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In this study, a wear-resistant ultra-thin wear layer was fabricated with polyurethane as an adhesive to investigate its durability for pavement applications. Its road performance was investigated based on indoor tests. First, the abrasion test was performed using a tire–pavement dynamic friction analyzer (TDFA), and the surface elevation information of the wear layer was obtained by laser profile scanning. The relationship between the anti-skid properties of the wear layer and the macro-texture was analyzed. Second, a Fourier infrared spectrometer and scanning electron microscope were employed to analyze the evolution of polyurethane aging properties in the pull-out test and accelerated ultraviolet (UV) aging test. The results showed that the mean profile depth (MPD), arithmetic mean wavelength of contour (λa), surface wear index (SBI), stage mass loss rate (σ), and total stage mass loss rate (ω) of the abrasive layer aggregate had significant multivariate quadratic polynomial relationships with the skidding performance of the abrasive layer. The tensile strength of the polyurethane ultra-thin abrasive layer decreased by only 2.59% after 16 days of UV aging, indicating a minimal effect of UV action on the aggregate and structural spalling of the polyurethane abrasive layer. [ABSTRACT FROM AUTHOR]

The skid resistance of asphalt pavement is an important factor affecting road safety. However, few studies have characterized the contribution of the macro- and micro-texture to the skid resistance of asphalt pavement. In this paper, the generalized extreme studentized deviate (GESD) and neighboring-region interpolation algorithm (NRIA) were used to identify and replace outliers, and median filters were used to suppress noise in texture data to reconstruct textures. On this basis, the separation of the macro- and micro-texture and the Monte Carlo algorithm were used to characterize the skid resistance of asphalt pavement. The results show that the GESD method can accurately identify outliers in the texture, and the median filtering can eliminate burrs in texture data while retaining more original detail information. The contribution of the macro-texture on the skid resistance is mainly attributed to the frictional resistance caused by the adhesion and elastic hysteresis, and the main contribution of the micro-texture is a micro-bulge cutting part in the friction mechanism. This investigation can provide inspiration for the interior mechanism and the specific relationship between the pavement textures and the skid resistance of asphalt pavement. [ABSTRACT FROM AUTHOR]

In order to study the influence of aggregate types on the long-term skid resistance of asphalt pavement, six different types of aggregates such as arkose, red sandstone, limestone, basalt, diabase, and granite were selected. The one-third-scale model mobile load simulator (MMLS) was used to conduct wear tests on porous asphalt mixtures (PA-13) prepared with six types of aggregates. The antiskid performance indicators of British pendulum number (BPN) and macrotexture depth (MTD) of the mixture were measured under different loading times. After wear, the microtexture, hardness, and mineral composition of the aggregates were tested using a laser scanning confocal microscope (LSCM), Vickers hardness tester (VHT), and X-ray diffractometer (XRD) to reveal the mechanism of antiskid durability of different aggregates. The results show that the asphalt mixture prepared with sandstone and granite aggregate has the best antiskid durability, and the attenuation rate and loss rate of antiskid performance are the smallest. The micro-texture of the worn aggregates shows that sandstone and granite are the roughest, whereas limestone is the smoothest. The correlation between texture index of Rsk and the antiskid performance is the greatest. The more complex the mineral composition of the aggregate and the greater the Vickers hardness, the better the antiskid durability of the asphalt mixture. [ABSTRACT FROM AUTHOR]

Silica serves as the primary filler in the fabrication of eco‐friendly tires, and achieving an optimal dispersion of polar silica within the natural rubber matrix is crucial for crafting high‐performance rubber composites. In this study, biodegradable surfactants polyethylene glycol (PEG) with molecular weights of 200, 400, and 800 were employed to modify silica. The modified silica was characterized by Fourier‐transform infrared spectroscopy; PEG‐modified silica with different molecular weights was compounded with Si69, a conventional silane coupling agent, in the formulation. This aimed to reduce Si69 dosage and mitigate the emission of volatile organic gases, such as ethanol, generated during the silanization reaction between Si69 and silica. Experimental findings revealed that compared with natural rubber composites containing six parts of Si69, the addition of PEG‐modified silica enhanced filler dispersion in the composite while reducing Si69 dosage by three parts. This led to accelerated vulcanization rates, effectively decreased energy consumption during production, and significantly improved wet slip resistance, while maintaining optimal rolling resistance. Rubber composites prepared with PEG800‐modified silica exhibited a 10% increase in elongation at break, a 12% increase in tensile product coefficient, and a 19% enhancement in wet slip resistance. Highlights: Silica is modified by polyethylene glycol with molecular weight of 200, 400, and 800.The amount of silane coupling agent and VOC emissions are reduced.The interfacial bonding between silica and rubber matrix is enhanced.The tensile product coefficient and wet slip resistance are improved by 12% and 19%. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An Open-Graded Friction Course (OGFC) presents a rough surface and a porous structure and provides skid resistance under wet conditions, differing from that of a dense graded mixture. This study explored the distribution of surface macrotexture with depth in OGFC. Using cross-sectional images and semantic image segmentation techniques, the internal structure, porosity, and void size distribution were analyzed to assess the effectiveness of rainfall drainage. Skid resistance was evaluated with a British Pendulum Tester, focusing on the influence of surface macrotexture and internal macrostructure, particularly with regard to contact depth. Results show that finer gradations increase surface roughness peaks, which are concentrated near the top surface. In contrast, coarser mixtures exhibit a greater effective contact depth and more peaks with higher curvature. Finer gradations also result in lower porosity, greater void dispersion, and smaller average void diameters. During heavy rainfall, OGFC-13 exhibits the highest friction coefficient due to its effective contact, surface roughness, and internal voids, which facilitate water expulsion. This research provides insights into the skid resistance mechanism of OGFC in wet conditions and offers practical guidance for selecting the optimal gradation. [ABSTRACT FROM AUTHOR]

The application of microwave heating technology can significantly enhance the water evaporation rate of emulsified asphalt mixtures post paving. To improve the microwave absorption and curing performance of these mixtures, SiC-Fe3O4 composite material (SF) was incorporated. This addition aims to enhance the microwave absorption efficiency and accelerate the curing process of emulsified asphalt mixtures under microwave heating. This study begins with an analysis of the microwave absorption principles pertinent to emulsified asphalt mixtures. Subsequently, the microwave heating temperature fields of ordinary emulsified asphalt mixture (EAM), SiC emulsified asphalt mixture (S-EAM), Fe3O4 emulsified asphalt mixture (F-EAM), and SiC-Fe3O4 emulsified asphalt mixture (SF-EAM) were simulated using COMSOL Multiphysics finite element software (COMSOL 6.2). The early strength variations in SF-EAM under different microwave heating durations were then examined through adhesion tests, leading to the proposal of a microwave heat curing process for SF-EAM. Finally, the wear resistance, water damage resistance, rutting resistance, and skid resistance of SF-EAM post-microwave curing were evaluated through wet wheel wear tests, wheel track deformation tests, and road friction coefficient tests. The results indicate that the optimal microwave heating time is 90 s, with the microwave absorption performance of the materials ranked as follows: EAM, S-EAM, F-EAM, and SF-EAM, from lowest to highest. The road performance of SF-EAM complies with specification requirements, and its wear resistance, water damage resistance, and rutting resistance are notably improved after microwave heating. [ABSTRACT FROM AUTHOR]

Ultra-thin overlays (UTOL) are a standard highway pre-maintenance method used to improve the road surface performance of asphalt pavements and to repair minor rutting and cracking. However, the thin thickness makes it very sensitive to external changes, which increases its wear and shortens its life. So, this paper aims to prepare a durable and skid-resistance asphalt ultra-thin overlay using epoxy asphalt (EA) and steel slag. First, the physical properties of EA were characterized by penetration, softening point, flexibility, and kinematic viscosity tests. The dynamic shear rheometer (DSR) test characterizes EA's rheological properties. Differential Scanning Calorimetry (DSC), kinematic viscosity, and Fourier transform infrared spectroscopy (FTIR) characterized the EA's curing process. Finally, the pavement performance of an epoxy ultra-thin overlay (EUTOL) prepared with EA and steel slag was tested. The results show that the epoxy resin particles increase with the increase in epoxy resin dosage, and at 40%, its epoxy particles are uniformly distributed with the most significant area share. With the addition of epoxy resin, the needle penetration of EA decreases and then increases, the flexibility decreases at a slower rate, and the softening point rises significantly. Moreover, the growth of the elastic component in EA significantly improved the high-temperature viscoelastic properties. Considering its physical and rheological properties, the optimal doping amount of 40% was selected. By analyzing the curing behavior of EA (optimum dosage), the combination temperature of EA is 150 °C, which meets the needs of mixing and paving asphalt mixtures. After 12 h of maintenance at 120 °C, its reaction is sufficient. The skid-resistance durability, high-temperature, low-temperature, water stability, and fatigue resistance of UTOL can be effectively improved using steel slag coarse aggregate. [ABSTRACT FROM AUTHOR]

Monitoring pavement conditions using crowdsourced vehicular data can significantly contribute to real-time and cost-effective pavement maintenance decision-making. This paper presents the development of various machine learning models for predicting crucial pavement characteristics essential for ensuring roadway safety, including roadway longitudinal grade, cross slope, international roughness index, surface rutting, and pavement skid resistance. The study collected vehicular sensing data and paired it with field pavement characteristics obtained using innovative instruments on selected asphalt and concrete sections in Oklahoma. Seven machine learning models were trained using the AutoGluon platform, yielding highly accurate predictions for safety-related roadway characteristics. The weighted ensemble L2, random forest, and category boosting (CatBoost) models exhibited the highest accuracy, with R-squared values exceeding 0.9, while the k-nearest neighbor algorithm and LightGBM models showed lower competitiveness. The inference latency of the models varied, with CatBoost demonstrating the lowest latency and weighted ensemble L2 achieving the highest accuracy at the expense of slightly higher inference latency. The choice of model depends on the specific application, whether it be pavement network management or real-time roadway condition monitoring. The findings from this research empower transportation agencies to efficiently screen the pavement network for further inspection or maintenance, thus enhancing transportation safety by providing instant alerts to drivers about potential high-risk pavement sections, resulting in safer and more reliable transportation infrastructure. [ABSTRACT FROM AUTHOR]

Yttria-doped tetragonal zirconia polycrystalline (Y-TZP) is one of the most widely used materials in thermal applications and as a structural component due to its mechanical properties. Its drawbacks are the high cost of the starting raw materials and its polymorphic transformation to monoclinic phase associated with the occurrence of mechanical failures. In the present work, tetragonal zirconia materials were obtained by slip casting and also ZrO 2 /ZrSiO 4 composites by partially replacing the zirconia with low cost and high corrosion resistance zircon. The different parts showed a high microstructural homogeneity, as well as high hardness and Young's modulus (up to 16.7 and 354 GPa, respectively), even with the incorporation of 20 vol% zircon. The zircon-containing composites subjected to hydrothermal low-temperature degradation (LTD) at 205 °C for 240 h exhibited similar mechanical properties, unaffected microstructural integrity, and a crystallographic phase composition equal to the as-sintered samples, without phase transformation from t-ZrO 2 to m-ZrO 2. [ABSTRACT FROM AUTHOR]

Copyright of Smart Rail Transit is the property of Smart Rail Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accurate assessment of road pavement friction is crucial for maintaining road safety. This study explores the prediction of the friction coefficient (µ) using 3D texture parameters of pavement surfaces. Measurements were conducted on 17 different rural road sections using the Traction Watcher One (TWO) for friction coefficients and a newly developed Static Road Scanner (SRS) for surface texture. Multiple linear regression models were created, incorporating texture parameters such as the valley material portion (Smr2,MIC), arithmetic mean peak curvature (Spc,MAC), and dale void volume (Vvv,PS). The results demonstrate a strong correlation between texture characteristics and friction, with R2 values up to 0.80 and an RMSE as low as 0.076, validating the model's accuracy. This approach highlights the potential of using non-contact texture measurements for reliable prediction of friction, offering a significant advancement in pavement management and safety. [ABSTRACT FROM AUTHOR]

This study seeks to identify the most suitable pavement texture resolution for accurately representing friction properties, employing the Dynamic Friction Model (DFM). Friction and texture measurements were conducted on various pavement surfaces at resolutions ranging from 10 μm to 5000 μm. Results indicate that the optimal resolution for accurate representation is unexpectedly found to be 500 μm, aligning with the Microtexture/Macrotexture limit. This contradicts current trends emphasizing higher resolutions for pavement surface representation. The article provides a foundational exploration, prompting discussions and further investigations into determining the ideal resolution for characterizing pavement surfaces in the context of friction properties. [ABSTRACT FROM AUTHOR]

This study evaluates the laboratory and field performance of stone mastic asphalt (SMA) mixtures with nominal maximum aggregate sizes (NMAS) of 9.5, 8.0, and 5.6 mm. Aggregates and fine aggregates of these sizes were produced using an impact crusher and a polyurethane screen. Mix designs for SMA overlays on aged concrete pavement were developed. Laboratory tests assessed rutting performance using full-scale accelerated pavement testing (APT) equipment and reflective cracking resistance using an asphalt mixture performance tester (AMPT). Field evaluations included noise reduction using CPX equipment, skid resistance using SN equipment, and bond strength using field cores. Results showed that for 8.0 mm SMA mixtures to achieve the same rutting performance as 9.5 mm SMA, PG76-22 grade binder was required, whereas 5.6 mm SMA required PG82-22. The 8.0 and 5.6 mm SMA mixtures showed 22.2% and 25% reduced crack progression, respectively, compared with the 9.5 mm SMA mixtures. Field evaluations indicated that 8.0 mm and 5.6 mm SMA pavements reduced tire–pavement noise by 1.7 and 0.8 dB, increased skid resistance by 8.5% and 2.0%, and enhanced shear bond strength by 150%, compared with 9.5 mm SMA. Overall, the 8.0 mm SMA mixture on aged concrete pavement demonstrated superior durability and functionality toward sustainable pavement systems. [ABSTRACT FROM AUTHOR]

The alternating stress caused by periodic high-pressure injection and extraction in gas storage can potentially induce fault slippage, compromising the sealing integrity of faults within these storages sites. Understanding the mechanical behavior of faults under alternating stress is crucial for ensuring the long-term stability and safety of gas storage operations. To explore the impact of fault dip angle and fault gouge strength on fault slip characteristics, fault samples were prepared with uniaxial compressive strengths of 20.1, 30.2, 42.4, and 51.4 MPa at two distinct dip angles. Triaxial compression experiments were conducted under alternating stress conditions corresponding to operational pressures at a specific gas storage site in China. The results indicate that faults with dip angles of 30° and 45° tend to fail at their weakest points. The increasing strength of fault gouges shifts failure mechanisms from interfacial failure between gouges and the surrounding rock towards internal gouge failure, often accompanied by shear failure across sections, resulting in characteristic "X"-shaped conjugate shear failures. The decrease in the ratio of bedrock strength to fault gouge strength elucidates the observed phenomena of an initial reduction followed by increased fault deformation. Transition points for faults with 30° and 45° dips occur around the strength ratios of 1.7/1 and 1.2/1, respectively. Fault damage exhibits a negative correlation with fault gouge strength and a positive correlation with fault dip angle. Samples with a higher-strength fault gouge at a 30° dip angle generally incur less damage compared to those with a lower-strength fault gouge at a 45° dip angle. Moreover, higher maximum static friction coefficients denote greater fault resistance to slipping, with 30° faults consistently demonstrating superior resistance compared to 45° faults. Additionally, a higher-strength fault gouge consistently enhances slip resistance under identical dip angles. [ABSTRACT FROM AUTHOR]

At present, there are few research studies on the durability of microsurfacing. To further improve the service quality and durability of microsurfacing, five kinds of polymer‐modified emulsified asphalt were used to prepare microsurfacing mixture. Based on the mixing time, wet track abrasion test, and load wheel test, the composition rationality of the microsurfacing mixture was verified. The influence of different polymer‐modified emulsified asphalt on the water damage resistance, deformation resistance, and skid resistance of the microsurfacing was analyzed. The destructive effects of complex climatic conditions on the microsurfacing were simulated by means of damp heat aging, freeze‐thaw cycle, and xenon lamp light aging treatment. Taking the wear resistance and pull‐off properties after aging treatment and the change rate of various properties before and after treatment as evaluation indexes, the bonding durability of the microsurfacing was comprehensively evaluated by the ideal point method of entropy weight. The results show that the water damage resistance, abrasion resistance, and deformation resistance of the microsurfacing have a high correlation with the mechanical strength and adhesion performance of the modified emulsified asphalt binder. Xenon lamp aging has a significant impact on the bonding performance of the microsurfacing. Waterborne epoxy resin can effectively improve the bonding performance and bonding durability of the microsurfacing. Waterborne polyurethane can improve the freeze‐thaw resistance and xenon lamp aging resistance of the microsurfacing. [ABSTRACT FROM AUTHOR]

Background: With orthopedic surgery increasing year on year, the main challenges in bone drilling are thermal damage, mechanical damage, and drill skid. The need for new orthopedic drills that improve the quality of surgery is becoming more and more urgent. Methods: Here, we report the skidding mechanism of drills at a wide range of inclination angle and propose two crescent drills (CDTI and CDTII). The anti-skid performance and drilling damage of the crescent drills were analyzed for the first time. Inclined bone drilling experiments were carried out with crescent drills and twist drills and real-time drilling forces and temperatures were collected. Results: The crescent drills are significantly better than the twist drill in terms of anti-skid, reducing skidding forces, thrust forces and temperature. The highest temperature is generated close to the upper surface of the workpiece rather than at the hole exit. Finally, the longer crescent edge with a small and negative polar angle increases the rake angle of the cutting edge and reduces thrust forces but increases skidding force and temperature. This study can promote the development of high-quality orthopedic surgery and the development of new bone drilling tools. Conclusion: The crescent drills did not skid and caused little drilling damage. In comparison, the CDTI performs better in reducing the skidding force, while the CDTII performs better in reducing the thrust force. [ABSTRACT FROM AUTHOR]

Distinguished from traditional vulcanized rubber, which is not reusable, thermoplastic elastomer (TPV) is a material that possesses both the excellent resilience of traditional vulcanized rubber and the recyclability of thermoplastic, and TPVs have been widely studied in both academia and industry because of their outstanding green properties. In this study, new thermoplastic elastomers based on solution polymerized styrene butadiene rubber (SSBR) and thermoplastic elastomers (SEPSs/SEBSs) were prepared by the first dynamic vulcanization process. The high slip resistance and abrasion resistance of SSBR are utilized to improve the poor slip resistance of SEPSs/SEBSs, which provides a direction for the recycling of shoe sole materials. In this paper, the effects of different ratios of the rubber/plastic phase (R/P) on the mechanical properties, rheological properties, micro-morphology, wear resistance, and anti-slip properties of SSBR/TPE TPVs are investigated. The results show that the SSBR/TPE TPVs have good mechanical properties. The tensile strength, tear strength, hardness, and resilience of the TPVs decrease slightly with an increasing R/P ratio. Still, TPVs have a tensile strength of 18.1 MPa when the ratio of R/P is 40/100, and this reaches the performance of the vulcanized rubber sole materials commonly used in the market. In addition, combined with microscopic morphology analysis (SEM), it was found that, with the increase in the R/P ratio, the size of the rubber particles gradually increased, forming a stronger crosslinking network, but the rheological properties of TPVs gradually decreased; crosslinking network enhancement led to the increase in the size of the rubber particles, and the increase in the size of rubber particles made the material in the abrasion of rubber particles fall easily, thus increasing its abrasion volume. Through dynamic mechanical analysis and anti-slip tests, when the R/P ratio was 40/100, the tan δ of TPVs at 0 °C was 0.35, which represents an ordinary vulcanized rubber sole material in the market. The viscoelasticity of TPVs increased with the increase in the R/P ratio, which improved the anti-slip performance of TPVs. SSBR/TPE TPVs are expected to be used in footwear and automotive fields due to their excellent abrasion resistance and anti-slip performance. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There are many examples of steel structures subjected to severe environmental conditions with bolted connections directly exposed to climatic agents such as steel bridges, mining transfer towers, wind towers etc. In this experimental research, non‐slip joints with M16 and M20 bolts have been studied. The specimens were subjected to fourteen 12 h freeze‐thaw cycles, with periodic immersion in water and temperature oscillation. Subsequently, the connections were subjected to a slip test under monotonic load. The results were compared with other equal joints not subjected to freeze‐thaw cycles and kept at room temperature for the same time. Some interesting conclusions are extracted from this piece of research. It was observed that freeze‐thaw cycles negatively affect the slip resistance of non‐slip joints with GB+ZE surfaces, even with a slight increase in clamping force. Samples with SR and GB surfaces increase in their slip resistance was observed. [ABSTRACT FROM AUTHOR]

This study investigates the skid resistance performance of asphalt mixtures containing composite aggregates of basalt and limestone. The research aimed to predict the service life of the asphalt mixtures and identify the optimal basalt content for enhanced performance. Using an accelerated friction tester, friction indices such as the British pendulum number (BPN), mean texture depth (MTD), and dynamic friction coefficient (Dµ) were measured. The study conducted accelerated wear tests on mixtures with varying basalt contents under different water flow rates and loads. Results indicate that anti-skid performance decreased with increasing water flow, load, and wear cycles, initially showing a sharp decline followed by a gradual stabilization. Orthogonal experiments determined that basalt content had the most significant impact on skid resistance, followed by load and water flow rate. By converting skid resistance and MTD values into IFI values, a four-area diagram was created to illustrate skid resistance deterioration. The four-area IFI diagram also demonstrated that higher basalt content significantly enhances the skid resistance and service life of asphalt mixtures. Cost analysis based on life prediction showed that a 40% basalt content mixture is cost effective while maintaining excellent skid resistance. A test section study further validated that a 40% basalt content ensures good skid resistance, with indoor test predictions aligning closely with field data. Although the test section has been operational for only two years, ongoing monitoring will provide further insights into long-term skid resistance performance. [ABSTRACT FROM AUTHOR]

Skid resistance is a critical aspect for traffic safety since it significantly influences vehicle control and minimizes the distance required for emergency braking. The surface characteristics of pavements play a pivotal role in determining skid resistance. To achieve the optimal skid resistance performance, the pavement must sustain a specific level of friction. Thus, it is advantageous to apply surface treatments in areas that require enhanced friction. This study investigate the impact of factors such as the aggregate source, size, morphological properties, and abrasion levels on the skid resistance and frictional characteristics of a high-friction surface treatment (HFST). A complete investigation was conducted on HFST samples by analyzing the aggregate morphology using the Aggregate Image Measurement System and performing Micro-Deval abrasion testing. The skid resistance was evaluated with the British Pendulum Tester (BPT). The findings revealed that different aggregates and sizes exhibited varying behaviors post-polishing. Notably, fine-sized aggregates demonstrated higher British pendulum number (BPN) values, which indicate superior frictional performance. Models that predicted skid numbers based on the average texture and angularity indices initially demonstrated the balanced influences of both morphological properties before polishing. However, after polishing, the surface texture emerged as the primary determinant of the skid resistance, which overshadowed the angularity's impact. [ABSTRACT FROM AUTHOR]

Pavement skid resistance plays a crucial role in ensuring road safety and avoiding accidents. In the past, the laboratory evaluation of the skid resistance was carried out by studying only the coarse aggregates of the wearing course. To overcome this drawback, the Wehner-Schulze (WS) machine was developed in Germany in the 1960s. This equipment, composed of a polishing unit and a measuring unit, has great potential in predicting pavement skid resistance and its evolution over time, but is still little known in the pavement community (especially outside Europe). For these reasons, there is a need of a comprehensive review of the existing technical-scientific literature concerning the use of the WS machine. Specifically, this paper focuses on the main factors affecting the skid resistance in WS tests, the correlation of WS data with other laboratory test methods and with field skid resistance/polishing, and the available prediction models that have been validated through WS measurements. The critical analysis of the existing literature highlights that it is possible to correlate WS data with typical skid resistance field measurements as well as WS polishing with traffic polishing, but further efforts are needed in this regard. Future work should focus especially on open-graded mixtures and innovative asphalt mixtures (e.g., containing recycled materials and additives). From the perspective of pavement management, based on a theoretical background, the WS test results could be used as starting point for simplified prediction models of the in-situ skid resistance.

Abstract Background With orthopedic surgery increasing year on year, the main challenges in bone drilling are thermal damage, mechanical damage, and drill skid. The need for new orthopedic drills that improve the quality of surgery is becoming more and more urgent. Methods Here, we report the skidding mechanism of drills at a wide range of inclination angle and propose two crescent drills (CDTI and CDTII). The anti-skid performance and drilling damage of the crescent drills were analyzed for the first time. Inclined bone drilling experiments were carried out with crescent drills and twist drills and real-time drilling forces and temperatures were collected. Results The crescent drills are significantly better than the twist drill in terms of anti-skid, reducing skidding forces, thrust forces and temperature. The highest temperature is generated close to the upper surface of the workpiece rather than at the hole exit. Finally, the longer crescent edge with a small and negative polar angle increases the rake angle of the cutting edge and reduces thrust forces but increases skidding force and temperature. This study can promote the development of high-quality orthopedic surgery and the development of new bone drilling tools. Conclusion The crescent drills did not skid and caused little drilling damage. In comparison, the CDTI performs better in reducing the skidding force, while the CDTII performs better in reducing the thrust force.

A high number of old buildings are currently being demolished and also volumes of waste are produced every year. The aggregates obtained from construction and demolition waste (CDW) can be exploited as a renewable resource and an economical alternative to natural materials. In this study, the possibility of constructing roller-compacted concrete pavements (RCCPs) from the nonselected recycled CDWs was evaluated. For this purpose, the waste was acquired from the landfill site in Line 4 of the Hesar zone, located in Iran. In total, 12 samples and four combinations were used for the experimental production of the RCCP from the CDW. Geotechnical laboratory tests, including modulus of elasticity (MOE), compressive strength, skid resistance, flexural strength, and split tensile strength, were employed to characterize samples and combinations. The results of this study indicated that both the compressive strength and flexural strength of the concrete made from the recycled mixtures were 14% higher and 15% lower than those of the control mixture, respectively. The split tensile strength ratio and the ratio of flexural strength to compressive strength were also lower and higher than those of the control mixture, respectively. Comparing the different recycled mixes revealed that the RCCP-C-F50 mixture had higher compressive and flexural strength than the others, and thus it is recommended for use in future works. Moreover, test results revealed that recycled aggregates (RAs) can be used for producing RCCPs and could be of great help to engineering in terms of solving the problems facing CDW landfill sites, and this study can also play an important role in realizing sustainable development. [ABSTRACT FROM AUTHOR]

Skid resistance of pavement plays a vital role in transportation safety, and it continuously deteriorates because the pavement was exposed to traffic and environmental loadings. Although the evaluation law of asphalt pavement skid resistance has been intensively studied, few has focused on its impact on driving safety. To close this knowledge gap, the current study used the CarSim/Simulink simulation and back-propagation (BP) neural network method to establish the relationship between pavement characteristics and vehicle driving safety. The skid resistance performances of nine types of asphalt mixture specimen were evaluated using a full life cycle dynamic friction testing machine (LCDFM), and results showed that the deterioration rate of the dynamic friction coefficient (μLCDFM) first increases rapidly, then slowly decreases and finally stabilizes. The early-stage increase resulted from the polish of asphalt film from the aggregate surface. The simulation studies indicated that driving speed exhibits the most significant impact on driving safety, followed by vehicle type, mean texture depth (MTD), and polishing time. The MTD is negatively correlated with μLCDFM , and the other factors are positively correlated. The driving safety rankings of the three pavement types and three gradations examined are open-graded friction coarse (OGFC) > stone mastic asphalt (SMA) > asphalt concrete (AC). Meanwhile, a greater value of nominal maximum aggregate size (NMAS) also induces better driving safety owing to the more abundant surface macrotexture. The research findings from this study provide reference to the materials design and pavement skid resistance prediction. [ABSTRACT FROM AUTHOR]

The frictional properties of aggregates play a significant role in determining pavement skid resistance. To preserve natural aggregates, reclaimed asphalt pavement (RAP) has been widely used for decades. However, its use in pavement surface courses is often limited due to its unknown frictional properties. Therefore, this research aimed to quantitatively investigate both aggregates and RAP to develop a quick evaluation method for frictional properties. Nine types of aggregates from Tennessee were selected for relative frictional tests. X-ray fluorescence was utilized to quantify the silica dioxide (SiO2) contents, establishing correlations with polish stone value (PSV), micro-Deval (MD) abrasion loss, and surface morphological characteristics of aggregates tested via the aggregate image measurement system. Subsequently, to develop a quick way to measure the SiO2 of RAP, laboratory-produced RAP and field-sampled RAP were compared. Laboratory-produced RAP was fabricated and compared with chemical trichloroethylene (TCE) and a hammer-crushed processing method to accurately measure the SiO2 content for the application of field-sampled RAP. Field pavement friction tests were conducted to correlate the laboratory findings to field measurements. Results show that the coefficients of determination (R2) of SiO2 from raw aggregates with PSV, MD loss, and texture loss are 0.81, 0.60, and 0.78, respectively. Field-sampled RAP washed by TCE three times could provide more accurate SiO2 content compared with hammer crushing. The field pavement friction test demonstrates that pavements with lower SiO2 contents exhibit reduced skid resistance due to texture loss caused by traffic polishing. These findings offer a straightforward method for evaluating pavement friction and selecting RAP with high skid resistance, where higher SiO2 content provides higher friction properties. As a result, this research provides a valuable strategy for the rapid evaluation of aggregates and RAP for skid resistance. [ABSTRACT FROM AUTHOR]

Precipitation hardening, a cornerstone of alloy strengthening, finds widespread application in engineering materials. Comprehending the underlying mechanisms and formulating models bear crucial significance for engineering applications. While classical macroscopic theoretical models based on the line tension model have historically guided research efforts, their reliance on simplifications, assumptions, and parameter adjustments limits their predictability and expansibility. Moreover, the challenge of understanding the intricate coupling effects among various hardening mechanisms persists. One fundamental question to achieve the transition of material design paradigms from empirical trial-and-error methods to predictive-and-design approaches is to develop more physics-based multiscale modelling methods. This review aims to elucidate the physical mechanisms governing precipitation hardening and establish a tailored bottom-up multiscale modelling framework to steer the design of new alloys. The physical scenarios of precipitation hardening are firstly summarized, including particle shearing, Orowan bypass, and dislocation cross-slip and climb. Afterwards, an in-depth discussion is given regarding the application of macroscopic models and their correlation with the mechanisms and precipitation characteristics. As for the multiscale modelling methods, we categorize them into three main types: slip resistance based approaches, misfit stress field based approaches, and energy based approaches. By integrating multiscale modelling with the physical scenarios, we systematically addressed the key idea of the multiscale coupling framework, and their scale transfer procedure, applicability, advantages, and limitations. Some examples of coupling different types of multiscale methods and considering precipitates with complicated shapes are also presented. This study not only furnishes insightful comprehension of precipitation hardening, but also guides the development of multiscale modelling methodologies for other types of hardening effects in alloys. [ABSTRACT FROM AUTHOR]

Surface course is an important constituent part of highway pavement structures with complex stress conditions. These conditions result in difficulty for the traditional mix proportion design method to simulate actual situation in asphalt mixture production and construction. In order to conform the actual load bearing situation of highway asphalt pavement mixtures, the study proposed to use Superpave method to design the mix ratio of asphalt mixture, and compared the pavement performance of SMA and AC asphalt mixtures designed by Marshall design method. By Marshall compaction test of three types of asphalt mixtures designed by two mix proportion design methods, the optimal asphalt-aggregate ratios of SMA-16, Superpave-16, and AC-16I were determined. Thereafter, according to the current standard test method, the immersion Marshall test, low temperature bending test, 60 °C rutting test and indirect tensile fatigue test were carried out on three types of asphalt mixtures, and analyzed the pavement performance test results comparatively. On this basis, the related factors affecting the pavement performance of the three asphalt mixtures were analyzed. Test results show that, the optimal asphalt-aggregate ratio of SMA-16 is considerably higher than those of Superpave-16 and AC-16I, indicating that the greater the amount of fine aggregate, the higher the asphalt content. Pavement performance test results manifest the significantly better high-temperature stability and skid resistance of SMA-16 and Superpave-16 than AC-16I, which can lengthen the service life of highway asphalt pavements. The conclusions provide a significant theoretical reference for applying the Superpave design method to the mix proportion design of asphalt mixtures. [ABSTRACT FROM AUTHOR]

The surface texture of asphalt pavement has a significant effect on skid resistance performance. However, its contribution to the performance of skid resistance is non‐homogeneous and subjects to local validity. There are also a few deep learning models that take into account the effective contact texture region. This paper proposes a convolutional neural network model based on the effective contact texture region, containing macro‐ and micro‐scale awareness sub‐modules. In this study, the asphalt mixture with varying gradations was designed to accurately obtain the effective contact texture region. Then, the textures were disentangled into macro‐ and micro‐texture scales by applying the fast Fourier transform and fed into the model for training. Finally, the area of effective contact texture region was calculated, and the effective contact ratio parameter was then proposed using the triangulation algorithm. The results showed that the effective contact texture area of pavement varies by the asphalt mixture type. The effective contact ratio parameter exhibited a significant positive correlation (Pearson correlation coefficient is 0.901, R2= 0.8129) with skid resistance performance and was also influenced by key sieve aggregate content from 2.36 to 4.75 mm. The data of effective contact texture region following disentanglement significantly released the model performance (the relative error dropped to 1.81%). The model exhibited improved precision and performance, which can be utilized as an efficient, non‐contact alternative method for skid resistance analysis. [ABSTRACT FROM AUTHOR]

Pavement maintenance is significant to maintain an efficient and safe operation of the road network and meet the need of the drivers and their vehicles. The soundness of the pavement layers affects the overall performance of the pavement, with surface course being the layer that requires high quality materials to withstand direct contact with repeated traffic loading in all weather conditions. Surface treatments are a common maintenance measure to maintain serviceability, safety, and pavement longevity. In this paper, a surface treatment named cold microsurfacing containing water-based epoxy-modified bitumen emulsion (WEB), a more eco-friendly and cost-effective material than conventional microsurfacing, is studied in the laboratory. Three laboratory tests were conducted to characterise microsurfacing: sand patch test, pendulum test and indirect tensile strength test (IDT). Volumetric properties and microscopic analysis of the compacted specimens using a digital microscope are also shown. The results showed that unmodified bitumen emulsion samples had higher air void content (%) than WEB samples and higher mass loss. Overall, WEB samples exhibited fluctuating curing rates although storing conditions were similar to all tested samples. Voids filled with asphalt (VFA) (%) and voids in mineral aggregate (VMA) (%) were higher for unmodified bitumen emulsion samples and VFA results from all samples indicated an equally effective coating of aggregates. WEB samples exhibited better skid resistance characteristics and greater braking resistance than unmodified bitumen emulsion samples. IDT strength tests were comparable for all samples. [ABSTRACT FROM AUTHOR]

Pavement texture and skid resistance are pivotal surface features of roadway to traffic safety, especially under wet weather. Engineering interventions should be scheduled periodically to restore these features as they deteriorate over time under traffic polishing. While many studies have investigated the effects of traffic polishing on pavement texture and skid resistance through laboratory experiments, the absence of real-world traffic and environmental factors in these studies may limit the generalization of their findings. This study addresses this research gap by conducting a comprehensive field study of pavement texture and skid resistance under traffic polishing in the real world. A total of thirty pairs of pavement texture and friction data were systematically collected from three distinct locations with different levels of traffic polishing (middle, right wheel path, and edge) along an asphalt pavement in Oklahoma, USA. Data acquisition utilized a laser imaging device to reconstruct 0.01 mm 3D images to characterize pavement texture and a Dynamic Friction Tester to evaluate pavement friction at different speeds. Twenty 3D areal parameters were calculated on whole images, macrotexture images, and microtexture images to investigate the effects of traffic polishing on pavement texture from different perspectives. Then, texture parameters and testing speeds were combined to develop friction prediction models via linear and nonlinear methodologies. The results indicate that Random Forest models with identified inputs achieved excellent performance for non-contact friction evaluation. Last, the friction decrease rate was discussed to estimate the timing of future maintenance to restore skid resistance. This study provides more insights into how engineers should plan maintenance to restore pavement texture and friction considering real-world traffic polishing. [ABSTRACT FROM AUTHOR]

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To date, the exploration of multi-principal element alloys (MPEAs) has rarely ventured into the realm of hexagonal close-packed (HCP) structures. In this research, we embarked on a pioneering systematic comparison between a single-phase Ti-Zr-Hf HCP-MPEA and Ti regarding their dislocation activities and mesoscale deformation homogeneity. Through large-area high-resolution quasi-in-situ slip trace analysis and crystal plasticity finite element modeling, we identified HCP-MPEA's significantly enhanced pyramidal slip activities—resulted from minimized disparities among different deformation modes—notably improve the material's intragranular deformation homogeneity. Alongside MPEA's intrinsically high slip resistance, it renders HCP-MPEA an outstanding strength-toughness combination relative to its conventional HCP counterparts. [ABSTRACT FROM AUTHOR]

Turkey's Highway Technical Specification (HTS) necessitates gritting of pavement surface courses for the regions where the high-polishing resistant aggregate (PSV ≥ 50) is lacking or hard to reach. The gritting is defined as the spreading of 1–3 mm magmatic origin aggregates with the rate of 1.5–2 kg/m2 to the pavement surface after the roller's first pass. This study investigates the effect of gritting construction parameters (aggregate type, size, amount, and time of spreading) on pavement surface texture and skid resistance by monitoring the performance of nine test sections over more than three years under real traffic and environmental conditions. Considering the field observations, reduction in skid resistance with respect to traffic, in terms of equivalent standard axle load, is modeled for all test sections, and their service life is calculated. The results show that test sections gritted with the slag-origin aggregates perform better and yield nearly twice the service life of the one specified in the HTS. Accordingly, using slags in pavement gritting would provide safer and more sustainable highways. [ABSTRACT FROM AUTHOR]

Glaciers and ice streams flowing over sediment beds commonly have a layer of ice‐rich debris adhered to their base, known as a "frozen fringe," but its impact on basal friction is unknown. We simulated basal slip over granular beds with a cryogenic ring shear device while ice infiltrated the bed to grow a fringe, and measured the frictional response under different effective stresses and slip speeds. Frictional resistance increased with increasing slip speed until it plateaued at the frictional strength of the till, closely resembling the regularized Coulomb slip law associated with clean ice over deformable beds. We hypothesize that this arises from deformation in a previously unidentified zone of weakly frozen sediments at the fringe's base, which is highly sensitive to temperature and stress gradients. We show how a rheologic model for ice‐rich debris coupled with the thermomechanics of fringe growth can account for the regularized Coulomb behavior. Plain Language Summary: Many glaciers move by sliding over sediment beds. As the glacier flows downslope, ice can infiltrate the underlying sediments, forming a layer of ice‐rich debris attached at the glacier's base. We investigated how this frozen fringe impacts glacier motion by simulating glacier slip in a cold‐room facility with a specialized ring shear device. We recreated glacier conditions, sliding ice over granular beds to form the fringe, and then assessed how frictional resistance at the slip interface varied under different stresses and ice speeds. We found that frozen fringe influences the relationship between ice speed and frictional resistance, known as the "slip law." As ice speed increased, basal friction increased to a threshold that matches the strength of the ice‐free sediment bed—mirroring the "regularized Coulomb slip law" inferred for clean ice over soft beds. We attribute this behavior to deformation in a weakly frozen zone at the base of the frozen fringe and show how this behavior can be incorporated into existing parameterizations of glacier slip. Key Points: Ring shear experiments show frozen fringe alters basal slip dynamics for soft‐bedded glaciersDeformation in a zone of weakly frozen sediments within the fringe leads to a regularized Coulomb slip response [ABSTRACT FROM AUTHOR]

Current UK specifications permit up to 10% of reclaimed asphalt (RA) to be routinely incorporated into surface courses. The incorporation of RA provides significant economic and environmental benefits by effectively using recycled materials. Trials of thin surface course systems incorporating more than 10% RA have been installed on the strategic road network since 2004, and have demonstrated the feasibility of incorporating higher RA contents and the necessary quality controls. The trial sites have now been in service for a significant period, providing an opportunity to understand their performance. Current practice and trials undertaken for >10% RA contents in the UK are summarised in this paper. Detailed analysis of the performance of junctions 6–7 and 7–8 of the M25 clockwise (23% RA, installed in 2007) and junctions 7–6 of the M25 anti-clockwise (40% RA, installed in 2009) is presented. Quantifiable evidence regarding the performance of surface course materials containing RA > 10% is provided. The analysis demonstrates that surface courses containing RA have performed equivalently to control sections containing no RA over a significant period of time. The trials indicate that the inclusion of RA, when subject to the appropriate quality control processes, has had no detrimental impact on skid resistance. The conclusions support the incremental increase of the maximum permitted RA content from 10% to 20% with appropriate quality controls in the future revision of PD 6691:2015. [ABSTRACT FROM AUTHOR]

Reliable determination of rate-and-state friction (RSF) parameters depends on achieving steady-state (SS) friction conditions before and after experimental velocity-stepping friction tests. This operation, through nonlinear least squares fitting, is commonly preceded by the removal of any overall slip weakening/hardening after friction velocity steps (VSs) through a sufficiently large window of slip displacement at SS ( = linear detrend). However, to date, the identification of SS and thus the correct linear detrend is dependent on the user, which potentially results in differing RSF outputs from the same data set. Here, we demonstrate that large errors in the determination of the fitted RSF parameters can result if SS conditions are not reached before and after VSs. Such errors can be particularly relevant for materials characterized by long evolution of frictional resistance with slip, such as clay-rich gouge layers, in which identifying SS after VSs is not always obvious. To this end, we propose a methodology to accurately and consistently identify where SS is achieved after VSs. This methodology is coded into a new MATLAB-based routine, steadystate. We show the key features of the methodology, as well as how to use steadystate and read its output. We also illustrate the broad applicability of the approach to friction data with different noise levels and sampling frequencies referenced to slip velocity, by reviewing observations from synthetic data sets and specific examples of experiments from different laboratories involving various sheared materials. [ABSTRACT FROM AUTHOR]

Post-doping construction technology overcomes the difficulties of demanding construction requirements of warm-mix epoxy asphalt mixture (EAM) that limit its application, and it provides a new idea for the scaled application of EAM. To provide reliable support for the application of an epoxy asphalt ultrathin overlay (EAUTO), warm-mix EAM was prepared by simulating the post-doping method in the lab, and the Marshall molding method with reduced specimen thickness was considered. EAUTO moisture susceptibility, raveling resistance, and cracking resistance were evaluated to verify the feasibility of EAUTO molding. Furthermore, EAUTO long-term skid resistance and stripping resistance were analyzed in detail. The results showed that thin-layer molding solves the problem of the inappropriateness of conventional Marshall stability equipment for EAM and has cost-saving and efficiency advantages. The recommended molding parameters for the warm-mix EAUTO were 25 blows/face and a thickness of 30.0±0.6 mm. Despite the reduction in specimen thickness, moisture damage resistance and raveling resistance of the thin-layer EAM specimens were slightly attenuated compared with the original specimens but were acceptable, and the mechanical properties were still better than those of SBS-modified asphalt. Regarding cracking resistance, the evaluation results for the thin-layer specimens demonstrate consistency with those of the original specimens. Additionally, the cracking resistance of gap-graded mixes was better than that of dense-graded ones. The EAUTO showed excellent long-term stripping resistance and skid resistance durability compared with asphalt modified with styrene-butadiene-styrene (SBS). However, it is worth noting that the traditional texture depth was not suitable as a separate indicator for evaluating long-term skid resistance. [ABSTRACT FROM AUTHOR]

Background: Falls are a global concern affecting people of all ages; however, older adults are particularly vulnerable to age-related factors and foot-related issues. Footwear is critical for preventing falls, as it provides stability and protection against slips, trips, and falls (STFs). However, a significant gap exists in the systematic exploration of the safety aspects of footwear design for fall prevention in older adults. Methods: This comprehensive review applied a meticulous search strategy encompassing prominent databases, including Google Scholar, ScienceDirect, SCOPUS, MEDLINE, ResearchGate, and PubMed. This review synthesized and analyzed existing research to bridge knowledge gaps and provide insights into optimal footwear choices for older adults in terms of design features such as fit, fixation, heel height, collar height, slip resistance, and sole/ insole hardness. Results: The results underscore the importance of specific design features for preventing falls among older adults. A proper fit, secure fixation, appropriate heel and collar heights, slip resistance, and sole/insole hardness significantly contributed to fall prevention. These findings offer valuable guidance for optimizing footwear designs to enhance comfort, stability, and safety in the daily lives of older individuals. Conclusion: This comprehensive review fills a critical knowledge gap regarding the safety of footwear designs for fall prevention in older adults. The identified design features play a vital role in reducing the risk of falls and offer practical recommendations for the development of safer footwear. Ultimately, this study contributes to the existing knowledge base and supports efforts to prevent STFs in older adults through improved footwear design. [ABSTRACT FROM AUTHOR]

Traditional asphalt concrete (AC) and stone matrix asphalt (SMA), which are used as thin asphalt overlays, are common maintenance strategies to enhancing ride quality, skid resistance, and durability. Recently, several studies have used a novel asphalt mixture known as a high-friction thin overlay (HFTO) to improve surface characteristics. However, it remains uncertain whether the laboratory properties of HFTO differ significantly from those of conventional mixtures. This study aims to evaluate the laboratory properties of HFTO mixtures and compare them with those of AC and SMA. Those mixtures with nominal maximum size of 9.5 mm were produced in the laboratory, and performance tests were conducted, including wheel tracking test, low temperature flexural creep test, moisture susceptibility test, Cantabro Abrasion Test, Marshall Test, sand patch test, British pendulum test, and indoor tire-rolling-down test. The results showed that the HFTO exhibited a lower tire/pavement noise than the AC and SMA. Additionally, HFTO had superior high-temperature stability, larger macro texture, and higher skid resistance in comparison to those of AC, but lower than those of SMA. Consequently, HFTO mixtures may be considered a suitable replacement for traditional AC mixtures in regions where skid resistance and noise reduction are concerns. [ABSTRACT FROM AUTHOR]

This paper presents a procedure to estimate runway overrun risks of landing aircraft under different combinations of operating factors, including aircraft landing weight, landing speed, landing location, pavement skid resistance, and runway length. The procedure consists of two main parts: determination of braking distance, and calculation of overrun risk. A significant contribution is the determination of available skid resistance as a function of aircraft speed and pavement conditions in the calculation of braking distance. Any aircraft type as well as dimensions of pavement grooves, if present, can be considered. The impacts of low skid resistance on overrun risk, owing to either wet weather conditions, traffic polishing effect on pavement surface texture, or changes of groove dimensions caused by contamination or load-induced deformation, are considered. A demonstrative example is presented to (1) calculate the braking distances of a B777 aircraft for different landing weights, landing speeds, pavement groove dimensions, and pavement skid resistance states; and (2) determine the corresponding overrun risks as a function of aircraft landing speed, landing location, and available runway length. Compared with existing overrun risk prediction methods, the proposed method is unique in that it deterministically considers airport- and runway-related factors in the overrun risk calculation, and it does not require any historical incident and accident data. It estimates aircraft-specific overrun risk for the specific runway analyzed under actual runway operating conditions. [ABSTRACT FROM AUTHOR]

Staple yarn is the basic element of most textiles, and its strength affects the performance and processing efficiency of the final textile products. Meanwhile, its strength is the combination of the resistance to breakage and slip of fibers in the yarn. In this paper, a computational model is proposed to predict the strength of staple yarn. The resistance to breakage and slip of each fiber were first computed based on the random arrangement of the fibers and the idealized yarn structure, and the strength was computed by identifying fiber breakage or slip in the yarn breakage zone. The reliability and applicability of the model were verified on viscose and polyester ring-spun staple yarns. The results show that the mean error of prediction is mostly less than 5%, indicating that the model has good accuracy and applicability; and the correlation coefficient R is mostly greater than 0.95, indicating that the predicted strength is in good agreement with the tested strength. [ABSTRACT FROM AUTHOR]

The main bridge of Wanlong Bridge under construction is the first spatial self anchored suspension bridge with elliptical steel tower in the world. The saddle of this bridge adopts an self-adaptive space cable saddle combined with casting and welding, which has the following technical difficulties: the force of space cable saddle is complex. The longitudinal stiffness of the elliptical tower is large, and the slip resistance of the main cable saddle is prominent. The bottom of the saddle is a flexible support, the cable saddle and the main tower are co-deformed, and the tower-saddle connection structure is complicated in force transmission. In order to master the key technology of the main cable saddle and the tower-saddle connection structure of the self-anchored suspension bridge with elliptical tower and space cable, this paper carries out a systematic study by using numerical analysis method. The research conclusions are as follows: (1) When the bridge is subjected to (dead load+car+crowd+tap water+temperature+wind), the minimum friction coefficient µ that satisfies the requirements is 0.215, and the 12 mm vertical friction plates are required. (2) The maximum Von Mises stress and maximum vertical deformation of the main cable saddle under the condition of maximum cable force are 186.2 MPa and 1.572 mm, which meet the requirements of strength and stiffness. (3) In the structure connecting the main cable saddle and the steel tower, the force of the main cable saddle is transferred to the web of the steel tower in the form of vertical shear force through the supporting baffle. The shear force of the supporting baffle at the end is significantly greater than that of the middle baffle, and the non-uniformity coefficient of shear transfer is 1.29. (4) The support plate of the main cable saddle has a certain angle at the edge of the saddle area. The maximum longitudinal angle under the condition of empty cable is 0.366‰ rad, which should be taken into consideration in the saddle pushing construction. [ABSTRACT FROM AUTHOR]

This paper conducts an in-depth study and evaluation of pedestrian paths, with a particular focus on the anti-slip performance and walking comfort of wooden chip pedestrian walkways. Through controlled experiments, a comparative analysis was performed between wooden chip pedestrian walkways and ordinary paved brick walkways. The experimental results indicate that under dry conditions, the anti-slip performance of various road surfaces is good. However, in wet environments, the anti-slip performance of paved brick roads deteriorates significantly. In contrast, wooden chip pedestrian walkways, especially those mixed with asphalt and wood chips, exhibit excellent anti-slip properties and comfort. Additionally, the study reveals that the comfort of wooden chip pedestrian walkways is significantly better than that of paved brick walkways, and the comfort of asphalt materials is slightly better than emulsified asphalt. It is worth mentioning that fine wood chips provide less comfort than coarse wood chips. Although reducing the thickness can enhance comfort, considering the service life of the road, a thickness of 4–6 cm is most suitable. Finally, asphalt and wooden chip mixtures with coarse wood chips possess good water permeability, making them suitable for permeable drainage pavement designs, effectively reducing road surface water accumulation. [ABSTRACT FROM AUTHOR]

To accurately evaluate the skidding resistance of asphalt pavements, a texture imaging device was developed to realize the standardized acquisition of pavement images. Based on the gray-level co-occurrence matrix and multifractal theory of texture structure, the influence of segregation degree and gradation type on the texture properties of asphalt pavement was studied. Meanwhile, a comprehensive evaluation index of skidding resistance was proposed for asphalt pavement. Furthermore, the attenuation characteristics of the anti-skidding performance for asphalt mixture were explored, and the corresponding attenuation model of asphalt pavement was established. The results show that the segregation degree and gradation type significantly affected the texture parameters and anti-skidding performance of asphalt mixture. Specially, with an increase in the segregation degree of coarse aggregate, the parameters of energy, entropy, and multifractal spectrum width gradually increased, whereas the inertial moment gradually decreased. The variation range of the multifractal spectrum difference initially increased and subsequently decreased. For the texture parameters such as energy, entropy, inertial moment, and multifractal spectrum width Δα, the values of the asphalt mixture with larger nominal maximum particle were higher than those of the mixture with smaller nominal maximum particle, whereas the multifractal spectrum difference value showed the opposite law. In addition, the texture parameters of energy, entropy, and multifractal spectrum width exhibited good linear correlation with the texture depth (TD) of asphalt mixtures with various segregation levels and gradation types. The index based on the texture parameters of energy, entropy, and multifractal spectrum width effectively evaluated the skidding resistance of asphalt pavements, which showed the same trend as the TD with the increase of the abrasion number. The achievement provides an effective solution for the evaluation of skidding resistance and attenuation characteristics of asphalt mixtures. [ABSTRACT FROM AUTHOR]

The preparation of four types of epoxidized iron‐based comb butadiene‐isoprene rubber (EBIR) with different epoxidation degrees (4.7%, 6.4%, 10.2%, and 12.3%) was investigated for the first time in this study. The modification involved the use of hydrogen peroxide and formic acid as raw materials for the epoxidation process. Following this, silica/EBIR composites were prepared by mixing EBIR with silica nanoparticles, without the use of a silane coupling agent (SCA). The objective was to investigate the influence of the epoxidation degree on the structure and properties of the resulting silica/EBIR nanocomposites. The results indicated that the introduction of epoxy groups had a positive effect on the interfacial interaction between the rubber and filler, leading to improved dispersion of the silica nanoparticles in the rubber matrix. Consequently, the tensile properties, wet skid resistance, and abrasion resistance of the silica/EBIR composites were found to be superior to those of the un‐epoxidized silica/BIR composites. Furthermore, comparing the silica/EBIR‐12.3 nanocomposites with silica/BIR‐Si69 nanocomposites, it was revealed that silica/EBIR‐12.3 showed a 69.4% enhancement in wet skid resistance and an 8.0% reduction in rolling resistance. These findings demonstrate the potential of silica/EBIR composites for high‐performance tire tread rubber applications, offering environmental benefits and improved properties. [ABSTRACT FROM AUTHOR]

Tennis is a sport in which the surface plays an important role in performance and injury risk. Professional players face an extensive competition calendar in which they must adapt to different types of surfaces. However, unlike other sports, tennis lacks standards that regulate surface properties affecting athlete–surface interaction. The objective of this study was to mechanically evaluate shock absorption, vertical deformation, energy restitution and slip resistance in different types of tennis surfaces, compare them with each other and look for correlations between variables. Thirty-six tennis courts (12 hard court, 16 clay, 8 artificial grass) were evaluated. All variables differed significantly between surfaces (p < 0.001). Shock absorption (1.1 ± 0.5 to 13.9 ± 3.4%) and vertical deformation (0.02 ± 0.04 to 1.07 ± 0.19 mm) were lower on hard court compared to clay and artificial grass; energy restitution (72.5 ± 4.7 to 89.9 ± 1.5%) showed the opposite; and slip resistance (in Pendulum Test Value) was lower on clay (53.6 ± 2.5) compared to grass (61.4 ± 1.3) and hard court (66.6 ± 1.1). No significant correlations between variables were identified in hard court. However, both clay and artificial grass showed a significant positive correlation (p < 0.001) between shock absorption and vertical deformation (0.872 and 0.947, respectively), and a significant negative correlation (p < 0.001) between shock absorption and energy restitution (− 0.807 and − 0.981, respectively). Also, significant negative correlations were found between vertical deformation and energy restitution both in clay (− 0.802; p < 0.001) and artificial grass surfaces (− 0.890; p < 0.01). As for the shock absorption, only a significant negative correlation with vertical deformation in artificial grass (− 0.715; p < 0.05) was identified. This study contributes initial evidence for further research to inform future International Tennis Federation regulations aimed to assess and control the mechanical properties of tennis surfaces affecting athlete–surface interaction. [ABSTRACT FROM AUTHOR]