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Reconfiguring practices within the construction industry through the utilization of diverse industrial byproducts is a crucial endeavor. This study was devoted to promoting sustainable construction methodologies while mitigating environmental implications. The focus of the research was the incorporation of reclaimed asphalt pavement (RAP) aggregates into GPC for application as pavement quality concrete (PQC). Leveraging fly ash (FA) and ground granulated blast furnace slag (GGBS) as viable aluminosilicate sources emerged as a judicious strategy for formulating blends that exhibit exceptional attributes at ambient temperatures, thereby circumventing the challenges posed by impractical on-site oven curing. Natural coarse aggregates were replaced with RAP at varying percentages ranging over 25% to 100% and the performance of the binders was assessed across a range of NaOH molarities (10M to 16M). The 14-M, 50% RAP mix exhibited superior strength and durability, achieving permissible compressive and flexural strength after just 7 days of ambient curing (41.80 and 4.72 MPa, respectively), in contrast to the 28 day of curing required for conventional cement concrete. This designed mix also showcased significant resistance to surface abrasion and carbonation, along with exemplary thermal stability as determined by thermogravimetric analysis (TGA). Upon exposure to a 2% H2SO4 concentration (to gauge performance in aggressive environments), higher RAP replacement levels revealed to influence mass and strength loss, but the effect of molarity remained quite moderate. Furthermore, toxicity characteristic leaching potential (TCLP) tests confirmed the immobilization of heavy metals in GPC blends with integrated RAP, thereby endorsing their environmental suitability for the construction of rigid pavements. [ABSTRACT FROM AUTHOR]

This paper presents an effort to address urgent issues associated with semitruck platooning. The weigh-in-motion data were first examined to determine the characteristics of naturally formed semitruck platoons. A safety-based two-vehicle platoon model was then utilized to determine the critical headways for assessing the safety of semitruck platooning in various driving scenarios. The possibilities for passenger vehicles to cut into semitruck platoons were assessed using actual vehicle headway data. Finally, the potential impacts of semitruck platooning on typical interstate highway pavements were assessed using finite element analysis. Most semitruck platoons consist of two to three vehicles. An optimal platoon gap of 0.94 s was identified for connected and automated semitruck platooning. The potential impacts of truck platooning on concrete pavement were negligible for a platoon gap greater than 0.2 s. The maximum possible impact was less than 4% in terms of the service life reduction for interstate asphalt pavement. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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 present study was carried out to establish the proportion of Coarse Reclaimed Asphalt Pavement (C-RAP) containing varying percentages of asphalt for preparing Pavement Quality Concrete (PQC) mixes. RAP was collected from the 5-year-old pavement and separated into coarse RAP (C-RAP) and fine RAP (F-RAP) aggregates using a 4.75 mm sieve. Asphalt content in the C-RAP and F-RAP was found to be 4.12% and 4.33%, respectively. The C-RAP was immersed in the toluene solvent for a different predetermined time and asphalt content was reduced to 3.05%, 2.12%, and 1.24%. Using this exercise, C-RAP containing four different percentages of asphalt (4.12, 3.05, 2.12, and 1.24%) was produced. Then, the cement concrete mixes were prepared in the laboratory by replacing Natural Coarse Aggregate (NCA) with C-RAP varying from 25% to 100% with an increment of 25% in each type. Manufactured Sand (M-Sand)/ Crushed Stone Sand (CSS) was used as a fine aggregate. Altogether, 17 concrete mixes (one control and 16 mixes containing C-RAP) were produced while keeping the water-cement ratio unchanged in all the mixes and evaluated their fresh and hardened concrete properties. As the asphalt presence in the RAP is sensitive to the temperature, the strength of concrete containing RAP at different temperatures was also examined. The current study showed that the amount of NCA substituted by C-RAP and the quantity of asphalt present in the C-RAP influenced the properties of concrete. The study also established that NCA up to 100% could be replaced with the C-RAP containing low asphalt content. Using test results, empirical models were developed to estimate the properties of hardened concrete by considering the percentage of C-RAP, percentage of asphalt in C-RAP, and compressive strength of concrete as predictor variables. The developed models were found statistically significant, supported by R²adj > 92%. [ABSTRACT FROM AUTHOR]

As the total mileage of roads with asphalt concrete pavement is increasing rapidly, using ground-penetrating radar (GPR) to estimate the dimension of internal distresses of the asphalt pavement is of great significance for pavement maintenance. However, the relationship between the dimension of road distress and the characteristics of road distress's radar echo has not been quantified. Therefore, in this paper, a GPR forward modeling toward base cracks and interlayer voids is conducted to investigate the relationship, and a model test is conducted to verify the forward modeling. The results indicate that it is feasible to use a GPR image to estimate the dimension of interlayer voids and base cracks. For vertical dimension estimation, the vertical dimension of the distressed area has a positive relationship with the difference in the return time of radar echoes from the top and bottom of the distressed area. However, the area's vertical dimension must be at least a quarter of the length of the electromagnetic wave used in the GPR to be correctly identified. Otherwise, it is not easy to distinguish the overlapping echoes from each other. For horizontal dimension estimation, the base crack's horizontal dimension has a quadratic correlation with the echo's amplitude, and the horizontal dimension of an interlayer void is approximately equal to the length of its echo's flat segment. [ABSTRACT FROM AUTHOR]

For the characteristics of semi-rigid base asphalt pavement prone to cracking, various stress-absorption layers are applied widely by decreasing stress concentration, improving interlayer bonding and waterproofing. Existing studies on the anti-cracking effect of stress absorbing layers rarely consider top-down fatigue cracking on the outside of the boundary of the vehicle loading zone. Firstly, this paper proposes a finite element model setting a downward expansion of fatigue crack in pavement based on fracture mechanics. The influence law of modulus and thickness of stress absorbing layer on stress intensity factor of crack tip and the fatigue life of the pavement is analyzed furthermore. Numerical calculation results demonstrate that shearing stress intensity factor increases with stress absorbing layer thickness and decreases with stress absorbing layer modulus, while fatigue life of pavement grows with the modulus of the stress absorbing layer and decreases with its thickness. Sensitivity analysis indicates that the modulus of the stress absorbing layer has a greater effect on the fatigue life of the pavement relative to thickness, which offers reference for further promotion and application of stress absorbing layer. [ABSTRACT FROM AUTHOR]

Featured Application: Review on performance regarding mechanical, sustainability, permeability, design, and Life Cycle Assessment characteristics of asphalt pavement and interlocking concrete block pavement for urban road applications. This paper aims to review the performance analysis of interlocking concrete block pavement with by-products such as coconut fibers, and construction and demolition recycled materials, and to compare their skills with asphalt pavement, especially for light-traffic urban road applications. The focus is on mechanical behavior (mix parameters and the influence of by-products), pavement design, sustainability (the heat island effect), the management of contaminant concentrations within infiltration related to permeability, and Life Cycle Assessment. Considering the overall performance analysis, interlocking concrete block pavement was the most attractive alternative because it was approximately 33–44% cheaper in the maintenance process, cooler over a range of 2.2–15 °C, and more permeable by 0.4 cm/s to 0.6 cm/s than asphalt pavement, saving costs and improving drainage and human thermal comfort. However, asphalt pavement was around 35% cheaper during the construction phase (mainly due to energy consumption), and it presented a 32% lower nitrogen oxide concentration. This paper showed the advantages and disadvantages of both types of pavements. A further breakdown should be developed and integrated into the decision-making process about choosing between solutions. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical 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.)

Construction and demolition waste (CDW) materials account for a considerable part of waste materials throughout the world. As these materials are not usually recycled, reusing them in construction projects is of major significance. In this study, recycled concrete, bricks, and glass were used as 100% aggregates of chip seal, which is a corrective or preventive pavement maintenance method. A cationic rapid setting (CRS-2) bitumen emulsion was also used to prepare the chip seal. Different tests, including the sand patch test, sweep test, British pendulum tester (BPT), interface bond, and Vialit test, were conducted. The results of these tests revealed that all these materials had sufficient aggregate embedment for vehicle speeds of more than 70 km/h, and the number of chips was less than 10%, indicating their good performance. All developed chip seals ranked as high skid resistance pavement at ambient temperature. The chip seals developed with concrete and glass showed the best adhesion with an asphalt pavement surface and an aggregate–bitumen adhesion at very cold and ambient temperatures due to the fact of their chemical compositions. Overall, using concrete aggregates to develop chip seals under different traffic loads is recommended. Finally, these findings can provide a novel approach for recycling CDW materials with low costs. [ABSTRACT FROM AUTHOR]

The present study investigated the performance characteristics of concrete paver block (CPB) mixes with incorporated reclaimed asphalt pavement (RAP) aggregates under different curing regimes, namely, continuous water curing (WC), air curing (AC1 and AC2), intermittent water and air curing (WAC), water spray curing (WSC) and heat curing (HC). Seven CPB mixes were formulated by volumetrically replacing virgin coarse and fine aggregates partially and in combination with coarse RAP, fine RAP, and combined RAP fractions. For better refinement of agglomerated particles present in the RAP and to achieve a dense microstructure, the block specimens were fabricated using a design methodology that included a staged mixing approach and time-controlled compaction simultaneously with a vibratory hammer and table vibrator. Hardened CPB specimens were tested to assess mechanical (compressive, flexural, and tensile splitting strength) and durability (water absorption, porosity, and carbonation) properties of the concrete. CPBs fabricated from the considered RAP-inclusive concrete mixes manifested great potential to be used for pavement applications having medium to very heavy traffic when cured with the WC, WAC, WSC, and AC2 curing regimes. Curing regimes WAC and WSC, which involved a combination of water and air curing, were found to be the most effective for the RAP CPB mixes, resulting in superior strength properties. The presence of carbonation was detected in all the RAP CPB mixes when exposed to air curing (AC2) for a prolonged period of time. [ABSTRACT FROM AUTHOR]

The low-altitude technology of unmanned airborne infrared detection system is used to effectively monitor the temperature segregation in the paving stage and realize the temperature uniformity control of asphalt pavement construction. The image mosaic method can splice two images with overlapping areas together to form a panoramic image. In order to solve the problems of long time-consuming and low accuracy of aerial image mosaic algorithm, the low-temperature area of the whole pavement can be obtained quickly and accurately. In this paper, threshold segmentation technology is introduced to convert the image captured by the unmanned aerial vehicle (UAV) into a binary greyscale image so as to compensate for the mosaic error caused by temperature difference. In order to improve the efficiency and accuracy of splicing, a reference plate is used, which can provide enough feature points for splicing. Finally, the image mosaic method proposed in this paper can quickly obtain the image of the whole low-temperature area of the newly paved asphalt pavement, which has practical value and positive significance for the quality control of asphalt pavement. [ABSTRACT FROM AUTHOR]

In the construction of asphalt pavement, poor quality is often the main reason for damage to the pavement, which necessitates the use of monitoring systems during the construction stage. Therefore, this study focuses on building an asphalt concrete pavement construction monitoring system to monitor the construction phase. Through a literature review and semi-structured interviews with industry experts, this paper provides an in-depth understanding of the goals and obstacles of asphalt pavement monitoring and discusses directions for improvement. Subsequently, based on the analysis of the interview results, a system framework for asphalt concrete pavement construction monitoring was constructed, and the system was successfully developed and applied to a highway construction project. The results show that the monitoring system significantly improves the construction quality of asphalt concrete pavement, improves the intelligent level of pavement construction management, and promotes the digital development of highway construction. [ABSTRACT FROM AUTHOR]

Asphalt composite concrete pavement is one of the common pavement forms in China. However, due to the influence of design, materials, construction quality, and other aspects, asphalt composite concrete pavement develops various degrees of cracks after being put into use, which affects the service performance and life of asphalt pavement. The Burgers model is used to examine the effects of fiber-volume-fraction and length–diameter-ratio on the viscoelastic mechanical behavior model parameters and viscoelastic properties of asphalt composite concrete through the bend test for creep of polyester fiber asphalt composite concrete beam. The findings indicate that the fiber's ability to control asphalt composite concrete bending creep deformation increases initially and subsequently diminishes as fiber-volume-fraction and length–diameter-ratio increase. Fiber-volume-fraction and length–diameter-ratio effects can be fully reflected by fiber amount characteristics. A viscoelastic mechanical behavior model of fiber-reinforced asphalt composite concrete is developed on this foundation while taking into account the influence of fiber amount characteristic factors. Theoretical study and practical research indicate that the ideal fiber volume ratio of polyester fiber asphalt composite concrete is 0.35 percent, the ideal length-to-diameter ratio is 324, and the ideal fiber amount characteristic parameter is 1.13. The test results can provide a certain reference value for the improvement of the long-term durability of fiber asphalt composite concrete pavement of road engineering. [ABSTRACT FROM AUTHOR]

This article presents the results of a study of the braking process in terms of assessing the longitudinal loading condition of transported cargo. The existing methods of securing cargo do not take into consideration the type of vehicle used to transport the cargo. This may result in cargo not being transported in compliance with the principles of proper cargo protection. This paper discusses the differences in maximum deceleration values achieved by different types of vehicles that are structurally suitable for freight transport. As a result of these differences in deceleration values, the values of forces acting on the transported cargo are also different. This paper presents and analyses the results of road tests that entailed the heavy braking of two vehicles structurally suitable for freight transport. One of them was a delivery vehicle, while the other was a semi-trailer truck. The experiment was carried out in six measurement series. Four of them were performed on an asphalt pavement, while the other two on a concrete pavement. One series included ten brake tests. Deceleration values registered during the tests were later used to determine the values of coefficient Cx, which were then compared with standardised values. It has been shown that failure to take into account in the selection process of cargo securing equipment, vehicle category, and type and condition of the pavement can result in cargo displacement and even traffic incidents. [ABSTRACT FROM AUTHOR]

Concrete structures cannot efficiently perform their functions over time due to chemical and physical external effects. Thus, enhancing the relationship between repair and aged structures, and also improving the durability properties of concrete is crucial in terms of sustainability. However, high costs, negative environmental effects, and incompatibility problems occur in repair/retrofit applications. Furthermore, three-quarters of the failures in the repaired/retrofitted structures are caused by a lack of repair durability. The need for repair in pavement/bridge decks is also frequently encountered, and early-age performance problems with repair materials cause pavement/bridge decks to be unavailable for certain periods of time. Engineered Cementitious Composite (ECC) can be effectively used as repair/retrofit and pavement/bridge deck material. It also has a minimal need for repair/retrofit thanks to its high durability properties. This article presents state-of-the-art research regarding the application of ECC as a repair/retrofit and pavement/bridge deck material. Studies in the literature show that the repair/retrofit properties of ECC outperform conventional concrete and steel fiber-reinforced concrete. ECC can be a solution to high early strength and drying shrinkage problems frequently encountered in the use of repair materials. It could also be used for different repair applications such as cast, sprayed, and trenchless rehabilitation. Moreover, ECC might fulfill specific requirements for pavement, pavement overlay, tunnel pavement, airfield pavement, and bridge deck. These superior performances are attributed to ECC's kink-crack trapping mechanism, uniquely large inelastic strain capacity, strain hardening, high tensile strain capacity, and multiple microcracking and ductile behaviors, especially bonding behavior and self-healing. [ABSTRACT FROM AUTHOR]

Although roller-compacted concrete pavement (RCCP) has been considered the most popular among its counterparts, it has not been widely used due to a number of reasons. The most dominant reason is the variability in mixture proportioning methods and material selection considering its unique behavior compared to conventional concrete mixes. Therefore, the present paper focuses on the above-mentioned parameters by critically reviewing the literature over the past four decades (1984–2021). Initially, the influence of conventional and recycled waste materials on the fresh & hardened state behavior of RCCP is reviewed in detail. Subsequently, the potential applications of various mineral & chemical admixtures and the different types of synthetic and metallic fibers for performance improvement are discussed. In addition, this study has critically appraised various mixture proportioning methods ranging from conventional concrete approaches to empirical, semi-empirical, and theoretical methods for RCCP. The study concludes by noting that all considered materials (alternative aggregates, chemical & mineral admixtures, and fibers) could be used to produce high-quality RCCP; however, an optimal proportion must be prudently selected. Consequently, RCCP could be effectively proportioned by adopting solid suspension, optimal paste volume, and gyratory compaction methods. In addition, it is observed that the strength of the RCCP is related to the aggregate-cement ratio (A/C), water-cement ratio (W/C), and coarse-sand ratio (C/S); the A/C ratio shows an inverse relationship with strength, whereas a mixed behavior between W/C and strength was found. Nevertheless, RCCPs having a vebe time, A/C ratio, and C/S ratio in the ranges of 30–50 s , 5–8 , and 1–1.4 , respectively, could be used for the surface course application of pavements. [ABSTRACT FROM AUTHOR]

• We comprehensively analyze various factors affecting pavement condition index (PCI) • We identify the important determinant features for building PCI prediction models. • We develop a new FCM-XGBoost modelling framework to effectively predict the PCI. Predicting Pavement Condition Index (PCI) is crucial for identifying potential pavement distresses and developing effective pavement maintenance strategies. Here, a new Fuzzy C-Means-eXtreme Gradient Boosting (FCM-XGBoost) PCI prediction system is developed. First, asphalt pavement sections and concrete pavement sections are distinguished, and the Fuzzy C-Means (FCM) clustering algorithm is employed to cluster the asphalt and concrete expressway sections respectively based on multiple factors influencing PCI. Next, an eXtreme Gradient Boosting (XGBoost) model is trained for each cluster of expressway sections. Finally, in the system application stage, the PCI of an expressway section for the next year is predicted using the XGBoost model trained for the specific cluster that the expressway section belongs to. Validation results based on actual pavement condition data indicate that the proposed FCM-XGBoost PCI prediction system can achieve slightly higher accuracy compared with several high performance benchmark models, which include the Random Forest model, the Gradient Boosting Decision Tree model, the Light Gradient Boosting Machine model and the XGBoost model. The developed PCI prediction system contributes to the improvement of PCI prediction approaches and can be potentially applied in deploying effective and cost-efficient pavement maintenance strategies. [ABSTRACT FROM AUTHOR]

In order to study the interlayer shear behavior of bridge deck pavement, a numerical simulation was conducted to analyze the influence of varying interfacial conditions on shear stress at the bottom of pavement layers under the moving loading effect. Moreover, the shear strength of the different adhesive and waterproof adhesive materials was evaluated by conducting laboratory tests. The results showed that improving the bonding condition at the upper interlayer led to the reduction of the shear stress at the bottom of the pavement layers. With the increase of the friction coefficient of the upper interface to the full bonding state, the resulting shear stress at the bottom of the upper layer declined to the lowest value, which was about 35% of that of the full slip state. When the lower interlayer was in the full slip or partial bonding state, the resulting shear stress at the bottom of the lower layer decreased linearly with the increase of the friction coefficient of the upper interlayer. Moreover, once the contact state of the upper interlayer reached the full bonding state, the resulting shear stress at the bottom of the lower layer reached the minimum, which is about 88% of that of the full slip state. To improve the integrity and shear resistance of the bridge deck pavement structure, interlayer bonding should be strengthened. In this regard, the resin emulsified asphalt was determined as an appropriate adhesive material to be applied at the upper and lower interlayers. In addition, interlayer shear bond strength, regardless of the type of adhesive materials, was decreased with increasing temperature. Finally, statistical analysis results indicated that all factors of structure type, type of adhesive material, and temperature statistically have a significant effect on interlayer bond strength. The findings of this study could provide a theoretical basis and experimental support for improving the interlayer design and construction in the concrete bridge deck pavement structure. [ABSTRACT FROM AUTHOR]

An investigative study was carried out on the assessment of engineering properties of asphaltic concrete used for pavement construction in Akwa Ibom State, South-south, Nigeria. A total of 225 compacted samples of wearing course asphaltic concrete were obtained from three different asphalt plants in Eket, Oron and Uyo designated as D, E, and G, respectively. The test results based on the outcome of the Marshal Stability for the three different asphalt plants ranged from 7.51-13.36 kN, 9.36-11.34 kN and 8.26-9.46 kN with corresponding flow values which ranged from 3.33-3.94 mm, 2.40-3.48 mm and 2.73-3.19 mm for asphalt plants D, E, and G, respectively. The test outcomes revealed that a good number of the test samples were within the benchmark of the Nigeria General Specifications for roads. Three predictive models were built for the estimation of Marshall Stability for the three different sites. Based on the outcome of t-test (paired two sample for means) and analysis of variance (ANOVA) single factor, there was no significant difference between the experimented values and model formulated results. Also, the formulated model yielded an excellent coefficient of determination (R2) of 0.9513, 0.9777 and 0.9777 for the three sites. This excellent coefficient of determination reflect the models could be used in prediction of stability strength. The correlation statistic and their respective p-values of each of the independent variables, BIT, VIM and VFB has shown to contribute more than the other variables in building the established models and thus expedient in forecasting the performance of asphalt pavements. [ABSTRACT FROM AUTHOR]

Airports strive to prevent safety issues, such as foreign object debris (FOD), by pavement management using the pavement condition index (PCI). The index is used in decision-making processes for overall pavement maintenance and repair, such as the prevention of additional damage due to cracks and the like. However, considering the current situation in Korea where mostly mid-sized and large commercial airports exist, problems regarding direct applications of the existing PCI deduct value have been consistently pointed out. In addition, as the relationship between the PCI and whether maintenance and repair are required is unrealistic, there have been difficulties in communication between maintenance and repair staff and decision makers. Therefore, to resolve these problems, this study first analyzed the calculation procedure of the existing PCI and then redefined the main distress type of Korean airport pavements. In addition, a deduct value curve (DVC) in terms of the severity level for six main distress factors of asphalt pavements and eight main distress factors of concrete pavements and a corrected deduct value curve (CDVC) for multiple distresses in terms of the pavement form were developed using panel rating, which is an engineering approach, by forming an airport pavement expert panel. Finally, a Korea airport pavement condition index (KPCI) was proposed using the curves, and the field application results were compared against the existing PCI to examine the adequacy of the KPCI. As a result, the developed criteria showed an overall trend lower than existing PCI. Moreover, it was verified that this trend increases with worsening pavement condition. It appears that a more discriminating evaluation may be possible when determining pavement conditions by PCI results of the developed criteria. [ABSTRACT FROM AUTHOR]

Based on thermal–mechanical coupling simulation analysis and physical engineering tracking observation, the mechanical behavior and response of a continuously reinforced concrete and asphalt concrete (CRC + AC) composite pavement layer were analyzed, and the causes of cracking on the surface and bottom of the asphalt layer were revealed. Studies have shown that under normal driving conditions, the AC layer, which is usually in the position of the wheel load gap and wheel load side, more easily generates a longitudinal "corresponding crack". Compared to normal driving, longitudinal cracks are generated more easily inside of the curve, and transverse cracks occur more easily on poor stadia curves. When the AC layer thickness is less than 8 cm, the AC layer is more prone to bottom-up cracking, and it is more prone to top-down cracking when it is more than 8 cm thick. Comprehensively considering the tensile stress, shear stress, and the thickness of the AC layer, it is recommended that the suitable thickness range of the AC layer is 8 cm~14 cm. The calculated results show good agreement with the physical engineering investigation. The research results can provide a theoretical and scientific basis for cracking control and the rational design of a CRC + AC composite pavement layer. [ABSTRACT FROM AUTHOR]

Considering the future shortage of natural aggregates, various researchers have promoted the recycling of by-products into various asphalt pavement types. This paper promoted a double-recycling technique, where thermally treated waste silt was used as a filler for the bituminous skeleton and grouting material of a geopolymer-based semiflexible pavement. Semiflexible pavements (SFP) inherit the flexibility of common asphalt pavements and simultaneously benefit from the rigidity of cement concrete pavements. For this purpose, waste silt obtained from a local asphalt plant was thermally treated at 750 °C and was used as the filler to produce the porous skeleton. Two different materials, including conventional cement-based and a geopolymer-based cement, were used as the grouting material. The geopolymer grout was produced by mixing metakaolin (MK), potassium-based liquid hardener and calcined silt as filler. The porous and grouted samples were characterized in terms of indirect tensile strength (ITS), the indirect tensile strength modulus (ITSM) and moisture sensitivity. The use of thermally treated waste silt as filler in porous asphalt demonstrated promising results and was comparable to the control samples produced with limestone as the filler. However, the control samples grouted with cement-based material outperformed the geopolymer grout in all aspects. Moreover, the addition of calcined silt improved the low-temperature fatigue performance of porous and grouted asphalt pavements. [ABSTRACT FROM AUTHOR]

In recent years, the promotion of green travel and the emergence of bicycle sharing have dramatically increased the population of people traveling by bicycle in China. Bicycle sharing has become an indispensable daily means of travel for some people. Therefore, the ride comfort and safety of bicycle lanes should be paid more attention. Toward meeting the demand for smooth bicycle lanes, we propose a new method of testing the roughness of bicycle lanes based on the riding condition and explore the possibility of its realization. A riding profiler is assembled and designed, and its test repeatability is verified by repeated measurements. The riding profiler is also applied to different pavement types with various speeds for roughness testing. The results demonstrate that the speed and pavement type affect the vibration acceleration and vertical displacement during riding, and the greater the riding speed, the stronger the vibration sensation. In addition, the vibration is strongest when riding on concrete block pavement and weakest on dense asphalt pavement. On the basis of the test results, the acceleration interference is taken as an evaluation index to analyze riding comfort under different conditions. [ABSTRACT FROM AUTHOR]

Remaining life is an important indicator of pavement residual effective service time and is directly related to maintenance decision-making with limited funds. This paper proposes a fast and non-destructive model to predict the remaining life of rigid PCC (Portland cement concrete) pavement, with or without asphalt overlay. Firstly, a model was constructed according to the current Chinese design specifications for concrete pavement integrating an inverse design concept. Secondly, the prediction model was applied to three typical pavement sections with 1430, 1250 and 1000 slabs, respectively. Ground penetrating radar (GPR) was utilized to determine the geometric parameters in the predictive model and the physical state of the pavement. A falling weight detector (FWD) was utilized for determination of the mechanical parameters. A more reasonable equivalent elastic modulus of foundation was back-calculated instead of using the limited model in the design specification. Thirdly, the remaining life was predicted based on the current mechanical and geometric parameters. The distributions of the remaining life of the three pavement sections was statistically analyzed. Finally, a decision-making system to inform maintenance strategy was proposed based on the remaining life and the technical condition of each slab. The results showed that the relationship between the remaining life and the mechanical parameters, geometric parameters and the physical state of the pavement was highly consistent with engineering experience. The success rate of the prediction model was as high as 96%. The proposed fast and non-destructive prediction model showed good engineering applicability and feasibility. The decision-making system was shown to be feasible in terms of economic benefits. [ABSTRACT FROM AUTHOR]

Concrete pavement proportions are increasing in Korean expressways, resulting in increased maintenance cost. The length of degenerate concrete pavements that have exceeded the design life (20 years) was 1150 km in 2015 and 2605 km in 2020 and is expected to rapidly increase. To extend the service life of concrete pavements, life-cycle cost (LCC) analysis was conducted on asphalt and concrete overlays, based on the different maintenance methods. LCC analysis was performed when the shoulder was used and when it was not used between 6000 and 35,000 AADT traffic according to the two-lane and four-lane traffic. During overlay, one lane was completely blocked, and the value per vehicle was converted into the user cost using the Construction Analysis for Pavement Rehabilitation Strategies software, according to whether the shoulder was used to maintain the number of lanes. In addition, LCC analysis was conducted by examining the construction cost and life-cycle according to each overlay method. When the shoulder was used, the total construction cost decreased, owing to the reduction in user cost, indicating that the implementation of the traffic measure of using the road shoulder improves user satisfaction and cost. The asphalt overlay was observed to be more favorable than concrete overlay in terms of the initial total construction cost. However, under a 20-year cycle, the economic efficiency of concrete overlay was higher than that of asphalt overlay. After repairing the deteriorated target sections of concrete pavements, the overlay method (asphalt or concrete) ought to be selected according to the target service life for beneficial economic effect. Concrete overlay was to obtain about 20% or greater LCC effect compared to asphalt overlay, and at least 5% or more additional LCC effect obtained when the shoulder was used. [ABSTRACT FROM AUTHOR]

From the perspective of sustainable waste management and its environmental impact, waste biomass bottom ash (BA) remains problematic and challenging to use as a recycling material for civil engineering infrastructures. This study evaluated the performance of lateritic soil (LS), stabilized with cement and biomass BA, as a subbase material. BA has been considered a replacement material in LS prior to the introduction of hydraulic cement stabilization means. The geotechnical engineering tests comprised the modified Proctor test, the California Bearing Ratio (CBR) test, and the unconfined compression test. X-ray fluorescence (XRF) and X-ray diffraction (XRD) tests were conducted to investigate the mineralogical properties of the stabilized soil samples. The leachate test was performed with a permeability mold to measure the release of heavy metals. Finally, the benefits of using the stabilized subbase material were assessed using the mechanistic–empirical (M–E) pavement design approach. Based on the results obtained, the strength and stiffness characteristics of the stabilized soils indicate that the efficiency of the mix satisfied the Thailand highway specification. The admixture of 80% BA and 5% cement is suggested for use as a soil–cement subbase material for flexible pavements, due to its good engineering and environmental properties. The results of the M–E design demonstrate the effectiveness of the stabilized soil presented herein. The study's outcomes are predicted to promote the utilization of waste BA as a promising pavement material. [ABSTRACT FROM AUTHOR]

The treatment and repair strategies for reflective and fatigue cracking that initiate at the pavement surface (i.e., top-down cracking) and at the bottom of the asphalt concrete layer (i.e., bottom-up cracking) are noticeably different. However, pavement management engineers are facing difficulties in identifying these cracks in the field because they usually appear in visually identical patterns. The objective of this study was to develop artificial neural network (ANN) and convolutional neural network (CNN) applications to differentiate and classify top-down, bottom-up, and cement-treated reflective cracking in in-service flexible pavements using deep-learning models. The developed CNN model achieved an accuracy of 93.8% in the testing and 91% in the validation phases, and the ANN model showed an overall accuracy of 92%. The ANN classification tool was developed based on variables related to pavement and crack characteristics including pavement age, annual average daily traffic, thickness of the asphalt concrete layer, type of base, crack orientation, and crack location. [ABSTRACT FROM AUTHOR]

To solve the problem of the insufficient anti-slip performance of steel bridge deck wear layers, a kind of new epoxy asphalt mixture FAC-10 (Full Epoxy Asphalt Content is shortened to FAC) is proposed in this paper based on the design method of an asphalt-rich mix proportion. The FAC-10 pavement layer was tracked and tested using a pavement texture tester to study the change in its skid resistance under traffic load from a macroscopic and microscopic perspective. The influence of traffic load on the deformation of the FAC-10 wearing layer was also simulated and analyzed via lab tests. The results show that the new FAC-10 epoxy asphalt mixture is superior to the traditional EA-10 epoxy asphalt mixture in terms of skid resistance. During the monitoring and testing period, the three-dimensional (3D) structure depth of the pavement surface showed a decreasing trend followed by an increasing trend, while the density of microtexture distribution showed the opposite trend. After a wheel pressure rutting test, the rutted slab showed slight deformation and a certain degree of reduction in 3D structure depth; the deformation of the rutted slab mainly occured in the surface layer, and the internal deformation was negligible. [ABSTRACT FROM AUTHOR]

In order to comprehensively analyze the dynamic response of full-depth asphalt pavement under moving load, a three-dimensional model of pavement structure and dynamic load moving zone are established based on ABAQUS finite element software. Based on the time history curves of different structures, the stress-strain states at the bottom of each structural layer in different structures under moving load are analyzed. The results show that the stress, strain, and shear stress of the middle layer of full-depth pavement are smaller than those of semirigid base pavement, and rutting is closely related to the deformation of this layer. The dynamic response results of the same structure at different speeds are similar, but the increase of the maximum speed will increase the shear stress at the bottom of the layer, and the road is more prone to longitudinal crack. [ABSTRACT FROM AUTHOR]

Many roads in hot regions of the world are exposed to very high temperatures especially in desert areas during the summer season, where the temperature could reach more than sixty Celsius degrees. Temperature variations cause a lot of distress in flexible and rigid pavement such as rutting, vertical transverse (i.e., thermal) cracking, thermal fatigue damage, blow up/buckling, in addition to generating warping stresses. Accurate detection of the surface temperature of flexible pavement is very important for pavement design analysis. This research presents a new model to estimate the temperature of flexible pavement layers under extremely high temperatures as a set of simultaneous equations. The proposed model included Clear-Sky as sub-model to estimate the solar energy of beam and diffuse radiation of the pavement surface. Ambient temperature was calculated by solving the model depending on the time of the day. The proposed model was validated via experimental data collected from one-year measurements at instrumented pavement section in New Sohag, Egypt. The asphalt surface temperatures were measured for summer, winter solstices and vernal and autumnal equinoxes. It was found that the model provides reasonable estimates compared to the experimental data. The proposed model is deemed appropriate for estimating pavement layers temperature in hot regions. [ABSTRACT FROM AUTHOR]

Featured Application: Replacement of black pavements by high-reflective concrete pavements is an easy and cost-effective measure to stem climate change. In addition, concrete is a building material that is fully recyclable at the end of its service life. Furthermore, the construction of concrete pavements demands local resources, avoiding greenhouse gas emissions due to transport. Pavements store heat, which is subsequently released into the atmosphere, heating the surrounding air. Therefore, this process contributes to climate change and global warming. For this reason, the use of high-solar-reflectance (albedo) pavements is seen as one of the potential mitigation methods for climate change. Concrete pavements have a much higher albedo than asphalt due to their light gray color compared with black pavements. Accordingly, the widespread utilization of highly reflective concrete pavements will improve local climate change mitigation. Nevertheless, concrete albedo slightly decreases over time because of weathering. Albedo and solar reflectance index (SRI) measurements were taken on actual precast concrete pavements made with different mixes. The methodology applied for this project is based on the comparison between the asphalt and concrete pavements' reflectivity. Conventional concrete mix designs can provide cool pavements with SRI higher than 29. Replacement of black pavements by highly reflective concrete pavements appeared to be a cost-effective and easily implemented measure to combat climate change. Finally, multidisciplinary studies considering factors such as building materials' albedo, among other mitigation measures, should be performed to provide more precise and reliable guidance to policymakers, stakeholders, decision makers and urban planners. [ABSTRACT FROM AUTHOR]

Geogrid reinforcement effectively controls the rutting of pavements under traffic loads, especially when constructed over soft subgrades. In this study, extensive large-scale model pavement experiments (LSMPEs) were performed to quantify the rut depths of flexible pavements. In all, 20 LSMPEs were performed on pavement sections overlying subgrades of different strengths with California bearing ratio (CBR) values varying from 1% to 5%. Three geogrid types were considered to study the effects of material type [polypropylene (PP) and polyester (PET)] and tensile strengths (30–60 kN/m) on the rutting behavior of flexible pavements. LSMPEs were first performed under monotonic loading to obtain the optimum depth of reinforcement within the base layer of flexible pavement. Thereafter, a series of repetitive load (haversine loading) was applied on paved sections of reinforced flexible pavements using a high-end, linear, double-acting actuator system. Rut deformations were measured at both the surface and the subgrade levels of the model pavements. The rut deformations were found to distinctly vary in accordance with the condition of the subgrade, the thickness of the pavement layers, and the type of geogrid used. The rut depth reduction (RDR) at the pavement surface was found to range from 22% to 69% for PP- and PET-geogrid reinforced base layers. Geogrid reinforcement significantly reduced the rut depths at the subgrade level (as high as 90%) compared to unreinforced sections. In addition, the model pavements were instrumented with the earth pressure cells to measure the vertical pressures transferred to the subgrade due to surface loading. The ability of geogrid reinforcement to distribute loads to wider areas was quantified in terms of the vertical stress distribution angle, αmax , at the end of the load cycles (N=100,000 cycles). The αmax maximum values for geogrid (GG1/GG2/GG3)-reinforced pavements built over weak subgrade (CBR=1%) varied from 28.4° to 32.2°, while it was 25.7° for unreinforced pavements. Likewise, αmax values for geogrid-reinforced pavements overlying a relatively fair subgrade (CBR=5%) varied from 34.5° to 43.6° against 30.4° for an unreinforced case. [ABSTRACT FROM AUTHOR]

Continuously reinforced concrete pavement has the potential to provide a long term, "zero - maintenance" service life under heavy traffic, provided proper design and quality construction practices are utilized. Concrete mixes containing 0%, 5%, 10%, 15%, 20%, 25%, and 30% of rice husk ash was prepared and cured in portable water. The compressive strengths of concrete specimens were evaluated at the 3rd, 7th, 14th, 28th, 56thand 91st day old. The split tensile strength and the flexural strength were evaluated at the 14th and 28th day. The compressive strength values, split tensile strength values and flexural strength values of the concrete specimens increased with increase in age and also increased with increase in 5% and 10% percentage replacement of cement with rice husk ash. The concrete specimens containing 0% to 25% percentage replacement of cement with rice husk ash satisfied the minimum compressive strength requirements specified in the relevant standard specifications and manuals. The study therefore concluded that up to 25% of rice husk ash should be used as partial replacement of cement in continuously reinforced concrete pavement. [ABSTRACT FROM AUTHOR]

This paper focuses on the disposal of iron tailings sand (ITS) and reclaimed inorganic binder stabilized aggregate (RAI), and a new "ITS plus RAI" solid waste treatment method is innovatively proposed, which uses ITS and RAI as a new base course material to replace of new aggregates by 100%. It is found that the new ITS and RAI mixture has excellent compressive performance by designing the material composition of the mixture, which can meet the design strength of different levels of pavement under various load conditions. A series of laboratory tests are used to study the effect of the content of special cementitious material and iron tailings on the uniaxial compressive strength, flexural-tensile strength, compressive resilience modulus, and flexural-tensile resilience modulus of recycled mixture. And, the scanning electron microscope test (SEM) and X-ray diffraction test (XRD) are used to compare the surface morphology characteristics and hydration products of the recycled mixture under different ratios and to discuss the formation mechanism of the strength of the mixture. The test results show that the macroscopic change pattern in laboratory tests is basically consistent with the results in microanalysis. The relationship between compressive strength and compressive resilience modulus and flexural resilience modulus is also established by linear regression. This solid waste treatment method is applied to the pavement renovation project of national and provincial roads in Shanxi Province (within Linfen), to replace the existing base material by using recycled mixture, and the results show that it can save not only the carbon emission from stone mining and processing but also the construction cost, while producing good social and economic benefits and promoting the process of carbon neutralization in the world. [ABSTRACT FROM AUTHOR]

This paper presents the use of crude oil ash in asphalt flexible pavement and concrete rigid pavement. Conventional micro-size fly ash produced from burning crude oil in Jizan electrical power plant in Saudi Arabia was used in this study. The size of conventional crude oil ash waste reduced from micro-scale to nano-scale using ball-milling techniques. The first series of testing investigate the development of flexible pavement using asphalt bituminous AC60/70 incorporated conventional and nano-crude oil fly ash waste. The percentage of conventional and nano-ash used in asphalt mixes was varied from 0 to 15% of asphalt binder. The use of nano-fly ash increases the rutting factor by 0%, 33%, 61% and 38% at 0%, 5%, 10% and 15% nano-fly ash content, respectively. The nano-fly ash improves the rutting factors and bearing load capacity of flexible pavement mixes more than the control mix and mixes containing conventional micro-fly ash. The second series of testing investigates the use of nano-fly ash in rigid pavement asphalt concrete. Conventional and nano-fly ash replaced cement content in concrete material at 0%, 5%, 10%, and 15%. Concrete material incorporated nano-fly ash shows higher compressive strength and lower absorption compared to concrete control sample and concrete containing conventional micro-fly ash. The strength of concrete incorporated nano-fly ash increases by 14.8%, while absorption of concrete improves by 20.1% at 10% nano-fly ash content. The optimum nano-fly ash content was 10% to achieve the highest performance of both pavement materials. The use of nano-crude oil fly ash improves the performance of both pavement materials and helps in reducing the cost of repair in road and highway construction. Moreover, the use of nano-fly ash in paving materials can help in the recycling of this toxic waste to produce sustainable and environmentally friendly road construction materials. [ABSTRACT FROM AUTHOR]

Due to greater durability and lower maintenance costs, concrete pavements are more competitive than asphalt pavements in areas where rigid pavements are required. To ensure the surface skid resistance of concrete pavement for driving safety, appropriate textures must be created on the concrete pavement surface. Common surface texturing treatments in Germany include exposed aggregate, grinding and grooving, and sealing methods. To investigate the influence of different surface texturing methods on the wearing resistance of concrete pavement, concrete pavement samples with six different surface textures were manufactured in this study. The advanced Aachen Polishing Machine (APM) was used to simulate the different polishing states on the extracted samples with 0, 16, 33, 100, 200, and 300 min of real-tire polishing effect. After each polishing stage, a series of surface characteristic tests was conducted to evaluate the wearing characteristics of pavement samples. The test results showed that different surface textures have different long-term polishing resistances. Of the texturing methods investigated, the exposed aggregate and sealing treatments provide the best long-term polishing resistance for plastic and hardened concrete, respectively. This research provided a comprehensive evaluation of and significant guidance on the selection of surface treatment methods for new construction of cement pavement and surface maintenance of hardened concrete pavement. [ABSTRACT FROM AUTHOR]

Warm-mixed reclaimed asphalt pavement technology, as an environmental recycling method to reuse waste materials, has been widely investigated around the world. However, the skeleton of the reclaimed asphalt mixture is unstable due to the existence of the reclaimed materials. Semiflexible pavement has been successfully used in heavy traffic area due to its high rutting resistance. For combination with these two methods, a warm-mixed reclaimed semiflexible pavement material was proposed in this study. In order to investigate the interfacial weakening effect of the warm-mixed reclaimed semiflexible pavement material in a microstructural perspective, an image-based two-dimensional microstructural finite element model was presented. Results show that the maximum compressive stress of the new and RAP aggregates and cement mortar with interface is greater than that without interface and the compressive stress of the material increases when considering the interface. Besides, the maximum compressive strain of the material with interface is greater than that without interface and the strain values in the models with interface at all three positions are greater than those without interface. [ABSTRACT FROM AUTHOR]

In concrete structures (concrete), damage from cracks, deterioration, amorphization, and delamination occur in some structures, causing disaggregation (concrete changed to very fine particles) and hollowing out of the concrete. In concrete pavements, damage from large amounts of pop-out of aggregate occurs from the surface of the concrete pavement 4–5 hours after spraying of snow melting agent on the surface of the pavement. The damage from disaggregation, blistering, cracks, and peeling-off of a surface course have also been observed in asphalt runways and highways. The damage from disaggregation, cracks and pop-out of aggregate in asphalt pavements and concrete structures have long been seen as strange and unexpected and have defied explanation. As a result of examinations in various experiments, it was concluded that all of the unexplained kinds of damage of both asphalt pavements and concrete structures were caused by Trace Quantities of Organic Matter (TQOM), Air Entrained (AE) water reducing agent in air and/or cement, and surfactant in snow melting agent. The emission sources of TQOM and these organic substances were also identified by chemical analysis for these unexpected and unexplained phenomena. The TQOM includes phthalate compounds (phthalates in the following), amine compounds, phosphate compounds, snow melting agent and Sodium Polyoxyethylene Nonyl phenyl Ether Sulfate (SPNES). SPNES is a surfactant in windshield washer fluid for automobiles. We found that the water content and content of organic matter in damaged asphalt pavements and concrete structures are also important indicators for the damage. Further, a new evaluation method for amorphization was proposed in this study and it appears suitable for evaluating the safety of concrete structures along roads which were exposed to TQOM in severely air-polluted environments. [ABSTRACT FROM AUTHOR]

Pavement segregation usually cause engineering quality problems such as early damage of asphalt pavement. Therefore, it is of great significance to carry out segregation detection in the construction process. However, existing image detection technology has two problems: 1) the segregation boundary and the index are not clear; 2) the segregation assessment is localized. In order to find useful solutions to these two problems, this study proposed an Aggregation Segregation Generative Adversarial Network (AG-GAN) to generate virtual pavement images with segregation failure. Moreover, a multi-scale fusion method of Recurrent Neural Network (RNN) and the Global Averaging Sliding Window (GASW) algorithm is developed to achieve globalized aggregation evaluations. Based on extensive experiments tests, conclusions obtained that the accuracy rate of re-current neural network for segregation determination of pavement sequence can be up to 84.62%. In addition, automatically assessment of the segregation condition of pavement section can be achieved, which proves the practical application effectiveness of the proposed algorithm in the actual paving process. [Display omitted] [ABSTRACT FROM AUTHOR]

Foamed asphalt cold-recycled mixtures have been increasingly used in China. However, the interlayer shear performance between the foamed asphalt cold-recycled layer and its top and bottom layers is still not clear. In this study, we explored factors affecting the interlayer shear performance of foamed asphalt cold-recycled layers (FACRL). Regarding the interlayer performance between the foamed asphalt cold-recycled layer and cement-treated base (CTB), the optimal content of the prime coat asphalt was 0.8 kg/m2 , and the prime coat asphalt was recommended to be applied on the surface of the base as soon as the base was paved. Styrene-butadiene-styrene (SBS)-rubber modified asphalt with a content of 2.3 kg/m2 and aggregates with a size range of 4.74–9.5 mm was recommended for use in the seal coats. The aggregates used in the seal coat were recommended to be premixed with a 0.3% asphalt binder to improve the adhesion and to be paved with a spreading area of 65%. Regarding the interlayer performance between the foamed asphalt cold-recycled layer and top hot-mix asphalt (HMA), the interlayer shear strength and fracture energy increased and then decreased with the added tack coat asphalt. The shear strength and fracture energy of the interlayer at 50°C was only 20% and 8% of that at 25°C, respectively. The optimum usage percent of the tack coat binder is 0.4 kg/m2. [ABSTRACT FROM AUTHOR]

This study discusses the effect of utilizing coarse reclaimed asphalt pavement (RAP) aggregates as a replacement to natural coarse aggregates (NCAs) for the production of pervious concrete pavement (PCP) mixes. Coarse RAP (RC) aggregates were utilized in proportions of 0%, 25%, 50%, 75%, and 100%, respectively. It was observed that the porosity and permeability coefficient of the PCP mixes increases considerably as the RAP replacement level increases. Meanwhile, the incorporation of RC was also found to negatively affect the mechanical properties of the PCP mixes. However, the compressive and flexural strength values were noted to be well within the prescribed limits (5–25 MPa and 1–3.2 MPa) required for a PCP mixture. On the other hand, the incorporation of RC was observed to reduce the hardened density, resistance to abrasion, and resistance against aggressive environment of chlorides and sulfates. Therefore, in order to prepare a PCP mixture such that there exists a fine balance in various properties, it is recommended that RC up to 50% may be utilized as a replacement to NCA. In view of achieving maximum sustainability, RC up to 100% may be completely utilized for the production of PCP mixes provided a binary gradation is adopted. Utilization of RAP in preparation of pervious concrete pavement mix will not only resolve the issues related to clearance of an enormous amount of RAP dumps, but would go a long way in dealing with various other environmental and ecological impacts. [ABSTRACT FROM AUTHOR]

This paper focused on the optimization of the C40 fly ash concrete pavement, which was considered as a measure to accelerate the consumption of industrial solid wastes such as fly ash, committing to the goal of zero waste. By comparing with three groups of ordinary mix proportion, the performances (e.g., mechanical properties, durability, and brittle property) of the optimized mix proportion were evaluated via multiple mechanical and physical tests. Their air voids' structure was characterized by the BJH method (a method to calculate pore size described by Barrett, Joyner, and Halenda), and the results were combined with the road performances of concrete to analyze the formation mechanism of high durability of optimized fly ash pavement concrete. As for the experimental results for the optimized, its 28 d compressive strength peaked at 50.8 MPa together with corresponding 28 d flexural strength at 8.2 MPa, which indicated a favorable mechanical performance for wide application in pavement construction. Except for the mechanical properties, the better durability indicators obtained after optimization also provided a more compact pore structure for the optimized. The raw materials and construction technology of the two kinds of pavements were compared. Promoting the use of optimized fly ash pavement concrete can break the situation of the asphalt pavement monopolizing heavy-haul highway and greatly reduce the industrial wastes which can be used as raw materials in the production of cement, such as blast furnace slag and fly ash. It was proved that the optimized fly ash concrete pavement can be used to replace the asphalt pavement under the premise of achieving the same working performances. [ABSTRACT FROM AUTHOR]

Bitumen is mainly used to construct wearing courses of flexible pavements and runways. Due to its viscoelastic and thermoplastic properties, it plays a major role in the performance of pavements, where temperature and rate of loading have significant effects. Due to high intensity of traffic, overloading of vehicles and significant variations in climate, early development of distress indices, like rutting, cracking, undulation, potholes, ... etc., has been found in flexible pavements. Conventional bitumen fails to give longer life for pavements. Hence, it is required to modify conventional bitumen for improving its properties. There are several modifiers available in the market, where polymer modifiers are the most commonly used, such as Styrene Butadiene Styrene (SBS), Styrene Butadiene Rubber (SBR), Ethylene Vinyl Acetate (EVA), ... etc. In the present study, EVA was used as a modifier in VG-30 grade bitumen to reduce rut depth for bituminous concrete (BC) mixes. Marshall stability test was performed to determine Marshall stability, flow value and volumetric properties, such as air voids (Vv), Voids in Mineral Aggregates (VMA) and Voids Filled with Bitumen (VFB). A wheel rut tester was used to study the rutting defect with varying temperature and number of repetitions. [ABSTRACT FROM AUTHOR]

Precast concrete pavement (PCP) has proven itself to be one of the most efficient methods for repair and replacement of concrete pavement, as well as for construction of new pavement in the areas of heavy traffic. The application of PCP ensures fast construction of concrete pavement without compromising the quality of concrete. This paper provides a brief of various types of PCP that have been used worldwide and their application in the repair of damaged pavement, continuous construction of pavement, Airfield application and temporary pavement construction. It further discusses critical aspects of PCP that require careful analysis prior to its field implementation. The paper specially focuses on panel dimensioning, load transfer mechanism, lifting arrangement, stacking arrangement, transportation and base preparation for PCP. Suitability of different types of PCP for varying site conditions has been discussed. Innovative developments related to PCP and the future scope of this technology have also been discussed. [ABSTRACT FROM AUTHOR]

With the rapid development of autonomous vehicles (AV) and high-definition (HD) maps, up-to-date lane marking information is necessary. Over the years, several lane marking extraction approaches have been proposed with many of them based on accurate and dense Light Detection and Ranging (LiDAR) point cloud data collected by mobile mapping systems (MMS). This study proposes a normalized intensity thresholding strategy and a deep learning strategy with automatically generated labels. The former extracts lane markings directly from LiDAR point clouds while the latter utilizes 2D intensity images generated from the LiDAR point cloud. Additionally, the proposed approaches are also compared with state-of-the-art strategies such as original intensity thresholding and a deep learning approach based on manually established labels. Finally, each strategy is evaluated in asphalt and concrete pavements separately to assess their sensitivity to the nature of pavement surface. The results show that the deep learning model trained with automatically generated labels performs the best in both asphalt and concrete pavement area with an F1-score of 84.9% and 85.1%. In asphalt pavement area, original intensity thresholding strategy shows a lane marking extraction performance comparable to the other strategies while in concrete pavement area, it is significantly poor with an F1-score of 65.1%. Between the proposed normalized intensity thresholding and deep learning model trained with manually labeled data, the former performs better in asphalt pavement area while the latter obtains better results in concrete pavements. [ABSTRACT FROM AUTHOR]

During the last three decades, concrete pavement or rigid pavement became a widely used alternative of flexible pavement (asphalt pavement) at freeways and highways with high traffic of heavy vehicles, due to its durability, long life, and less need of maintenance; however, the cost of construction for rigid pavement is very high compared to asphalt pavement. Developing a new concrete mixture to increase the performance and reducing the required thickness of concrete pavement became an important issue in rigid pavement design in order to reduce the high construction cost. In this study, a new concrete mixture was developed using specific amounts of steel fibers and steel slag (as a supplementary cementing material to replace a part of the cement). Several mixtures with different concentrations of fibers were prepared, and samples were tested for workability, early flexural strength, and ultimate flexural strength. The results showed that the new concrete mixture could achieve an increase in flexural strength between 48.9% and 50.5% compared to normal concrete mixture without steel fibers and steel slag, with minimum acceptable workability, and therefore, the required pavement thickness could be decreased by more than 24%. [ABSTRACT FROM AUTHOR]

In this study, the temperature distribution of a pavement was predicted by developing an analytic algorithm. The Laplace and inverse Laplace transform techniques and Gaussian quadratic formula were applied to a pavement system of an asphalt overlay placed over an existing concrete pavement. The temperature distribution of the previous cement concrete pavement with an asphalt overlay can be estimated with the proposed analytical method regardless of the depth and time. To conduct the method, the layer thicknesses, material thermal properties and climatic factors (including air temperature, wind velocity and solar radiation) were firstly input. Then, a discrete least-squares approximation of the interpolatory trigonometric polynomials was used to fit some specific measured climatic factors considered in the surface boundary condition, i.e., the measured solar radiation intensity and air temperature. The pavement surface convection coefficient can be approximately calculated by the wind speed. The temperature solutions are validated with the measured pavement temperature data of two different periods of a whole year (summer and winter). The obtained results demonstrate the feasibility of the developed analytical approach to predict the temperature distribution of the existing cement concrete pavement with an asphalt overlay in different weather conditions with acceptable accuracy. [ABSTRACT FROM AUTHOR]

The rehabilitation process of asphalt pavements using the technique of milling and filling can cause several environmental problems due to either the disposal of the milled asphalt mix or the exploration of natural resources. One alternative to mitigate these impacts is to reuse this milled material, known as reclaimed asphalt pavement (RAP), in the construction of new pavement layers. Within the several available techniques to reuse the RAP, cold recycling using an emulsified asphalt-recycling agent has shown great potential. The aim of this study is to evaluate the application of a cold recycled asphalt mix using 100% RAP with an emulsified asphalt-recycling agent as a new pavement base course. A trial section was built employing this material as a pavement base course in a heavy traffic highway in Brazil, and its structural behavior was monitored for 12 months using a Falling Weight Deflectometer (FWD) to assess its performance over time. Furthermore, a laboratory-testing program was performed to evaluate the recycled mixture stiffness and strength through resilient modulus and indirect tensile strength tests. These tests were used to investigate the influence of the storage interval (7, 14, and 28 days) considering the time between mixing and compaction of the mixture. The effect of the curing time after compaction (1, 3, 7, 26, and 56 days) was also assessed. It was verified in laboratory and in the trial section that the stiffness increases with curing time. Furthermore, the backcalculated elastic resilient moduli indicated values in the same order of magnitude to those obtained in the laboratory tests. In addition to the laboratory test findings, it was also observed that the longer the period of storage, the higher the values of stiffness and tensile strength for short periods of curing. This behavior was not verified when longer curing periods were used. In general, the use of cold recycled asphalt mixtures as base course of new pavements proved to be a promising alternative to reuse RAP. [ABSTRACT FROM AUTHOR]

As part of developing a safe, efficient, and sustainable transportation infrastructure, health monitoring of pavements and bridges, as well as the monitoring of real-time roadway conditions for safety, have become increasingly important. The sensors, data acquisition, and data transmission equipment needed for such monitoring require electricity that is often unavailable, in short supply, unreliable, or a combination of the three. The development of a more robust and capable health and safety monitoring equipment will be greatly facilitated by a more ample, reliable source of electricity than is currently available. This investigation explores the concept of using pavements as thermoelectric generators to produce and supply electricity, using the temperature differential that exists between a pavement's surface and its underlying layers. A thermoelectric module was placed within a hot-mix asphalt pavement system and a Portland cement concrete pavement system in the laboratory and subjected to full-spectrum lights. The amount of electricity generated was measured, and the results indicated that electricity can be generated. Initial power generation suggests that one square meter pavement surface area may be capable of providing about 62000 microwatts, enough power for 620 wireless transmitters and the accompanying sensor. It is estimated that it may be possible to produce up to 300 W/lane-km. [ABSTRACT FROM AUTHOR]