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In order to study the effect of polyethylene glycol phase change material on the snow melting and ice melting ability of asphalt mixture, phase change material was added in the asphalt mixture mixing process, and the applicability of polyethylene glycol phase change material was considered, two gradations of AC-10 and AC-13 were adopted, and three methods were designed for evaluation: sponge freezing test, ice adhesion test and ice melting test. The results show that the PEM will accelerate the thawing of the sponge, and the higher the content of the PCM, the greater the light intensity, and the shorter the freezing time of the sponge and asphalt mixture・ Polyethylene glycol phase change material can greatly reduce the adhesion between ice and asphalt pavement; the cumulative ice melting quality and ice melting rate of phase change asphalt mixture are greater than those of ordinary asphalt mixture, and the increase of phase change material content and the decrease of ambient temperature will improve its relative snow melting and ice melting capacity・ Polyethylene glycol phase change material has a good effect of melting snow and ice in different gradations, and can be applied to winter pavement de-icing. [ABSTRACT FROM AUTHOR]

As the demand for sustainable and environmentally friendly road construction materials increases, corn stalk fiber modified with NaOH is a promising candidate due to its renewable and eco-friendly nature. This study employs an orthogonal experimental design to optimize the investigation of multiple factors (corn stalk fiber length, content, and modifier concentration) in the experiments, ensuring that the effects of different factors on the high and low temperature performance of asphalt binder can be independently estimated. Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests were conducted. The bonding between fiber and asphalt was analyzed by infrared spectroscopy, and the action mechanism of fiber in asphalt was revealed from a microscopic perspective by scanning electron microscopy and fluorescence microscopy. Evidently, the concentration of modifier is the main factor affecting the rheological properties of fiber asphalt mortar. Considering the influence of various factors on the rheological properties of modified corn stalk fiber asphalt mortar, the optimal modifier concentration is 7%, the fiber length is 6mm, and the content is 1.5%. After adding modified corn stalk fiber, the asphalt mortar did not produce new characteristic peaks, and the fiber and asphalt were mainly bonded by physical action. The large surface roughness of the modified corn stalk fiber determines its good adsorption capacity, which is conducive to increasing the bonding force of the asphalt. Fibers with a large aspect ratio are easy to bridge with each other, restraining the expansion of cracks and thus enhancing the crack resistance of the mortar. [ABSTRACT FROM AUTHOR]

Road cracks are a common road traffic safety problem. Methods such as manual measurement of cracks do not facilitate large-scale inspections, which affects the normal operation of roads and the safety of pedestrians and vehicles. In this paper, a visual measurement technique based on convolutional neural networks and morphological operations is proposed for automated and efficient detection of road cracks. This method adopts the U-Net network as the infrastructure, changes the backbone feature extraction network to the VGG-16 network and introduces multiple Indicators to establish a new loss function to alleviate the sample imbalance problem. Finally, the crack features are combined to perform morphological operations on the image to enrich the recovered detail features. After experiments on the road crack dataset, this method has better crack segmentation capability and reliability compared to other algorithms. [ABSTRACT FROM AUTHOR]

A visual workload model was constructed to determine and evaluate drivers' visual workload characteristics in high-density interchange-merging areas. Five interchanges were selected, and a real-vehicle driving test was conducted with 47 participants. To address the differences in drivers' visual characteristics in the interchange cluster merging areas, the Criteria Importance Through Intercriteria Correlation (CRITIC) objective weighting method was employed. Six visual parameters were selected to establish a comprehensive evaluation model for the visual workload in high-density interchange-merging areas. The results show that the average scanning frequency and average pupil area change rate are most strongly correlated with the visual workload, whereas the average duration of a single gaze has the lowest weight in the visual workload assessment system. Different driver visual workloads were observed depending on the environment of the interchange-merging areas, and based on these, recommendations are proposed to decrease drivers' workload, thereby increasing road safety. [ABSTRACT FROM AUTHOR]

Sufficient light and high UV intensity pose significant challenges to the long-term performance of polymeric geonet materials for slope-protection structures. This study investigates strength degradation under the effect of UV radiation; five different types of geonets were selected, which can be categorized as polyamide (PA), polypropylene (PP), and polyethylene (PE) materials. A comprehensive experimental investigation was performed, including tension strength, peer strength, artificially accelerated aging, and SEM tests, to further establish a service life prediction method used for slope-protection design. The results showed that the tension strength, percentage of breaking elongation, and peer strength all depict a descending trend with aging-elapsed time, especially in the early 600 h. The decreasing tendency of these mechanical properties' magnitude differed in the diversity of direction and material type. Significant changes have been generated on the geonet surface after aging; materials with smooth surfaces exhibit a strong ability against strength degradation. Fitting results affirmed the predictive technique as a useful engineering tool for tension strength assessments, offering guidelines for using and designing of geonets for slope-protection structures. [ABSTRACT FROM AUTHOR]

The length of basalt fibers affects the performance of asphalt mixtures. To explore the influence of different lengths of basalt fibers on the performance of asphalt mixtures, this study selected basalt fibers with lengths of 6 mm, 9 mm, and 12 mm to design gradations that were incorporated into asphalt mixtures to prepare specimens. High-temperature rutting tests, immersion Marshall tests, freeze-thaw splitting tests, and low-temperature splitting tests were conducted, resulting in 11 test mix designs and 12 test indicators. Then, a multi-objective grey target decision method was used to optimize the optimal combination ratio of basalt fiber lengths. The results indicate that compared to asphalt mixtures with single-length basalt fibers, incorporating well-combined basalt fibers significantly enhances the high-temperature, low-temperature, and water stability performance of asphalt mixtures. According to the grey target decision method, this study determined that a basalt fiber combination ratio of 3:4:3 for lengths of 6 mm, 9 mm, and 12 mm provides the best overall performance of asphalt mixtures. Additionally, when designing asphalt mixtures with graded basalt fibers, the inclusion of 9 mm fibers should be the primary control point. These research findings provide important guidance for the enhanced application of basalt fibers in road engineering. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of 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.)

Modifying agents 2,2-Bis(4-glycidyloxyphenyl) propane (2BPE) and dibutyl phthalate (DBP) were selected to enhance the compatibility. By using molecular simulation software (Materials Studio, MS), nine systems were constructed, including molecular models of aged asphalt and WVO monomers with 2BPE and/or DBP. The solubility parameters, Flory-Huggins parameters, and interaction energies of these systems were calculated to determine the impact of 2BPE and DBP on the compatibility of WVO and aged asphalt. Results showed that the addition of 2BPE and DBP reduced the difference in the solubility parameters between WVO and aged asphalt, thus improving the compatibility between WVO and aged asphalt. Additionally, using a combination of 2BPE and DBP in both aged asphalt and rejuvenator was found to be more effective than using either 2BPE or DBP alone. Finally, it was determined that evaluating the compatibility of WVO and aged asphalt using Van der Waals potential and non-bonding energy as evaluation indicators was more accurate than using electrostatic potential energy. [ABSTRACT FROM AUTHOR]

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.)

A three-dimensional ground-penetrating radar (GPR) captures non-destructively internal pavement distress characteristics. However, interpreting radar images and data analysis pose challenges. To improve the accuracy of distress identification, a three-dimensional digital model of internal pavement distress was established. Firstly, initial electromagnetic signal data were pre-processed to effectively eliminate spurious signals and enhance distress characteristic signals. The distress was located, and GPR images of typical distress were extracted and summarised. Next, the 3D dataset was constructed based on the pre-processed electromagnetic echo signals. A 3D digital model of internal pavement distress was generated using the inverse distance weight and ray-casting methods with trilinear interpolation. Finally, relying on the physical project, cores were extracted to validate the distress model. The method effectively reflects the internal pavement distress, and enables realise the interactive images between the pavement entity and the digital model, which can essentially contribute to the digital twin of pavement systems. [ABSTRACT FROM AUTHOR]

To better construct an energy consumption model for the asphalt mixture production stage, this study divides the production process into four phases: aggregate dust removal, aggregate drying, asphalt heating, and mixture blending. Utilizing measured data from various regions in Anhui Province, the model considers factors such as season, mixture type, and energy consumption type. The study quantitatively compares and analyzes the energy consumption results obtained from three calculation methods: the theoretical method, the quota method, and the energy consumption model method. The results indicate that the total energy consumption shares of the aggregate dust removal, aggregate drying, asphalt heating, and mixture blending phases are 4.23%, 69.50%, 17.75%, and 8.52%, respectively. The primary energy consumption during the asphalt mixture production stage is concentrated in the aggregate drying and asphalt heating phases. The energy consumption model based on on-site measurements effectively reflects the actual energy consumption levels during the asphalt mixture production stage. Moreover, the total energy consumption calculated by the three methods follows the order quota method > energy consumption model method > theoretical method. By constructing an energy consumption model based on measured data, it is possible to more accurately assess the energy usage during the asphalt mixture production process. This helps optimize production techniques, reduce energy consumption and carbon emissions, and provide a scientific basis for sustainable road construction. [ABSTRACT FROM AUTHOR]

Asphalt was modified with butyl desulphurized rubber, so the butyl desulphurized rubber modified asphalt was prepared. The pavement performance and microstructure of asphalt were analyzed by conventional physical parameters, high temperature rheology, fluorescence microscopy, Fourier infrared spectroscopy and glass transition temperature. The results showed that with the increase of R-IIR content, the softening point, viscosity at 135 P and viscosity at 175 of modified asphalt gradually increase, but the softening point begin to decrease when the content was greater than 35%, the optimum content of R-IIR is 35% based on the analysis of temperature sensitivity and storage stability; the addition of R-IIR greatly improves the stability of asphalt at high temperature; with the increase of the content, the dissolution of R-IIR in asphalt is a process from simple swelling to the formation of a rigid network structure. When the content is greater than 35%, R-IIR is unevenly dispersed and precipitated in asphalt; during the modification of asphalt by R-IIR, there are not only simple physical changes, but also chemical changes recombination with asphalt after R-IIR crosslinking bond is broken; the glass transition temperature of asphalt is increased with the addition of R-IIR. [ABSTRACT FROM AUTHOR]

Waste plastic polyethylene wax has been widely studied by researchers for its ability to improve the performance of asphalt pavement and its good economic benefits. This article selected new polyethylene wax (NPEW) and recycled polyethylene wax (RPEW) as warm mix agents (PEW) in an equal ratio, and added PEW and rejuvenator (LBS) to the virgin and aged blending asphalt to prepare polyethylene wax warm mix rejuvenated asphalt. The virgin and aged blended asphalt contained 20%, 30%, and 40% aged SBS-modified asphalt (AAM), respectively, to simulate the proportion of old asphalt in the actual road surface rejuvenation process. The temperature sensing performance, high and low temperature performance, and viscosity reduction effect of warm mix recycled asphalt with different PEW and AAM dosages were analyzed through the conventional test and Brookfield viscosity. The results show that the addition of AAM and PEW reduced the temperature sensitivity of warm mix rejuvenated asphalt. When the AAM content in warm mix rejuvenated asphalt was constant, with the increase of PEW content, the high-temperature deformation resistance and low-temperature crack resistance performance were significantly improved. When the content of AAM in warm mix rejuvenated asphalt was low, the addition of PEW effectively reduced viscosity. When the AAM content was 30% and the PEW content was 2%, warm mix rejuvenated asphalt had the best performance and economic benefits. [ABSTRACT FROM AUTHOR]

In order to solve the problems in predicting the asphalt aging behavior, such as the large performance deviation between simulated aging asphalt and actual aging asphalt, the lack of scientific evaluation index easy to promote in the practical engineering, properties of natural aging SBS (Styrene Butadiene Styrene Triblock Copolymer) modified asphalt from an in-service expressway were tested by Asphalt Binder Quality Test System (ABQT) . Then, some indexes, including maximum creep deformation, elastic recovery rate, loading deformation rate coefficient and rebound deformation rate coefficient, were proposed to evaluate the changes of asphalt’s properties; meanwhile, the accuracy of evaluating asphalt aging behavior with the above indicators were also analyzed by analyzing the differences between the above indicators and conventional performance indicators in evaluating the asphalt aging properties. On this basis, the nonlinear prediction model for asphalt aging was established based on the above indicators, and the aging rate values of asphalt were obtained to analyze the degradation laws of asphalt properties under natural aging conditions, and ultimately a reasonable preventive maintenance time was proposed. Results showed that, the maximum creep deformation, loading deformation rate coefficient and rebound deformation rate coefficient can effectively characterize the decay process of asphalt aging properties under natural aging conditions. Meanwhile, the nonlinear prediction model for asphalt aging established based on the above indicators had strong applicability, which can achieve bidirectional calculation for asphalt performance and aging time. Furthermore, as the aging time prolonged, the aging rate values corresponding to the maximum creep deformation, loading deformation rate coefficient and rebound deformation rate coefficient all decayed in the form of a cubic function model； and the turning points of aging rate were 6. 67 a, 5. 56 a, and 6. 67 a, respectively. Therefore, considering the safety of asphalt mixture performance, it was suggested that 5. 56 a as the threshold for intervention in preventive maintenance measures to restore asphalt performance. [ABSTRACT FROM AUTHOR]

When the tire is in contact with the wet road, the anti-skid performance is significantly reduced. In order to reveal the mechanism of the decline of the anti-skid performance of the tire when driving on the wet road, combined with the source of the friction force in the interaction between the tire and the road, this paper improved the use method of the British pendulum and conducts an indoor test. At the same time, the contact model between the tire and the road surface was established by the method of molecular dynamics, and the relationship between the change of energy in the model and the macroscopic anti-skid performance index of the laboratory was analyzed. The results show that the pendulum value of the asphalt mixture specimen in the wet state is obviously lower than that in the dry state, and as the temperature increases, the pendulum value decreases more, and the maximum value can reach 8.1%;The existence of water molecules significantly reduces the absolute value of van der Waals energy between rubber molecules and aggregate molecules, and weakens the interaction between tires and road surfaces; water molecules exist between the rubber and aggregate molecules, which will weaken the adhesion between the two. The variation of van der Waals energy between rubber molecules and aggregate crystals with temperature has no obvious correlation with the variation trend of indoor macroscopic anti-slip performance index pendulum value BPN (British Pendulum Number). The variation of adhesion energy with temperature has a strong correlation with the variation trend of BPN in the laboratory test. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) is a material with high modulus, high tensile strength, good flexibility and large specific surface area. This material has become very popular and has been also applied as an asphalt modifier. In the current research, multi-walled carbon nanotubes (MWCNTs) and styrene-butadiene-styrene (SBS) were employed as modifiers to fabricate MWCNTs/SBS composite-modified asphalt binder (hereinafter referred to as MCSA). The technical performance of MCSA was evaluated by performance tests and the optimal content of MWCNTs was determined. MCSA dispersion characteristics and interactions of components were investigated by microscopic test methods. Interactions of molecules and tensile behavior of MWCNTs in MCSA were explored by molecular dynamics (MD) simulation. The modification mechanism of MWCNTs was studied at the macro, micro and molecular levels. The following conclusions were drawn: According to macroscopic test results, the optimal content range of MWCNTs was 0.4% to 0.6%. MWCNTs modification process on asphalt binder was a physical modification. MWCNTs enhanced interactions among components and this effect was most obvious when MWCNTs content was 0.6%. The results of the macroscopic test were verified by the microscopic test. MWCNTs molecules could couple with SBS modifier as well as asphalt component molecules, thereby enhancing the interaction of each component in the system. MWCNTs mainly enhanced molecular interactions by increasing van der Waals energy in MCSA system, to make it more stable. MWCNTs do not break during the pull-out process. The molecules of asphalt component, SBS modifier and MWCNTs penetrated each other, which enhanced system stability to resist external loads and improved the mechanical properties of MCSA. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of 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 China Sciencepaper is the property of China Sciencepaper 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 Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society 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.)

Copyright of Journal of Shenzhen University Science & Engineering is the property of Editorial Department of Journal of Shenzhen University Science & Engineering 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.)

The East Asia black cotton soil (BCS) cannot be used as embankment filling directly due to its high clay content, liquid limit, plasticity index, and low CBR strength (CBR < 3%). This study evaluates the effects of treating East Asia BCS with lime, volcanic ash, or a combination of both on its engineering properties. Experiments were conducted to analyze the basic physical properties, swelling characteristics, and mechanical properties of the treated soil. Results indicate that lime addition significantly reduces the free swelling rate, improves limit moisture content, increases optimum moisture content, decreases maximum dry density, and enhances CBR value. Although volcanic ash also improves BCS performance, its effects are less pronounced than those of lime. The combined treatment with lime and volcanic ash exhibits superior performance, greatly reducing expansion potential and significantly increasing soil strength. Specifically, a mixture of 3% lime and 15% volcanic ash optimizes the liquid limit, plasticity index, and CBR value to 49.2%, 23.8, and 24.7%, respectively, meeting the JTG D30-2015 requirements and reducing construction costs. The treatment mechanisms involve hydration exothermic reactions, volcanic ash reactions, and semipermeable membrane effects, which collectively enhance the soil's properties by producing dense, high-strength compounds. [ABSTRACT FROM AUTHOR]

At present, construction waste recycled aggregates only partially replace natural aggregates to prepare road-based materials. This study addressed this limitation and experimentally investigated the mechanical properties of cement-stabilized macadam base materials utilizing a construction waste recycled aggregate. The feasibility of using these raw materials to prepare cement-stabilized macadam bases was established via experimental validation. Subsequently, compaction tests were conducted to ascertain the maximum dry density and optimum moisture content in the mixture. The mechanical characteristics were further examined using unconfined compressive strength tests, analyzing and discussing the influences of varying cement dosages and curing periods on the material strength. The results indicate that the properties of the recycled aggregates satisfied specification requirements, demonstrating satisfactory mechanical properties. The unconfined compressive strength with a 7-day curing period and a 5% cement content fulfilled the technical standards for expressway-grade heavy and extremely heavy traffic, while that with a 6% cement content (with an added curing agent) met these requirements after just 1 day. Additionally, the curing agent enhanced the early strength of the recycled aggregate base material. This study has broken through the technical bottleneck of low content of recycled aggregate, achieved 100% replacement of natural aggregate, and promoted the sustainable development of the industry. [ABSTRACT FROM AUTHOR]

Abstract Emulsified asphalt mixtures’ cold mix and paving features facilitate asphalt pavements in fulfilling dual-carbon and energy-saving demands. Anionic emulsifiers can enhance emulsion stability, ensure uniform dispersion of oil and water, possess good decompression viscosity, thickening, and lubricating properties, and maintain good stability under acidic conditions. Nevertheless, anionic emulsified asphalt is restricted in engineering applications due to problems like its storage stability. In this paper, eight anionic emulsifiers and two preparation procedures were chosen for stability tests. Through static tests, storage tests, sieve residue tests, and laser particle size tests, the impacts of emulsifiers on the storage stability and dispersion of asphalt were analyzed. Waterborne epoxy resin exhibits excellent adhesive properties, mechanical properties, chemical resistance, and heat stability. A fluorescence microscope test, static and storage test, laser particle size test, and cementation test were employed to explore the effects of different preparation processes and waterborne epoxy mixing ratios on emulsified asphalt’s storage stability, dispersion stability, and structural stability. The results showed that: (1) the emulsified asphalt prepared with the BWH-02 emulsifier exhibits the best storage stability, and blending with 20% of the waterborne epoxy modifier can notably enhance the bonding properties; (2) the shear strength of the BWH-02 waterborne epoxy emulsified asphalt prepared can reach 1.543 MPa, and the tensile viscosity can reach 0.848 MPa; (3), The emulsified asphalt prepared by the process of modification has better storage stability than that prepared by the side of the emulsification process. Moreover, the storage stability of emulsified asphalt prepared by emulsification and modification is superior to that of the emulsification and modification process. This research provides theoretical and technical support for popularizing and applying cold-mixed cold-paving asphalt mixtures.

Recent trends in road engineering have explored the potential of incorporating recycled solid wastes into infrastructures that including pavements, bridges, tunnels, and accessory structures. The utilization of solid wastes is expected to offer sustainable solutions to waste recycling while enhancing the performance of roads. This review provides an extensive analysis of the recycling of three main types of solid wastes for road engineering purposes: industrial solid waste, infrastructure solid waste, and municipal life solid waste. Industrial solid wastes suitable for road engineering generally include coal gangue, fly ash, blast furnace slag, silica fume, and steel slag, etc. Infrastructure solid wastes recycled in road engineering primarily consist of construction & demolition waste, reclaimed asphalt pavements, and recycled cement concrete. Furthermore, recent exploration has extended to the utilization of municipal life solid wastes, such as incinerated bottom ash, glass waste, electronics waste, plastic waste, and rubber waste in road engineering applications. These recycled solid wastes are categorized into solid waste aggregates, solid waste cements, and solid waste fillers, each playing distinct roles in road infrastructure. Roles of solid waste acting aggregates, cements, and fillers in road infrastructures were fully investigated, including their pozzolanic properties, integration effects to virgin materials, modification or enhancement solutions, engineering performances. Utilization of these materials not only addresses the challenge of waste management but also offers environmental benefits aiming carbon neutral and contributes to sustainable infrastructure development. However, challenges such as variability in material properties, environmental impact mitigation, secondary pollution to environment by leaching, and concerns regarding long-term performance need to be further addressed. Despite these challenges, the recycled solid wastes hold immense potential in revolutionizing road construction practices and fostering environmental stewardship. This review delves into a bird’s-eye view of the utilization of recycled solid wastes in road engineering, highlighting advances, benefits, challenges, and future prospects.

The interfacial bonding contact state is one of the key factors in determining the integrity of asphalt pavement multilayered composite structure, and the mechanical response of each structural layer will be affected by the interfacial contact state significantly. The non-destructive testing falling weight deflectormeter (FWD) was utilized to study on the identification asphalt pavement interfacial contact state according to deflection basin parameters. Based on the reconstruction and expansion project of Beijing-Shanghai Expressway, a three-dimensional dynamic finite element model of pavement structure was established to analyze the correlation between each FWD deflection basin parameter and the critical stresses of base layer and surface layer under different base layer-surface layer contact states, respectively. The FWD deflection basin index DD1/DD2 (DD1 = D0 - D20,DD2 = D20 -D60,Where D0, D20 and D60 represent the deflection values of 0, 20,60 cm from the load center) was constructed to comprehensively reflect the base layersurface layer stress characteristics, and the regression shows that this index is well on the power relationship with the base-surface interlayer friction coefficient. Considering the fatigue equation of core sample in situ and the finite element simulation results as well, the minimum requirement of friction coefficient between the base-surface layers is derived, which could ensure the life expectancy of asphalt pavement. On this basis, the durability of existing pavement is evaluated, and the results are in consistent with the real engineering case. The proposed method can provide a new approach and theoretical basis for estimating interlayer friction coefficient and evaluating pavement fatigue durability using FWD. [ABSTRACT FROM AUTHOR]

Volume parameters such as the volume of voids (VV), voids filled with asphalt (VFA), and voids in mineral aggregates (VMA) all have significant impact on asphalt mixtures. In this study, the vertical vibration compaction method (VVCM) was employed to produce a large-particle-size asphalt mixture (LSAM-50). The correlations between the mechanical strengths of VVCM specimens, static compression test (PCT) specimens, and in situ core samples were verified. Additionally, the influence of volumetric parameters on the mechanical properties of VVCM specimens was assessed. Based on the principle of optimal mechanical properties, volume parameter design standards for the LSAM-50 asphalt mixture were proposed. Results indicated that the mechanical properties correlation between VVCM specimens and in situ core samples was substantial, reaching over 90%. With increasing VV and VFA, the compressive strength, splitting strength, and dynamic stability of the LSAM-50 asphalt mixture initially increased and then decreased. The design standards for VV were proposed to be between 3.5% and 4.8%, and for VFA between 49.7% and 52.9%. There was no clear correlation between VMA and the mechanical properties of the mixture; hence, based on the standards, the minimum design value for VMA was set at 7.5%. [ABSTRACT FROM AUTHOR]

Vibratory compaction stands as a crucial engineering technique in highway subgrade compaction works, rapidly and effectively enhancing the strength and overall stability of the subgrade materials. Additionally, the continuous compaction control technology based on vibratory compaction offers novel technical means for monitoring and managing the quality of subgrade compaction. To investigate the vibratory roller response characteristics during the compaction process and the suitability of commonly used harmonic ratio-based compaction quality real-time evaluation indicators at different compaction stages, the interaction between the vibratory roller and the subgrade system was analyzed in this study. The dynamic models for the contact and detachment conditions were established respectively, and the step function δ (Fc) was used to unify the dynamic equations for both scenarios. Simulink was utilized to simulate these dynamic equations, and the simulation results were analyzed to assess the response characteristics of vibratory compaction and the applicability of indicators. It is indicated that the subgrade compaction process can be divided into four stages by comparing the variation cycle Tc of the contact force between the vibratory roller and the soil with the excitation period T0 : Tc = 0, Tc = T0, Tc = 2T0 and Tc > 2T0. During the Tc = 0 stage, integer multiples of harmonic signals are observed, and the amplitude of these harmonics increases with the stiffness of the soil. At the Tc = 2T0 stage, signals of 0. 5 times the harmonic are observed. . Comparative analysis reveals that the CCV (compaction control value) and THD (total harmonic distortion) indicators exhibit better applicability throughout the entire compaction process compared to the CMV (compaction meter value) indicator. Furthermore, the RMV (resonance meter value) indicator accurately reflects the compaction process reaching stage three (Tc = 2T0). [ABSTRACT FROM AUTHOR]

Based on the grasp of the current situation of modified bio-asphalt research, the paper summarizes the preparation process of modified bio-asphalt, analyzes its modification mechanism and evaluates its modification effect, aiming to provide reference for the research and application of modified bio-asphalt. The analysis shows that:balancing the high and low temperature performance of modified bio-asphalt is the key to solving the defects of bio-asphalt in the future; the establishment of a joint preparation system of modifier, bio-oil and matrix asphalt is conducive to improving the availability and research value of bio-asphalt. [ABSTRACT FROM AUTHOR]

Use waste tire glue powder, G-type high adhesive, and matrix asphalt to prepare a high-viscosity modified asphalt. The dynamic shear rheometer DSR was used to test the high temperature rheological properties and fatigue performance of asphalt, and the low temperature bending beam rheometer BBR was used to test the low temperature creep strength and creep rate of asphalt. The results show that:G-type high viscosity agent can effectively adjust the proportion of each component of rubber asphalt, improve its elastic proportion of components, and form a network structure in the rubber asphalt, to improve its colloidal stability, and gready enhance the high temperature deformation resistance, low temperature ductility, elastic recovery, stress sensitivity, fatigue and other properties of the rubber asphalt, and G-type high viscosity agent appropriate dosage in rubber asphalt is 8%. Compared with rubber asphalt, the viscosity, high temperature stability, low temperature flexibility, and anti-fatigue properties of rubber high viscosity asphalt have increased significantly, which can effectively protect the road performance and service life of drainage asphalt pavements. [ABSTRACT FROM AUTHOR]

In order to explore the performance of bright color asphalt pavement, different amounts of silicone-polypropionate (SMP) were selected to modify the bright color asphalt, and carries out three indexes and Brookfield viscosity test. The performance of different graded asphalt mixture is analyzed by rutting test wheel tracking test, low temperature beam bending test, immersion Marshall test and freeze-thaw splitting test. The results show that SMP modifier can improve the viscosity of the modified bright colored asphalt with the increase of the SMP content. In addition in AC (SK70), AC (SBS), CSMA, COGFC four graded types of asphalt mixture, COGFC bright color asphalt mixture has the best rut resistance, and SMP modifier has a certain improvement on the low temperature performance of colored asphalt mixture, but SMP modifier will have adverse effects on the water stability of colored asphalt mixture. [ABSTRACT FROM AUTHOR]

In order to study the effects of different amounts of waste vegetable oil, diffusion temperature and time on the mutual diffusion behavior between waste vegetable oil and aged asphalt, a three-layer molecular diffusion model considering the change of asphalt aging degree with the depth of asphalt film was proposed. Combined with Fourier transform infrared spectroscopy (FTIR) test and macroscopic softening point test, the mutual diffusion behavior between waste vegetable oil regenerant and aged asphalt was analyzed. The results show that the waste vegetable oil regenerant realizes the regeneration of aged asphalt by supplementing the light components in the aged asphalt and reducing the agglomeration of asphaltene. The increase of temperature, waste vegetable oil content and diffusion time will enhance the mutual diffusion efficiency of waste vegetable oil and aged asphalt, and the influence of temperature is the most significant. However, as the temperature increases, the increase in diffusion efficiency decreases. The results of Pearson correlation analysis show that the diffusion coefficient between simulation and macro is significantly correlated, and the three-layer molecular diffusion model can effectively characterize the mutual diffusion behavior of rejuvenator and aged asphalt. [ABSTRACT FROM AUTHOR]

As an important part of straw, cellulose is the key to determine its mechanical strength. If applied to asphalt pavement, it is expected to improve the performance of the pavement and solve the problems of straw degradation and aging in the pavement. Firstly, the central composite design-response surface method was used to explore the influence of the extraction process of cellulose in straw on the performance of asphalt, and the optimum extraction process of cellulose was determined. Secondly, the effects of cellulose on high temperature stability, low temperature crack resistance and storage stability of asphalt were studied by rheological property test, segregation test and infrared spectrum test. The results show that the cellulose extracted under the condition of NaOH concentration of 2.5% and HNO3 concentration of 4.3% has the best effect on improving the physical properties of asphalt. At the same time, the incorporation of corn straw cellulose improves the high temperature stability, low temperature crack resistance and deformation resistance of asphalt under high-speed vehicle load shear. When the content of corn straw cellulose is 7%, the comprehensive performance of asphalt is the best, and there is no serious segregation phenomenon. Compared with matrix asphalt, the high temperature continuous grading temperature (TLH) of cellulose content at 7% is increased by 13 °C, and the low temperature performance is increased by 49.3%. In addition, cellulose only bonded with each other by physical enhancement to improve the performance of asphalt, and no chemical reaction occurred. [ABSTRACT FROM AUTHOR]

This paper proposes a novel treatment scheme for expansive soil slopes, incorporating a flexible facing, steel cables, and soil nails. Based on completed practical engineering projects, a series of high-precision numerical models for differently supported expansive soil slopes were established. These include hard facing with soil nails, flexible facing with soil nails, and the newly proposed flexible facing with steel cables and soil nails. By comparing safety coefficients, soil displacement patterns, slope surface strain distributions, soil nail force diagrams, and steel cable force distributions under different conditions with or without considering expansion forces, the study thoroughly elucidates the working mechanisms of various support schemes in addressing expansive soil slopes. A comprehensive comparative analysis reveals the irreplaceable advantages of the proposed flexible facing incorporating steel cables incorporating soil nail support (flexible-cable-nail support, FCN support) scheme in the treatment of expansive soil slopes. [ABSTRACT FROM AUTHOR]

Currently, there are limitations in the research on the use of carbon fiber geogrids to prevent low-temperature cracking in asphalt pavements. This study aims to comparatively investigate the effects of carbon fiber-based geogrid type and dense-graded asphalt concrete mixture (AC) surface combined body (SCB) type on the low-temperature cracking resistance of reinforced asphalt pavement through low-temperature bending damage tests. Two geogrid types were prepared: a carbon fiber geogrid (CCF) and a glass/carbon fiber composite qualified geogrid (GCF). Two SCB types were studied: AC-13/AC-20 and AC-20/AC-25. The results show that the improvement in the flexural tensile strength of CCF is similar to that for GCF. Moreover, under reinforced conditions, the improvement in the low-temperature cracking resistance of AC-20/AC-25 is better than that for AC-13/AC-20 by 16.26–24.57%. Based on the analysis, the reasonable ratio range of the aperture sizes to the major particle sizes in the dense gradation can achieve a more effective interlocking effect. This can improve the low-temperature cracking resistance of carbon fiber-based geogrid-reinforced samples. Then, increasing the bending absorption energy is a key way of improving the low-temperature cracking resistance of carbon fiber-based geogrid reinforcements. Eventually, the fracture type of carbon fiber-based geogrid-reinforced samples is a mixed plastic–brittle fracture. These results can provide a reference for the road failure analysis of geogrid-reinforced asphalt pavement. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department 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.)

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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.)

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.)

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.)

To achieve the efficient resource utilization of municipal sludge and promote the sustainability of pavement materials, this study employed liquefaction technology to process municipal sludge. The resulting liquefied-sludge-derived heavy oil was blended with 50# asphalt to prepare a bio-asphalt that can replace petroleum asphalt. Firstly, orthogonal experiments were conducted to analyze the effects of the solid–liquid ratio (dried sludge:anhydrous ethanol), liquefaction temperature, and reaction time on the yield of the sludge-derived heavy oil. Then, the basic characteristics of the sludge-derived heavy oil were studied using an elemental analyzer, gel permeation chromatography, thermal analysis, gas chromatography–mass spectrometry, and Fourier transform infrared spectroscopy, and the differences between the sludge-derived heavy oil and petroleum asphalt were compared. Finally, to determine the appropriate content range of sludge-derived heavy oil in bio-asphalt, a comprehensive evaluation of the three major indicators, aging resistance, storage stability, low-temperature performance, and high-temperature performance was carried out for the prepared bio-asphalts. The results indicated that the optimal preparation process for liquefied sludge oil involves a liquefaction temperature of 275 °C, a solid–liquid ratio of 1:15, and a reaction time of 1 h, resulting in an oil production rate of 22.36%. The sludge-derived heavy oil demonstrated good thermal stability, with its primary components being aliphatic compounds (carboxylic acids, ketones, aldehydes, alcohols, alkanes, esters, etc.), with esters being the most abundant. Furthermore, the sludge-derived heavy oil was highly compatible with 50# asphalt, but no chemical reaction occurred between them. When the sludge-derived heavy oil content ranged from 5% to 20%, bio-asphalt showed favorable aging resistance and storage stability. As the content of the sludge-derived heavy oil increased, its low-temperature performance improved, but there was a slight decrease in high-temperature performance. Additionally, correlation analysis highlighted that the influence of sludge-derived heavy oil content on the high-temperature performance of bio-asphalt was notably greater than on other properties. Therefore, the recommended dosage of sludge-derived heavy oil should be between 5% and 10%. [ABSTRACT FROM AUTHOR]

To improve the improvement effect of rice straw fiber on asphalt mixes, a surface response experimental design method was used to study and the optimal blending method of rice straw fiber asphalt mixture was obtained. The fiber asphalt mixes were prepared according to the optimized scheme and analyzed by rutting test, direct tensile test, water immersion Marshall test, freeze–thaw splitting test, and four-point bending fatigue test for related road performance. The results showed that the optimal solution for the fiber ratio of rice straw fiber asphalt mixture was that the fiber length was 9 mm, the fiber content was 4%, and the oil-to-stone ratio was 5.16%. Rice straw fiber can improve the high-temperature performance and water damage resistance of the asphalt mixture. The stability of the mixing material, the stability of the residual stability and the frozen split intensity of the mixing material were 130.6%, 114.1%, and 116.9% of the matrix asphalt mixture, respectively. At the same time, the fiber can enhance the low-temperature performance of asphalt mixes and extend the fatigue life of asphalt mixes. However, when the fiber and dosage were too large, it would weaken the effect of improving the high- and low-temperature performance and water stability of asphalt mixes. [ABSTRACT FROM AUTHOR]

Asphalt concrete is a typical heterogeneous composite material at the mesoscale. Under the action of external load, its internal dispersion cracks interact with each other, thereby changing the crack propagation behavior, especially in low-temperature environments. In this context, this study developed a meso-structure model of asphalt concrete with randomly distributed dispersion cracks based on the Taylor medium model and the discrete element method. A virtual semicircular bending test was performed to obtain macro and micro parameter data, including stress–strain curves, data regarding the crack propagation process, and the crack-area stress field, to analyze the propagation characteristics of dispersion cracks with various crack density parameter values, f , in asphalt concrete. The results indicated that (1) the predictions based on the Taylor medium model exhibit a good correlation with the numerical simulation results, demonstrating the reliability of the simulation. Moreover, the interference between dispersion cracks hinders crack propagation, significantly enhancing the low-temperature crack resistance of asphalt concrete. This interference effect is most pronounced when f is set to 0.6. (2) Crack interference between dispersion cracks primarily occurs during the crack incubation stage, extending the incubation time of internal cracks in asphalt concrete and improving early crack resistance. (3) When f is less than or equal to 0.6, the predominant failure mode of asphalt concrete is tensile stress failure. However, when f exceeds 0.6, the fracture mode of asphalt concrete shifts from tensile fracture to shear fracture. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of 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 Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of 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 Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering 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.)

In China, a substantial portion of highway asphalt pavements are no longer capable of accommodating increasing traffic volumes and necessitate renovation and expansion. Prior to commencing such activities, it is crucial to evaluate the performance of the existing asphalt pavements. This study developed a novel normal cloud framework integrating a comprehensive weighted indicator system for existing asphalt pavement. Five key performance indicators including riding quality index (RQI), rutting area ratio (Rr), cracking area ratio (Cr), patching area ratio (Pr), and pavement structural strength index (PSSI) were selected to holistically represent the pavement condition in highway renovation and expansion projects. Subsequently, a method was proposed to determine the weights of these indicators by integrating the analytic hierarchy process (AHP) and entropy. A normal cloud model was constructed to address data characteristics and representation of indicator fuzziness/randomness through digital cloud modeling. The model was applied to 12 sections of the Jingjintang Expressway (Tianjin section). The results revealed only one section where the normal cloud model differed from the pavement maintenance quality assessment (PQI) model. The 3D ground-penetrating radar detection results of this different section indicated that the normal cloud model more closely aligned with the road structure condition. Compared to absolute pass/fail criteria of the traditional PQI model, the cloud model offered enhanced sensitivity to define graded condition assessments essential for reconstruction planning and decision analysis. Therefore, the normal cloud model is more suitable for assessing the performance of existing asphalt pavements in highway reconstruction and extension projects compared to the PQI model. [ABSTRACT FROM AUTHOR]

Many small-spacing interchanges (SSI) appear with the improvement of the expressway network. To investigate the speed and mental workload characteristics in the SSI and acquire the mechanism of the influence of speed on the drivers' workload, 37 participants were recruited to perform a field driving test. Each driver performed four driving conditions (i.e. ramp-mainline, mainline-ramp, mainline driving, and auxiliary lane driving). The speed and drivers' electrocardiogram (ECG) data were collected using SpeedBox speed acquisition equipment and PhysioLAB physiological instrument. The heart rate increase (HRI) index was used to analyse the drivers' mental workload regularity. The relationship model between speed and HRI was developed to examine the impact of speed on HRI. The results show that the speed variation in the SSI displayed two patterns: 'decrease - increase and continuous decrease.' The drivers' HRI variation presented four patterns: 'convex curve, continuously increasing, continuously decreasing and concave curve'. SSI's influenced area length is given based on the speed and HRI variation regularity. HRI is significantly higher when driving in the ramp-mainline condition in the SSI than when driving in other conditions, indicating that drivers are more nervous when merging with the mainline traffic. HRI increases significantly in the first 50% of the weaving area in four driving conditions, indicating that vehicle weaving greatly influences the drivers' mental workload. A positive correlation exists between vehicle speed and drivers' HRI without interference from other vehicles and road alignment. The shorter spacing of the interchange will result in a more difficult driving task for the drivers. This study shows that drivers have the highest mental workload in ramp-mainline driving condition at small-spacing interchanges. The first half of the weaving area is the area where drivers' mental workload increases significantly, and is a high-risk section for small-spacing interchanges. This study can provide a reference for the revision of the allowable minimum interchange spacing in the corresponding specification, and the calibration of the simulation test parameters for similar scenarios. [ABSTRACT FROM AUTHOR]

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Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. 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.)