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Bituminous materials play a crucial role in the construction industry, serving as essential binders in asphalt mixtures. Understanding their bonding behavior, mechanism, and characterization is imperative for enhancing pavement performance, durability, and sustainability. Despite the widespread use of bituminous materials, challenges persist in optimizing their physical, rheological, and mechanical properties, addressing aging effects, and developing eco-friendly alternatives. The modification can be made by incorporating modifiers or additives, such as anti-stripping agents, surfactants, and bonding promoters, at their optimal dosages. Technically, the cohesion and adhesion bonds could be reinforced by adding a designated percentage of additives to the asphalt binder and within the asphalt-aggregate interfaces in asphalt mixtures. Prior to improving the pavement materials for road construction, adhesion and wetting properties also need to be given crucial attention. The inter-surface characteristics and their morphological behavior significantly influence the adhesion and cohesion bonding within binder-aggregate matrices, as indicated by the good correlations in both dry and wet conditions between failure pattern and bond strength. This review highlights recent breakthroughs in bituminous material research, emphasizing innovative approaches to enhance performance, durability, and environmental compatibility, providing insights for future advancements in asphalt pavement engineering. To advance the development of robust, environmentally sensitive asphalt pavements and guarantee a sustainable and effective transportation infrastructure for years to come, cooperation between researchers, engineers, and industry stakeholders is important.

Bio-oil resulting from biodiesel production, currently used for energetic valorisation, can be added to the bitumen, producing a bio-bitumen and acting as a bitumen extender by reducing its viscosity. Thus, this paper analyzes the feasibility of using bio-oil to create bio-bitumen. Two base bitumen were used, namely, 0/10 and 35/50 pen bitumen, combined with bio-oil from biodiesel production content of up to 10%. Bio-bitumen characterisation evaluated the chemical, physical and mechanical properties of the bio-bitumen and asphalt mixtures with bio-bitumen. Models for the prediction of bio-bitumen properties were developed. The results obtained in this work confirm that bio-oil from biodiesel production can be added to bitumen, obtaining a sustainable destination for this residue from biodiesel production, proven by the physical and mechanical behaviour obtained for the bio-bitumens and asphalt mixtures with bio-bitumen compatible with base bitumen and asphalt mixtures with conventional binders.

Smart inverters of distributed energy resources can enable cloud computing, condition monitoring, result visualization, remote control, and peer-to-peer energy trading in advanced power systems. However, the advent of data injection attacks in the communication architecture can alter measurement characteristics of power grids and have devastating consequences. In this article, we propose a time sequence machine learning-based anomaly detection methodology for detecting cyber intrusion into control signal setpoints and dc voltage signal measurement bias of the voltage source converter (VSC) in wind generators. We first investigated the effects of four types of denial of service, tampering signal, and stealthy-type data intrusion attacks on smart VSCs and overall wind farms. We then proposed a novel time sequence machine learning-based intrusion detection framework that can be implemented to detect different cyberattacks in the VSCs. The performance of the proposed framework has been compared with that of autoencoder and clustering-based intrusion detection framework. The proposed framework was validated by using the IEEE 39 bus power system in the presence of four wind farms in different locations. Using several metrics for intrusion detection performance, we validated the effectiveness of the proposed framework.

Asphalt modifications either involved commercial or recycled waste materials modifiers help optimise and improve the deficient properties of asphalt mixtures relative to current standards. This manuscript reviews the recycling of waste materials generated from various sources such as household, agricultural and industrial to minimise natural resources exploitation, lower energy demand, and enhance overall pavement performance. The actual development and implementation of recycled asphalt pavement in numerous countries in Asia, North America, South America, Europe and Africa are emphasised, and their influence on the performance of asphalt pavements is reviewed. Modified pavement showed satisfying performance for years as maintenance and restoration are not required. Generally, solid wastes are required to undergo pre-requisite treatments via mechanical, biological stabilization, thermal or chemical methods before the implementation as asphalt modifiers to ease the handling process. Moisture damage issues have been spotted in the implementation of several types of solid wastes and consequently reduced the strength and durability of pavement. Therefore, potential hydrophobic treatment can be adopted to improve the quality of asphalt mixtures by modifying the hydrophilic characteristics that are contributed by the hydroxyl groups on the cellulose nanocrystals (CNCs) or providing a superhydrophobic coating onto the particles. The treatments greatly weakened the moisture sensitivity of modified materials by reducing their water absorption and increasing their water contact angle. The modified mixtures are necessary to have identical or enhanced pavement performance to the conventional mixtures. Besides, future researchers are encouraged to broaden the research field in pavement engineering by considering chemical treatments in improving material properties to achieve cost-saving, efficient waste management, and higher commercial feasibility. Before implementing any virgin materials, waste materials and by-products as alternative substances or modifiers, it is strongly advised to consider the environmental and economic impacts of the material properties and their optimal incorporation.

Microgrids consisting of photovoltaic (PV) power plants and wind farms have been widely accepted in power systems for reliability enhancement and power loss reduction. Microgrids are capable of providing voltage and frequency support, improving power quality, and achieving proper power-sharing. To achieve such goals and deal with the nonlinear behavior in such systems, appropriate robust control strategies are required to be adopted. This article presents a comprehensive review of robust control methods for microgrids, including AC, DC, and hybrid microgrids, with different topologies and different types of interconnection to conventional power systems based on recently published research studies. The main control objectives, along with proposed control methods, are comparatively discussed for different types of microgrids. Furthermore, several research gaps in this area related to the scalability, robustness assessment, and evaluation approach are discussed. Recommendations are made that can potentially open new research lines to enhance the effectiveness of robust controllers for AC, DC, and hybrid microgrids.

The construction industry is the largest consumer of raw materials which are under the risk of exhaustion and depletion in the near future, which has prompted the usage of waste materials for the conservation of resource and as a solution for waste management. Two wastes that are widely produced but often inefficiently disposed are eggshell and waste tire. Hence, this paper aims to evaluate the rheological and mechanical properties of concrete incorporating eggshell and waste tire rubber using Response Surface Methodology (RSM). Concrete with eggshell as cement replacement and waste tire rubber as sand replacement was prepared with an interval of 5% up to 15% replacement of both materials. Rheological properties of concrete were accessed using slump cone test while mechanical properties were studied through compressive strength and flexural strength test. Result showed that eggshell replacement has a minor effect on concrete slump while tire rubber reduces workability considerably. Result also showed that concrete mechanical strength was optimum at 5% and 10% eggshell replacement, while tire rubber reduced mechanical strength with percentage of replacement. Non-destructive tests indicated that concrete has excellent quality but excessive tire replacement beyond 10% compromised structural integrity of concrete. Overall, RSM models were able to model the properties of concrete with high accuracy and minimal deviation.

The objective of this paper is to establish the state of knowledge on fast pyrolysis of bio-oil and bio-asphalt binder and to facilitate efforts in improving the overall performance of bio-asphalt and maximizing its road application. On the basis of reviewing the relevant literature recently, the fast pyrolysis (FasP) preparation process of bio-oil and its main properties, the preparation process of bio-asphalt and its performance and the application of bio-asphalt have been summarized. Due to the variations in raw materials, the adopted methods of FasP to prepare bio-oil could be different, and the properties of bio-oil from different sources are also different. At present, the plant-based bio-oil (mainly derived from wood waste and sawdust) has been widely used to prepare the bio-asphalt. Research on the low-temperature flexibility, high-temperature rheology, workability and other performance of biological asphalt showed that the workability and high-temperature performance of most asphalt are improved after adding bio-oil. However, the low-temperature performance is found to relatively reduce. Also, with regards to its application as a rejuvenator, bio-oil can considerably rejuvenate the aged asphalt's mixture performance. By far, most of research on bio-asphalt is still focused on the performance of bio-asphalt binder in the laboratory; its application in practical road engineering is still to be examined. This review also provides an outlook for the future, for example, establishing an integrated preparation process from bio-oil to bio-asphalt, and evaluating the properties of bio-asphalt by new standards.

One of the most challenging issues of the modern power grid is the communication delay, which has adverse effects on the power quality. This paper proposes two methods, such as the fuzzy logic controller (FLC) based approach and the modified predictor method, to minimize the negative effects of time delay on the power quality enhancement in a hybrid power grid consisting of synchronous and wind generators. The thyristor switched capacitor has been used as a power quality enhancement means for the grid. Time delays ranging from 0–700 ms have been considered for the analysis. Both balanced and unbalanced temporary and permanent faults at different locations in the power network have been considered. Two indices, namely the voltage index and the total harmonic distortion have been used to evaluate the power quality of the system. The performance of the FLC-based method has been compared with that of the modified predictor method. Simulations have been performed by using the MATLAB/Simulink software. Simulation results show that both the proposed methods can minimize the negative effects of time delays on the power quality enhancement of the system. However, the FLC method performs better than the modified predictor method.

The consistency of the ethanol foamed binders and mixtures prepared using asphalt binders foamed by the manual injection technique and laboratory foaming device were evaluated and compared in this study. The asphalt binders foamed using both methods was prepared at 120 °C, 130 °C and 140 °C. The performance of ethanol-foamed binders was evaluated in terms of rotational viscosity, expansion ratio, and low temperature cracking. Meanwhile, the performance of foamed WMA mixtures was tested using semi-circular bending (SCB), disk-shaped compact tension (DCT), and tensile strength ratio (TSR) tests. In order to conduct the TSR test, the samples were conditioned using the Moisture Induced Stress Tester (MIST) to simulate the pore pressure and scouring effects due to a tire passing over wet pavement. The foamed WMA mixtures were produced using pre-heated aggregates at 80 °C and 100 °C and foamed asphalt binders produced at 130 °C. The nano-hydrated lime was used as the filler and anti-stripping agent. Overall, the properties of ethanol-foamed binders and WMA mixtures produced via both methods are significantly comparable, except the resistance to moisture damage test result. However, the findings indicate that the ethanol-foamed WMA mixtures prepared using both techniques are having good resistance to moisture damage, based on the TSR values more than 0.8. The foamed WMA mixtures also exhibited a better resistance to cracking, as indicated by a higher tensile strength compared to the control HMA. Additionally, the WMA specimen prepared at 100 °C was less susceptible to rutting than the samples produced at 80 °C.

The escalating mass of solid waste at an overwhelming sum requires a global attention to strive for efficient waste management and to outsource the ecological treatments. The asphalt pavement industry that consumes a vast scale of natural resources while contributing to thermal and greenhouse emissions is viewed as a high potential alternative for the application of solid waste as asphalt modifier and substantial waste reduction. In efforts to urge for cleaner and greener asphalt production, a growing trend towards usage of solid waste as a renewable material is paving a sustainable future for the asphalt pavement industry. The economic options of incorporating solid waste into the asphaltic mixture coupled with proven effective performances are a green and cost-effective alternative to mitigate various pavement distresses. Various options either as coarse or fine aggregates and as fillers in powder, ash, or fibre form are to stimulate further research interest to incorporate a diversified range of solid waste into the asphalt binder and asphalt mixture. Prior to incorporating solid waste into the asphaltic mixture through the selected options, prerequisite tests in addressing engineering limitations due to the unknown properties of solid waste are reviewed. The concerns on environmental impact are given heavy metals leaching possibilities into water sources are addressed by Toxicity Characterization Leaching Procedure test, to leverage further the systematic reuse of solid waste in steering towards the cleaner production of the asphalt mixture. The microcosmic traits of solid waste namely surface morphology, mineralogical composition and chemical composition are summarized based on the usage of Scanning Electron Microscope, X-Ray Diffraction, and X-Ray Fluorescence, respectively. This systematic review is an enactment and stimulus for researchers to have a general overview before incorporating solid waste into asphalt mixture.

Nowadays, Wi-Fi fingerprinting-based positioning systems provide enterprises the ability to track their various resources more efficiently and effectively. The main idea behind fingerprinting is to build signal strength database of target area prior to location estimation. This process is called calibration and the positioning accuracy highly depends on calibration intensity. Unfortunately, calibration procedure requires huge amount of time and effort, and makes large scale deployments of Wi-Fi based indoor positioning systems non-trivial. In this research we present a novel location estimation algorithm for Wi-Fi based indoor positioning systems. The proposed algorithm combines signal sampling and hyperbolic location estimation techniques to estimate the location of mobile users. The algorithm achieves cost-efficiency by reducing the number of fingerprint measurements while providing reliable location accuracy. Moreover, it does not require any additional hardware upgrades to the existing network infrastructure. Experimental results show that the proposed algorithm with easy-to-build signal strength database performs more accurate than conventional signal strength-based methods.

This project integrates recent innovations of recycled materials used in designing and building sustainable pavements. An increasing environmental awareness and the demand for improving economic and construction efficiencies, through measures such as construction warrantees and goals to reduce air pollution under the Kyoto Protocol, have increased the efforts to implement sustainable materials in roadways. The objective of this research is to develop a systematic approach toward selecting optimum combinations of sustainable materials for the construction of asphalt pavements. The selected materials, warm mix asphalt (WMA), recycled asphalt shingles (RAS), and reclaimed asphalt pavement (RAP) were incorporated in this study. The results of this research are intended to serve as guidelines in the selection of the mixed sustainable materials for asphalt pavements. The approach developed from this project draws upon previous research efforts integrating graphical modeling with optimizing the amount of sustainable materials based on the performance. With regard to moisture susceptibility and rutting potential test results, as well as the MIM analysis based on a 95% confidence interval, the rutting performance and moisture susceptibility of asphalt mixtures are not significantly different regardless of the percentages of RAS, RAP, or WMA. The optimum mixture choices could be made by the plant emission rankings with consideration of the optimal WMA types, percentages of RAS/RAP, and WMA production temperatures. The WMA mixtures prepared with 75% RAP and Advera®WMA have produced the lowest CO2emissions among the investigated mixture types.

Foamed asphalt typically relies on water as a foaming agent because water becomes gaseous at elevated temperatures, generating numerous tiny bubbles in the asphalt and causing spontaneous foaming. In this study, ethanol was used as a potential alternative to water as a foaming agent. Ethanol is expected to be a physical blowing agent in the same manner as water, except it requires less energy to foam due to its 78 °C boiling point. This study compares the performance of water and ethanol as foaming agents through the measurements of rotational viscosity, the reduction in temperature during foaming, and volatile loss. The ethanol-foamed asphalt binders were prepared at 80 °C and 100 °C, while the water-foamed asphalt binders were prepared at 100 °C and 120 °C. Additionally, the rolling thin film oven (RTFO) was used to generate short-term aging of the foamed asphalt binders. A rotational viscometer was used to determine the viscosity of the asphalt binders at 80 °C, 100 °C, 120 °C, 140 °C, and 160 °C. Overall, ethanol can function in the same manner as water but requires less energy to foam. It is proven based on the smaller drop in temperature of the asphalt binder foamed using ethanol compared with that prepared with water. This is due to the lower latent heat capacity of ethanol, which requires less energy to vaporize compared with water. Through the rotational viscometer test, ethanol performs better in lowering the viscosity of asphalt binders, which is essential in allowing production processes at low temperatures, as well as a better workability and aggregate coating. Ethanol can be expelled from the foamed asphalt binders at a higher rate due to its lower boiling point and latent heat.

Latex as an asphalt modifier has gained popularity in the asphalt industry as it improves the durability of asphalt pavement. However, the elastomeric properties of latex stiffen the asphalt binders, resulting in additional energy consumption during the production of asphalt mixtures, which may cause a higher emission of greenhouse gases. This is undesirable for sustainable development and the environment. In this study, the applicability of diluted methanol and water was comparatively evaluated as foaming agents in the production of warm mix asphalt (WMA) mixtures incorporating latex. Diluted methanol was used because it has a lower boiling point and latent heat than water, allowing the asphalt mixture to be produced at a lower temperature and thus consuming less energy. The performance of the foamed asphalt mixture was investigated through service characteristics, mechanical performance, and moisture susceptibility of mixtures. The service characteristics, on the other hand, were measured in a laboratory while preparing and compacting the asphalt mixture, which refers to the amount of energy required during the production and construction stages in the asphalt plant and on the construction site, respectively. The degree of energy required was assessed based on the workability index, coatability index, and the compaction energy index. The mechanical performance of asphalt mixtures was characterized by indirect tensile strength, resilient modulus, and dynamic creep tests. The resistance to moisture damage was evaluated based on the common parameter, indirect tensile strength ratio. The findings revealed that the use of diluted methanol foaming agent helped improve the workability of latex modified asphalt mixtures. The foamed latex-modified WMA demonstrated better performance compared to asphalt mixtures prepared using water as the foaming agent.

This paper studies the application and control of three series flexible AC transmission system (FACTS) devices namely, the gate-controlled series capacitor (GCSC), the thyristor controlled series capacitor (TCSC), and series braking resistor (SBR), in order to enhance the low voltage ride-through (LVRT) in fixed-speed wind turbine generator systems (FSWTGS). Modeling and simulations are carried out in order to investigate and compare the performance of these devices, considering (1) successful reclosing of circuit breakers (CBs), (2) unsuccessful reclosing of CBs, and (3) connection of a dynamic load to the point of common coupling (PCC). Simulation results exhibit significantly enhanced transient stability of FSWTGS due to the employment of the GCSC. Furthermore, the GCSC is competitive with the TCSC and the SBR, and it requires less power rating to stabilize the wind generator system. Therefore, the proposed GCSC can be considered an effective tool to improve the LVRT of FSWTGS.

Given the great advancements in soft computing and data science, artificial neural network (ANN) has been explored and applied to handle complicated problems in the field of pavement engineering. This study conducted a state-of-the-art review for surveying the recent progress of ANN application at different stages of pavement engineering, including pavement design, construction, inspection and monitoring, and maintenance. This study focused on the papers published over the last three decades, especially the studies conducted since 2013. Through literature retrieval, a total of 683 papers in this field were identified, among which 143 papers were selected for an in-depth review. The ANN architectures used in these studies mainly included multi-layer perceptron neural network (MLPNN), convolutional neural network (CNN) and recurrent neural network (RNN) for processing one-dimensional data, two-dimensional data and time-series data. CNN-based pavement health inspection and monitoring attracted the largest research interest due to its potential to replace human labor. While ANN has been proved to be an effective tool for pavement material design, cost analysis, defect detection and maintenance planning, it is facing huge challenges in terms of data collection, parameter optimization, model transferability and low-cost data annotation. More attention should be paid to bring multidisciplinary techniques into pavement engineering to tackle existing challenges and widen future opportunities.

This paper evaluates the influence of temperatures and loading rates on the shear strength of dense asphalt (AC14) prepared based on the Malaysian Public Works Department specification. In this study, different specimen conditioning temperatures, 10°C, 20°C, 30°C, and loading rates of 20.88mm/min, 40.88mm/min, 50.88mm/min, and 60.8mm/min were used to assess the performance of specimens by using Layer-Parallel Direct Shear (LPDS) test. Based on the results, both parameters have significant effects on the shear strength of the asphalt specimens. The results indicate that the loading rate is directly proportional to the shear strength of asphalt specimens. It is because the stiffness of the asphalt mix increases as the loading rate increases. Hence, it enhanced the shear strength of asphalt specimens. On the other hand, the temperature is inversely proportional to the shear strength of asphalt mixes. As the temperature increases, the stiffness of the asphalt mixture reduces due to the lower resilient modulus; therefore, it reduces the shear strength of the specimen.