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Ultrasonic testing is widely used in the industrial field because of its high sensitivity, safety and low-cost, which plays an increasingly important role in detecting defects on industrial. However, at present, defect detection only stays in scanning surface defects and classifying the internal defects of the specimen. The accuracy of quantitative imaging of the morphology of the internal defects of the specimen is still an issue to be improved. In this paper, the simple defects in several specimens are detected by ultrasound based on finite element simulation software and the accuracy of the signal can be verified by ultrasonic experiment. Then, the features can be extracted by signal processing method. The neural network imagines the inversion results with the Gaussian weight function fusion model. Finally, this paper uses the signals of simple shape defects as the training set to detect the shapes of complex defects and obtain the corresponding imaging results. • The defect detection using moving ultrasonic A-scan testing and signal processing. • Defect image inversion by neural network and Gaussian weight data fusion algorithm. • Complex defect inversion by learning the features of simple defects. [ABSTRACT FROM AUTHOR]

Over the last two decades, the integration of big data and deep learning technologies has demonstrated remarkable effectiveness across various domains of civil engineering, leading to significant advancements in machine learning methodologies. Regardless of significant progress in various aspects of civil engineering, there appears to be a striking absence of thorough and all-encompassing evaluations that adequately cover critical domains such as structural damage identification (SDI), accurate prediction of concrete properties, precise crack detection, detailed analysis of crack properties and thorough non-destructive testing (NDT) methods applied specifically to concrete structures. This gap in the existing literatures hinders a comprehensive understanding and application of advanced techniques in these crucial areas. To bridge this knowledge gap, this paper offers an all-encompassing exploration of the recent developments and utilizations of artificial intelligence in civil engineering. Emphasizing concrete-centric structures, this study prioritizes two crucial facets: the automatize detection of concrete specific mechanical attributes and crack detection. To achieve this numerous recent surveys have utilized intelligent algorithms primarily grounded in image statistics, coupled with extensive data analytics and deep learning methodologies. By delving into this research, the paper sheds light on the trajectory and challenges encountered by artificial intelligence in civil engineering over the past few years. It highlights studies that emphasize structural maintenance and management, quality control, design optimization, and more, accomplished through image processing and computer vision techniques. In essence, this review seeks to unveil the profound impact of artificial intelligence in transforming civil engineering practices, with a strong emphasis on exploiting image processing and computer vision methods to tackle concrete-related issues. • Impact of image centric artificial intelligence to predict concrete properties. • Features Non-Destructive Testing methods, digital image-based setups on concrete. • Offers qualitative analysis of research trends in computer vision and data mining. • Intelligent algorithms aid for concrete structural maintenance and quality control. • Challenges and advancements of concrete technology based on artificial intelligence. [ABSTRACT FROM AUTHOR]

The capital cost of setting up a Laminated Veneer Lumber (LVL) plant which produces continuous LVL billet products, through a continuous veneer assembly and hot-pressing processes, is significant. However, the utilisation of batch-type presses, similar to those employed in the plywood industry, could significantly reduce this initial cost and may provide new opportunities for small to medium scale operations. This process would produce shorter billet lengths which would need to be joined together to produce lengths viable for structural products. Scarf joints have been used commercially to join some veneer-based engineered wood products but have limitations, while finger joints are a common method for jointing sawn timber products and offer some key advantages but is not a common method to join veneer-based products. Consequently, this paper focusses on investigating the influence of key manufacturing parameters on the performance of finger jointed LVL. The effect of the joint orientation (horizontal or vertical), the finger length, the gluing pressure and the adhesive type on the joint strength and stiffness were investigated. The finger jointed LVL were tested in edge bending, flat bending and tension, and the results were compared to reference unjointed LVL. The bending performance of the finger jointed LVL was also compared to scarfed jointed LVL. In total 304 tests were performed. The results indicated that the average strength values of finger jointed LVL can reach up to 99% of the average strength of unjointed LVL and compares to scarf jointed LVL on flat bending. Horizontal joints, being more practical to produce for deep beams, performed similarly to vertical joints. The 25 mm joints were found to have no mechanical advantages over the 20 mm investigated finger joints. A gluing pressure lower than the Eurocode's recommended level for solid timber achieved sufficient bonding for the products to be utilised. The gluing pressure was also found not to influence the performance of the joint, for the range of pressures investigated. Both polyurethane and resorcinol-formaldehyde adhesives produced high performing products, with the latter displaying superior adhesive bond durability. The paper concludes that finger jointing LVL represents a viable solution to manufacture usable LVL lengths from short LVL billets, but have lower edge bending efficiency than scarf jointed LVL. • Investigation to reduce capital cost of setting up a timber LVL plant is presented. • Performance of finger and scarf joints is investigated and compared. • Finger joints represent a viable and efficient solution for jointing LVL sections. • Finger joints perform similarly to scarf joints. • Manufacturing parameters are investigated and presented. [ABSTRACT FROM AUTHOR]

• The mechanism of rolling resistance of asphalt pavements is presented. • The measuring and modelling approaches of rolling resistance are summarised. • The prediction methods of fuel consumption and environmental impact are reviewed. In the context of climate change and global warming, the attention on the environmental cost of pavements is increasing. To scientifically quantify the environmental cost of pavements, accurate prediction of rolling resistance and fuel consumption is important. In this paper, a comprehensive review on rolling resistance of asphalt pavements and its environmental impact was presented. At first, the commonly used definitions of rolling resistance and texture characterisation methods of pavement surface were introduced. Then, the influence of different factors on rolling resistance was discussed. Next, the measuring and modelling approaches of rolling resistance were reviewed. At last, methods which can be used to predict fuel consumption and environmental impact were presented. It was found that an ideal approach for texture characterisation of pavement surface is to make use of the entire wavelength spectrum of road profiles and consider the enveloping curve of tire treads. Furthermore, the fact that rolling resistance can be influenced by different factors introduces difficulties in accurate measurement and modelling of rolling resistance. Moreover, testing methods and conditions have a significant effect on the empirical modelling of rolling resistance, while it is difficult and time-consuming to consider all the energy loss in the computational modelling of rolling resistance. In addition, the prediction of fuel consumption and environmental impact highly depends on the formulating methods and measuring conditions. The work presented in this paper will help to gain more insight into rolling resistance and its environmental impact, which ultimately promotes the construction of environmentally friendly pavements. [ABSTRACT FROM AUTHOR]

Ultra-high-performance concrete (UHPC) has emerged as a suitable material for pavement rehabilitation, particularly in the context of bridge engineering. This material' attributes and performance-related characteristics have attracted attention due to the numerous advantages and potential for enhanced long-term durability of deteriorated pavements, either cementitious or asphaltic. Because of its relevance and increased use in recent years for pavement engineering applications, this paper presents a comprehensive review of recent case studies that investigate the application of UHPC in bridge pavement rehabilitation or reconstruction projects. The selected case studies include projects conducted in America, Asia, and Europe, and provide valuable insights into the design, construction, and performance of UHPC overlays. These showcase the effectiveness of UHPC in addressing common issues such as cracking, rutting, and structural deficiencies in bridge pavements. Furthermore, these highlight the superior flexural and compressive strength of UHPC, which contributes to improved load-carrying capacity and resistance to permanent deformation. Moreover, some environmental benefits derived from UHPC such as smaller carbon footprint are highlighted in the paper as well as cost-effectiveness considerations in light of the long-term performance and reduced maintenance obtained with UHPC overlays. Overall, the comprehensive literature review and case studies presented in this paper provide valuable data on material properties, project types, construction techniques, and post-rehabilitation evaluations. These findings can guide future research and assist practitioners in making informed decisions regarding the implementation of UHPC overlays for pavement rehabilitation. Finally, this paper contributes to the existing body of knowledge on UHPC overlays and emphasizes their significance in improving the longevity and sustainability of bridge pavements. • UHPC overlays enhance pavements: cracking, rutting, and structural issues addressed. • UHPC delivers strength and durability: improved load capacity and reduced deformation. • UHPC's environmental benefits: smaller carbon footprint, cost-effectiveness. • Efficient construction with UHPC: reduced time and costs using specialized machinery. [ABSTRACT FROM AUTHOR]

• Introduction of new type of wood building material based on glulam from spruce and veneers from beech. • Inherently reinforced wood product with high capacity for load redistribution. • Proof of significantly improved properties perpendicular to the grain and in shear. • Multiplied load-carrying capacities at details such as notches, holes and cross-connections. • Homogenization of multiple glued veneer layers leads to mean tensile strengths > 100 MPa. This paper deals with the development of a novel veneer-reinforced timber product for load-bearing applications – veneer-reinforced timber. For this composite timber product, veneers are inserted vertically into a glulam cross-section to act as reinforcement for shear and tension stresses perpendicular to the grain. By arranging the veneer layers between the glulam components at angles of 0°, 45° and 90°, the highly anisotropic strength and stiffness properties of glulam are homogenized. By means of numerical simulations and experimental investigations, the load-bearing behavior and the efficiency of veneer-reinforced timber are investigated. The results substantiate a considerable increase in load bearing capacities of veneer-reinforced timber with notches, holes or cross connections. Studies and derived recommendations on the effect of the inclination of the veneer on the shrinkage behavior of this composite timber product conclude this paper. [ABSTRACT FROM AUTHOR]

Due to the scarcity of urban land resources, the development model of building over rail transit has rapidly emerged. The turnouts near the train depots and stations have become significant sources of environmental vibrations. This paper employs on-site experimental methods to measure the vibration acceleration of rail, track slab, and tunnel wall at multiple sections in the turnout area when a subway train passes through. The vibration intensities at different sections of the turnout area are analyzed, and the vibration reduction effects of vibration isolation fasteners and steel-spring floating slabs in the turnout area under similar conditions are compared. Finally, an energy evaluation method is used to analyze the vibration propagation characteristics on the non-isolated turnout frog section. Obtained the propagation and attenuation characteristics of vibrations in different frequency bands in the turnout area based on on-site test data. • A method to extract wheel set passing times using vertical vibration acceleration data from steel rails. • The paper compares the vibration reduction effects of fastener and slab-type methods in the turnout area. • Analyzed the key excitation source and vibration frequency induced by trains at a fixed frog. • Analyzed vibration energy propagation along the track's longitudinal direction in the turnout area. [ABSTRACT FROM AUTHOR]

Rapid urbanizations impose increasing challenges on safety decompositions of those buildings that reached service life, so there is an urgent call for eco-friendly demolition methods. As a green demolition method, the technique of soundless cracking demolition agents (SCDAs) can effectively eliminate dust and noise pollution commonly encountered in conventional methods, and thus attract rising attention in light of increasing concerns for sustainable and low-carbon developments. Herein, this paper provides a state-of-art review of SCDAs and associated applications. SCDA, a powdery material, mainly consists of quicklime (CaO), which tends to expand significantly when mixed with water. The expansion properties of SCDAs are susceptible to internal and external factors, such as compositions, ambient temperature, mixing water temperature, and water/cement (W/C) ratio, restraint conditions, among others. Therefore, substantial efforts have been made to improve the expansion performance of SCDAs by regulating the abovementioned factors. The resulting expansion force from SCDA expansion can effectively crack brittle materials, e.g., concrete and rocks, the cracking process of which can be measured using strain gauges and Acoustic Emission (AE). More recently, digital image correlation and computed tomography have been employed to monitor the SCDA-induced cracking process, and the implementation of those new techniques promotes the observations of crack developments and underlying mechanisms. To gain a cost-effective application of SCDAs, extensive efforts have been undertaken to optimize the design in hole parameters. Accordingly, several empirical equations have been proposed for determinations of optimal hole parameters, but the application of the equations is restricted to particular conditions where they are proposed. Despite the successful usage of the SCDA technique in demolitions of construction structures, mining, unconventional gas and oil recovery, some limitations, namely hard rock fragmentation, precise numerical works and blowout, still need to be addressed for further applications. Overall, this paper gives a brief review of SCDAs, covering scopes of compositions, expansion properties, applications, inadequacies and prospects, deepening our understanding of SCDAs, and providing recommendations for future research priorities. • Factors influencing the expansion characteristics of SCDAs are analyzed. • Some new technologies for observing the process of crack development are presented. • The optimum usage of SCDA related to the hole design parameters is summarized. • Further work in the research and application of SCDA is proposed. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of incorporating a hybrid combination of structural polypropylene fibers on the flexural behavior of concrete beams reinforced with steel, GFRP, and innovative hybrid bars. A new ductile hybrid bar with equivalent bilinear stress-strain characteristics has been developed to address steel corrosion and FRP ductility issues. Fourteen half-scale RC beams were fabricated and tested under four-point loading configuration to study the flexural response. The tensile reinforcement types (steel, GFRP, and hybrid), hybrid reinforcement ratios (0.85 %, 1.26 %, and 1.70 %), reinforcement hybridization schemes (hybrid-hybrid, hybrid-GFRP, and GFRP-steel), and hybrid fiber ratio (0.0 %, 1.0 %, and 2.0 %) are the major parameters studied. The test results were recorded and analyzed in terms of mid-span deflection, cracking load, flexural capacity, and failure mechanism. The results demonstrated that the addition of hybrid fibers and using hybrid bars significantly improved the peak strength, ductility index, and bending stiffness. Moreover, the hybrid-reinforced concrete beams exhibit large inelastic deformations similar to steel-reinforced concrete beams. The inclusion of hybrid fibers improves the post-peak response of the tested beam due to fiber bridging capabilities. For design purposes, a simplified formula proposed by ACI 544 for predicting the nominal flexural capacity of hybrid fiber concrete beams reinforced with hybrid bars was presented, compared with experimental results and validated with 44 specimens from other studies. The predicted and test results were in good agreement with a standard deviation of 0.12. Additionally, 3D nonlinear finite element analysis was developed to validate the test results, demonstrating reasonable accuracy in predicting the flexural behavior of the beams. • This paper investigates the effectiveness of adding a hybrid combination of structural polypropylene fibers on the flexural behavior of (steel, GFRP, and hybrid) reinforced concrete beams. • A new ductile hybrid bar with equivalent bilinear stress-strain characteristics has been developed to overcome traditional steel corrosion and FRP ductility problems. An experimental program of 14 half-scale RC beams was fabricated and tested under a four-point loading configuration. • The variables were: tensile reinforcement types, the addition of hybrid fibers, the hybrid fiber ratio, beam cross section, and the hybrid reinforcement ratio. • The test results were recorded and discussed in terms of mid-span deflection, cracking load, flexural capacity, and mode of failure. • To facilitate the design process, a simplified formula proposed by ACI 544 for predicting the nominal flexural capacity of hybrid fiber concrete beams with hybrid bars was presented. • A finite element analysis using ABAQUS/CAE6.14 was performed to verify the experimental outcomes. [ABSTRACT FROM AUTHOR]

• Brickwork cavity walls are very vulnerable to seismic loading. • This paper analyses a new retrofitting method based on the use of FRCM coating and GFRP ties. • GFRP rods were used to reinforce the masonry walls against in-plane and out-of-plane actions. • Reinforced structures presented enhanced behavior and increased mechanical properties. This paper offers the results of an experimental investigation aimed at assessing the seismic vulnerability of a type of cavity wall, with a brief discussion of the advantages of this form of construction. Cavity walls were mainly designed to carry vertical loads and to improve the thermal behaviour of the building envelope: these are made of two single-wythe walls (typically using low-perforated bricks) with a cavity filled with a polystyrene panel. Cavity walls often exhibit poor seismic performance. A total of 12 full-size cavity-wall panels were tested in this experimental programme at the laboratory, by conducting shear and bending tests aimed at studying the in-plane and out-of-plane structural responses under simulated seismic actions. In addition, different retrofit solutions were studied and used to reinforce the cavity-wall panels: this included the traditional method to tie the wall leaves with steel connectors, an innovative method made of GFRP (Glass Fiber Reinforced Polymers) rods, and a mortar coating reinforced with a composite grid, known as FRCM (Fiber Reinforced Cementitious Matrix). It was found that the lateral bending-capacity of the panels reinforced with the GFRP rods and a FRCM coating greatly increased over that of the control unreinforced specimens. The proposed reinforced method was able to provide some seismic resisting capacity to the cavity walls, especially against bending and out-of-plane loading, in a more effective way than the traditional method of steel ties. [ABSTRACT FROM AUTHOR]

• SAXS is an advantageous technique for analyzing the microstructure of asphalt. • The primary factor responsible for microstructural changes is the aggregation of micelles. • The microstructure of recycled asphalt is mainly affected by the mass ratio of old and new asphalt. The microstructure of asphalt plays a crucial role in determining its overall performance. However, the lack of comprehensive research on parameterizing the microstructure of asphalt has hindered the establishment of a clear relationship between microstructure and macroscopic performance. To address this gap, this paper conducted a study involving small-angle X-ray scattering (SAXS) experiments to investigate the changes in the microstructure of asphalt during aging and regeneration processes. The SAXS experimental results were then subjected to fitting using the Unified function, enabling us to derive key microstructural parameters. The SAXS data profiles obtained from virgin, aged, and recycled asphalt samples exhibit a remarkable degree of similarity, suggesting that their microstructural features are highly comparable. Additionally, the scattering characteristics observed in the SAXS data point to the presence of secondary structure scatterers within the asphalt samples. The presence of secondary structure scatterers suggests that the asphalt samples consist of microstructural entities, such as micelles or aggregates, which form the basis for the scattering patterns observed. During the aging of asphalt, the size of micelles and the heterogeneity of their sizes undergo a progressive increase. Simultaneously, the surface activity of these micelles gradually diminishes. However, a notable reduction in micelle size and size heterogeneity is achieved when regenerating aged asphalt using virgin asphalt. Furthermore, the surface activity of micelles is improved through the regeneration process. On the contrary, the rejuvenator used in this study did not exhibit a significant restorative effect on the microstructure of aged asphalt. Rheological analysis indicates that the observed viscoelastic changes in asphalt during aging and regeneration align with microstructural variations, but the effect of the rejuvenators on viscoelasticity do not correlate directly with their impact on microstructure. The differences between rejuvenators in improving the properties of aged asphalt cannot be solely inferred from their effect on microstructure. The findings in this paper contribute significantly to our understanding of asphalt microstructure and its evolution during aging and regeneration processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The properties of red mud used for filling resin composites are reviewed in the field of building materials. • The environmental hazards of red mud are described. • The processing methods and principles used to research red mud as a filler for resin composites are compared. • The technical difficulties in the research and application of red mud in resin composites are described. • Methods and suggestions for using red mud to enhance the properties of resin composites are provided. Red mud is a harmful alkaline waste discharged during alumina production, and the environmental pollution caused by red mud accumulation has become an increasingly serious problem. Incorporating red mud into resin composites can improve the properties of the composites because of its special structure and composition. It can also reduce the use of non-renewable resources required for resin production, such as petroleum, thereby reducing carbon emissions and production costs. Incorporating red mud into resin composites is expected to protect the environment from the harm caused by red mud while achieving sustainable economic and environmental development. This paper mainly provides a comprehensive review of the research status of red mud used to fill and modify resin composites in the field of building materials. Different treatment methods for red mud fillers and different composite preparation processes are used to improve the properties of composites, which are discussed in detail. The theory of the formation and bonding of the interface between red mud filler and resin is described. The importance of this paper is in summarising the technical difficulties incorporating red mud into resin composites and providing suggestions and prospects for future research. [ABSTRACT FROM AUTHOR]

• LSS used as a NS substitute in FA/GGBS-based mortar increases compressive strength. • GO-modified mortars show superior viscosity recovery to NC-modified ones. • LSS mortars offer higher strength and lower drying shrinkage than NS mortars. • Formwork-free conditions increase drying shrinkage in 3D printed mortars. • High temperature & humidity reduce drying shrinkage in printed GO/NC modified mortar. The environmental impact of concrete 3D printing (C3DP) has become a concern due to its large cement consumption and over-exploitation of natural resources. This study investigates the viability of using geopolymer mixtures in C3DP prepared with fly ash (FA)/ground granulated blast furnace slag (GGBS) and underutilised aggregate as substitutes for ordinary Portland cement (OPC) and natural aggregate, respectively. This paper focuses on the rheological, mechanical, and shrinkage properties of FA/GGBS-based geopolymer mortar with lead smelter slag (LSS) as natural sand (NS) substitute and the impact of adding nanoclay (NC) and graphene oxide (GO), as thixotropy agents, on the yield stress development and viscosity recovery properties of the mixtures. The effect of various outdoor environmental conditions of 24 °C -50 %RH, 35 °C -90 %RH and 35 °C -50 %RH on pore water evaporation and 28-day drying shrinkage of 3D printable geopolymer mortar was studied, considering the effect of NS, LSS, NC and GO in free-formed and control conditions. LSS GO-modified mortars exhibited superior viscosity recovery capacity and yield stress evolution compared to their NC-modified counterparts. Moreover, using LSS instead of NS resulted in increased 28-day compressive strength under various environmental conditions, and LSS mortars exhibited lower drying shrinkage in both conventional casting and free-formed conditions. The findings of this paper will serve as a benchmark for further studies on the effect of different curing techniques (internal or external) on the hardened state dimensional stability of 3D printed products using alkali-activated binder systems to improve the structural integrity by controlling the water evaporation and drying shrinkage development. [ABSTRACT FROM AUTHOR]

• This paper worked on the shear behavior of reinforced concrete tapered beams with discrete recycled strap fiber. • Show the results and discussion regarding to mechanical properties of fiber concrete materials. • Show the precise cracking and load–displacement behavior. • Proposed shear models for predicting shear strength. • Show the efficiency of the shear models and proposed one. Haunched beams also known as tapered beams, are structural elements characterized by varying depths along their span. In light of the growing concern over plastic accumulation on a global scale which provides a threat to the environment, and the challenges associated with employing traditional stirrups in the construction of tapered elements, this research paper has emerged. The approach of this study is divided into two main parts: an experimental phase and an analytical phase. In the initial stage, eight beams were subjected to testing to investigate the influence of tapered angles and the presence of recycled strap fiber on the shear behavior of tapered beams. The outcomes of this experimentation revealed a significant trend: as the tapered angles and fiber contents increased, the shear strength of haunched beams also increased. The subsequent phase of the study focused on an analytical examination, incorporating models proposed in various literature sources. A comprehensive database of 91 beams was assembled to facilitate the selection of the most suitable shear model for modification. Building upon the analysis of this extensive dataset, an equation was proposed. Additionally, a smaller dataset featuring tapered beams with fiber was collected to apply further analysis and demonstrate the models' performance. The predicted results by the proposed model showed good agreement with experimental test results. [ABSTRACT FROM AUTHOR]

• Evaluate the nano silica (NS) types, dispersion methods and fabrication methods of utilizing NS in cementitious composites. • A small content of NS can significantly enhance the mechanical properties and durability of cementitious composites. • NS can also improve the multifunctional properties of cementitious composites. • The modification mechanism of NS on cementitious composites is nano-core effect. • NS has a potential to develop the low carbon cementitious composites. To reduce the life-cycle carbon emissions of cementitious composites, potential pathways are to use more low-carbon raw materials, enhance the composites' performance and further extend the service life of their structures. Nano silica (NS), dividing into powder and colloid, and colloidal NS is less harmful to human than that of powdery NS. NS holds nanomaterial characteristics, pozzolanic activity, and more reactive compared with traditional supplementary cementitious materials (SCMs). Therefore, a small content of NS can significantly improve in the mechanical properties, durability, and multifunctionalities, expected to achieve carbon emission reduction of cementitious composites. This paper provides a comprehensive review on the fabrication (NS, mix proportion, and fabrication method), microstructures (hydration products and microstructures), and properties (early performance, mechanical properties, durability, volume stability and functional properties), and applications of cementitious composites modified with NS. The paper also concludes with an outline of some future risks, challenges, and future development of cementitious composites modified with NS. [ABSTRACT FROM AUTHOR]

[Display omitted] • This paper presents a critical review on sustainable 3D printing concrete (3DPC). • The performance of 3DPC based on recycled aggregate and fibre is investigated. • Effect of fibre on mechanical and anisotropic properties of 3DPC is evaluated. • Structural behaviour, environmental impact and cost of 3D printed strucrure is given. This paper presents a critical review of reducing the life-cycle environmental impact of 3D printing concrete (3DPC) systems from the perspectives of material preparation, construction process and structure level. The material requirements of 3DPC are first introduced, then the utilization of low-carbon cementitious materials, recycled aggregates, admixture and fibres in 3DPC is explored, along with their effect on workability and mechanical property. The potential for improving the environmental benefits by applying better design and printing parameters are discussed in the subsequent part. Two main delivery systems and the effect of printing parameters (including printing speed, standoff distance) are presented. Finally, the behaviour of 3D printing components (beam, slab and column) is examined at the structural level. 3D printing technology has a high degree of freedom, thus better understanding of the component behaviour can save materials and improve strength. Finding a balance between component's performance and environmental impact is a crucial work in future. [ABSTRACT FROM AUTHOR]

• A innovative way to obtain realistic traction-separation curves is investigated. • Fluid-solid coupling model based on cohesive unit cracking behaviour is developed. • Evaluation of sealing capacity of cementing interface by fluid–solid coupling model. • Factors affecting the sealing capacity of cementing interfaces are investigated. Estimating the sealing property of the cementing interface is vital for judging the quality of well cementing construction. The main methods currently used to evaluate the sealing property of the cementing interface (hydraulic cementing strength method and shear cementing strength method) are susceptible to the effects of specimen geometric regularity, interfacial cementing condition, and shear damage pressure source, and the measurement results are not stable, making it difficult to use them as effective methods to evaluate the real cementing interface sealing performance. In this paper, based on the cracking behavior of cohesive units, a method to evaluate the sealing performance of the cementing interface by simulating the cracking process of fluid breaking through the cementing interface in ABAQUSTM FEA software was investigated. The research process includes two parts: first, using a self-designed holding stretching device after eliminating the errors caused by non-interface displacement in the conventional stretching method by repeated stretching and subtraction. The real interfacial traction-separation curve and formation cohesion unit parameters were obtained. Secondly, the cohesive unit parameters obtained in the first step were input into ABAQUSTM FEA software to build a fluid–solid coupling model to simulate the cracking process in the interface region when the fluid breaks through the cementing interface, in which obtaining the solid interface cracking sealing pressure and evaluating its sealing performance are finished. And the accuracy and feasibility of this method were verified by a homemade physical sealing model of the cementing interface. In addition, the factors affecting the fluid pressure at the breakthrough of the cemented interface were investigated in this paper, and it was concluded that changing the elastic modulus of sandstone and cement sheath had a more significant effect on the fluid pressure at the breakthrough of the cemented interface than their Poisson's ratios. Furthermore, the results of this paper also indicate that when the permeability of cement sheath and sandstone is in the range of 0.001 mD–10 mD, the fluid pressure at the time of breaking the cemented interface decreases as the permeability of cement sheath and sandstone increases, and beyond this interval, the effect of the sudden change in permeability of cement sheath and sandstone on the fluid pressure at the time of breaking the cemented interface is no longer obvious. [ABSTRACT FROM AUTHOR]

[Display omitted] • In this paper, the mechanical behavior and crack propagation of cement fly ash stabilized brick-concrete gravel base mixture under three-dimensional compression were studied by triaxial loading test. This method comprehensively simulates the stress of the mixture in the actual project, so as to obtain more accurate test results. • Based on the triaxial test, the SEM images of different proportions were analyzed by PCAS pore analysis software, and the influence of confining pressure on the microstructure parameters of the mixture was studied in depth. Through the analysis of the micro level, the evolution law of the mechanical properties of the mixture and its strength failure mechanism are better revealed, which provides a theoretical basis for the optimization of material properties. • In this paper, the discrete element model is used to simulate the stress–strain curve of the specimen under triaxial loading, and a visual three-dimensional failure mode model is proposed to show the failure mode of the specimen in a more intuitive way. In addition, based on the indoor test results, the mesoscopic parameters are continuously optimized, so that the optimized results are in good agreement with the simulation results, and the numerical simulation results can better reflect the actual situation. This numerical simulation method is a powerful supplement to the traditional test, which can greatly save the test time and cost. In order to explore the mechanical behavior and crack propagation of cement fly ash stabilized brick-concrete gravel (CFBC) base mixture under three-dimensional compression, firstly, the triaxial loading tests of three different proportions of mixtures were carried out through laboratory tests. The axial load is controlled by a load control loading system, the sampling frequency is 5 Hz, and the triaxial specimen is loaded at a rate of 0.1 MPa /s.The stress–strain curves of the mixture under four different confining pressures were obtained, and the failure characteristics and strength characteristics were analyzed. Secondly, the SEM analysis of the specimens under different confining pressures was carried out, and the microstructure parameters of the mixture under four different confining pressures of 0 MPa, 0.5 MPa, 1.0 MPa and 1.5 MPa were studied based on the PCAS analysis software. On this basis, a three-dimensional discrete element model was established to numerically reproduce the triaxial test of the specimen. The results show that the failure mode of the specimen is mainly related to the confining pressure, and the crack shape has the characteristics of top-down in the direction of principal stress.Through the stress–strain curve, it can be seen that with the increase of confining pressure, the peak stress of the specimen is also increasing. In the BCA1 ratio, the peak stress of the 1.5 MPa confining pressure is increased by 23 % compared with the non-confining pressure. In addition, the cement fly ash stabilized brick-concrete gravel mixture specimen has a larger bearing capacity than other concrete brittle materials.PCAS pore analysis showed that the main controlling factors affecting the porosity of the mixture were brick content and confining pressure, which in turn affected the shear strength and peak stress of the mixture, and the porosity of BCA1 < BCA3 < BCA5; the numerical simulation results show that the failure mode and stress–strain curve of the specimens with the shear strength error of less than 3 % and the friction angle error of less than 6 % are in good agreement. The maximum displacement particle clusters appear on the upper and lower edges of the specimen, and the sliding zone angle of the specimen is about 45° under all stress paths except the horizontal sliding zone under the uniaxial stress state, which reflects that the numerical model is consistent with the mechanical response at the macro scale. The use of three-dimensional discrete element models in the field of construction engineering can simulate and optimize the use of the above materials in construction sites to minimize waste and maximize efficiency. [ABSTRACT FROM AUTHOR]

• Energy absorption properties of coir fibers at different compression speeds. • Energy absorption properties of differently stacked coir fibers under compression. • Measuring the rate sensitivity of coir fiber. • Calculation of crushing efficiency from experimental results. • Scanning electron microscopy was taken to verify the results. Coir fiber, a natural plant fiber material, is known for its excellent shock absorption ability and potential to improve the performance of composite materials. This paper investigates the compression and energy absorption of coir fibers arranged horizontally and vertically at different speeds to determine their velocity sensitivity. A quasi-static compression speed test was conducted on coir fiber blocks using a universal testing machine. Load displacement changes were observed at speeds of 1 mm/Min, 2 mm/Min, 4 mm/Min, and 50 mm/Min, and Dynamic Increase Factor (DIF) was introduced to evaluate speed sensitivity. The microstructure of the fibers was evaluated using a scanning electron microscope (SEM). According to the results, vertical fibers have better energy absorption characteristics than horizontal fibers, resulting in an increased energy absorption effect ranging from 25.7 % to 45.38 %. On the other hand, horizontal fibers exhibit high sensitivity under low-speed compression, with a significant increase in energy-absorbing effect as speed increases. However, this sensitivity is significantly reduced when compression occurs at high speed. The energy-absorbing effect of horizontal fibers increases from 6.96 % to 33.58 %. Vertically placed fibers, on the other hand, exhibit low sensitivity under low-speed compression but greater sensitivity as speed increases. As speed increases, the energy absorption effect becomes more apparent, resulting in an increase in the energy absorption of vertical fibers from 12.88 % to 17.99 %. This paper presents a methodology for evaluating the compression properties of coir fibers, which can be used as a reference for studying the impact resistance of natural fibers. [ABSTRACT FROM AUTHOR]

This paper presents an innovative hierarchical meta-modelling approach for predicting the effective elastic properties of stone injected with composite cement grouts containing Carbon NanoTubes (CNTs) for structural rehabilitation purposes. The study first addresses the homogenization of the nano- and micro-scales through numerical representative volume elements. The first numerical model focuses on the cement matrix doped with randomly oriented CNTs, while the second model represents the porous stone with CNT/cement grout filling the pores. However, the computational burden associated with these models poses a significant limitation when analysing large-scale macrostructural elements. To overcome this challenge, a hierarchical meta-modelling approach based on two nested Kriging surrogate models is proposed. This approach offers a fast and accurate alternative to bypass the time-consuming numerical homogenization process. The first surrogate model establishes a connection between the microstructural characteristics of the CNTs and cement and the effective elastic properties of the composite grout. Subsequently, a second meta-model expands over the first one by introducing two additional variables: the elastic modulus of the stone and the porosity, allowing for estimation of the overall elastic properties of CNT/cement/stone composites. The accuracy and efficiency of the proposed hierarchical meta-model is demonstrated through detailed parametric analyses. To showcase its potential for optimizing rehabilitation interventions, the paper is closed with its application to a benchmark case study of a stone column injected with CNT/cement grout. • Composite CNT/cement grouts are investigated for the first in the literature. • A novel nested surrogate modelling approach is proposed for multi-scale composites. • Fast stiffness estimates of porous stone injected with CNT/cement grout are obtained. • The proposed approach is used to assess the performance of grout injected columns. [ABSTRACT FROM AUTHOR]

• EOS of concrete specimens was determined from high pressure hydrostatic tests. • The effect of different mixtures at same compressive strength was examined. • Mix parameters were: water content, coarse aggregate amount and max aggregate size. • It was proven that EOS depends on mix properties and not on compressive strength. • The differences between hydrostatic and oedometric based EOS were determined. High intensity impact loading on a concrete structure induces three dimensional high intensity stresses, the analysis of which requires appropriate constitutive relationships describing the isotropic and deviatoric stress components. The isotropic component known as the hydrostatic relationship or the equation of state (EOS) is in the focus of this paper. The literature relates the EOS of concrete to its uniaxial compressive strength. This paper aims at refuting this relationship and validating the conjecture that the EOS depends on the concrete mixture. For that purpose, different concrete mixes of equal strength have been tested. The mixture parameters are the water content (with the same w/c ratio), the coarse aggregate content and the maximum aggregate size. Using a unique test setup, hydrostatic tests were carried out to extremely high pressures at the 1GPa level. The results clearly show the pronounced differences between EOS curves representing different mixtures having the same concrete strength, thus validating the above conjecture. As the EOS is sometimes derived from oedometric tests, the present investigation exploited oedometric tests results on exactly the same concrete mixtures and strength to compare the hydrostatic and oedometric resulted EOS curves. The comparisons show that for most cases the stress at a certain volumetric strain in the oedometric curves are somewhat lower than these in the hydrostatic EOS curves. However, for mixes with a large maximum aggregate size with a high aggregate content, the oedometric EOS merges with the hydrostatic EOS curves in the mid-to high pressure levels. Finally, statistical analysis using Analysis of Variance has been employed to identify the effect of different mixture parameters and their combination on the differences in the EOS. These new results enhance the insight on concrete behavior under triaxial high pressures and contribute to the development of a new generation of EOS curves. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of brick from industrial and agricultural wastes are a step towards sustainable development. • Various properties of different waste incorporated bricks using fired and unfired process are comprehensively presented. • The effect of replacement of waste on different properties is discussed. • Ongoing research work at the Author's Institute on the development of brick using marble waste is presented. • Bricks developed using different waste is compared with conventional bricks and Indian standards. • Further research work is required to boost the commercialization of various waste incorporated bricks. Growing urbanization leads to the generation of significant amount of different kind of wastes, which has raised concerns among citizens and governments, globally. On the other side, Masonry brick is an essential building unit which is used in the construction industry around the world. It is well known that the process of fired brick manufacturing is an energy intensive, and thus imparts higher carbon emission. Therefore, the main aim of this study is to promote sustainability and lower CO 2 emissions in brick manufacturing process. As a result, extensive research has been carried out to develop eco-friendly masonry bricks using various industrial and agricultural waste materials like fly ash, marble powder, ground granulated blast furnace slag, glass waste, sludge from various industry, rice husk, sugarcane fiber, etc. There are mainly two kinds of process being used for the manufacturing of bricks e.g., the process of the fired system, and of the unfired system. The process of the fired system is the most commonly used method for the manufacturing of brick. However, the process of an unfired system is preferable due to its environmentally friendly nature. This paper provides up-to-date comprehensive studies of the innovative brick made by using different kind of waste in terms of different properties such as physical, mechanical, durability, microstructural attributes and thermal properties. The presented paper is also discussed the effect of replacement percentage of waste on different properties, method of preparation of brick and firing temperature. The findings suggested that the performance of these bricks improved when compared to conventional bricks. Therefore, waste incorporated bricks have good potential to be used in construction of masonry buildings, reinforced-concrete buildings, etc. Along with the literature reviews, the ongoing research work at the Author's Institute on the development of different waste added bricks is also discussed. [ABSTRACT FROM AUTHOR]

• Hydration mechanism and hydration products of MPC are introduced. • Effects of temperature, mixing proportion and raw material properties on the setting time of MPC are discussed. • Effects of retarders and mineral admixtures on the setting time of MPC and mechanisms of reaction are analyzed. As a low-carbon and good-performance cementitious material, magnesium phosphate cement (MPC) has been widely studied in recent years. However, excessively rapid setting and hardening has been the main reason limiting the engineering applications of MPC. Therefore, this paper presents a comprehensive literature review of 146 papers published from 1970 to 2023 in which we analyzed the effects of raw material properties and ratios, temperature variations, retarder and admixture contents on the setting time of MPC-based materials, and we summarized the approaches to regulating the solidification and hardening of MPC. More importantly, this paper focuses on the mechanism of the effects of mixing proportion and the admixtures on the solidification and hardening of MPC. Finally, this paper suggests research directions about MPC's setting that are worth investigating in the future. This review enables scholars and engineers to have a clearer understanding of the solidification process of MPC. As such, this review serves as a valuable reference for advancing the field of MPC. [ABSTRACT FROM AUTHOR]

• Parameters of concrete geometry needed for mesostructure generation. • Shape description of aggregate and generation method of ITZ, voids and fibers. • Review and comparison on mesostructural generation strategies. • Critical review of random aggregate model and overlap detection algorithm. • Discussion on 2D or 3D model, parametric or image-based modelling. Numerical modelling at the mesoscale is a time- and cost-efficient tool to optimize concrete mix design and to analyse the phenomenological causes of mechanical failure, e.g. when developing novel concrete with unconventional materials. A successful mesoscale model strongly depends on a compromise between a realistic and an efficient representation of the mesoscale phases of concrete - coarse aggregates, mortar matrix, and interfacial transition zone (ITZ). Different approaches to achieve this goal have been developed. This paper identifies relevant parameters that are needed for general geometric modelling, including geometric properties of aggregates (shape, grading, volumetric fraction), and intrinsic phenomena of the mesostructure of concrete - the ITZ, wall effects and aggregate settlement, as well as model size and boundary. Methods to integrate these parameters into modelling are presented. The main topics of the paper are: (1) methods to model aggregate's geometry, either by parametric equations or by image analysis reconstruction; (2) critical review and evaluation of strategies to construct the mesostructure regarding convenience and realistic modelling; (3) methods related to random aggregate modelling and respective strategies to implement overlapping detection algorithms to be used during the random placement of aggregates; (4) evaluation of methods that deal with the modelling of the ITZ, voids, and fibres. The paper also argues that certain options of mesostructural models are not yet experimentally validated. [ABSTRACT FROM AUTHOR]

• Pumpability and buildability of Portland cement/GGBS binders presented. • Pumpability correlates with w/b ratio, whereas buildability with w/b ratio and printing speed. • Process of crack formation presented to provide insights into structural behaviours of 3D printed arch truss. • Estimation of tensile strength of 3D printed truss elements should consider restrained shrinkage effects. • Potential of GGBS for reducing the embodied carbon of 3DP cementitious binder highlighted. The work presented in this paper forms part of a wider research programme being undertaken on the development of low-carbon cementitious mortars for 3D printing applications. Specifically, this paper investigates the potential of ground granulated blast-furnace slag (GGBS) as a partial replacement for Portland cement. Five mortar mixes with varying water/binder (w/b) ratios (0.35 to 0.45) were tested, and to investigate their pumpability and buildability, a series of wall-like specimens were printed using a custom-built 3D printer under a range of speeds of 2 to 4 m/min. Pumpability was found to be directly related to w/b ratio, whereas buildability was found to be dependent upon both test parameters. Mortar mixes with w/b ratios in the range 0.37 to 0.40 demonstrated promising pumpability and buildability characteristics when extruded at the optimum printing speed of 2.5 m/min. Moreover, to demonstrate the application of the optimised mix, an arch truss prototype was printed and subsequently tested to failure to provide insights into the structural behaviour of a 3D printed arch truss member. From the process of crack formation and accompanying analysis, it was found that although the development of tensile stresses in the 3D printed prototype was minimal (a direct result of the arch geometry), it still governed the overall member behaviour due to the presence of internal stresses induced by restrained shrinkage. [ABSTRACT FROM AUTHOR]

• Analysis of the impact of recycled wastewater on the physical, chemical, and mechanical aspects of concrete. • Comprehensive assessment of recycled wastewater influence on concrete durability, microstructure, and strength properties. • Examination and elucidation of interrelationships among diverse properties of environmentally friendly concrete. • Future research insights and recommendations to drive innovation in sustainable concrete practices. The present paper endeavors to examine the viability of utilizing recycled wastewater as a foundational component in the creation of eco-friendly concrete. This paper entails an in-depth analysis of the chemical and physical attributes inherent in recycled wastewater, with a particular focus on its potential as a substitute for conventional freshwater in the concrete mixing process. To address limitations observed in prior research and to achieve a more profound comprehension of recycled wastewater's performance within green concrete, this study conducts an exhaustive review of existing literature. Through a systematic evaluation, the study meticulously assesses the influence of recycled wastewater on diverse properties inherent to green concrete, encompassing pivotal factors like flexural and compressive strength, alongside durability properties. The outcomes drawn from this investigation accentuate the viability and efficacy of recycled wastewater as a feasible alternative to freshwater in the production of green concrete. Notably, this approach holds promise for ameliorating detrimental environmental impacts while concurrently reducing the cost burden associated with sustainable concrete fabrication. Nevertheless, a central message emerges concerning the necessity for vigilant monitoring and meticulous regulation of recycled wastewater's quality and composition. This requisite vigilance is aimed at ensuring its compatibility and appropriateness for integration into concrete formulations. By virtue of delivering a comprehensive and thorough analysis of recycled wastewater's effects on the production of green concrete, this study plays a pivotal role in bridging gaps in knowledge and advancing the boundaries of this field. The practical implications of these findings extend to the development of sustainable and ecologically mindful concrete structures, while also serving as a guiding light for future research endeavors in this pivotal domain. [ABSTRACT FROM AUTHOR]

• The first large-scale field trial of microcapsule-based self-healing concrete in the UK. • Microcapsules were developed and implemented in concrete on site. • Self-healing process was demonstrated both in field and laboratory assessment. • Crack width and depth and permeability reduction and strength recovery was achieved. Maintaining the health and reliability of our infrastructure is of strategic importance. The current state of the UK infrastructure, and the associated huge costs of inspection, maintenance, repair and eventual replacement, is not sustainable and is no longer environmentally viable. The design of infrastructure, mainly concrete, remains traditional and poor material performance continues to be the main cause of deterioration and failure in our infrastructure systems. Biomimetic materials, that emulate natural biological systems in their ability to self-healing, provide an exciting and plausible solution. Embedding cementitious materials with in-built capabilities to sense and respond to their environmental triggers could potentially eliminate all external interventions and deliver a resilience infrastructure. The work presented in this paper forms part of a national initiative that has been developing biomimetic cementitious infrastructure materials which culminated in the first large-scale field trials of self-healing concrete in the UK testing four different but complementary technologies that were developed. This paper focuses on one self-healing technology, namely microcapsules, which contain a healing agent that is released on their rupture as a result of crack propagation. The paper will present details of the microcapsules used, their implementation in concrete and in the field trials and time-related, field and laboratory, assessment of the self-healing process. It also highlights challenges faced and improvements that are now on-going to produce the next generation of the microcapsule self-healing cementitious system. [ABSTRACT FROM AUTHOR]

This study presented experimental results of mechanical properties of RAC containing mineral admixtures at 500 °C. Four different mineral admixtures (fly ash (FA), waste paper sludge ash (PSA), silica fume (SF), metakaolin (MK)) were used in RAC containing 100% coarse RCA through the addition or replacement method. The results indicated that mineral admixtures significantly enhanced the resistance of RAC to the high temperature. The addition method increased the resistance of RAC to the high temperature better than the replacement method. FA improved the residual compressive strength of heated RAC the most followed by MK, PSA, cement, and SF although SF, MK, and PSA concrete showed the higher improvement of compressive strength than others at 20 °C. The addition of 5% and 10% FA in RAC increased 38.45% and 35.23% the residual compressive strength of heated RAC, respectively. The mineral admixtures had an insignificant effect on the UPV values and density of RAC. The addition of mineral admixtures in RAC substantially improved the slope of ascending branch of stress-strain curves of heated RAC. Moreover, the incorporation of mineral admixtures in RAC contributed to an increase in the elastic modulus, toughness, and critical strain of RAC at the elevated temperature. The study also proposed the equations to predict the residual compressive strength and elastic modulus of heated RAC, which can provide references for practical application of RAC. [ABSTRACT FROM AUTHOR]

• Geometric models of lap joints of aluminium and 3D printed polymer adherends. • Hybrid joints of aluminium and 3D printed polymer adherends. • The use of VHB adhesive tape in lap joints of aluminium and 3D printed polymer adherends. The paper presents a novel concept of purely adhesive and hybrid joints fabrication with the application of Additive Manufacturing (AM) technology. 5 different models of metal-polymer single lap joints (SLJ) were manufactured using VHB (Very High Bonding) 5925 double-sided tape and experimentally tested. To reduce the SLJ eccentricity during the tensile loading an appropriate chamfering of the polymer part shape was proposed by applying the AM technology. The Zortax M300 printer was used to produce the polymer adherends and "dog bone" type specimens, which allowed the determination of tensile strength, which value was 6.62 MPa. The effectiveness of the joints was assessed by the maximum force values, the absorption energy, and the repeatability of the results for each model. The highest force of 400.4 N was obtained for the single-lap reference model. Finally, hybrid joints were produced by the application of double-sided tape and mechanical connectors, like tenons placed in the 3D printed polymer part and mortises situated in the aluminium adherends. This new joining technique allowed for an increase in maximum force to a value of 832.5 N. [ABSTRACT FROM AUTHOR]

• Cementation and FT cycles reduce soils' water retention capacity. • Moisture sensitivity of M R , q u , E 1% , S u1% reduce upon cementation and FT cycles. • Proposed equations to predict the M R for cementation and FT influenced soils. This study evaluates the effects of post-compaction wetting–drying (WD) process, freeze–thaw (FT) cycles and cement content (CC) on the microstructure, volumetric strain (ε v), soil–water characteristic curve (SWCC), resilient modulus (M R), unconfined compressive strength (q u), and reloading modulus (E 1%) and axial stress (S u1%) at 1% strain level of a cement-stabilized expansive soil. The specimens compacted with different CC (i.e. 0%, 2%, 4% and 6%) were subjected to different number of FT cycles (i.e. N FT = 0, 1, 3 and 10). They were then dried or wetted to different moisture contents before the determination of the (i) SWCC using filter paper method, (ii) M R from cyclic triaxial tests, and (iii) q u , E 1% , and S u1% from unconfined compression tests. The microstructural changes in the test specimens were determined using mercury intrusion porosimetry and scanning electron microscope tests. Experimental results reveal that cement stabilization and cracks induced during FT cycles cause a significant reduction in the specimen's water retention capacity and the scale of volumetric strain upon moisture content fluctuation. The M R , q u , E 1% and S u1% typically decrease with N FT but increase with CC. However, their variation with moisture content changes is less significant after stabilization or FT cycles. Performance of several empirical models for predicting the M R , q u , E 1% or S u1% was examined. Similar trends in behavior were found for M R - q u , M R - E 1% and M R - S u1% relationships for the specimens tested with different CC, N FT and water content. A simple hyperbolic model proposed in this study for predicting these relationships is validated. The studies presented in this paper are helpful for the design and analysis of stabilized expansive soils used as pavement subgrade considering the influence of complex environmental factors. [ABSTRACT FROM AUTHOR]

• Multi-scale modelling illuminates concrete deterioration at varying length scales. • Multi-scale modelling significantly contributes to sustainable infrastructure. • Challenges like data accuracy and computational complexity necessitate advancements. • Facilitates precise performance predictions, aiding informed decisions in maintenance. The properties of concrete are degraded during service by coupled physical and chemical processes that operate at several length scales, and the prediction of its performance in engineering structures requires multi-physics, multi-scale modelling approaches. The aim of this paper is to provide a comprehensive overview of the current modelling techniques for analysis of concrete deterioration. The paper covers the fundamentals of modelling at several length scales, as well as the bridging/transition between scales, and the numerical methods based on continuum and discrete formulations appropriate to different scales. Considered are the key chemical and physical deterioration processes of carbonation, chloride ingress, freeze–thaw damage, and abrasion. The paper also reviews the validation and verification of multi-scale models and discusses future trends such as data science integration and sustainable concrete design. It is expected that the information presented here will be a valuable resource for researchers and practitioners in the field, highlighting advancements and stimulating future research in multi-scale modelling of concrete deterioration. [ABSTRACT FROM AUTHOR]

• The composition and fundamental principles underlying ECAC are introduced. • The key aspects related to the design and preparation of ECAC are summarized. • The multi-functionality and potential practical applications of ECAC are presented. • The insights and guidance for developing ECAC are proposed. Electrically conductive asphalt concrete (ECAC) is an innovative material that offers numerous possibilities by directly incorporating functional additives (such as metal-based or carbon-based materials) into asphalt binder and mixing it with traditional aggregates and mineral filler. With such a strategy, ECAC possesses a high electrical/thermal conductivity, making it an ideal candidate for sustainable repair methods based on induced heating-healing, snow and ice melting systems on pavements, and piezoresistive sensors for traffic detection in pavement engineering. This paper aims to provide a systematic review of the design and development of ECAC, with a particular focus on the advancements made over the past decade (from 2013 to 2023). The review begins by introducing the composition and fundamental principles underlying ECAC. Subsequently, it summarizes the key aspects related to the design and preparation of ECAC. Moreover, this paper delves into the remarkable multi-functionality exhibited by ECAC, showcasing its potential in practical applications. Through examining various case studies, the review highlights the successful utilization of ECAC in diverse scenarios. This review work can serve as a valuable resource, offering insights and guidance for developing ECAC in the context of smart and sustainable pavement construction. [ABSTRACT FROM AUTHOR]

• A comprehensive overview on the structural application of ECC is conducted. • Future potential research areas of ECC are suggested. Engineered cementitious composites (ECC) has been extensively studied due to its excellent tensile performance in recent decades. ECC can significantly enhance the structural performance of either newly-built or existed structures. This paper reports a state-of-the-art review on ECC at structural level, including its constitutive model, bond behavior, and structural application in several critical areas. The static and dynamic constitutive models as well as the bond behavior between steel or FRP bar and ECC are firstly introduced. The structural behaviors of ECC components are further analyzed in details, including reinforced ECC (R/ECC) beams, columns, beam-column joints, shear walls and coupling beams. The applications of ECC in retrofitting and strengthening the existed masonry and concrete structures are also summarized. Further, the dynamic responses of R/ECC and ECC strengthened structures under impact and explosion are investigated. Future potential research areas of ECC are finally suggested. This paper provides the ECC community a comprehensive overview on the structural application of ECC. [ABSTRACT FROM AUTHOR]

• PHBV (poly-3-hydroxybutyrate-co-3-hydroxyvalerate), has a potential to replace crude-oil based polymer as a bitumen modifier. • PHBV thermal (softening) properties are compatible to the asphalt mix preparation temperate 160oC. • PHBV shows similar physical properties as the bitumen, ie. soft and sticky to the touch when hot/warm and hard when cold. • HV monomer content in PHBV compound regulates its stiffness, low HV content = high stiffness, high HV content = low stiffness. Bitumen is a key constitutive material in asphalt pavements. It binds together the rock scaffolding of a pavement. Bitumen provides asphalt pavement with flexibility and enables it to respond to traffic loading and return to its original condition after the loading, i.e. bitumen restores/repairs the damage. In Porous Asphalt (PA) or Stonemastic Asphalt Mix (SMA) asphalt mixtures, due its open graded structure, bitumen modifiers are used to improve or restore bitumen physical and mechanical performance. Traditionally bitumen modifiers are made with products of crude oil, such as: ethylene vinyl acetate (EVA) copolymers and styrene–butadiene–styrene (SBS). As crude oil production declines and the environmental and financial costs of crude oil extraction increase, there is a need to identify environmentally sustainable alternatives to use in bitumen. Bitumen modifiers generated from biological sources offer an environmentally friendly and economically viable alternative to crude oil based bitumen modifiers. This paper describes how PHBV (poly-3-hydroxybutyrate-co-3-hydroxyvalerate), a bio-based co-polymer, might be used as an alternative bitumen modifier. The effect of PHBV on 70/100pen was investigated for this paper. The chemical and physical effect of the PHBV on the bitumen performance was investigated using Gel Permeation Chromatography, Fourier Transformed Infrared Spectroscopy, Differential Scanning Calorimetry, microscopic imaging and Dynamic Shear Rheometer tests. The results indicate that PHBV has significant potential as a bitumen bio-polymer modifier. [ABSTRACT FROM AUTHOR]

• The tire-pavement mechanism and the measurement methods of pavement friction coefficient are reviewed. • The pavement surface characteristics and the measurement methods of pavement texture are provided and discussed. • The anti-skid evaluation models are summarized and discussed. • The anti-skid overlays are overviewed. Deep insight on the skid resistance of highway tunnel pavement is vital to driving safety of vehicles. This paper presents a review on the skid resistance of cement concrete pavement in highway tunnel. Firstly, this paper summarizes the pavement working environment in highway tunnel. Secondly, tire-pavement friction mechanism, friction measurement methods and the pavement skid resistance inside and outside highway tunnel are reviewed and discussed. Then, the pavement surface texture and the measurement methods are provided and discussed. The anti-skid evaluation models are also reviewed. Finally, the anti-skid methods of cement concrete pavement including resurfacing techniques, and anti-skid overlays are overviewed. Research results show that hysteresis and adhesion can be considered as the main effects contributing to the overall friction force. But the interface contact issues of rubber are also significant for the tire-pavement friction mechanism, which are recommended for further study. Friction measurement methods have different application conditions and indicators. There remains a need to further conduct normalization research on different friction measurement methods. For pavement texture measurement methods, non-contact measurement methods exhibit greater potential for application in pavement texture measurement. Compared with the traditional empirical models, the finite element models can not only provide higher accuracy and reliability in evaluating tire-pavement interaction, but also be more cost-effective and efficient. However, the pavement texture morphology, in particular, pavement micro-texture takes a significant role in investigating the micro-contact, which requires more attention. For tire dynamics models, adaptive models possess substantial potential in tire dynamics modeling and simulation. Compared with resurfacing techniques, anti-skid overlays can provide higher skid resistance and longer service life. The Novachip ultra-thin wearing layer presents a more promising outlook for application in highway tunnel pavement compared to other anti-skid overlays. [ABSTRACT FROM AUTHOR]

[Display omitted] • This is a state-of-art review of rubberized recycled aggregate concrete (RRAC) and fiber-reinforced rubberized recycled aggregate concrete (FRRAC). • Different mechanical properties, microstructural analysis, and life cycle assessment of RRAC and FRRAC have been reviewed. • Extensive regression analysis has been conducted to predict different mechanical properties of RRAC and FRRAC. • Crumb rubber (CR) and recycled coarse aggregate (RCA) reduced the strength, however, fiber addition could have a positive response. • Addition of CR and fibers enhanced the toughness and ductility of RRAC; however, excessive amount of CR negatively affected the toughness. • RCA and CR can be used up to 30% and 10%, respectively. The growing population demands rapid development of infrastructures. However, the construction industry is searching for environmentally sustainable and eco-friendly building materials to fight climate change. Millions of tires are discarded globally, and only certain percentages are recycled. The use of rubber tires as a natural aggregate replacement in concrete has gained popularity among the research community in the past few years, primarily due to its ductility and toughness properties. A significant number of investigations have been reported in the past using recycled coarse aggregates (RCA), crumb rubber (CR), and fibers separately in concrete. The results revealed that the addition of rubber particles along with RCA in concrete reduced the strength. However, the inclusion of fibers in the same mixtures significantly improved the mechanical properties of concrete by acting as a bridge within the concrete matrix for the surrounding cracks. In this review paper, over 220 research articles from the last 30 years reporting the effect of RCA, CR, and fibers on the mechanical and physical properties of rubberized recycled aggregate concrete (RRAC) and fiber-reinforced rubberized recycled aggregate concrete (FRRAC) are summarized. This paper presents in detail the influencing factors that affect the physical and mechanical properties of RRAC and FRRAC. The performance of FRRAC depends on the types of fiber and CR, treatment of CR, RCA sources, and the mix design of concrete. Based on the review, recommendations are provided for optimized FRRAC production. Simplified equations have been proposed to predict the tensile and flexural strength and modulus of elasticity of RRAC and FRRAC. An overview of predicting the mechanical properties of rubberized concrete using different machine-learning algorithms has been presented. Finally, this review paper will help scholars understand the use of RCA and CR in concrete as aggregate replacement materials and create waste material utilization opportunities for the sustainable green construction industry. [ABSTRACT FROM AUTHOR]

• The current similar simulation materials are featured with the contradiction between low strength and high rockburst tendency, thus being unable to simultaneously realize the qualitative rockburst of small size specimen and the impact damage restoration of large size model. Developed a new similar simulation material for coal with both low strength and strong rockburst tendency in this paper. • In this paper, we propose for the first time to develop similar simulation materials using water glass as binder, sodium silicofluoride as curing agent and talcum powder as aggregate. And the optimal doping of the new similar simulation material was obtained by orthogonal experiment and multiple linear regression method. • It was confirmed that the modulus index is a simplified evaluation index that can comprehensively evaluate rockburst. And according to the similarity criterion, the rockburst evaluation criteria of modulus index for similar simulation materials are obtained by deriving theoretical equations. • Micro-macroscopic experiments were utilized to monitor in real time the energy-temperature-strength synergistic change characteristics and similarities between this material and the coal with a strong RT. The feasibility of the material was confirmed in terms of physical parameters, degree of rockburst and homologous energy and temperature characteristics. • This study also revealed the multi-parameter precursor characteristics of rockburst damage in the specimen, which can lay a foundation for the prevention and study of impact ground pressure disaster. The current similar simulation materials (SSM) are featured with the contradiction between low strength and high rockburst tendency (RT), thus being unable to simultaneously realize the qualitative rockburst of small size specimen and the impact damage restoration of large size model. In this case, this study developed a new SSM of low strength and high RT by using water glass (WG) as cement, talcum powder (TP) as aggregate and adding curing agent sodium silicofluoride (SSF). Under the requirements of initial set volume shrinkage rate (IVSR), long-term volume decay rate (LVDR), uniaxial compressive strength (UCS) and modulus index (MI), the optimal ratios of SSF and TP were obtained 20% and 70% by orthogonal experiment and multiple linear regression method, respectively. Micro-macroscopic experiments such as uniaxial compression, scanning electron microscope (SEM), acoustic emission (AE) and Infrared thermal imager were utilized to monitor in real time the energy-temperature-strength synergistic change characteristics and similarities between this material and the coal with a strong RT. The experimental results show that: the UCS value of this material is 6.11 MPa and its MI is 11.57, which meets the requirements for low strength and high RT. Meanwhile it satisfies a certain similar proportionality between its physical parameters and those of coal. In the whole process of uniaxial compression, there are energy and temperature homologous changes in the characteristics of consistency, and both materials conform to the stress–strain phase law. The infrared radiation temperature displays a trend of "slowly decreasing-gradually warming-continuously cooling-suddenly warming-sharply cooling". The AE energy count rate shows a trend of "calm transition and sudden increase before and after the stress peak". All are characterized by strong RT. There is still some difference between the two specimens during energy and temperature changes, due to their different molding characteristics and load-bearing capacity. The feasibility of the material was confirmed in terms of physical parameters, degree of rockburst and homologous energy and temperature characteristics. Meanwhile, this study revealed the multi-parameter precursor characteristics of rockburst damage in the specimen, which can lay a foundation for the prevention and study of impact ground pressure disaster. [ABSTRACT FROM AUTHOR]

The adoption of natural construction materials can help mitigate the environmental impact of the construction industry by reducing the amount of energy required and emissions. Among the natural materials, bamboo is a remarkable option, combining high mechanical resistance with a low specific weight and a very high growth speed; however, its application is limited by the absence of a suitable grading method. This paper aims at filling this lack by providing a strength-based grading methodology relying on a four-point bending test. Experimental results were processed considering bamboo both as a homogeneous material and as a non-homogeneous material and using the ANOVA test. Results show that statistical groups can be defined which are not based on the bamboo species, but on the values of the mechanical properties, hence supporting the appropriateness of strength classes. The bending tests used in this paper could be a crucial test for bamboo grading: it is easier to perform than a tensile test and it gives complete information on the change of material properties along the culm wall thickness. The study focuses on six different species of bamboo grown in Italy, for which little data is present in the literature. • Four-point bending test could be a crucial test for bamboo grading. • The flexural properties of six species of bamboo grown in Italy are discussed. • A strength-based grading methodology based on a four-point bending test is provided. • A classification scheme can be defined based on the mechanical properties of bamboo. [ABSTRACT FROM AUTHOR]

• Study found how multiple factors influence asphalt mixture's pore characteristics evolution. • Explored mesoscopic pore characteristics and macro mechanical strength correlation. • Built on AASHTO T283 and JTG E20-2011, proposed mesoscopic moisture-sensitivity method for asphalt. This paper explored the mesoscopic pore characteristics of asphalt mixtures by considering the coupling effects of grading segregation, dynamic pore water, and salt erosion, utilizing CT scanning technology. The study yielded the following key findings: 1) Under the coupling effects of grading segregation, dynamic pore water, and salt erosion, the sample with heavy segregation of coarse aggregate (HC) exhibited the highest variation in porosity, followed by the sample without gradation segregation (D), while the sample with heavy segregation of fine aggregate (HF) showed the least change. 2)The influence of gradation segregation on different mesoscopic pore characteristics demonstrated significant dispersion before and after the coupling effects of multiple factors. 3)From a mesoscopic scale perspective, this paper proposes a method to assess moisture sensitivity. The results obtained through this method indicate that the coordination number (CN) exhibits significantly stronger moisture sensitivity compared to other mesoscopic pore parameters. [ABSTRACT FROM AUTHOR]

• The feasibility of waste concrete powder-based geopolymer reclaimed concrete was verified. • Carbonation depth, uniaxial compressive strength and dynamic elastic modulus of under different carbonation time were studied. • The changes of mineralogical phases and micromorphology characteristics of reclaimed concrete were analyzed. • The deterioration mechanism of carbonization and freeze–thaw-carbonization of reclaimed concrete was revealed. • It makes it possible to achieve the complete recycling of waste concrete. In order to realize the complete recycling of waste concrete, this paper used waste concrete powder (WCP), fly ash (FA) and granulated ground blast furnace slag (GGBS) as raw materials to prepared geopolymer, mixed with recycled waste concrete aggregates to prepare waste concrete powder-based geopolymer reclaimed concrete (WCPGRC). The WCPGRCs cured for 28 days were carried out carbonization test (group C-28d) and freeze–thaw cycle carbonization test (group DC-28d), and the WCPGRCs cured for 84 days were carried out carbonization test (group C-84d) to study their durability. The carbonation depth, uniaxial compressive strength (UCS) and dynamic elastic modulus (DEM) of three groups of WCPGRC under different carbonation times and different freeze-thawed-carbonation times were tested respectively. The mineralogical phases and micromorphology characteristics of WCPGRC before and after carbonization and freeze-thawed-carbonization were characterized through XRD and SEM. The results show that: (1) The carbonation depth of WCPGRC in groups C-28d, DC-28d and C-84d all increased with the carbonation time and freeze-thawed-carbonation time, and the maximum carbonation depth was 4.4 mm, 4.9 mm and 4.1 mm, respectively. (2) The UCS of C-28d increased by 9.7% from 39.11 MP to 42.56 MPa with carbonization time; The C-84d increased by 4.6% from 40.51 MPa to 43.31 MPa; The DC-28d first increased and then decreased with the increase of freeze–thaw-carbonization time, and the maximum UCS was 40.51 MPa on the 28th day. (3) The DEM of C-28d increased by 16.5% from 17.22GPa to 20.06GPa with carbonization time; The C-84d increased by 7.6% from 20.05GPa to 21.57GPa; The DC-28d first increased and then slightly decreased with the increase of freeze–thaw-carbonization time, the maximum DEM was 18.41 GPa on the 14th day. (4) Prolonging curing time increased the UCS and DEM, while freeze–thaw decreased the UCS and DEM of WCPGRC. (5) After the carbonization of WCPGRC, new carbonate crystals and geopolymer gels were generated, continued to fill the voids and cracks, making the overall structure denser. However, after the freeze–thaw-carbonization, the freeze–thaw cycle inhibited the geopolymerization, and the freeze–thaw damage intensified the carbonization, which reduced the structural integrity of WCPGRC. [ABSTRACT FROM AUTHOR]

• A novel FRP family with high stiffness and ductility was developed. • Tensile behavior and damage mode of glass/PP composites was evaluated. • The delamination was the sole appropriate failure mode for glass/PP composites. • A two-limit tensile constitutive model for glass/PP composites was developed. Traditional interlayer fiber reinforced polymer (FRP) composites utilized in civil engineering are deficient in either the sufficient stiffness or ductility. For this, a study was conducted on the tensile behavior of interlayer hybrid FRP composites, which were composed of polypropylene (PP) and glass fabrics with an epoxy resin as the matrix and a central layer of glass fabric. This paper presents the design concept, failure mode, and constitutive model for glass/PP FRP composites. The experimental results indicate that the glass/PP FRP composites exhibit higher stiffness and ductile compared to traditional FRP composites, thereby demonstrating superior mechanical properties. Moreover, the finite element (FE) method was employed to identify all potential failure modes of glass/PP FRP composites, and it was concluded that only delamination failure mode is applicable in civil engineering. Based on the FE results, a failure mode map was generated for glass/PP FRP composites, which can facilitate rapid identification of its failure modes. To quantify the tensile behavior of these composites, a two-limit tensile constitutive model was developed. Considering that composites are typically designed for tension, the research presented in this paper can offer theoretical support for the implementation of glass/PP composites in civil engineering applications. [ABSTRACT FROM AUTHOR]

• Multiphase pipeline flow and its detection of cemented backfilling slurry in metal mine is discussed. • Multi-dimensional characterization and modelling prediction in the pipeline transportation of cemented slurry is systematically proposed. • The wall erosion behavior, wearing reduction and controlling features in slurry transportation is summarized. The underground cemented backfilling of tailings slurry in metal mines is an important guarantee for controlling goaf, reducing tailings storage, and ensuring mining safety. As a typical multiphase flow, the slurry and its pipeline flow transportation are important factors that affects mining efficiency and leads to poor pipeline wear. To better understand the flow regime and its pipeline transportation characteristics, this paper systemically reviews following aspects: 1) the non-full/full pipeline flow regimes, patterns, and key evaluating parameters (distribution of pressure drop, velocity, etc. of slurry flow); 2) the breakthroughs, findings and limitations by using the slurry rheology experimental (loop pipeline test, etc.), or undisturbed detections methods (electrical resistance tomography, magnetic resonance imaging, Micro-CT, etc.) of slurry pipeline transportation; 3) the computational fluid dynamic models and numerical simulations, and 4) the generating mechanism, major modes and its controlling methods of slurry pipeline wear and undesirable erosion are critically summarized. It conducts that the non-full pipeline transportation, slurry composition heterogeneity, coarse particles segregation/sedimentation, pipeline shapes and its layout, and even electrochemical corrosion caused by acidic/alkaline slurry could be key causes for the high resistance and poor effectiveness of slurry pipeline transportation. These discussions in this review paper will contribute to offering good supports to understand slurry pipeline flow behaviour and potential wearing controlling methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rheological parameters of the test group first decrease and then increase. • The rheological parameters obtained by different operating modes vary greatly. • The operating mode of step change is considered as the optimal mode of rheometer. An appropriate amount of air-entraining agent improves the wet shotcrete fluidity, and the accurate measurement of rheological parameters accurately expresses the rheological characteristics of sprayed concrete. In this paper, eBT2 rheometer was used to measure time variation of rheological parameters of high air content wet shotcrete (HACWS). At the same time, in order to investigate measurement accuracy of shotcrete rheology, the influence of rheometer operating modes (OM) on rheological parameters was studied. This paper selected four rheometer OM to comprehensively analyze the rheological characteristics and rheometer measurement accuracy of HACWS. The results showed that relative plastic viscosity (RPV) and relative yield stress (RYS) of HACWS both tended to decrease first and then increase with time. The torque measured by eBT2 rheometer remained constant at high shear rates. The rheological parameters obtained with different OM differed significantly, and OM-B was recommended to analyze the rheological properties of fresh concrete. This paper provides a reference for the selection of air-entraining agent type and rheometer OM. [ABSTRACT FROM AUTHOR]

• Mechanical properties of SSC concrete were reduced by FA replacement. • Shrinkages of SSC concrete was mitigated by FA replacement. • The replacement of FA decreased the relaxed stress of SSC concrete. • Nonlinear relationship between viscoelastic behaviors was revealed. This paper aimed to study the early-age properties and viscoelastic behaviors of supersulfated cement (SSC) concrete with different replacement ratios (15%, 30%, and 50%) of fly ash (FA). Ordinary Portland cement (OPC) concrete was also designed for reference. Mechanical properties and free shrinkage were tested. Stress relaxation and creep as the significant viscoelastic behaviors were investigated in restrained ring test with different degrees of restraint. The results showed that later mechanical properties of SSC concrete approached or exceeded that of OPC concrete while replacement of FA caused a significant reduction. The workability of SSC concrete was improved with FA replacement. Free shrinkage was mitigated by FA due to the significant reduction on autogenous shrinkage of SSC concrete. At a high degree of restraint, SSC concrete with a FA replacement ratio of 50% exhibited a high cracking resistance. At a relatively low degree of restraint, cracking potential was reduced by FA replacement due to its significant mitigation on shrinkages. Relaxed stress of SSC concrete decreased with an increase on FA replacement ratio. The nonlinear relationship between relaxation and creep coefficients of SSC concrete was established regardless of FA replacement ratios and degrees of restraint, which was different from OPC concrete. The results obtained in this paper might promote the reliable applications of SSC concrete in the future. [ABSTRACT FROM AUTHOR]

• A new type of FRP truss was proposed and fabricated in this paper to solve the problem of the closed-loop created in the steel truss of the ballastless track slab. • Investigate the mechanical performance of the sleepers reinforced by this new FRP truss under the stacking condition by the compressive test. • The new FRP truss reinforced sleepers still have sufficient stiffness and bearing capacity compared to the traditional sleepers. • The height of the FRP truss has a significant effect on the failure modes, including joint failure after the web rod yielding (the height less than 89 mm) and the FRP truss buckling after the web rod yielding (the height greater than 108 mm). • The finite element model of the friction coefficient is set up can accurately predict the load–displacement curves of specimens under the stacking condition. The main objective of this research was to overcome the problem of the closed-loop created in the steel truss of the ballastless track slab. Therefore, a new type of FRP truss was proposed and fabricated. However, the mechanical performance of the sleepers reinforced by this new FRP truss under the stacking condition was not clear. In this paper, five different types of truss reinforced sleepers were fabricated and tested in the stacking state by the compressive test. The test results show that: (1) the new FRP truss reinforced sleepers still have sufficient stiffness and bearing capacity compared to the traditional sleepers, and the hand-made FRP joints not only have high strength, but also provide early warning of joint failure; (2) the height of the FRP truss has a significant effect on the failure modes, including joint failure after the web rod yielding (the height less than 89 mm) and the FRP truss buckling after the web rod yielding (the height greater than 108 mm); (3) the finite element model of the friction coefficient is set up can accurately predict the load–displacement curves of specimens under the stacking condition. [ABSTRACT FROM AUTHOR]

• A database of cracked, uncracked and segmented images with scale was developed. • Classification of cracks was implemented using a Convolutional Neural Network. • Then, the U-Net algorithm was used to identify crack shapes with pixel-perfect accuracy. • A new method is introduced to calculate crack width using U-NET output image. • A Semi-automated geographic crack information system was proposed. Applications of Artificial Intelligence (AI), Deep Learning (DL), and Machine Learning (ML) are becoming common in the field of civil and infrastructure engineering. This paper proposes an innovative asphalt pavement health monitoring framework based on state-of-the-art deep learning algorithms, a convenient data collection strategy, a novel crack width calculation algorithm, and a novel geolocation-based crack visualization method. Furthermore, this paper introduces a 2000-image (1440 × 1440) dataset for crack classification, an 8000 image dataset (360 × 360) dataset and another dataset with manually segmented images. Transfer learning based DL model achieved a validation accuracy of 99%. A novel crack width calculation algorithm is proposed based on the skeletonization and gradient calculation on binary images to quantify the severity of the crack. Locations of the cracked surface positions were identified using geotagged images, and a geospatial mapping method was proposed to visualize the crack locations for health monitoring and maintenance purposes. [ABSTRACT FROM AUTHOR]

• Recent advances in development and innovation of high strength lightweight concrete (HSLWC) were presented. • Novel type of HSLWC (i.e. ultra high-performance lightweight concrete) was introduced and reviewed. • Effective strategies for producing HSLWC with different lightweight materials were reviewed. • Functional properties, durability and practical applications of HSLWC were presented and discussed. • An outlook on future research and challenges were provided to broaden HSLWC applications. Lightweight cementitious composite has been used in construction for thousand years. However, before the Second World War, lightweight concrete was mainly limited to non-loadbearing blocks. With the increasingly demanding requirements of modern construction, especially in harsh environments, there is an urgent need to develop high strength lightweight concrete (HSLWC) capable of loading bearing purposes. The adoptions of supplementary cementitious materials, high-quality lightweight materials and fibers contribute to developing HSLWC, which enable the production of structural components. Numerous studies have been conducted on HSLWC with a compressive strength exceeding 40 MPa and a density below 2000 kg/m3. This paper aims to provide an in-depth review of HSLWC, covering its development strategies, functional and durability properties, and structural applications. Particular emphasis is given to the emerging technology of ultra high-performance lightweight concrete, characterized by low density, ultra high strength and superior durability. Compared to normal weight concrete, HSLWC offers better thermal insulation and fire resistance. The use of HSLWC in structures can increase load capacity and span, reduce seismic inertial forces, and improve structural efficiency. Numerous research and projects have demonstrated the feasibility and advantages of using HSLWC in various construction fields, including high-rise buildings, bridges and offshore structures. The excellent in-service performance of HSLWC in marine structures highlights its durability. To expand the applications of HSLWC in civil engineering, the paper proposes current opportunities and challenges that should be addressed to attract more attentions and foster further research in this area. [ABSTRACT FROM AUTHOR]

• The morphologies of aggregates can be quantified using photography and processed through ImageJ. • The number of aggregates and volume of mortar in an asphalt mixture is enough to predict its porosity, stiffness, stability, and flow. • New design models enable to select optimal aggregate's number and mortar's volume to achieve desired performance of asphalt mixtures. • New design models help checking whether one asphalt mixture fulfils performance requirements. Conventional asphalt mix design methods require numerous experiments to verify the efficacy of various recipes, resulting in significant time and labour costs. Therefore, there is a need for an alternative method that is both efficient and convenient. To address this issue, this paper proposes a novel asphalt mix design method that reduces the reliance on time-consuming and resource-intensive physical and mechanical tests to determine the properties of new asphalt mixtures. The method focuses on the quantity of aggregates and the volume of mortar to estimate the air voids content, resilient stiffness modulus, Marshall stability, and flow requirements in accordance with industry standards. Statistical analysis shows that the key properties of asphalt mixtures are primarily influenced by the number of aggregates and volume of mortar. Nomographs are provided to predict these properties based on the mixture's gradation and mortar volume. The proposed method's feasibility is demonstrated by accurately predicting the gradations and properties of six different mixtures. Additionally, the paper suggests the use of 3D models for asphalt mixtures, allowing for the observation of aggregate distribution and air voids before testing the mixtures' mechanical properties. [ABSTRACT FROM AUTHOR]

• The numerical model's setup for the steel fibre reinforced concrete (SFRC) segment. • Numerical simulations of GPR detection for SFRC segment under different conditions. • Optimum frequency selection of the SFRC segment. • Validation of an SFRC segment detection based on a model test. • Calculation of the equivalent relative dielectric constant (ERDC) of SFRC segments. The SFRC segment is gaining attention in shield tunnels due to their better mechanical properties. However, the existence of steel fibres poses a greater difficulty when attempting to utilize ground penetrating radar (GPR) for nondestructive quality inspection compared to conventional reinforced concrete segments. This paper presented a refined numerical model of SFRC segments with gprMax software, to investigate the penetration characteristics of GPR. The numerical model incorporated four different steel fibre contents, namely 0%, 0.5%, 2.5%, and 5%. The model also included an internal void and a surface metal plate to compare and analyze the waveform characteristics of GPR with the normal sections of the segment. The orthogonal test of numerical simulation investigates the imaging characteristics, power attenuation patterns, and imaging features of three different GPR frequency gradients: 200 MHz, 500 MHz, and 1000 MHz. This analysis helps in selecting the appropriate detection frequency based on the observed energy attenuation patterns and imaging characteristics. Then, the model test was conducted at the selected frequency to study the penetration performance of GPR. The research results indicate that the numerical model established in this paper demonstrates good effectiveness in studying the waveform characteristics of steel fibre-reinforced concrete under various conditions. The numerical model established in this paper realized the study of the penetration characteristics and imaging features of different steel fibre contents, GPR frequencies, and detection targets. Analysis of waveform characteristics, power attenuation, and imaging results indicates that GPR at 500 MHz exhibits better detection performance for SFRC segments. The results of the numerical simulation were verified through model tests of real SFRC segments, demonstrating that 500 MHz has good penetration performance for SFRC segments. This paper also proposed a calculation method for equivalent relative dielectric constant (ERDC) based on the model test results and validated its rationality through the analysis of numerical simulation results and real GPR waveforms. [ABSTRACT FROM AUTHOR]

• This investigation shows the mechanical performance of starch-hemp agro-composite materials for thirty different compositions. • The failure of the starch-hemp composite materials is due to the great displacement. • The stereoscopic images of agro-composite in compression (ARAMIS système) show that the gradient of the strain is neither homogeneous and nor regular. • The obtained results reveal an optimal composition for this agro-composite building materials. The use of Hemp/Lime concrete has gained popularity due to its lightweight, low thermal conductivity, and good sound absorption properties. However, the emission of CO 2 from lime and the non-durability and non-recyclability of lime-hemp concrete make it less sustainable. In this paper, we studied new Starch/Hemp agro-composite materials as an alternative building material. The physical and mechanical properties of these materials strongly depend on the mixture of hemp shive and binder, making it challenging to determine the optimal composition for specific applications. This paper presents the experimental results obtained from one hundred and eighty specimens for the optimal composition. We used thirty different mixtures, including three Hemp/Starch (H/S) ratios of 6, 8, and 10, and five mixtures with hemp shive sizes of 5 mm (H k), 15 mm (H i), and 20 mm (H j). We studied and analyzed the influence of the H/S ratio and hemp shive size (H k , H i , H j) on mechanical properties, including density, flexural tensile strength, compressive strength, Young's modulus, and Poisson's ratio. The experimental results demonstrate that the starch-based binder allows for the transfer of mechanical strength to the hemp shive and gives the desired shape to the agro-composite material. The equations describing the evolution of the physical and mechanical characteristics (ρ, σ c , σ t , E, ν) should help researchers and building professionals manufacture this agro-resource and determine the optimal composition for building based on intended applications. [ABSTRACT FROM AUTHOR]