Search Results (43)

The permeability of porous asphalt pavements is a critical skid resistance indicator that directly influences driving safety on wet roads. To ensure permeability (water infiltration capacity), it is necessary to assess the degree of clogging in the pavement. This study proposes a permeability evaluation model for porous asphalt pavements based on 3D laser imaging and deep learning. The model utilizes a 3D laser scanner to capture the surface texture of the pavement, a pavement infiltration tester to measure the permeability coefficient, and a deep residual network (ResNet) to train the collected data. The aim is to explore the relationship between the 3D surface texture of porous asphalt and its permeability performance. The results demonstrate that the proposed algorithm can quickly and accurately identify the permeability of the pavement without causing damage, achieving an accuracy and F1-score of up to 90.36% and 90.33%, respectively. This indicates a significant correlation between surface texture and permeability, which could promote advancements in pavement permeability technology. Full article

In this study, the feasibility of using three-dimensional (3D) printing technology to investigate the impact of macrotexture and microtexture on the skid resistance of asphalt pavement was verified. The macrotexture characteristics of the five types of real asphalt mixtures were captured, reconstructed, and printed. The comparison analysis of the skid resistance between the pavement and printed specimens was conducted, and the correlations and contribution proportions of the macrotexture and microtexture on skid resistance were also calculated. Results show that five printed asphalt mixtures present good consistency in the microtexture with a roughness of about 100 nm. The impact of thin water film on the skid resistance is insignificant for real asphalt mixtures, while it is significant for printed mixtures. The printed specimens under dry conditions show a similar British pendulum number (BPN) with the real pavement specimens under wet conditions, while the BPN under wet conditions for printed specimens are much smaller than the real ones but follows a similar variation trend. Mean profile depth (MPD) values of four printed asphalt concrete (AC) mixtures are well linearly correlated with their BPN under dry and wet conditions, especially for wet conditions with the R² of 0.91. The contribution proportion of macrotexture to the skid resistance is nearly 90% for the dry condition and about 50% for the wet condition. Full article

To investigate the influence of pavement texture on tire hydroplaning, this study utilized laser scanning to capture the surface characteristics of three asphalt mixtures—AC-13, SMA-13, and OGFC-13—across fifteen rutting plate specimens. Three-dimensional (3D) pavement models were reconstructed to incorporate realistic texture data. Finite element simulations, employing fluid-structure interaction and explicit dynamics in Abaqus, were conducted to model tire-water-pavement interactions. The results indicate that the anti-skid performance ranks as OGFC > SMA > AC. However, despite OGFC and SMA exhibiting comparable anti-skid metrics (e.g., pendulum friction value and mean texture depth), OGFC’s superior texture uniformity results in significantly better hydroplaning resistance. Additionally, tire tread depth critically influences hydroplaning speed. A novel Anti-Slip Comprehensive Texture Index (ACTI) was proposed to evaluate pavement texture uniformity, providing a more comprehensive assessment of anti-skid performance. These findings underscore the importance of texture uniformity in enhancing pavement safety under wet conditions. Full article

The characteristics of pavement texture are key determinants of skid resistance, directly affecting tire-pavement interactions. This study examines the relationship between separated pavement textures and friction coefficients under dry and wet conditions. Using 3D laser scanning, texture data were collected from 40 asphalt pavement sections in Nanchang. The data were processed through Fourier Transform and Butterworth filtering, enabling separation of macro- and micro-textures. Based on ISO 25178-2, 16 parameters—including S_a (Arithmetic Mean Height), S_tr (Texture Aspect Ratio), V_mc (Core Material Volume), and S_sk (Skewness)—were selected to represent macro- and micro-texture features. These parameters were analyzed against dry and wet friction coefficients, and regression models were developed to predict F_Dry and F_Wet. The results show significant effects of both macro- and micro-texture parameters on friction coefficients. Among macro-texture parameters, S_a and V_mc strongly correlate with F_Dry, suggesting that greater surface roughness and core material volume enhance friction in dry conditions. Conversely, S_sk negatively correlates with F_Dry, indicating that negatively skewed profiles improve skid resistance. Other macro-texture parameters also influence F_Dry to varying extents. For micro-texture, S_dc (Material Height Difference), S_pd (Peak Density), and V_vv (Valley Void Volume) primarily affect F_Wet, with all showing significant positive correlations. This indicates that sharp peaks and void structures in micro-texture enhance skid resistance in wet conditions. The regression models effectively predict both friction coefficients, reducing field testing complexity and cost. These models provide an efficient tool for evaluating skid resistance and supporting pavement performance and maintenance management. This study highlights the distinct roles of macro and micro-texture in skid resistance, offering insights for optimizing pavement design and maintenance. Full article

To address the issue of air pollution caused by automobile exhaust in China, a titanium dioxide/graphite carbon nitride (TiO₂/g-C₃N₄) composite photocatalyst capable of degrading automobile exhaust was prepared in this study. It was used as an additive to modify styrene–-butadiene latex (SBR) emulsified asphalt. The basic properties of modified emulsified asphalt before and after aging were analyzed, and the dosage range of TiO₂/g-C₃N₄ (TCN) was determined. The environmentally friendly micro-surfacing of degradable automobile exhaust was prepared. Based on 1 h and 6 d wet wheel wear test, rutting deformation test, surface structure depth test, and pendulum friction coefficient test, the road performance of TCN environmentally friendly micro-surfacing mixture with different contents was analyzed and evaluated, and the effect of environmentally friendly degradation of automobile exhaust was studied by a self-made degradation device. The results show that when the mass ratio of TiO₂ and melamine was 1:4, the TCN composite photocatalyst had strong photocatalytic activity. The crystal structure of TiO₂ and g-C₃N₄ was not damaged during the synthesis process. The g-C₃N₄ inhibited the agglomeration of TiO₂. The introduction of N-Ti bond changed the electronic structure of TiO₂, narrowed the band gap and broadened the visible light response range. When the TCN content was in the range of 1~7%, the softening point of SBR- modified emulsified asphalt increased with the increase in TCN content, the penetration decreased, the ductility decreased gradually, and the storage stability increased gradually. The penetration ratio and ductility ratio of the composite-modified emulsified asphalt after aging increased with the increase in TCN content, and the increment of the softening point decreased. This shows that the TCN content is beneficial to the high-temperature performance and anti-aging performance of SBR-modified emulsified asphalt, and has an adverse effect on low temperature performance and storage stability. The addition of TCN can improve the wear resistance and rutting resistance of the micro-surfacing mixture, and has no effect on the water damage resistance and skid resistance. The environment-friendly micro-surfacing asphalt mixture had a significant degradation effect on NO, CO, and HC. With the increase in TCN content, the degradation efficiency of the three gases was on the rise. When the content was 5%, the degradation rates of NO, CO, and HC were 37.16%, 25.72%, and 20.44%, respectively, which are 2.34 times, 2.47, times and 2.30 times that of the 1% content, and the degradation effect was significantly improved. Full article

This study proposes a non-contact framework for evaluating the skid resistance of shared roadside pavements to improve cyclist and pedestrian safety. By integrating a friction tester and a laser scanner, we synchronize high-resolution three-dimensional (3D) surface texture characterization with friction coefficient measurements under dry and wet conditions. Key metrics—including fractal dimension (FD), macro/micro-texture depth density (HL_TX and WL_TX), mean texture depth (MTD), and joint dimensions—were derived from 3D laser scans. A hierarchical regression analysis was employed to prioritize the influence of texture and joint parameters on skid resistance across environmental conditions. Combined with material types (brick, tile, and stone) and drainage performance, these metrics are systematically analyzed to quantify their correlations with skid resistance. Results indicate that raised macro-textures and high FD (>2.5) significantly enhance dry-condition skid resistance, whereas recessed textures degrade performance. The hierarchical model further reveals that FD and MTD dominate dry friction (β = 0.61 and −0.53, respectively), while micro-texture density (WL_TX) and seam depth are critical predictors of wet skid resistance (β = −0.76 and 0.31). In wet environments, skid resistance is dominated by micro-texture density (WL_TX < 3500) and macro-texture-driven water displacement, with higher WL_TX values indicating denser micro-textures that impede drainage. The study validates that non-contact laser scanning enables efficient mapping of critical texture data (e.g., pore connectivity, joint depth ≥0.25 mm) and friction properties, supporting rapid large-scale pavement assessments. These findings establish a data-driven linkage between measurable surface indicators (texture, morphometry, drainage) and skid resistance, offering a practical foundation for proactive sidewalk safety management, especially in high-risk areas. Future work should focus on refining predictive models through multi-sensor fusion and standardized design guidelines. Full article

Fumed silica, a nanomaterial with a high specific surface area, excellent chemical stability, and electrical insulation, serves as an effective filler for rubber compounding. Compared to traditional carbon black, silica (SiO₂), the main component of fumed silica, improves the hardness and tear resistance of tread rubber, making it a viable substitute in some formulations. However, silica-filled compounds generally exhibit lower tensile properties and abrasion resistance than carbon black. Fumed silica, with its higher structural integrity, provides additional reinforcement points within natural rubber matrices, enhancing tensile strength and abrasion resistance. Studies demonstrate that replacing carbon black with an equivalent amount of fumed silica as the primary filler significantly improves tread rubber’s hardness (by 20%) and 300% tensile modulus (by 14%) while also reducing rolling resistance and enhancing wet skid performance. Fumed silica’s large specific surface area and low density (10–15% of conventional silica) make it challenging to use directly as a tread rubber filler due to dust formation and prolonged mixing times. This study developed a process combining fumed silica with deionized water, followed by drying and ball milling. This treatment reduces the material’s volume, forming a cohesive gel that, upon processing, minimizes dust and significantly decreases mixing time and difficulty. The interaction between the hydroxyl (–OH) groups on the surface of fumed silica and water molecules likely results in hydrated silica. This interaction enhances surface polarity and forms a hydration layer, improving the hydrophilicity and dispersion of fumed silica in rubber matrices. This reduces the shear modulus difference (ΔG′) between low and high strain, maintaining a consistent elastic modulus over a wide strain range. Such stability enables rubber to perform better under dynamic loads or in complex working conditions. The experimental results demonstrate that the hydration–ball milling process enhances the tensile strength of vulcanizates, improves the dispersion of fumed silica in rubber, strengthens the filler network, boosts dynamic performance, and enhances the wet skid resistance of tread rubber. Full article

With the updates and differences in the usage of reclaimed asphalt pavement (RAP) separation technology, the production of fine-particle RAP exceeds their usage, resulting in an excess of fine-particle RAP. How to apply this excess RAP on a large scale in micro-surfacing technology has become a challenge. This study aims to investigate the advantages and disadvantages of incorporating RAP into micro-surfacing. To this end, a mix design process for RAP-containing micro-surfacing, based on the current gradation design procedure and existing research findings, is proposed. The study examines the influence of six different RAP contents, as well as the effects of SBR emulsified asphalt, added water, and RAP on the micro-surfacing mix design. Subsequently, the effects of RAP content on the pavement performance of micro-surfacing are evaluated through rutting deformation rate, wet wheel abrasion, and British pendulum tests. Finally, an economic analysis from a construction perspective is conducted. The results indicate that the optimized mix design process meets specific usage requirements and is effective for RAP-containing micro-surfacing. The mix design results show that the addition of RAP reduces the asphalt demand and mixing time of slurry mixtures. Increasing the amount of added water can meet mixing requirements, but it leads to a reduction in early strength. As the RAP content increases, skid resistance improves, with a maximum increase of 14.9%; the rutting deformation rate increases, and this is the main factor limiting the RAP content, restricting it to no more than 40%; water damage resistance shows an initial increase followed by a decrease, but this does not affect the RAP content. Therefore, the maximum RAP content is limited to 40% without the addition of other additives, mainly due to the phenomenon of weak agglomeration in RAP. Finally, cost calculations show that incorporating 40% RAP can save approximately 17% of the construction costs. Full article

Rubber tires are fundamental components of modern society and industrial operations, holding an irreplaceable position in the global manufacturing and transportation sectors. The potential for traditional rubber tires to enhance performance is gradually approaching its limits, rendering it challenging to further improve low rolling resistance, high wet-skid resistance, and high wear resistance (called “magic triangle”). Moreover, the reliance on petroleum resources for rubber hinders the sustainable development of rubber tires. In this work, a series of novel polyurethane (PU) elastomers with potential applications in high-performance automotive tires were synthesized by CO₂-based poly(propylene carbonate) diol and bio-based poly(propylene oxide) glycol (PO3G). The comprehensive influences of PO3G on the thermal, mechanical, rolling resistance, and wear properties of the elastomers were systematically investigated. The results illustrated that increasing the PO3G content significantly enhanced the wear resistance by 98.43% and the wet-skid resistance by 73.21% and reduced the rolling resistance by 15.38% of the elastomers compared to commercial green tires (HT166). The rational design strategy of PU elastomers not only effectively addresses the “magic triangle” challenge in the tire industry but leverages CO₂ to contribute to the sustainable development of the automotive sector. Full article

Slip risk on surfaces used by humans or active in mechanisms is studied to mitigate its effects or harness its beneficial outcomes. This article presents pioneering research on the risk of surfaces created using 3D printing technology. The study examines three materials (Polylactic Acid, PLA; Polyethylene Terephthalate Glycol, PET-G; and Thermoplastic Polyurethane, TPU), considering three print head movement directions relative to the British Portable Skid Resistance Tester (BSRT) measurement direction. In addition, surface roughness tests were performed. Dry tests showed that the structure created by the printing direction perpendicular to the movement direction is the safest in terms of slip risk. The SRVs of the measured samples on a qualitative scale were classified on this scale as materials with low or extremely low slip risk (ranging from 55 to 90 SRV dry and 35 to 60 SRV wet). Referring to the influence of the type of material on the SRV, it was found that the safest material in terms of reducing the risk of slipping in dry conditions is TPU and, in wet conditions, PLA. During wet tests, the best properties that reduce the risk of slippage in most cases are shown by the printing direction on a horizontal plane at an angle of 45° to the direction of movement. Statistical analysis showed that the printing direction and roughness do not have a statistically significant effect on the SRV, but the type of material and the type of method (dry and wet) and their interaction have a significant effect. Full article

Winter road safety is significantly compromised by ice formation, leading to increased vehicular accidents due to reduced friction. Traditional anti-icing strategies, such as chemical deicers, present environmental and structural drawbacks, necessitating innovative solutions. This study evaluates methyl methacrylate (MMA)-based resin composites for anti-icing and skid-resistant applications. These composites are particularly intended for application on asphalt and concrete pavements in urban roads, highways, and other high-traffic areas prone to icing during winter. MMA composites exhibit excellent mechanical properties, including tensile strength of up to 10 MPa and compressive strength of 34 MPa under optimized formulations. These composites are specifically developed for application on asphalt and concrete pavements commonly found in urban roads, highways, and other high-traffic areas, where icing and skid resistance are critical challenges during winter conditions. Anti-icing performance was enhanced by incorporating additives like magnesium chloride hexahydrate, achieving a freezing point reduction to −12.9 °C and a heat of solution of 0.429 kJ/g. Laboratory tests revealed that increasing anti-icing additives reduced ice adhesion and melting time, with a trade-off in compressive strength, which decreased from 30 MPa (unmodified) to 16 MPa at higher additive concentrations. Skid resistance was improved through the addition of high-friction aggregates, ensuring durability under icy and wet conditions. These results highlight MMA composites as a sustainable and cost-effective alternative to traditional deicing methods, offering enhanced road safety and reduced environmental impact. Further research is recommended to optimize formulations and validate performance through field trials under varying climatic conditions. Full article

Silica, as a high-quality reinforcing filler, can satisfy the requirements of high-performance green tread rubber with high wet-skid resistance, low rolling resistance, and low heat generation. However, the silica surface contains abundant silicon hydroxyl groups, resulting in a severe aggregation of silica particles in non-polar rubber matrix. Herein, we explored a carbon black (CB)/silica hybrid reinforcing strategy to prepare epoxidized natural rubber (ENR)-based vulcanizates. Benefiting from the reaction and interaction between the epoxy groups on ENR chains and the silicon hydroxyl groups on silica surfaces, the dispersion uniformity of silica in the ENR matrix was significantly enhanced. Meanwhile, the silica can facilitate the dispersity and reinforcing effect of CB particles in the ENR matrix. By optimizing the CB/silica blending ratios, we realized high-performance ENR vulcanizates with simultaneously improved mechanical strength, wear resistance, resilience, anti-aging, and damping properties, as well as reduced heat generation and rolling resistance. For example, compared with ENR vulcanizates with only CB fillers, those with CB/silica hybrid fillers showed ~10% increase in tensile strength, ~20% increase in elongation at break, and ~20% increase in tensile retention rate. These results indicated that the ENR compounds reinforced with CB/silica hybrid fillers are a promising candidate for high-performance green tread rubber materials. Full article

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. Full article

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. Full article

Waste rubber tires are an area of global concern in relation to reducing the consumption of petrochemical products and environmental pollution. Herein, eco-friendly high-performance thermoplastic polyurethane (PU) elastomers were successfully in-situ synthesized through the incorporation of ground tire rubber (GTR). The excellent wet-skid resistance of PU/GTR elastomer was achieved by using mixed polycaprolactone polyols with Mn = 1000 g/mol (PCL-1K) and PCL-2K as soft segments. More importantly, an efficient solution to balance the contradiction between dynamic heat build-up and wet-skid resistance in PU/GTR elastomers was that low heat build-up was realized through the limited friction between PU molecular chains, which was achieved with the help of the network structure formed from GTR particles uniformly distributed in the PU matrix. Impressively, the tanδ at 60 °C and the DIN abrasion volume (Δrel) of the optimal PU/GTR elastomer with 59.5% of PCL-1K and 5.0% of GTR were 0.03 and 38.5 mm³, respectively, which are significantly lower than the 0.12 and 158.32 mm³ for pure PU elastomer, indicating that the PU/GTR elastomer possesses extremely low rolling resistance and excellent wear resistance. Meanwhile, the tanδ at 0 °C of the above-mentioned PU/GTR elastomer was 0.92, which is higher than the 0.80 of pure PU elastomer, evidencing the high wet-skid resistance. To some extent, the as-prepared PU/GTR elastomer has effectively solved the “magic triangle” problem in the tire industry. Moreover, this novel research will be expected to make contributions in the upcycling of waste tires. Full article