Binder Compatibility: From Microscale Characterization to Molecular Dynamics

by Xiangyang Xing, Jiyang Wang, Qingyue Zhou, Jiupeng Zhang, Guoqing Sun, Shiru Guo and Yong Wen

Coatings 2024, 14(12), 1480; https://doi.org/10.3390/coatings14121480 - 22 Nov 2024

Viewed by 265

Abstract

CaCO₃ whiskers, as a micron-level inorganic fiber material, can enhance and toughen composite materials. In order to study the technical feasibility of CaCO₃ whisker-modified asphalt, two types of silane coupling agent (SCA), KH-550 and KH-570, were applied to treat the surface [...] Read more.

CaCO₃ whiskers, as a micron-level inorganic fiber material, can enhance and toughen composite materials. In order to study the technical feasibility of CaCO₃ whisker-modified asphalt, two types of silane coupling agent (SCA), KH-550 and KH-570, were applied to treat the surface of CaCO₃ whiskers, and the treatment effects of the original and treated whiskers were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS) and contact angle test. Meanwhile, models of CaCO₃ whiskers, SCA, and asphalt molecules were established by Material Studio (MS, 2020 version) software, and the adhesion mechanism between the CaCO₃ whiskers-and-asphalt interface was predicted. The results of microscopic characterization experiments indicate that the surface of the whiskers treated with SCA became rougher. Compared with the original whiskers, the contact angle between the treated whisker surface and water increased from 50° to 92.2° and 103.4°, and the surface of whiskers changed from hydrophilic to hydrophobic. The results of molecular dynamics simulation analysis show that the adhesion performance between the CaCO₃ whisker surface and asphalt increased from 100.1 mJ/m² to 112.5 mJ/m² and 126.6 mJ/m² after modification with SCA, and the increase in adhesion energy of KH550 is greater than that of KH570. The above research results indicate that the micro-characterization results were consistent with the molecular dynamics simulation results; that is, after treatment with SCA, the adhesion energy between the whiskers and asphalt was increased to varying degrees. The research method in this article combines micro-characterization with molecular dynamics simulation, which has a certain degree of innovation. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

12 pages, 1994 KiB

Open AccessArticle

Performance and Thermal Properties of 3D Printed CF-Reinforced PLA Monofilaments

by Pen Jin, Tuo Pan, Yaxuan Li, Tianran Zhong, Jing Jiang, Chengcui Pu and Chunyang Ma

Coatings 2024, 14(12), 1479; https://doi.org/10.3390/coatings14121479 - 22 Nov 2024

Viewed by 307

Abstract

This study reports the fabrication of carbon fiber-reinforced poly(lactic acid) (CF-PLA) monofilaments using 3D printing technology. The effects of print head movement speed and retraction rate on the diameter of the CF-PLA monofilaments were investigated. The surface morphology and properties were analyzed using [...] Read more.

This study reports the fabrication of carbon fiber-reinforced poly(lactic acid) (CF-PLA) monofilaments using 3D printing technology. The effects of print head movement speed and retraction rate on the diameter of the CF-PLA monofilaments were investigated. The surface morphology and properties were analyzed using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The CF-PLA monofilaments were also printed into boards with varying CF content, and the mechanical properties of these boards were assessed. The results showed that the optimal printing parameters were a nozzle diameter of ϕ0.4 mm, fiber feed rate (V_f) of 3 mm/s, print head movement speed (V_m) of 40 mm/s, and retraction speed (V_r) of 5 mm/s. At a CF-PLA monofilament diameter of ϕ135 µm, the tensile strength and Young’s modulus reached maximum values of 48.3 MPa and 2481.8 MPa, respectively. Numerous CF monofilaments (approximately 135 µm in diameter) were observed on the surface and within the CF-PLA boards, significantly enhancing their strength. When the CF content was 4 vol%, the thermal decomposition temperature of the CF-PLA monofilament was 312.53 °C. At 8 vol% CF content, the thermal decomposition temperature increased to 342.62 °C—approximately 30 °C higher than that of the monofilament with 4 vol% CF. The CF-PLA monofilaments fabricated at 8 vol% demonstrated high thermal stability. Full article

14 pages, 3582 KiB

Open AccessArticle

Nonlinear Oxidation Behavior at Interfaces in Coated Steam Dual-Pipe with Initial Waviness and Cooling Temperature

by Bo Yuan, Ke Wang, Xiaofeng Guo, Junxiang Gao and Pengfei Chen

Coatings 2024, 14(12), 1478; https://doi.org/10.3390/coatings14121478 (registering DOI) - 22 Nov 2024

Viewed by 282

Abstract

A numerical simulation method is proposed to investigate the nonlinear growth of thermally grown oxide (TGO) on a novel coated steam dual-pipe system operating at 700 °C. Utilizing oxidation kinetics data from high-temperature water vapor experiments, the study examines interface stresses and morphology [...] Read more.

A numerical simulation method is proposed to investigate the nonlinear growth of thermally grown oxide (TGO) on a novel coated steam dual-pipe system operating at 700 °C. Utilizing oxidation kinetics data from high-temperature water vapor experiments, the study examines interface stresses and morphology evolution, considering initial surface waviness and cooling temperature effects. The findings indicate that the parabolic law accurately describes the nonlinear growth of TGO during high-temperature water vapor oxidation, with the TGO growth oxidation rate constant being

4.5 \times 10^{- 4} μ m^{2} / h

. The growth rate of TGO thickness decreases with increasing oxidation duration. Stress concentrations are found to develop at TGO interfaces, particularly in regions with high curvature, and those with elevated wavy amplitudes. The primary factor influencing stress redistribution and morphology evolution is the wavy amplitude of the TGO. Additionally, variations in cooling temperature affect interface stresses along the axial direction of the pipe system during nonlinear oxidation, resulting in relatively minor changes in morphology. Full article

(This article belongs to the Section Ceramic Coatings and Engineering Technology)

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1 pages, 129 KiB

Open AccessCorrection

Correction: Zhao et al. Plasma Spraying NiCoCrAlY-Cr₂O₃-AgMo Coatings: Fabrication and Tribological Mechanisms. Coatings 2024, 14, 1233

by Yafei Zhao, Yanping Gao, Zhaoyang Zhai, Yanchao Zhang and Dongya Zhang

Coatings 2024, 14(12), 1477; https://doi.org/10.3390/coatings14121477 - 22 Nov 2024

Viewed by 179

Abstract

In the published paper [...] Full article

13 pages, 6488 KiB

Open AccessArticle

Microstructure and Tribological Properties of FeCrCoMnSi_x High-Entropy Alloy Coatings

by Shuling Zhang, Di Jiang, Shengdi Sun and Bo Zhang

Coatings 2024, 14(12), 1476; https://doi.org/10.3390/coatings14121476 - 22 Nov 2024

Viewed by 360

Abstract

For shaft parts, 45 steel has been widely used due to its favorable mechanical properties and low cost. However, the relatively low wear resistance of 45 steel limits its application. In this work, high-entropy alloy of FeCrCoMnSi_x (x = 0, 0.3, 0.6, [...] Read more.

For shaft parts, 45 steel has been widely used due to its favorable mechanical properties and low cost. However, the relatively low wear resistance of 45 steel limits its application. In this work, high-entropy alloy of FeCrCoMnSi_x (x = 0, 0.3, 0.6, 0.9, 1) coatings were prepared on the surface of a 45 steel substrate using laser cladding technology to improve the wear performance of 45 steel. The effect of the Si element on the microstructure and tribological property of these coatings is investigated. The results show that the structure of FeCrCoMn coatings is mainly an FCC + HCP dual-phase solid solution, grown in equiaxial crystals. When a small amount of Si (x = 0.3) is added, the BCC phase is generated in the coating; meanwhile, the microstructure is transformed into the divorced eutectic character. When the content of Si is x = 0.6, the eutectic structure is promoted, and the microstructure is refined and becomes denser. When the content of Si increases to x = 0.9 and 1.0, the metal silicate phase containing Mn and Cr is formed due to the precipitation of supersaturated solid solution. At the same time, the microstructure is transformed into dendritic crystals due to the composition super-cooling effect by the excessive Si element, inducing serious element segregation. The hardness of FeCrCoMnSi_x high-entropy alloy coatings increases to 425.8 HV when the Si content is 0.6 under the synergistic effect of the solid-solution and dense eutectic structure. The friction and wear analysis shows that the friction and wear mechanisms of the coating are mainly abrasive wear and oxidative wear. The coefficient of friction and the wear rate of the FeCrCoMnSi_x high-entropy alloy coating decreases to 0.202 and 4.06 × 10⁻⁵ mm³/N·m, respectively, when the content of Si is 0.6 due to the dense microstructure and high hardness. The above studies prove that the presence of Si in the FeCrCoMnSi_0.6 high-entropy alloy coating induces a refined eutectic microstructure and improves the coating’s anti-wear properties by increasing hardness and decreasing the coefficient of friction. Full article

(This article belongs to the Section Laser Coatings)

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27 pages, 1946 KiB

Open AccessReview

Solid–Liquid Composite Lubrication (SLCL) Based on Diamond-Like Carbon (DLC) Coatings and Lubricating Oils: Properties and Challenges

by Wei Qi, Lei Chen, Hui Li, Lieming Tang and Zhiliang Xu

Coatings 2024, 14(12), 1475; https://doi.org/10.3390/coatings14121475 - 21 Nov 2024

Viewed by 546

Abstract

In the field of industrial lubrication, solid–liquid composite lubrication (SLCL) techniques based on diamond-like carbon (DLC) coatings and lubricating oils are emerging recently, which may be applied in many fields in the near future, especially automotive industries. The tribological behaviors of SLCL systems [...] Read more.

In the field of industrial lubrication, solid–liquid composite lubrication (SLCL) techniques based on diamond-like carbon (DLC) coatings and lubricating oils are emerging recently, which may be applied in many fields in the near future, especially automotive industries. The tribological behaviors of SLCL systems depend strongly on the compatibility between DLC coatings and oils. This review describes the advantages of SLCL techniques by pointing out the synergistic effects between DLC coatings and lubricating oils. Then the main factors determining the tribological performance of SLCL systems are discussed in detail. Finally, a conclusion about the characteristics of reported SLCL systems is made, and a prospect about the potential development of SLCL technology is proposed. On the basis of the relevant literature, it could be found that the tribological properties of SLCL systems were influenced by many more factors compared with individual DLC lubrication or individual oil lubrication due to the complicated tribo-chemical reactions involving DLC and oil during friction. And under some optimized working conditions, the tribological performances of SLCL systems (friction and wear reduction) are superior to individual DLC lubrication and individual oil lubrication. However, the tribological performance of SLCL systems needs to be further improved (for example, to achieve superlubricity and ultra-low wear simultaneously) by adjusting the structures of DLC coatings, regulating the compositions of oils, and most importantly, enhancing the physicochemical and tribological synergies between DLC coatings and oils. This review provides a comprehensive understanding of the SLCL technology, which may be very helpful for the researchers and engineers in the field of industrial lubrication and tribology. Full article

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19 pages, 12688 KiB

Open AccessArticle

Comprehensive Study on the Thrust Estimation and Anti-Freezing Lubricant of Pipe Jacking in Frozen Soil

by Kai Wen, Wei Zeng, Qing Ye, Hideki Shimada, Siliang Qin and Benhao Fu

Coatings 2024, 14(12), 1474; https://doi.org/10.3390/coatings14121474 - 21 Nov 2024

Viewed by 289

Abstract

Recent advancements in underground construction have led to the widespread utilization of pipe jacking. However, the engineering challenges posed by frozen ground in pipe jacking projects have not been extensively studied. This research aims to address the critical challenges linked to employing pipe [...] Read more.

Recent advancements in underground construction have led to the widespread utilization of pipe jacking. However, the engineering challenges posed by frozen ground in pipe jacking projects have not been extensively studied. This research aims to address the critical challenges linked to employing pipe jacking in frozen ground for underground construction. It is widely recognized that the accurate calculation of jacking thrust and mitigation of pipe–soil interaction plays a crucial role in determining the success or failure of pipe jacking operations. To explore these issues, this study conducted numerical simulations and comparative analyses, considering various factors such as soil properties, geometric dimensions, and burial depth, to assess their influence on jacking thrust. Additionally, the study also examines the freeze–thaw effect on concrete pipes and the injected lubricant. The results indicate that the numerical model, which considers the temperature effects and static friction instead of sliding friction, provides a more reliable estimation of jacking thrust in frozen ground compared to traditional theoretical models. Furthermore, the freezing point depression method was successfully employed in the development of an anti-freezing lubricant, which can effectively reduce pipe–soil interaction even at extremely low temperatures of up to −10 °C. Full article

(This article belongs to the Section Environmental Aspects in Colloid and Interface Science)

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