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The bridgehead settlement problem continues to be one of the most chronic issues affecting long-term bridge performance. In addition, the magnitude of non-staggered-step settlement across the bridge approach transition has not been quantified. Non-contact measurement is considered an alternative to manual inspection, enabling automated damage evaluation for structural maintenance. This paper proposes an inexpensive automatic system using an inertial navigation sensor and a line scanning camera to evaluate the non-staggered-step bridgehead settlement with acceptable accuracy. By analyzing road longitudinal slope data, driving distance, and pavement images, this paper established a calculation model and algorithm of non-staggered-step bridgehead settlement, in which case, a new calculation index named the settlement point ratio (SPR) was proposed. Moreover, the effect of the vehicular detection system and the distance gradient tested at three speeds were measured. The results illustrate that the system has a good performance in longitudinal slope data with an absolute error of less than 1.5%. In addition, 31 bridges in China, Ningbo city, were selected. Combined with the test data, 50 groups of SPR were output using the established model and algorithm. By validating the system’s output with the standard measurement method, correlation, and regression analysis were carried out in order to verify the SPR model’s reliability. The correlation coefficient is 0.934, and the determination coefficient of the regression model is 0.872, which confirms its capability for accurate data collection and settlement measurement. Therefore, the proposed method is scientific and reasonable for detecting and quantifying non-staggered-step bridgehead settlement, effectively completing the research blank of bridgehead settlement detection.

In order to make full use of aged asphalt, a light oil regenerant for cold mixing was prepared in this paper, and the ratio of regenerant and regeneration effect was studied through the performance test of recycled asphalt. The ratio of regenerant was determined by 60 °C kinematic viscosity, mass loss before and after aging, and asphalt three indicators. The thermogravimetric analysis determined the four-component ratio of recycled asphalt, and the mechanical properties of the recycled asphalt mixture were determined by the 15 °C splitting and 20 °C compression tests. Finally, the road performance of the recycled asphalt mixture was analyzed by rutting, low-temperature bending, and dry-wet splitting tests. When the mass ratio of light base oil: plasticizer: stable equilibrium agent: penetrant: the anti-aging agent is 80:20:25:8:5, it has a good regeneration effect. After adding 8% regenerant, the regenerated asphalt is compared with the recycled asphalt. The content of saturates and aromatics increases, and the content of resins and asphaltenes decreases. The four-component content of recycled asphalt is close to that of new asphalt. The mechanical properties test shows that the optimum content of the regenerant is 0.9%. With increased RAP content, the water stability and low-temperature crack resistance are also improved, and the high-temperature stability is reduced. However, it still meets the requirements of the regeneration specification.

This paper aims to study the application feasibility of steel slag powder (SSP) in replacing limestone powder (LP) to enhance the heat release and self-healing properties of asphalt and an asphalt mixture. First, the microwave-heating characteristics of SSP and LP asphalt mortar were analyzed, and the differences in the microstructure and chemical composition between SSP and LP were compared. Secondly, through the DSR frequency sweep test, the optimal healing temperature of the two asphalt mortars was determined. Finally, asphalt mixtures with different SSP contents were prepared by replacing part of LP in the mixture in a gradation with SSP. Under microwave radiation, the temperature distribution of the mixture was explored, and the self-healing properties and factors affecting the healing were analyzed. Results demonstrated that there are metal oxides with high electromagnetic parameters such as Fe2O3 and CaO in SSP, therefore, asphalt and a mixture containing SSP were seen to have excellent microwave absorption capacity. The healing temperature of the two kinds of asphalt mortar was between ~50 °C and 60 °C. Under microwave radiation, the temperature of the asphalt mixture increased with the increase in SSP content, and the temperature difference decreased with the increase in SSP content. Asphalt mixtures with an LP content of 30%, 40%, 50%, 60%, and 70% replaced by SSP increased the healing index by 8.7%, 17.3%, 22.1%, 26.9%, and 27.7% compared with conventional asphalt mixtures. Temperature is the most important factor affecting the healing behavior of the asphalt mixture. With the increase in the damage times of the asphalt mixture, the overall healing index of the asphalt mixture showed a downward trend. However, the healing index of an asphalt mixture containing SSP can still be maintained at more than 50% after repeated mechanical damage.

The morphology of coarse aggregate has a significant impact on the road performance of asphalt mixtures and aggregate characterization studies, but many studies were based on the two-dimensional morphology of coarse aggregate, which failed to consider morphological characteristics in a holistic manner. In order to quantitatively analyze the shape, angularity, and texture characteristics of roadway coarse aggregates, a rapid and accurate multiparameter characterization method of coarse aggregate 3D morphology is explored in this article. A 3D laser scanner is used to obtain the 3D point cloud data of pebble, granite, and basalt, and the solid models of the three coarse aggregates are reconstructed. In addition, the fitted ellipsoidal algorithm and Laplace smoothing algorithm are proposed for the characterization analysis of the overall shape, angularity, and surface roughness of coarse aggregate, and the variation rules of multicharacteristic parameters of coarse aggregate are summarized. The results of the study show that the ratio of the three axes of the fitted ellipsoid can be used to classify the shape of coarse aggregate into four types, among which the cubic shape accounts for the majority of the coarse aggregate. By analyzing the fitted ellipsoidal value and the change rate of angularity of coarse aggregate, it is concluded that the larger the values of both, the more angular the aggregate is. Moreover, the study finds that the fitted ellipsoidal value can characterize not only the shape of coarse aggregate, but also its angularity to some extent. Compared with the spherical value, the fitted ellipsoidal value has better variability and is more “sensitive” to the overall data. The change in surface area can well characterize the texture of coarse aggregate. When the particle size is small, the larger the surface area change rate of the coarse aggregates, the better the roughness of the aggregates, among which the surface area change rate of basalt is the largest. The influence of aggregate morphology was not adequately considered in previous studies of asphalt-aggregate adhesion, and this study provides parameter help for subsequent quantitative analysis of the relationship between asphalt-aggregate adhesion and coarse aggregate morphology.

This document contains some of the relevant theoretical foundations, models and concepts used in road engineering. The list is not exhaustive, but far from it. The purpose is to show the road engineering courses students that behind design and engineering principles, standards, and guidelines there is a vast scientific body of knowledge. This booklet is meant to be studied mainly independently by the students attending road engineering courses. Some sections are used as course materials, for example in lecture presentations and demonstrating case examples. Tiivistelmä Tämä kirjanen sisältää Oulun yliopiston tietekniikan perusteet I ja II sekä tien suunnittelu ja rakentaminen -kurssien suorittamista tukevia teoriaosuuksia. Teoriaosuudet on tarkoitettu opiskelijoiden itseopiskeluun ja tähtäävät tietekniikan syvällisempään ymmärtämiseen, erilaisiin teorioihin, malleihin ja käsitteisiin. Kirjaseen on koostettu vain pieni osa tietekniikassa sovellettavista teorioista, malleista ja käsitteistä ja tarkoitus onkin antaa valmiuksia syvällisempiin pohdintoihin ja kysymyksiin. Teoriaosuuksien materiaalia käytetään soveltuvin osin opetusaineistoissa sekä esimerkkilaskelmissa ja -tapauksissa.

In the present study, an integrated framework for automatic detection, segmentation, and measurement of road surface cracks is proposed. First, road images are captured, and crack regions are detected based on the fifth version of the You Only Look Once (YOLOv5) algorithm; then, a modified Residual Unity Networking (Res-UNet) algorithm is proposed for accurate segmentation at the pixel level within the crack regions; finally, a novel crack surface feature quantification algorithm is developed to determine the pixels of crack in width and length, respectively. In addition, a road crack dataset containing complex environmental noise is produced. Different shooting distances, angles, and lighting conditions are considered. Validated through the same dataset and compared with You Only Look at CoefficienTs ++ (YOLACT++) and DeepLabv3+, the proposed method shows higher accuracy for crack segmentation under complex backgrounds. Specifically, the crack damage detection based on the YOLOv5 method achieves a mean average precision of 91%; the modified Res-UNet achieves 87% intersection over union (IoU) when segmenting crack pixels, 6.7% higher than the original Res-UNet; and the developed crack surface feature algorithm has an accuracy of 95% in identifying the crack length and a root mean square error of 2.1 pixels in identifying the crack width, with the accuracy being 3% higher in length measurement than that of the traditional method.

Temperature distribution and the deformation behavior under temperature are important parameters in the design and evaluation of concrete pavements. In this paper, in order to study the horizontal distribution of the temperature effect on rubberized concrete pavement (RCP), the distribution differences of temperature, temperature gradient and strain at different horizontal locations were analyzed based on fiber Bragg grating test technology. The relationships between temperature and strain and between temperature gradient and strain were also investigated. The results show that within a cycle of temperature or temperature gradient change, the time of temperature increase or temperature gradient increase is only 1/4 of the whole cycle, significantly less than the time of the temperature or temperature gradient decrease. Comparing the center, edges and corner of the pavement, the horizontal distribution of temperature and temperature gradients in the RCP is uneven, and the greatest negative temperature gradient is experienced at the corner of the pavement, which is 25 °C·m−1 greater than the temperature gradient at the center. The negative temperature gradient at the corner of the concrete pavement exacerbates the bottom deformation at the center and edge of the pavement, especially in the X-axis direction at the center and in the Y-axis and Z-axis directions at the edge. The relationships between temperature and horizontal strain at the center and edge of the RCP have a significant hysteresis effect and are markedly stronger than those at the corner. Moreover, when the temperature gradient is less than −23.4 °C·m−1 or greater than 14.5 °C·m−1, the curling effect at the edge of the RCP is more obvious.

The original bottle-neck of difficulty in processing, inconsistent performances and pollution during processing of crumb rubber modified asphalt （CRMA） were summarized and analyzed from chemical engineering perspective， the source， composition and basic properties of crumb rubber were analysized， the relationship between the perpetually changing multi-networks structure and properties of crumb rubber during selection， breaking or activization， asphalt binder or mixture processing and recycle were elucidated with 69 references. The performance and optimization methods of CRMA mixture were also reviewed from engineering perspective. The development direction of CRMA was prospected and development suggestions were put forward.

For the concerns of investigating the viscoelastic properties of recycled asphalt mixtures incorporating high content reclaimed styrene-butadiene-styrene (SBS) modified asphalt pavement (RAP-SBS), asphalt mixture performance tester (AMPT) was applied to analyze the dynamic modulus and phase angle of recycled mixtures by the influence of RAP-SBS content, temperature, loading frequency, long-term aging (LOTA), and the incorporation of a rejuvenating agent. Master curves of recycled asphalt mixture regarding dynamic modulus and phase angle are developed, and the viscoelastic properties of recycled mixtures within a wide frequency range are characterized with the Christensen–Anderson–Marastean (CAM) model. Eventually, the one-way analysis of variance (ANOVA) was applied to investigate the role of factors on the viscoelasticity of recycled mixtures. The research indicates that (1) the elastic component of recycled mixtures elevates with the increasing of RAP-SBS content and loading frequency; as a result, the high-temperature stability of it enhances, while it is prone to cracking at low temperatures; (2) RAP-SBS content should be selected according to specific characteristics of pavement. For most cases, a content of 50% is recommended; (3) the recycled mixtures incorporating high-content RAP-SBS mixed with a rejuvenating agent has outstanding aging resistance performance; (4) RAP-SBS content is observed to have a significant influence on the viscoelasticity of recycled mixtures.

With the increase of expressway construction in seasonal frozen soil region, the freeze-thaw problem of subgrade soil has attracted more and more attention. In addition, the comprehensive utilization of industrial solid waste has become an important measure to build a resource-saving and environment-friendly society. In order to improve the frost resistance of subgrade soil and realize the resource utilization of industrial solid waste, carbide slag (CS) and coal gangue powder (CG) were applied to the subgrade soil. The unconfined compressive strength (UCS) test, freeze-thaw cycle test, dry shrinkage test, temperature shrinkage test and scanning electron microscope (SEM) test were carried out on CS-CG stabilized soil with a ratio of CS:CG = 70:30 and dosages of 5%, 10% and 15%. The freeze-thaw cycle degradation model of CS-CG stabilized soil was constructed to show the freeze-thaw deterioration mechanism after the mechanical properties, pore structure, and durability characteristics of the stabilized soil were examined. The results showed that the CS-CG stabilized soil had good frost resistance. After 6 freeze-thaw cycles, the UCS at 7d and 28 d was 2.86 MPa and 3.79 MPa, respectively, which were 22.6% and 35.5% lower than in samples that underwent no freeze-thaw action. The CS-CG stabilized soil had good crack resistance, slightly better dry shrinkage strain than lime stabilized soil, and excellent temperature shrinkage performance. With the increase of CS-CG dosage, the hydration products increased continuously. After freeze-thaw cycles, however, large pores and cracks gradually appeared in the stabilized soil, which led to an increase of porosity and pore diameter, and a decrease of pore abundance. Due to the influence of hydration degree, the porosity change at 7 d was less than that at 28 d. There was a f(n)/f0=βexp−λΔh relationship between UCS residual ratio and porosity variation of the CS-CG stabilized soil, and it had a good correlation. The CS-CG stabilized soil had good frost resistance and shrinkage characteristics, and could replace traditional cementitious materials such as Portland cement (PC) and lime for subgrade soil improvement in regions with seasonal frozen soil. Future research needs to focus on the performance regulation of CS-CG stabilized soil, which can make it more widely used.

Road geometric information and a digital model based on light detection and ranging (LiDAR) can perform accurate geometric inventories and three-dimensional (3D) descriptions for as-built roads and infrastructures. However, unorganized point clouds and complex road scenarios would reduce the accuracy of geometric information extraction and digital modeling. There is a standardization need for information extraction and 3D model construction that integrates point cloud processing and digital modeling. This paper develops a framework from semantic segmentation to geometric information extraction and digital modeling based on LiDAR data. A semantic segmentation network is improved for the purpose of dividing the road surface and infrastructure. The road boundary and centerline are extracted by the alpha-shape and Voronoi diagram methods based on the semantic segmentation results. The road geometric information is obtained by a coordinate transformation matrix and the least square method. Subsequently, adaptive road components are constructed using Revit software. Thereafter, the road route, road entity model, and various infrastructure components are generated by the extracted geometric information through Dynamo and Revit software. Finally, a detailed digital model of the road scenario is developed. The Toronto-3D and Semantic3D datasets are utilized for analysis through training and testing. The overall accuracy (OA) of the proposed net for the two datasets is 95.3 and 95.0%, whereas the IoU of segmented road surfaces is 95.7 and 97.9%. This indicates that the proposed net could accomplish superior performance for semantic segmentation of point clouds. The mean absolute errors between the extracted and manually measured geometric information are marginal. This demonstrates the effectiveness and accuracy of the proposed extraction methods. Thus, the proposed framework could provide a reference for accurate extraction and modeling from LiDAR data.

Runoff depth distribution on the concave and circular curve sections is obtained from a two-dimensional numerical simulating model in order to analyze the temporal and spatial variation of the pavement runoff on the curve section. The two-dimensional model verified by the field data can depict the alignment of pavement more accurately as compared to the empirical equation and a one-dimensional model. The runoff on the concave section and circular curve section is compared for the free water drainage and centerline drainage. Results show that a two-dimensional model is essential for the analysis of the centerline drainage. The runoff depth can be controlled by a reasonable curb height and location interval. The drainage type affects the variation of the runoff depth on the nearside lane, and the maximum water depth can be up to more than 80 mm on the concave section and nearly 60 mm on the circular curve section under centerline drainage. Besides the existing hydroplaning results, the runoff depth difference of the wheel trace should be considered to evaluate driving safety. Sideslip will occur when the depth difference becomes more than 6 mm under condition that the runoff depth is less than the tread depth (7 mm). When the runoff depth is more than the tread depth, sideslip will occur once the depth difference exceeds 4 mm.

Fatigue and rutting phenomena are major distresses in asphalt pavements. Asphalt mixture properties are highly dependent upon the asphalt binder and the mastic behavior. The purpose of this study was to investigate the behavior of the asphalt binder and the mastic, modified by the synthesized polyurethane, at high and intermediate temperatures. The filler/asphalt binder ratio (by weight) was 1.0. The dynamic shear rheometer (DSR) was used to measure fatigue (G∗sin δ) and rutting (G∗/sin δ) parameters. In this study, the multiple stress creep and recovery (MSCR) test was also utilized to calculate the rutting potential of the asphalt binder and the mastic. Parameters of the non-recoverable compliance (Jnr) and the percentage recovery (%) were evaluated at high temperatures. The obtained results indicated that the synthesized polyurethane improved the rutting and fatigue properties. There was a significant correlation between the asphalt binder and the mastic in terms of the complex modulus (R2 = 0.9958), rutting (R2 = 0.9944), and the non-recoverable compliance (R2 = 0.9707). For the fatigue parameter (R2 = 0.9852), the complex modulus (R2 = 0.9855), and the phase angle (R2 = 0.8262), significant relationships were observed between the asphalt binder and mastic samples at intermediate temperatures. Overall, the chemical reaction between the filler and the asphalt binder could be effective in different behaviors of the mastic and asphalt binder. There was a 112%–164% increase in the G∗sin δ parameter for mastics, compared to that of the asphalt binder. The complex modulus was 6 times higher by adding the filler content.

Premixing and activation of rubber by castor oil via heating and microwave were performed and the activated rubber modified asphalt was prepared.Rolling thin film oven test （RTFOT）, dyna-mic shear rheology test, multiple stress creep and recovery test, bending beam rheology test and linear amplitude sweep test were conducted to investigate the effects of the two kinds of premixing and activation method on the performance of the activated rubber modified asphalt, and the activation mechanisms of the activated rubber modified asphalt by the two kinds of premixing and activation method were explored by Fourier transform infrared spectroscopy.The results showed that heating and microwave activation of rubber with castor oil could effectively improve the high-temperature performance, low-temperature performance, anti-fatigue performance and aging resistance of the rubber modified asphalt.Compared with the unactivated rubber modified asphalt, the activated rubber modified asphalt exhibi-ting superior resistance to permanent deformation and deformation recovery could adapt to lower temperature conditions, and resistance to fatigue damage was enhanced and the performance decay of before and after RTFOT short-term aging was reduced.Castor oil could effectively activate the surface of rubber in the process of heating and microwave premixing and activation, which was helpful to increase swelling rate of rubber in asphalt and improve the modification effect.

It is significant to make full use of solar energy to reduce the deterioration of asphalt pavements and the negative impact on the environment due to temperature changes. Using phase change materials (PCMs) in asphalt mixture could increase temperature regulation and reduce thermal degradation due to temperature cycling. In order to study the effect of a new solid–solid PCM called PPGC-PCM on the performance of asphalt mixture, a series of tests were carried out. The control group and six different contents of PPGC-PCM were added into AC-13 asphalt mixtures. The effects of PPGC-PCM on the mechanical, moisture resistance, high-temperature, and low-temperature cracking resistance properties of asphalt mixture was analyzed. The influence of PPGC-PCM on the thermal properties in asphalt mixture was analyzed by thermal conductivity test. Results showed that the addition of PPGC-PCM could improve the moisture resistance and low-temperature cracking resistance of asphalt mixtures, as well as greatly reduce the thermal conductivity of the asphalt mixture. The optimal application could be achieved by using the PPGC-PCM with 7.5% addition ratio. In addition, the cooling test proved that the addition of PPGC-PCM could significantly improve the heat preservation capacity of the asphalt mixture. The temperature difference between PPGC-PCM and control testing groups was up to 3.8°C, and the mixture was cooled from 21°C to 0°C with a delay of 18–21 min.

There are known problems of dissolution, consistency of performance, segregation, and instability with the crumb rubber currently used in asphalt for road engineering. A silane coupling agent (KH550) solution was therefore used to pretreat the crumb rubber so as to improve its interfacial characteristics. The effects of KH550 on the properties of asphalt rubber were studied using high- and low-temperature performance tests, temperature sensitivity test, and compatibility test. On the basis of these tests, the optimum concentration of KH550 pretreated crumb rubber is 1.0%. The surface properties and micromodifications of the treated crumb rubber were analyzed using scanning electron microscopy and an infrared spectrometer. The performance and economic benefit of the modified asphalt rubber was compared to styrene-butadiene-styrene (SBS) modified asphalt, and it was found that KH550 pretreated crumb rubber is able to significantly improve the high-temperature performance of asphalt rubber, thus offering notable potential economic benefits.

Investment in road infrastructure, i.e. its construction and maintenance, requires significant financial resources. When it comes to undeveloped and developing countries with limited funds, the available resources must be exploited in the most rational manner while obtaining the maximum benefits. One of the possible solutions is a public-private partnership (PPP) model. This paper analyzes different examples of applying PPP models in road engineering and their different rates of success. The analysis highlighted several key factors for the success of road infrastructure designs financed according to a PPP model. The key factors involve the appropriate traffic flow prediction, high-quality design process and construction cost prediction, the public partner’s decisive and strong attitude in negotiation with the private partner, as well as the contract based on positive regulations and containing thoroughly defined obligations of all parties. The conducted analysis should help decision-makers when making decisions regarding the selection of the appropriate PPP model in road design.

Fatigue failure of cement-stabilized macadam (CSM) base has always been a concern in highway construction. The microscopic initial defect is an important factor affecting its fatigue performance. T...

Asphalt pavements at high altitudes are susceptible to aging and disease under prolonged action of UV light. To improve their anti-ultraviolet aging performance, UV-531/SBS-modified asphalts with UV-531 dopings of 0.4%, 0.7%, and 1.0% were prepared by the high-speed shear method, and the effect of UV-531 on the conventional performance of SBS-modified asphalt before aging was studied by needle penetration, softening point and 5 °C ductility tests. The high- and low-temperature rheological properties of UV-531/SBS-modified asphalt before and after aging were also analyzed by high temperature dynamic shear rheology test and low-temperature glass transition temperature test. Finally, the effect of UV-531 on the anti-aging performance of SBS-modified asphalt was evaluated by three methods, including rutting factor ratio, viscosity aging index, and infrared spectroscopy. The results show that with the increase of UV-531 doping, the needle penetration and 5 °C ductility show an increasing trend, but the effect on the softening point is small. The high temperature stability of SBS-modified asphalt is not much affected by the addition of UV-531, and the low-temperature stability is improved, and when 0.7% UV absorber is added, SBS-modified asphalt shows better low-temperature performance. The results of all three evaluation methods show that the addition of UV-531 significantly improved the anti-UV aging performance of SBS-modified asphalt, with the amount of 0.7% providing the asphalt with the best anti-UV aging performance. The results of the study can provide an important reference for improving the anti-ultraviolet aging performance of SBS-modified asphalt.

In order to investigate the compaction characteristics of graded crushed stone under repeated utilization, it is necessary to improve the utilization rate of road recycling crushed stone and maintain its strength and stability during recycling. In the present study, repeated compaction characteristic curves of graded crushed stone were developed using repeated compaction and screening of the graded crushed stone. The correlations between the fractal dimension of particle size distribution and repeated compaction times, water content, and dry density were analyzed. The experimental results indicate that both the maximum dry density and the optimal water content increase as the repeated compaction times increase. The fractal dimension of the particle size distribution of the graded crushed stone used in this test is 2.33 to 2.57. The obtained results show that as the fractal dimension increases, the maximum dry density of the graded crushed stone increases. At a constant repeated compaction time, the fractal dimension of the particle size distribution of graded crushed stone increased and then decreased as the water content increased. In summary, the compaction performance of the structural layer of graded crushed stone can be tuned by adjusting the fractal dimension of the particle size distribution of the recycled pavement structural layer in practical applications. Moreover, the optimal graded materials can be prepared under the guidance of the fractal dimension, thereby achieving an optimized working performance of the recycled pavement structural layer.

Pavement surface texture evaluation is mainly analyzed based on elevation data in previous research, and attention also need to be paid to wavelength information. Furthermore, a well-established relationship model between surface texture and skid resistance for real road sections still needs further investigation to help provide useful information on appropriate maintenance time considering skid resistance attenuation. In this research, the macro-texture of asphalt pavement was evaluated from different aspects, including elevation, wavelength information, and geometry, and the relationship models between the macro-texture and skid resistance (at both low and high speeds) were established and compared using the multiple linear regression (MLR) and back propagation (BP) neural network to recommend a suitable one. In order to achieve this, this study monitored anti-skidding performance and the macro-texture of six road sections for 18 months. Firstly, the Dynamic Friction Coefficient (DFC) test and core drilling were conducted on site at three different service times. Additionally, a laboratory accelerated loading test was carried out on specimens prepared by similar material composition to one of the road sections, and the British Pendulum Number (BPN) was tested after different passes of loading. Secondly, 3D laser scanning was carried out on core samples from road sections and laboratory specimens after different passes of loading. The correlation degree between macro-texture indexes and anti-skidding performance was analyzed with the grey correlation entropy analysis method. Finally, the relationship models between the anti-skidding performance at high and low speeds and macro-texture were established based on the MLR and BP neural network. The results indicate that the macro-texture indexes calculated based on elevation data to characterize vertical irregularities have a good correlation with the skid resistance despite the different service times and pavement types. Compared with the BP neural network model, the MLR model has low correlation and noticeable error. The relationship model between F60 (DFC at the speed of 60 km/h) and macro-texture could be well established by the BP neural network. In addition, the relationship between F20, BPN, and pavement surface macro-texture is poor, making it impossible to establish a model with good correlation. Generally, it is recommended to use the BP neural network to establish the relationship model between macro-texture and skid resistance.

To explore the effect of different emulsifier contents on the stability performance of biomass-emulsified asphalt, three types of emulsified asphalt with 1%, 3%, and 5% anionic emulsifiers were prepared and analyzed by molecular dynamics simulation and macroscopic experiments. Firstly, we used molecular simulation software (Material Studio, MS) to construct a model of biomass-emulsified asphalt with different emulsifier contents and analyzed the microscopic mechanism of the emulsifier to improve the stability of the emulsified asphalt by the radial distribution function, interaction energy, interfacial layer thickness, and solubility parameters of the emulsified asphalt system with different emulsifier contents. The results were validated by macro and micro tests including storage stability, particle size determination, and infrared spectroscopy. The results show that at low emulsifier contents, the emulsifier can reduce the interfacial tension between the oil–water interface and expand the transition region between the two phases (interfacial layer thickness), which will prevent interparticle agglomeration and reduce the emulsion particle size, thus reducing the settling rate and ensuring the stability of the emulsion. When the emulsifier content is further increased beyond the critical micelle concentration, the emulsifiers will agglomerate with each other and show larger peaks in the radial distribution function, and the phenomenon of emulsifier agglomeration will appear in the five-day storage stability test, resulting in a corresponding decrease in the proximity of the infrared absorption peak area ratio in the same wavelength band of the upper and lower layers of the biomass-emulsified asphalt, and the emulsion stability decreases instead.

The traditional method of removing ice and snow on roads carries the risk of damaging roads and the environment. In this circumstance, the technology of salt-storage asphalt pavement has gradually attracted attention. However, snow-melting salts may also have an impact on asphalt mixture performance. To explore the effect of snow-melting salts on the mechanical and surface properties of salt-storage asphalt mixtures (SSAM), SSAMs were prepared with styrene–butadiene–styrene (SBS)-modified asphalt and high-elastic asphalt (HEA) as binders and snow-melting salts as fillers. The influence of the type of asphalt binder and the content of snow-melting salt on the performance of the SSAM was preliminarily investigated through laboratory tests. The results show that the high-temperature, low-temperature, and moisture resistance performance of the SBS group SSAM decreased by 9.8–15.1%, 1.6–12.3%, and 6.3–19.4%, respectively, compared with SBS00. The higher the amount of snow-melting salt, the greater the performance drop. The three mechanical properties of the HEA group containing high-elastic agent TPS are 11.3–19.7%, 4.2–12.3%, and 4.8–13.3% higher than that of the SBS group. Even when the content of snow-melting salt is 50% or 75%, the mechanical properties of the HEA group are better than that of SBS00 without snow-melting salt. Snow-melting salt has clear advantages in improving the anti-skid performance but decreases the anti-spalling performance. The surface properties of the HEA group were also better than that of the SBS group. Considering the mechanical properties and surface properties, the comprehensive performance of the HEA group is better than that of the SBS group, and HEA50 has the best comprehensive performance. In addition, the construction performance of the SSAM has also been verified, and the production of SSAM according to the hot mix asphalt can meet the specification requirements.

[ES] El uso y reúso de residuos es una de las mayores preocupaciones de la sociedad actual. De hecho, en el mundo se producen más de 6,5 mil millones de toneladas de residuos de construcción y demolición (RCD) cada año, de las cuales entre 2,6 y 3 mil millones de toneladas corresponden a residuos inertes de la construcción y de la demolición, dentro de los cuáles está el residuo cerámico. Entre los diferentes factores que están presentes en la falta de manejo de los residuos cabe destacar el desbordamiento de la producción de los mismos, la no aplicación de la política de las 3R, reciclar, reparar y reusar, y la falta de proyectos investigativos que incluyan experimentación con residuos inertes que puedan validar el uso de dichos materiales en diferentes producciones industriales. En ese sentido, construir concretos asfálticos con inclusión de residuos industriales como la cerámica triturada sin respaldo científico podría llevar a los gobiernos a realizar un detrimento patrimonial. Sin embargo, una investigación experimental que incluya el uso de residuos cerámicos en la elaboración de una mezcla de concreto asfáltico que permita conocer su desempeño por medio de ensayos de laboratorio de última tecnología, puede lograr disminuir la brecha de incertidumbre para que los gobiernos puedan tomar decisiones con soluciones económicas y competitivas en zonas con bajos y medianos niveles de tránsito. En esta tesis se desarrollan ensayos de módulos dinámicos en probetas de concreto asfáltico convencional y con inclusión de 30% y 35% de residuo triturado cerámico, tanto en España como en Colombia, lo cual permite analizar, comparar y evaluar internacionalmente el comportamiento de estas mezclas considerando diferentes temperaturas y confirmando su uso en vías de bajos y medianos volúmenes de tránsito. Finalmente, se propone el uso de mezclas asfálticas con inclusión de residuo triturado de cerámica al 30% para ofrecer una opción de reúso, que proporcione un respaldo científico que permita la implementación en carreteras y la integración de instrumentos regulatorios, económicos, educativos e informativos. De esta manera se ayuda a mitigar el problema de los residuos y se amplía la cobertura de la red pavimentada ofreciendo accesibilidad y movilidad a comunidades que de otra forma no podrían conectarse., [CA] L'ús i reus de residus és una de les majors preocupacions de la societat actual. De fet, en el món es produïxen més de 6,5 mil milions de tones de residus de construcció i demolició (RCD) cada any, de les quals entre 2,6 i 3 mil milions de tones corresponen a residus inerts de la construcció i de la demolició, dins dels quins està el residu ceràmic. Entre els diferents factors que estan presents en la falta de maneig dels residus cal destacar el desbordament de la producció dels mateixos, la no aplicació de la política de les 3R, reciclar, reparar i reusar, i la falta de projectes investigativos que incloguen experimentació amb residus inerts que puguen validar l'ús dels dits materials en diferents produccions industrials. En eixe sentit, construir concrets asfàltics incloent-hi residus industrials com la ceràmica triturada sense respatler científic podria portar als governs a realitzar un detriment patrimonial. No obstant això, una investigació experimental que incloga l'ús de residus ceràmics en l'elaboració d'una mescla de concret asfàltic que permeta conéixer el seu exercici per mitjà d'assajos de laboratori d'última tecnologia, pot aconseguir disminuir la bretxa d'incertesa perquè els governs puguen prendre decisions amb solucions econòmiques i competitives en zones amb baixos i mitjans nivells de trànsit. En esta tesi es desenrotllen assajos de mòduls dinàmics en provetes de concret asfàltic convencional i incloent-hi 30% i 35% de residu triturat ceràmic, tant a Espanya com a Colòmbia, la qual cosa permet analitzar, comparar i avaluar internacionalment el comportament d'estes mescles considerant diferents temperatures i confirmant el seu ús en via de baixos i mitjans volums de trànsit. Finalment, es proposa l'ús de mescles asfàltiques incloent-hi residu triturat de ceràmica al 30% per a oferir una opció de reus, que proporcione un respatler científic que permeta la implementació en carreteres i la integració d'instruments reguladors, econòmics, educatius i informatius. D'esta manera s'ajuda a mitigar el problema dels residus i s'amplia la cobertura de la xarxa pavimentada oferint accessibilitat i mobilitat a comunitats que d'una altra forma no podrien connectar-se., [EN] The use and reuse of waste is one of the greatest concerns of today's society. In fact, more than 6.5 billion tons of construction and demolition waste (CDW) are produced in the world each year, of which between 2.6 and 3 billion tons correspond to inert construction and demolition waste. demolition, among which is the ceramic waste. Among the different factors that are present in the lack of waste management, it is worth highlighting the overflow of their production, the non-application of the 3R policy, recycling, repairing and reusing, and the lack of research projects that include experimentation with inert waste that can validate the use of these materials in different industrial productions. In this sense, building asphalt concrete with the inclusion of industrial waste such as crushed ceramics without scientific support could lead governments to carry out a patrimonial detriment. However, an experimental investigation that includes the use of ceramic residues in the elaboration of an asphalt concrete mixture that allows knowing its performance through state-of-the-art laboratory tests, can reduce the uncertainty gap so that governments can take decisions with economic and competitive solutions in areas with low and medium levels of traffic. In this thesis, tests of dynamic modules are developed in conventional asphalt concrete specimens and with the inclusion of 30% and 35% of crushed ceramic residue, both in Spain and in Colombia, which allows the behavior of these mixtures to be analyzed, compared and evaluated internationally. Considering different temperatures and confirming its use in roads with low and medium volumes of traffic. Finally, the use of asphalt mixtures including 30% crushed ceramic waste is proposed to offer a reuse option that provides scientific support that allows implementation on roads and the integration of regulatory, economic, educational and informational instruments. In this way, it helps to mitigate the waste problem and expands the coverage of the paved network, offering accessibility and mobility to communities that otherwise would not be able to connect.

The phenomenon of structural destabilization damage to asphalt pavement is becoming increasingly serious as a result of high temperatures and heavy traffic. Considering the advantages of Qingchuan rock asphalt (QRA) in its durability, high-temperature rutting resistance, and good compatibility with asphalt, it was proposed to compound rock asphalt with SBS to ameliorate the high-temperature performance of asphalt. In this study, DSR and BBR were used to determine the rheological properties of Qingchuan rock-modified asphalt (QRMA) and Qingchuan rock–SBS-modified asphalt (QRA-SBSMA), and the optimum blending amount of rock asphalt was determined based on the PG classification results. Secondly, four different structures of ‘30 mm AC-10 upper layer (70-A, QRMA, SBSMA, QRA-SBSMA) + 50 mm AC-16 lower layer (70-A)’ double-layer composite specimens were prepared. Multiple high-temperature performance evaluation indexes (G*/sinδ, Ds, rutting depth, micro-strain, Fn, modulus) were used to assess the improvement effect of QRA. Finally, using a 1/3 scale accelerated loading testing machine, we simulated high-temperature, water, and high-temperature coupled environments to assess the impact of high temperature and water on the performance of QRMA and QRA-SBSMA, respectively. The findings demonstrated that QRA can increase the PG classification of 70-A and SBSMA as well as its resistance to high-temperature deformation. Multi-index comprehensive evaluation methods were used to consummate the asphalt high-temperature evaluation system. The QRA-SBSMA had the smallest rutting depth and creep rate and the largest dynamic modulus, characterizing its ability to optimally resist high-temperature rutting and deformation.

Sprinkled snow melting salt (SMS) exerts a snow melting effect and also has a negative impact on the asphalt pavement and the environment. Salt storage pavement technology can alleviate these two problems. However, non-alkaline SMSs may have the risk of affecting asphalt mastic properties and further affecting the mechanical properties of asphalt pavements. Therefore, the general properties and rheological properties of two styrene-butadiene-styrene-modified asphalts with and without high elastic polymer were studied after adding SMS. The asphalt mastic without a high elastic agent is defined as the SBS group, and the other group is the HEA group. Our results show that the HEA group shows a lower penetration and a higher softening point, ductility, and viscosity than the SBS group. The more the SMS, the more the reduction effect of the general performance. The elastic recovery of asphalt mastic decreases with the content of SMS. SMS has no obvious effect on the ratio of the viscous and elastic composition of asphalt mastic. The creep of asphalt mastic increases with the content of SMS. The high elastic polymer can significantly reduce the creep, and even the strain of HEA100 is smaller than that of SBS00. SMS increases the creep stiffness and reduces the creep rate at low temperature. Although SMS increases the potential of asphalt pavement to melt ice and snow, it also reduces the high-temperature rutting resistance and low-temperature crack resistance of asphalt mastic. Salt storage pavement materials can be used in combination with high elastic polymers to reduce the negative effects brought by SMSs.

Traffic crashes are one of the immediate and long-term serious problems all over the world including Vietnam. Speed is one of the direct causes of a crash. In recent years, Ho Chi Minh City has synchronously implemented many measures to manage speed, in particular, a pilot implementation of raised pedestrian crossing measures at many locations in the city. Technical efficiency assessment of this measure is necessary to help the city build more scientific evidence for scaling up successful measures. This study was conducted at four locations on Ton Duc Thang Street, District 1, with four vehicle groups including motorbikes, cars, trucks, and buses. The results indicate that this measure had a positive effect on V85 speed with four group of vehicles at 35.5km/h or more. The effectiveness was stronger for greater widths of raised pedestrian crossing i.e., more effective at 10.5m of raised pedestrian crossings width than 7.5m. This measure reduces V85 speed of vehicles by nearly 14% on 10.5m of raised pedestrian crossings width, and positive impacts are highest for cars (13.93%), and lowest for trucks (6.54%). While traffic volume and the surrounding context may impact on the result, they are not considered in this study. These results provide important scientific evidence for scaling up this measure city wide in the future.

In order to improve the implementability of municipal road design, the rational application of BIM Technology in the process of road design is a common method in current road engineering design units. The advantages of BIM Technology, such as visualization, simulation, coordination and optimization, are increasingly recognized by the industry. In this paper, the author draws on many years of practical experience to introduce the advantages of BIM Technology, as well as how to apply BIM Technology to optimize municipal road design work and to discuss some views, in the hopes of assisting in the further improvement of the level of municipal road constructions in China.

Porous asphalts have supplementary surface and volumetric properties (e.g., acoustic absorption, drain ability, texture, and friction). These properties are linked to intrinsic factors (e.g., gradation and bitumen content) and extrinsic factors (e.g., traffic load), while their evolution over time depends on complex phenomena and processes that cause their deterioration and therefore affect safety, noise, and budget. Despite the decay of so many and complex properties over time, there is a lack of criteria to synergistically optimize the pavement system. Consequently, the objective of this study is to set up and validate a design method that synergistically addresses the most relevant properties of friction courses as a part of a pavement structure. The abovementioned method is based on in-depth analyses of the literature and on laboratory and on-site tests carried for several years in order to evaluate the decay over time of the main surface and volumetric properties. The method was applied to a case study. Results show that 1) the level of fulfilment of single requirements varies over time and among the characteristics; 2) a sound optimization of the design of the mix in order to balance the different characteristics is needed; 3) further studies are needed because of uncertainty in predicting the main surface properties.

Asphalt pavement inevitably suffers rutting distress induced by repeated loads under high temperatures, which can be effectively alleviated by the modification of asphalt binders. This paper summarized the asphalt modifiers for enhancing the performance of asphalt pavement at high temperatures in terms of the modifier type, additive amount and improving effect. Then, the anti-rutting performance evaluation methods of asphalt binder were introduced with details, including the ring and ball (R&B) test, the dynamic viscosity test, the zero/low shear viscosity (ZSV/LSV) test, the dynamic shear rheometer (DSR) test, the repeated creep and recovery (RCR) test, and the multiple stress creep and recovery (MSCR) test. Furthermore, the sensitivity of the evaluation method to asphalt modifier was analyzed using the normalization method. It was found that the indicators from the MSCR test could clearly reveal the influence of asphalt modifiers on high temperature performance of asphalt binder. But it still had some limitations affecting the accuracy of evaluation results, such as the number of creep‐recovery cycles, the stress level and the recovery time. In addition, according to the rutting resistance improvement ratio (RRIR), the styrene-butadiene-styrene (SBS) modifier performed better in improving the rutting resistance of asphalt binder, compared with other modifiers when added within the usual dosage range.

Autonomous vehicles (AVs), including trucks, are already available and their adoption is coming at a rapid pace. Despite the fact that this new transportation technology will travel on existing pavement infrastructure assets, the study and investigation of the AVs structural impact on pavements has not reached the same level of attention and maturity as other related research areas. Considering the extensive investment on pavement construction and maintenance, the necessity to fully understand these impacts in the long term, is becoming evident. The present paper presents and discusses currently published relevant research and findings on the quantification of the wheel wander potential impact, both negative and positive, offering potential insightful future areas of enquiry to help mold and shape future research for this emerging field. The paper focuses on the impact of the AVs zero lateral wheel wander on both new flexible pavement design and the damage accumulation within existing flexible pavement structures. Other wheel wander distributions (normal, uniform, etc.) are investigated as well. The outcome and findings are that the AVs zero lateral wheel wander has a definable negative structural impact on flexible pavement structures in comparison to current human-driven (non-autonomous) vehicles that tend to follow a normal lateral wheel wander distribution. However, under certain defined conditions (optimal wheel wander distribution), the pavement service life can be potentially extended.

Asphalt pavements absorb and store more heat than natural surfaces. Thus, high temperatures are emitted from conventional asphalt pavements, subsequently releasing heat into the atmosphere and contributing to the urban heat island (UHI) phenomenon. Several cool pavement strategies, including the provision of additives and materials, surface coating and layer design, have been introduced to reduce the impact of UHI. This article provides a detailed review of the thermal properties of these mitigation measures in the context of cool asphalt pavements. The literature can be divided into three segments. The first segment discusses the impact of pavements on UHI and heat transfer mechanisms in pavements. The second segment focuses on various thermo physical properties that play an important role in mitigation measures; these properties include albedo (α), emissivity (e), solar reflective index, thermal conductivity (k), specific heat capacity (Cp) and thermal diffusivity. The third segment discusses cool asphalt pavement strategies which specifically cover the ability of the pavement to absorb and reflect solar energy on the basis of the materials and treatments used. The literature reveals that cooling strategies that deal with the pavement surface are important due to its direct incident solar effect, which depends on surface colour, material, shape and roughness. By using high-albedo and high-emissivity surfaces, the pavement can store less heat and lower the surface temperature. These results can also be achieved by designing the materials and pavement layers with low thermal conductivity and high specific heat capacity to reduce thermal diffusivity and pavement temperature and thus combat the heat radiated by the asphalt pavement.

Rutting is the major distress mode in flexible pavements occurring due to the repeated movement of traffic loading. Deformation in the pavements comprise of both recoverable (elastic) and irrecoverable (plastic) part. Overall deformation occurring in the flexible pavement system due to continuous vehicular movement is contributed from all the components of pavement. A number of empirical models have been proposed by several researchers for analysis and prediction of accumulated rutting in different components of pavement. The accumulated permanent strain has been expressed as the function of the number of load applications and deviator stress applications in most of the models proposed; however, factors such as stress state, moisture content, material type and environmental conditions also impose a significant influence on the permanent deformation characteristics of pavement materials under cyclic loading. In this article, a comprehensive review has been carried out covering every aspect of deformation related to distress occurring in pavements. Important rut models, modeling approaches and modern concepts in the rutting analysis of pavement structures have been presented. In addition to review, fallacy existing in the current design practices related to adaptation of stiffness parameters and negligence of shear strength aspect of subgrade soil has been also presented with the support of literatures.

The use of colored pavements for bicycle facilities represents an interesting strategy for supporting the implementation of a high-quality cycling network. The distinctive coloration of dedicated lanes, tracks or shared paths provides a clearly delineated route, making the infrastructure more attractive as well as legible and intuitive, especially through intersections and junctions. The additional emphasis resulting from the coloring enhances a change in the road users' behavior, but its safety effectiveness seems to be particularly related to several site-specific contextual features. Although some of these benefits are well established and multiple applications of colored pavements are widespread around the world, most of cycling design standards and guides, which are usually written only in the language of the country that drafted them and are often difficult to find, completely lack in technical recommendations and concepts regarding the use of color for cycling provisions. Thus, based on an extensive worldwide literature search from more than 80 official design guidelines, manuals and standards and 50 scientific articles, the authors have structured a guided overview of the state of the art/practice concerning the use of color for bike facilities at the international level, including the latest innovative and experimental schemes. The review is not intended to be a summary of manuals, but is conceived as a decision-makers’ and designers’ tool for a rational planning, construction, maintenance and management of colored cycling infrastructures, able to favor a cultural and technical interchange. After a first section in which the main locations where to use colored surfaces were highlighted (corridor or spot treatments), the commonly used colors (red, green and blue) have been identified, explaining the hierarchical and/or combined reasons (regulatory and legal limitations, visual-perceptual aspects and application/maintenance requirements) behind this choice. Finally, the different coloring techniques associated with the pavement materials have been described.

Typical climatic environments such as UV radiation, high temperature and strong wind in cold and arid regions have a significant effect on asphalt aging. The intent of this work is to reveal the evolution law of natural aging of SBS-modified asphalt under the complex adverse climate environment in cold and arid regions. Furthermore, the contribution rate of various environmental factors of natural aging of asphalt in cold and arid regions was analyzed. Based on rheological parameters, this paper characterized the influence of natural aging on the viscoelastic properties, rutting resistance at a high temperature, fatigue resistance and cracking resistance at a low temperature of SBS-modified asphalt. The evolution law of natural aging performance of SBS-modified asphalt was revealed. A quantitative evaluation index (CIi) of natural aging contribution rate of asphalt was put forward and the contribution rate of various environmental factors to asphalt natural aging was analyzed. The results showed that the effects of simulated aging and natural aging on asphalt properties were similar. After aging, the viscoelastic properties of asphalt were deteriorated, and the risk of fatigue cracking and low temperature cracking was increased. It also enhanced the deformation resistance of asphalt and increased the rutting resistance at high temperature. The aging contribution index CIi obtained based on rheological parameters such as complex modulus and rutting factor could directly reflect the influence of different natural factors on the performance of asphalt during aging. Among them, the effect of thermal oxygen was more obvious on the natural aging of SBS-modified asphalt.

Geocell is widely used in the treatment of poor roadbed, which can restrain soil laterally and improve the stability of soil. In cold area engineering, a change in temperature can influence the mechanical properties of geocell of different materials. To study the mechanical response of geocell at low temperatures, three types of geocell strips commonly used in engineering, namely the polyethylene (HDPE), polypropylene (PP), and polyester (PET), were studied via the uniaxial tensile test at the ambient temperatures of −5 °C, −20 °C, and −35 °C, respectively. Meanwhile, the tensile strength, fracture mode, and temperature sensitivity of geocell specimens were compared. It is concluded that: (1) at low temperatures, the tensile strengths of HDPE and PET geocell strips are significantly improved, while that of the PP geocell strip is less sensitive to the temperature. (2) The PP geocell is subject to a brittle failure at all ambient temperatures. The PET geocell strip experiences a hard-ductile failure at normal temperatures of −5 °C and −20 °C. While in the tensile test at −35 °C, it is prone to brittle failure and hard-ductile failure. The HDPE geocell strip suffers from ductile failure at all ambient temperatures. (3) At low temperatures, overall, the tensile properties of the PET geocell strip is better than those of the PP and HDPE geocell strips.

To evaluate the effects of the source and admixture of aged asphalt on the rheological properties of reclaimed asphalt binders, the relative viscosity (Δη), relative rutting factor (ΔG*/sinδ), and relative fatigue factor (ΔG*sinδ) were selected as evaluation indicators based on the Strategic Highway Research Program (SHRP) tests to characterize the rheological properties of a reclaimed asphalt binder under medium- and high-temperature conditions. The results of the study showed that the viscosity, rutting factor, and fatigue factor of the reclaimed asphalt binder increased with the addition of aged asphalt; however, the effect of the source and admixture of aged asphalt could not be assessed. The relative viscosity, relative rutting factor, and relative fatigue factor are sensitive to the source, admixture, temperature, and aging conditions, which shows the superiority of these indicators. Moreover, the relative viscosity and relative rutting factor decreased linearly with increasing temperature under high-temperature conditions, while the relative fatigue factor increased linearly with increasing temperature under medium-temperature conditions. In addition, the linear trends of the three indicators were independent of the source and admixture of aged asphalt. These results indicate that the evaluation method used in this study can be used to assess the effects of virgin asphalt and aged asphalt on the rheological properties of reclaimed asphalt binders, and has the potential for application. The viscosity of recycled asphalt increases, and the rutting factor and fatigue factor both increase. The high-temperature stability of reclaimed asphalt is improved, and the fatigue crack resistance is weakened.

Technological development and access are currently leading to changes in the habits of population such as access to information. Short videos and images are used in newspapers, social networks, and university education. Images or internet-meme has been used in several areas of knowledge to improve the students learning, but not in the road design, which content is hand-delivered traditionally. Therefore, this study aims to show an academic activity using internet memes to analyze a weekly topic before synchronous virtual classes. To do this, four groups of students from the Geometric Road Design course participated. They were asked to review the weekly academic content before the class and prepare an internet meme, and their classmates graded those images. As a result, the memes can be used as reading controls before attending the virtual session. They could also be employed before a face-to-face class. The students agreed with the use of memes but were less enthusiastic about the peer review. Despite this trend, the memes produced in combination with peer review increases the possibility of a student to understand the subject. The groups gave an average score to the course of 8.86/10. They were aware of their self-learning with an average rating of 7.74/10. This article describes the experience of students using internet-memes and evaluates the pros and cons. Resumen En la actualidad, el desarrollo y acceso tecnológico está llevando a cambiar diversos hábitos en población, como, por ejemplo, la forma en cómo se consume la información. Es así, que el uso de videos cortos e imágenes se usan los periódicos, redes sociales hasta alcanzar a la educación universitaria. Esta imagen o internet-meme ha sido usado en varias áreas del conocimiento para mejorar el aprendizaje de sus estudiantes, pero no en el diseño de carreteras, cuyo contenido se suele mantener las clases de forma tradicional. Por lo tanto, este estudio tiene por objetivo presentar una actividad académica que utiliza internet-memes para analizar un tema semanal antes de las clases virtuales síncrona. Para ello, participaron cuatro grupos de estudiantes de la materia de diseño geométrico de carreteras. Ellos debían revisar el contenido antes de la clase y elaborar un internet-meme, que era revisado por pares. Como resultado, los internet-memes pueden ser utilizados para controlar que el estudiante revise el material académico (videos, artículos, etc.), antes de asistir a la clave virtual, incluso se podría utilizar antes de una clase presencial. Los estudiantes estuvieron de acuerdo con el uso de los internet-memes, y en menor proporción con la revisión por pares. A pesar de esta última tendencia, la elaboración en combinación con la revisión por pares aumenta la posibilidad de que estudiante comprenda verdaderamente el tema. Por otro lado, los grupos dieron una valoración promedio del curso de al menos 8,86/10. Los estudiantes fueron conscientes del autoaprendizaje, quienes dieron una calificación promedio de al menos 7,74/10. Este artículo describe la experiencia de los estudiantes con el uso de los internet-memes, evaluando sus pros y contras de su uso. Resumo Atualmente, o desenvolvimento e o acesso tecnológico estão levando à mudança de diversos hábitos da população, como, por exemplo, a forma como a informação é consumida. Assim, o uso de vídeos curtos e imagens são utilizados em jornais, redes sociais até chegar ao ensino universitário. Essa imagem ou meme da internet tem sido utilizada em diversas áreas do conhecimento para melhorar o aprendizado dos alunos, mas não no projeto de estradas, cujo conteúdo costuma ser mantido nas aulas tradicionais. Portanto, este estudo tem como objetivo apresentar uma atividade acadêmica que utiliza memes da internet para analisar um tema semanal antes das aulas virtuais síncronas. Para isso, participaram quatro turmas de alunos da disciplina de projeto geométrico de rodovias. Eles tiveram que revisar o conteúdo antes da aula e criar um meme de internet, que foi revisado pelos colegas. Como resultado, os memes da internet podem ser usados para controlar que o aluno revise o material acadêmico (vídeos, artigos, etc.), antes de participar da chave virtual, podendo até ser usado antes de uma aula presencial. Os alunos concordaram com o uso de memes da internet e, em menor grau, com a revisão por pares. Apesar desta última tendência, a elaboração em combinação com a revisão por pares aumenta a chance do aluno de realmente entender o tópico. Por outro lado, os grupos deram uma avaliação média do curso de pelo menos 8,86/10. Os alunos estavam cientes do autoestudo, que deram uma nota média de pelo menos 7,74/10. Este artigo descreve a experiência dos alunos com o uso de memes da internet, avaliando seus prós e contras de seu uso.

This paper proposes an integrated life cycle assessment-life cycle cost (LCA-LCC) model of environmental and economic factors for highway engineering technical schemes to problems such as the limitations of single-dimensional assessment, their narrow scope, the difficulty in tracing sources, and the conflicts of various dimensions in existing integrated assessment methods. The latest documents issued by the Ministry of Ecology and Environment and the Ministry of Transport of China used as an integrated assessment database. Air pollution, water pollution, solid waste pollution, noise pollution, energy consumption, pre-project cost, project construction cost, project operation cost, and post-project cost were used to construct the integrated assessment index system of environmental and economic factors. An improved entropy method was adopted in the LCA-LCC model to overcome the problems of ambiguous results of the previous entropy due to too few assessment schemes, the inoperability of the method when it encounters a negative value or zero value, and unbalanced multi-angle assessments. This model was applied to the assessment of two asphalt pavement maintenance schemes of Highway US280 in Alabama and two improvement schemes of high liquid limit soil subgrade of Highway G360 in Hainan. The results show that the LCA-LCC model overcomes the limitations and imbalances of a single LCA or LCC. The gravel improved scheme and the cold recycling scheme were identified through quantitative assessment as more sustainable. This paper can provide a reference for the comprehensive quantitative assessment of environmental and economic benefits of highway engineering technical schemes.

Volcanic soil is a special soil that is well-known for its distinctive texture, vesicular nature, and particle fragility. The fragility characteristic of volcanic soil is the main factor affecting the foundation stability in road engineering. This study focuses on the mechanical properties and particle crushing characteristics of volcanic soil retrieved from Northeast China. A series of triaxial consolidation and drainage shear tests are performed on volcanic coarse-grained soil (5 mm > d > 0.075 mm) under different initial relative densities and effective confining pressures. Results show the peak friction angle of volcanic soil significantly decreases with the increase of confining pressure. The particle crushing degree of volcanic soil increases with the increase of confining pressure, particle size, and relative density. The relative breakage rate of the same particle size group has a good linear relationship with a fractal dimension. Moreover, for the same particle size, the relationship between plastic work and relative breakage rate can be fitted by a power function, which is not significantly affected by relative density or effective confining pressure. From an engineering view, in addition to increasing the compaction degree of volcanic soil, volcanic soil with fine particles used as a roadbed filler can significantly reduce the deformation of the roadbed and improve the bearing capacity of the foundation.

Soil heavy metal pollution is becoming an increasingly serious environmental problem. This study was performed to investigate the contents of surface soil heavy metals (Cu, Zn, Pb, Cd) near six roads in the southern part of the Tibetan Plateau. Multivariate statistics, geoaccumulation index, potential ecological risk, and a human health assessment model were used to study the spatial pollution pattern and identify the main pollutants and regions of concern. The mean Igeo was ranked in the order Cd > Cu > Zn > Pb, with the average concentrations of Cd, Zn, and Cu exceeding their corresponding background levels 4.36-, 1.00-, and 1.8-fold, respectively. Soil Cd level was classified as posing a considerable potential risk near national highways and a high potential risk near non-national highways, whereas soil Cu, Zn, and Pb were associated with a low potential ecological risk for each class of roads. Furthermore, the non-carcinogenic risk due to soil heavy metals for each class of roads was within the acceptable risk level for three exposure pathways for both adults and children, but the carcinogenic risk attributable to soil Pb exceeded the threshold for children near highways G318, G562, and G219 and for adults near highway G318. Our work not only underscores the importance of assessing potential threats to ecological and human health due to soil heavy metal pollution on road surfaces but also provides quantitative guidance for remediation actions.

Accelerated pavement testing (APT) is an effective method to study the long-term performance of pavement. Therefore, the dynamic strain behavior analysis of asphalt pavement has important guiding significance in the study of pavement failure modes. To explore the dynamic response of a high-content plant-mixed hot-reclaimed asphalt mixture under a dynamic load of vehicles, a full-scale test road was paved, and ALT biaxial accelerated loading test equipment was used to simulate the dynamic loads of vehicles. Based on parameters such as axle load, temperature, speed, and loading times, the development law for the bottom strain of the three pavement structures was analyzed. The test results show that the most unfavorable position of the asphalt pavement load is located just below the centerline of the wheel track on one side, and the damage effect of a single double-axle wheel load is far greater than that of two single-axle wheel loads. Then, the longitudinal tensile strain of the pavement bottom always maintains the alternating state of compression-tension and compression. The longitudinal tensile strain of the pavement bottom is larger than the transverse tensile strain, and transverse fatigue cracks appear first. Under normal temperature conditions, the bottom tensile strains of the three composite pavement structures under different axial loads are close, and the pavement performance of the hot-recycled asphalt pavement of structure A and structure B can meet the specification requirements. The relationship between the bottom strain and axle load is nonlinear and is directly related to the tire ground pressure, and the difference in the tensile and compressive strain values of the bottom of the three composite pavement structures is small. Under high temperature conditions, the bottom layer temperature of structure A and structure B is lower than that of structure C, and the thermal heat transfer efficiency of hot-recycled asphalt pavement is lower than that of ordinary asphalt pavement. Additionally, the longitudinal tensile strain is about 1–1.5 times that of the transverse tensile strain. Based on the Boltzmann function, the accumulative tensile strain prediction model was established to reflect the relationship between the cumulative strain at the bottom and the number of loads.

The purpose of this study is to analyze the behavior of the performance index of graphene-oxide-modified asphalt. The deviation problem caused by determining graphene oxide content by single performance or several independent properties is also investigated. By testing the physical properties of graphene-oxide-modified asphalt with different admixtures (0%, 0.5%, 1.0%, 1.5%, 2.0% by mass) in terms of viscosity, penetration, softening point, ductility, rheology, etc., it is concluded that the addition of graphene oxide could improve the individual properties of the matrix asphalt by 3% to 250%. Moreover, the grey correlation analysis method is used to calculate and analyze the correlation between the performance of graphene-oxide-modified asphalt and the content of graphene oxide. The latter has the most significant effect on the softening point, the penetration, and the 135 °C Brookfield viscosity of modified asphalt. The content of graphene oxide in graphene-oxide-modified asphalt is calculated based on the above three performance indexes, and an estimation error of less than 0.15% is observed. This proves that the new determination method is reasonable. Finally, by combining the macroscopic properties and the multi-factor statistical analysis, a reference basis is provided for the quality control of the graphene-oxide-modified asphalt.

The road layer modulus backcalculation based on the road deflection basin obtained by the Falling Weight Deflectometer is a key issue in road engineering. Traditional Falling Weight Deflectometer b...

Potholes are bowl-shaped distresses that negatively influence driving safety. Using 3D line laser technology, a high-resolution pavement profile can be acquired to derive pothole properties. This paper presents a novel method to measure pothole properties comprehensively and precisely by using 3D line laser data. A laboratory test was performed on a simulated pothole to validate the reliability of proposed method. The test results indicate that the relative error of pothole properties measurement ranges from 3.66% to 4.78%. And the small standard deviation shows good repeatability. In addition, this paper proposes that the longitudinal spacing between two adjacent transverse profiles is sensitive to pothole property measurements, and the optimum spacing should be less than 2 mm to accurately measure pothole properties. Using the optimum spacing, 2 field potholes data were collected on interstate way 107, Xi’an, Shaanxi Province. The field test results have shown that the relative error of pothole properties measurement can be less than 8%, which is sufficiently accurate for practical applications. This paper demonstrated that 3D line laser is very promising to provide a reliable measurement results for pothole properties.

Just owing to fatigue damage mechanics' obvious advantages that can reflect the essence of pavement cracking and facilitate the establishment of a connection between pavement performance and pavement structure, environment, and service life, the theory of fatigue damage mechanics has received increasing attention from road experts and scholars, and its application to asphalt pavement has been widely studied. However, current research still reveals problems that require urgent solutions, such as, the fundamentals of fatigue damage theory remain poorly understood, most research results have not yet been summarized, which hinder the development and wide use of fatigue damage theory. Therefore, this work conducts a systematic review of the fundamental content of fatigue damage mechanics and presents the research in the area of asphalt pavement, including the existing problems, some interesting topics that are worthy of further research are also suggested, which include the development of a triaxial damage constitutive model and a new damage evolution model capable of considering the influence of a mixture's viscoelastic characteristics, temperature, and loading rate on the damage evolution feature of the asphalt mixture. In addition, close-form solutions or viscoelastic calculation for asphalt pavement need to be derived, and other efficient large-scale or microscopic numerical methods for modeling pavement damage performance also need to be studied. The goal of the review is to promote the development and progress of fatigue damage mechanics in the area of asphalt pavement.

To solve the issue of the poor temperature stability of conventional modified asphalt, polyurethane (PU) was used as a modifier with its corresponding curing agent (CA) to prepare thermosetting PU asphalt. First, the modifying effects of the different types of PU modifiers were evaluated, and the optimal PU modifier was then selected. Second, a three-factor and three-level L9 (33) orthogonal experiment table was designed based on the preparation technology, PU dosage, and CA dosage to prepare the thermosetting PU asphalt and asphalt mixture. Further, the effect of PU dosage, CA dosage, and preparation technology on the 3d, 5d, and 7d splitting tensile strength, freeze-thaw splitting strength, and tensile strength ratio (TSR) of the PU asphalt mixture was analyzed, and a PU-modified asphalt preparation plan was recommended. Finally, a tension test was conducted on the PU-modified asphalt and a split tensile test was performed on the PU asphalt mixture to analyze their mechanical properties. The results show that the content of PU has a significant effect on the splitting tensile strength of PU asphalt mixtures. When the content of the PU modifier is 56.64% and the content of CA is 3.58%, the performance of the PU-modified asphalt and mixture is better when prepared by the prefabricated method. The PU-modified asphalt and mixture have high strength and plastic deformation ability. The modified asphalt mixture has excellent tensile performance, low-temperature performance, and water stability, which meets the requirements of epoxy asphalt and the mixture standards.

Funding Information: This research was funded by the Scientific and Technological Development Project of Guangxi Communications Investment Group Corporation Ltd., grant number 2021-001. Publisher Copyright: © 2023 by the authors. As the investigation indexes of low-temperature viscoelastic properties of polymer-modified asphalt (PMA) are unclear at present, in this paper, the creep stiffness (S), creep rate (m), low-temperature continuous classification temperature (TC), ΔTC, m/S, relaxation time ((Formula presented.)), and dissipation energy ratio ((Formula presented.)) were taken as a comparison sequence. The maximum flexural tensile strain (εB) of porous asphalt mixture (PAM) in a low-temperature bending test was selected as a reference sequence. Gray relational analysis was used to investigate the PMA’s low-temperature viscoelastic properties based on a bending beam rheometer (BBR). The results show certain contradictions in investigating the low-temperature properties of PMA when only considering the low-temperature deformation capacity or the stress relaxation capacity. The modulus and relaxation capacity should be considered when selecting the investigation indexes of the low-temperature viscoelastic properties of PMA. When rheological method is used to evaluate the low-temperature of polymer modified asphalt, TC and m/S are preferred. When only S or m is contradictory, m should be preferred. ΔTC can determine whether the low-temperature performance of PMA is dominated by S or m. The result can better guide the construction of asphalt pavement in areas with low temperatures. Asphalt can be selected quickly and accurately to avoid the waste of resources.

The automated detection of distress such as cracks or potholes is a key basis for assessing the condition of pavements and deciding on their maintenance. A fine-grained pavement distress-detection algorithm based on integrated data using a digital twin is proposed to solve the challenges of the insufficiency of high-quality negative samples in specific scenarios An asphalt pavement background model is created based on UAV-captured images, and a lightweight physical engine is used to randomly render 5 types of distress and 3 specific scenarios to the background model, generating a digital twin model that can provide virtual distress data. The virtual data are combined with real data in different virtual-to-real ratios (0:1 to 5:1) to form an integrated dataset and used to fully train deep object detection networks for fine-grained detection. The results show that the YOLOv5 network with the virtual-to-real ratio of 3:1 achieves the best average precision for 5 types of distress (asphalt pavement MAP: 75.40%), with a 2-fold and 1.5-fold improvement compared to models developed without virtual data and with traditional data augmentation, respectively, and achieves over 40% recall in shadow, occlusion and blur. The proposed approach could provide a more reliable and refined automated method for pavement analysis in complex scenarios.