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Natural rubber latex (NRL) and cellulosic fibre are promising additives for improving the performance and sustainability of cement composite. This study investigated the optimised inclusion of NRL into waste paper pulp (WPP)-ordinary Portland cement (OPC) composites to enhance mechanical and durability properties. Three mixing methods were compared, revealing pre-mixing WPP with OPC before adding diluted NRL as the most effective. Both high-ammonia NRL (HA-NRL) and prevulcanised NRL (PV-NRL) significantly reduced water absorption, with PV-NRL slightly outperforming HA-NRL. Flexural properties were optimised at an NRL/OPC/WPP ratio of 10/700/300 parts by dry weight, although excessive NRL content reduced modulus. NRL also enhanced fire resistance through a synergistic effect, forming an ash-char layer, with HA-NRL exhibiting superior performance due to chemical distinctions. Failure modes and crystal formation were analysed using FE-SEM. Overall, optimised NRL and WPP incorporation improved water resistance, flexural performance, and fire resistance, suggesting their potential for sustainable construction. Further research could explore additional performance aspects and optimise NRL and WPP dosages for broader applications. • NRL incorporation significantly enhances flexural strength and modulus, promising structural applications. • Optimised composite formulations with natural rubber latex and waste paper pulp offer sustainable construction materials. • Synergy between NRL and waste paper pulp enhances fire resistance, resulting in the formation of a ash-char layer, suggesting suitability for fire-prone environments. • Exceptional water resistance ensures durability and resilience against moisture-induced degradation. [ABSTRACT FROM AUTHOR]

This study investigates the impact of incorporating lime mud (LM) as a filler material to develop sustainable, cementless ultra-high performance concrete (UHPC) by replacing silica powder (SP) and silica sand (SS) at varying percentages. Flowability analysis reveals that LM, with its distinctive particle size, influences flow characteristics differently at different replacement levels. Compressive strength was improved by 5.4% with 30% SP replacement, showcasing the role of LM in nucleation, as well as its particle size advantage. The heat of hydration analysis indicates that LM likely influences the early curing stages, enhancing reactivity and nucleation. TGA analysis also confirms that LM plays a role in hydration reaction, influencing weight loss and hydration peaks. The mercury intrusion porosimeter results show the impact of LM on pore distribution, with 30% for SP and 50% for SS replacements, favoring denser matrices. Life cycle assessment (LCA) demonstrates reduced CO 2 emissions and favorable environmental performance, highlighting the sustainability potential of LM replacements. Overall, the incorporation of LM in UHPC shows promise in terms of enhancing its mechanical properties and environmental sustainability. [Display omitted] • Lime mud (LM) in UHPC boosts material strength, leading to denser, more effective concrete. • LM enhances hydration, flowability, and refines pore structure. • High LM ratios in UHPC increase sustainability and reduce CO 2 emissions. • LM's use in UHPC significantly advances its mechanical properties and eco-friendliness. [ABSTRACT FROM AUTHOR]

In recent years in India, fly ash-lime-gypsum (FaL-G) brick production has been adversely affected by the scarcity of fly ash and lime. Consequently, the current study aims to mitigate this problem. It delves into leveraging incinerated paper mill sludge ash (IPMSA) as a supplement to fly ash and lime in FaL-G brick production, aiming to present an eco-conscious alternative to conventional burnt clay bricks. It focuses on two blends: blend 1, replacing fly ash with IPMSA (2.5–30 wt%), and blend 2 substituting lime entirely with IPMSA (2.5–15 wt%). A thorough material analysis preceded brick manufacturing, involving techniques like energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, thermogravimetry differential thermal analysis, scanning electron microscopy, and X-ray diffraction spectroscopy. Subsequent tests evaluated compressive strength, water absorption, weight density, percentage of voids, initial rate of suction and chemical resistance of the resulting bricks. According to the XRD results, the higher IPMSA levels didn't induce any phase transformation. Remarkably, bricks incorporating IPMSA in blend 1 (2.5–20 wt%) and blend 2 (2.5–7.5 wt%) met the mechanical properties specified for 'class 10' bricks according to Indian and ASTM standards. Incorporating IPMSA increases the porosity of bricks, making them lighter. This aids in minimizing construction expenses by reducing labour and transportation costs as well as lowering expenditure on foundation construction. This sustainable approach efficiently uses resources, reduces landfill wastes, shows potential for industrial-scale production, making eco-friendly bricks a promising alternative to traditional methods and promoting greener construction practices. • Ecofriendly FaL-G bricks were developed using incinerated paper mill sludge ash (IPMSA). • Reusability of IPMSA in FaL-G brick production poses both economic and environmental benefits. • Use of IPMSA in FaL-G brick production reduces landfill waste and addresses waste management issues. • IPMSA is suitable for up to 20 wt% for fly ash and 7.5 wt% for lime in FaL-G brick production, meeting relevant standards. [ABSTRACT FROM AUTHOR]

The paper characterizes waste in the form of fly ash generated in a power plant during the combustion of biomass in a fluidized bed in terms of its possible use in the ceramic building materials industry. This is important from the point of view of environmental protection. In order to assess the possibility of using ash in the production of red ceramics (e.g. bricks), two different clay raw materials (Clay I and Clay II) were selected to prepare the raw material sets. First of all, the investigated fly ash was subjected to thermogravimetric TG-DTG analysis and its basic chemical composition was determined. Then the specific density was determined for all the raw materials, XRD analysis was also performed and finally characteristic temperatures were determined by means of a high-temperature microscope. The basic raw material sets included clayey raw material and fly ash in various contents: 5 wt%, 10 wt% and 15 wt%. Samples were pressed from the ready sets and fired at the temperature of 1000℃. Afterwards, the obtained samples were subjected to XRD and microstructural tests, then selected physical properties were determined, i.e. water absorption, porosity, apparent density, and compressive strength. Based on the research and analysis of the results, it was found that the introduction of fly ash from biomass combustion into the raw material set in the range of 5–15 wt% has a positive effect on the insulating properties of red ceramics. In addition, the density of the red ceramics decreases with the increase in the addition of fly ash, while its porosity and water absorption increase. Furthermore, the addition of fly ash decreases the compressive strength and visually brightens the microstructure of the products. • It is possible to use fly ash from combustion in the production of red ceramics. • The sintering process transforms dusty waste into a harmless product. • The addition of ashes to clay reduces the density of finished products. • Products with the addition of fly ash have higher porosity. • Ceramic products with the addition of ashes are full-value products. [ABSTRACT FROM AUTHOR]

The increasing global waste generated by industrial activities poses significant environmental challenges. Eco-waste management emerges as an economically viable solution for converting, valorizing, and repurposing these byproducts, aligning with circular economy principles, and aiming to reduce greenhouse gas emissions. Construction, known for its unsustainability due to high energy consumption, non-renewable resource utilization, waste generation, and greenhouse gas emissions, particularly from cement production, has led to the exploration of alternative materials. Magnesium oxide (MgO)-based cement, an alternative to Ordinary Portland Cement (OPC), has gained attention, leveraging Brazil's prominence as a major magnesite producer. This study explores the valorization of waste from kraft pulp mills of the paper industry, specifically lime sludge (LS) and lime slaker grits (grits), to produce magnesium oxysulfate (MOS)-based fiber cement boards. The effect of accelerated carbonation on cementitious composites produced with formulations containing grits and LS was investigated. Replacing 25% of the limestone with grits showed no noticeable differences in the properties of the boards, and MOR values close to 11.17 MPa were obtained. However, the physical-mechanical performance showed a decrease with the use of LS and higher concentrations of grits, associated with Na 2 SO 4.XH 2 O formation in the system and ITZ structure formed around the aggregated particle, respectively. Carbonation in a saturated atmosphere led to the carbonation of the 5–1–7 phase, which was related to the decrease in mechanical strength of the boards after the curing process. The thermal decomposition of the Hydrated Magnesium Carbonates (HMCs) formed during accelerated carbonation corroborated with the changes in the physical properties of the composites, demonstrating that the carbonation products are formed within the voids and pores of the material and contribute to the reduction in water absorption of the boards. • Global waste requires innovative environmental solutions for sustainability. • Investigation on eco-waste management aligns with circular economy principles, reducing environmental impact. • Article focuses on MgO-based cements as an alternative to Ordinary Portland Cement, highlighting global magnesite production. • Research emphasizes valorization by utilizing waste from kraft pulp mills (such as LS and grits) for MOS-based fiber cement production. • Exploration of accelerated carbonation impact on cementitious composites with LS and grits unveils shifts in physical-mechanical performance. [ABSTRACT FROM AUTHOR]

3D printing technology, as a rapid prototyping method, can accurately reconstruct the internal structural characteristics of samples, making it highly promising for rock engineering applications. However, current 3D printing materials used to reconstruct rocks suffer from low strength and high ductility, which is inconsistent with the high strength and brittleness of natural rocks. This paper explores the use of silane coupling agents KH550 (γ-aminopropyl triethoxysilane) and KH570 (γ-methacryloxypropyl trimethoxysilane) to modify nano SiO 2 powder. Through sample preparation and uniaxial compression tests, the mechanical properties and failure characteristics of the modified nano SiO 2 powder were analyzed. The results indicate that, using the preparation method with a mass ratio of E-44 epoxy resin, KH550 modified nano SiO 2 powder, and 593 curing agent at 80:40:26, the samples achieved an uniaxial compressive strength of up to 30.55 MPa without enhanced brittle post-processing. The failure characteristics exhibited significant axial tensile damage. Additionally, combining CT scanning technology demonstrated that the structural and mechanical properties of the samples can be effectively reproduced. Therefore, the 3D printing materials discussed in this paper provide a viable reference for accurately reconstructing high-strength and high-brittleness rock masses. • New printing material can model the high strength and brittleness of rocks. • Different silane coupling agents on nano SiO 2 -modified E-44 epoxy resin. • Mechanical properties and failure modes of samples with varying mass ratio. [ABSTRACT FROM AUTHOR]

This paper considered the effects of coarse aggregates and proposed a continuous bond-slip theoretical model between Ultra-high performance concrete with coarse aggregates (UHPC-CA) and rebar. Due to the impact of coarse aggregate on crack development and fiber distribution, an improved fiber-matrix discrete model was proposed, combining the thick-walled cylinder solution and the fictitious crack model to analyze the bond-slip behavior across the uncracked, partial cracking, and complete cracking stages. This paper investigated the effects of rebar diameter, coarse aggregate particle size, coarse aggregate content, bond length, and cover thickness on the ultimate bond strength. The results showed that rebar diameter had minimal impact on ultimate bond strength, while bond stress loss increased by 35.0 % as the coarse aggregate content increased from 10 % to 40 %. A total of 76 sets of pull-out test data were collected and compared, indicating that the predicted ultimate bond stress and peak slip of the proposed model had average ratios of 1.000 and 1.022 to the experimental values, with coefficients of variation of 0.124 and 0.284, respectively, and the error was generally within 20 %. Furthermore, the relative error between the predicted and test results remained within 15 %, while the bond-slip relationships based on different softening curves exhibited a relative error not exceeding 5.0 %. The proposed model accurately predicted the bond-slip relationship between UHPC-CA and rebar. • Proposed the improved fiber-matrix discrete model for fiber bond stress considering the influence of coarse aggregate characteristics. • Proposed the continuous model of bond-slip in UHPC-CA considering the effect of coarse aggregate. • Analyzed the main parameters affecting the proposed model between UHPC-CA and rebar. • Collected UHPC-CA pull-out test results confirmed the ultimate bond stress, peak slip and bond-slip relationship. [ABSTRACT FROM AUTHOR]

Polyisobutylene (PIB), commonly used as the primary sealant of double, triple, and multi glazed insulating glass units (IGUs), provides the key moisture barrier function and determines the expected lifespan of the IGUs and even the entire glass curtain wall systems (GCWSs). Slipping and debonding of the PIB, caused by temperature changes, have resulted in numerous instances of premature failure of building envelopes. However, available research is inadequate in accurately evaluating the service environment of IGUs and thermal-deformation behaviors of this energy-saving building material. This paper presented a simplified method for analyzing the thermal environment of IGUs, considering outdoor air temperature, solar radiation, wind speed, and angle to the horizontal. A numerical modeling method was proposed and validated with the heat transfer tests. Three finite element (FE) models were built and utilized for the precise analysis of temperature-induced deformations of double, tripled, and quadruple glazed IGUs. Simplified calculation formulas for the maximum thermal deformation of PIB in the X and Y directions under different temperature conditions were obtained, taking a new concept "cavity-to-pane ratio" into consideration. Finally, the relationship between the PIB's temperature-induced deformation and its probability was proposed. The results show that the IGUs in Beijing suffer more than 22 % of their time in harsh service conditions where the difference between indoor and outdoor temperatures exceeds 20 °C. For DIGUs, the maximum temperature-induced deformations of the PIB in X (along the short side of the panel) and Y (along the long side of the panel) directions are 0.142 and 0.214 mm, respectively, corresponding to shear strains of 28.4 % and 42.8 % for the PIB with a thickness of only 0.5 mm. For TIGUs, the maximum deformations increase to 0.159 and 0.239 mm, corresponding to shear strains of 31.8 % and 47.8 %. For QIGUs and the other multi-glazed IGUs, these values can increase to 36.8 % and 55.4 % or more. The methodology proposed in this paper aims to lay the groundwork for further addressing premature failure issues and optimizing edge bond constructions of multi-glazed IGUs. • An effective statistical method for analyzing the thermal environment of IGUs was proposed. • Three FE models were built for the thermal deformations of DIGUs, TIGUs, and QIGUs. • Simplified calculation formulas for the maximum thermal deformation of PIB were obtained. • A new concept "cavity-to-pane ratio" β was proposed and defined. • A clear correlation between the thermal deformations of IGUs with the square root of β was found. [ABSTRACT FROM AUTHOR]

To enhance the efficiency and quality of ultra-thin overlay, a new precast carpeted asphalt ultra-thin overlay was developed in this study. The paper introduces the structural design and forming process of the overlay and evaluates its bending property. In addition, the dynamic response characteristics of the ultra-thin overlay under coupled temperature and moving loads were analyzed using ABAQUS software to better understand its forces in real conditions. The paper concludes by emphasizing the contribution of this technology to sustainability in road engineering. Results indicated a significant improvement in the bending properties of the precast overlay compared to traditional overlays, with an increase of 159 % in both bending strain and mid-span deflection. In summer afternoons, the internal temperature of the ultra-thin overlay is about 20℃ higher than the ambient temperature. By enhancing the thermal conductivity, heat capacity, and emissivity of the asphalt mixture, or by reducing the solar radiation absorptivity, the internal temperature of the overlay can be effectively lowered during daytime high temperatures. The temperature stress inside the ultra-thin overlay reaches 2.39 MPa in winter, with a daily variation of 1.8 MPa. Different axle loads significantly impacted the force and deformation of the overlay, showing a linear increase trend of about 60 %. Speed variations also had a notable effect, with each index decreasing by over 30 % with increasing speed. Different horizontal force coefficients greatly influenced the shear stress of the overlay, reaching 0.264 MPa at the bottom during emergency braking. The temperature has a great influence on the force and deformation of the overlay, which is prone to cracking at low temperatures and shear failure and rutting at high temperatures. This technology holds great importance in promoting resource and environmental protection, as well as sustainable development in the field of road engineering. • A sustainable precast carpeted asphalt ultra-thin overlay was developed and evaluated for its bending properties using a three-point bending test. • The mechanical response characteristics of the precast ultra-thin overlay were analyzed under coupled temperature and moving loads. • Precast ultra-thin overlay can be directly paved on-site, avoiding the tedious processes of hot mixing, transportation, paving, rolling, and cooling of traditional ultra-thin overlays during on-site construction. This contributes to the sustainability of road engineering. [ABSTRACT FROM AUTHOR]

This paper investigates regional differences in temperature actions on railway steel-concrete composite girder bridge in China. A refined thermal-structural coupling finite element model (FEM) of a typical Chinese railway steel-concrete composite girder was established and validated. Using 40 years of meteorological data from major cities (A stations), numerical simulations were performed, and each resulting two-dimensional temperature fields was decomposed into four temperature actions based on derived formulas. Daily extreme values of these temperature actions were extracted from the decomposed data sets. Representative values of temperature actions with a 50-year return period for A stations across China were then determined using extreme value analysis theory. Additionally, numerical simulations were conducted using 2021 data from 401 meteorological stations, and the corresponding annual extreme values of temperature actions were extracted. To capture the nonlinear relationship between the spatial parameters and the annual extreme temperature action value of the steel-concrete composite girder, these extreme data and their corresponding spatial parameters (longitude, latitude and altitude) were utilized to train a neural network model. Using this neural network model, annual extreme temperature actions data were obtained, and isotherm contour maps of the extreme temperature values for 2021 were then plotted. Based on these 2021 temperature action isotherm maps and a BP neural network model, representative values of temperature actions across various regions in China were determined, and corresponding isotherm maps were plotted. The results indicated significant differences in the representative values of the four-temperature actions within China. The temperature actions obtained in this paper exhibit enhanced geographical resolution compared to existing codes. Using these refined temperature action values, the mean normal strain of the railway steel-concrete composite beam section and the sectional bending curvature around the x-axis and y-axis can be quickly calculated. • A refined thermal-structural coupling long-term finite element model is developed. • The decomposition formula of two-dimensional temperature field is derived. • The respresentive values of four temperature actions across China are obtained using extreme analysis theory and a BP neural network. [ABSTRACT FROM AUTHOR]

Traditional bamboo and wood components have different holes due to their own and external factors, and the appropriate hole repair technology is the key to improve the component's energy dissipation capacity. In this paper, based on the principle of in-situ free radical polymerization and hollow glass microsphere (HGM) reinforced polymer, PAM hydrogel (PAMHG) with better deformation recovery ability and PAM/HGM amide polymer (AP) with better mechanical properties were prepared. Based on the principle of self-energy dissipation of components, AP is used to improve the deformation capacity of hollow bamboo. The ratio of PAMHG and AP was optimized by single factor test and orthogonal test. The performance of AP was verified by bending test, SEM, energy consumption analysis，durability test and statistical analysis of small diameter round bamboo. The size of the bamboo sample is 250 mm (L)×15 mm (D)×2.5 mm (t), in accordance with LY/T 3347–2023 " Testing methods for physical and mechanical properties of small diameter round bamboo " (China). The results showed that an appropriate amount of glycerol could effectively improve the volume stability of the hydrogel. HGM effectively improved the strength of the polymer, and when the mass ratio of HGM/PAM was 0.48, the maximum compressive strength was 0.8 MPa, which was 2.4 times higher than that of the undoped HGM, and at this time, the optimal polymer ratios were 25 g of AM, 1 g of MBA, 0.01 g of APS, 2 g of TEA, 2 g of Carbomer SF-1, a volume ratio of 1:1 of glycerol/deionized water that the dispersion medium was 70 ml, and HGM was 12 g. The average energy dissipation of grouted bamboo at ultimate load was 2.02 times that of the control group, and the highest bending strength and elastic modulus were 128.01 MPa and 11.24 GPa, which were 41.39 % and 39.75 % higher than that of the control group, respectively. The SEM results revealed that the AP partially prepolymerized solution could infiltrate into the cells and pores of the bamboo material to achieve filling, bonding, as well as reinforcing the bamboo tissue. In addition, the durability test shows that AP has good resistance to environmental pressure. The results of this paper can provide a reference for the restoration materials of bamboo and wood components. • In pure PAMHG solvent deionized water, the introduction of glycerol can improve its thermal stability. • AP can fill the holes of bamboo and improve its ductility and energy dissipation capacity. • Typical failure modes of the small diameter round bamboo were listed. • The mechanism of AP improving bamboo properties was explored based on SEM. • The durability of treated bamboo was explored through three kinds of accelerated aging tests. [ABSTRACT FROM AUTHOR]

Seashell powder calcined sludge cement (SCSC) is a new type of green low-carbon ternary cement prepared by using waste sludge and waste seashells. It reduces carbon emissions in the cement production industry and solves environmental problems such as serious soil-water-air pollution caused by long-term stockpiling of waste sludge and waste seashells, which are difficult to be utilized in a resourceful manner. However, the reduced clinker content results in lower early strength of SCSC, which limits the application of SCSC in applications requiring high early strength such as precast concrete specimens. In this paper, the effects of different dosage of C-S-H seeds on the hydration process, mechanical properties and microstructure of SCSC slurries were investigated. The results showed that C-S-H seeds significantly increased the 12-hour compressive strength of SCSC, and the 2 % addition of C-S-H seeds increased its compressive strength by 271 %, but had less effect on its later strength. The proportion of large pores in the sample with a 1 % addition of C-S-H seeds decreased by 1 %. At 12 hours, 2 % addition of C-S-H seeds increased its total hydration exotherm by 141 %. The addition of C-S-H seeds decreased the fluidity of the slurry but did not change the flow pattern of the slurry. The relationship between the rheological parameters of the slurry and the addition of C-S-H seeds was well fitted with a primary function, and the rheological equations of SCSC slurries with different additions of C-S-H seeds were obtained. The results of this paper can further broaden the application scenarios of SCSC and lay the foundation for the large-scale application of SCSC. • The effect of C-S-H on the early performance of SCSC was studied for the 1st time. • C-S-H seeds significantly improved the 12-hour compressive strength of SCSC. • The rheological equation of SCSC slurries at different C-S-H additions were obtained. • 2 % C-S-H increased the total 12-hour heat release of SCSC by 141.75 %. • 5, The addition of appropriate amount of C-S-H refines the pore structure of SCSC. [ABSTRACT FROM AUTHOR]

Silicate wastes are used as supplementary cementitious materials (SCM) in Portland cement production, and as precursors to produce alkali-activated materials such as geopolymers to lower the environmental impact of construction. The high crystallinity of some of these wastes lowers their reactivity and hence the production of cementing hydrates. This paper includes a comparative analysis of the efficiency of alkali-fusion to activate three distinct types of silicate waste sourced from diverse sectors. The paper underscores the robustness of this method and its applicability in a wide composition range. It provides a solid foundation for the application of alkali-fusion across a wide spectrum of industrial waste types. Fly ash (FA), crop bottom ash (CBA) and aluminium processing sludge (APS); were fused with NaOH at 600 °C. XRD and FTIR analyses revealed that alkali-fusion disrupts highly cross-linked Si-O-Si structures transforming them into more reactive phases (sodium aluminosilicate and sodium silicates). Alkali-fusion is efficient even at low NaOH dosage(15 %). 15 % NaOH-fusion increased the mechanical activity index of FA, CBA and APS by 108.19 %, 494.61 % and 27.96 % respectively. The mineral composition of the wastes changed at 50 % alkali content: quartz was largely digested, and sodium silicate emerged as the dominant phase. After alkali-fusion, dense and compact matrices with rich hydrates were found evidencing the enhancement of the pozzolanic reaction. Alkali-fusion at relatively low temperature (600 °C) is successful in activating low-reactivity silicate waste, transforming the waste into valuable SCMs. • An effective method has been proposed to activate low-reactive silicate waste. • The Alkali fusion could convert quartz into reactive silicate. • Fusion with 15 % alkali, the activity of the inert silicate minerals is increased by up to 4 times. [ABSTRACT FROM AUTHOR]

To improve the simulation calculation accuracy of long-span composite girder bridges during construction and ensure high calculation efficiency, this paper presents a novel algorithm for analyzing internal force redistribution in steel–concrete composite girder bridges. Based on section equivalence theory, the expression describing the internal force distribution of the steel girder and the concrete deck is derived, and a new finite element model of a double-layer element, named virtual double-layer element model, is established. Based on the exponential recursive method of concrete beam element shrinkage and creep effects and the influence mechanism of concrete deck shrinkage and creep in steel–concrete composite girders, an analysis model of composite girder shrinkage and creep is established. Calculation expressions of the equivalent node force increment and fixed-end force increment of the composite girder integral element after conversion of a composite section are derived. The feasibility of the method proposed in this paper is verified through analysis of models of a continuous beam and a cable-stayed bridge. The algorithm was applied to calculate the construction process of the world's largest span cable-stayed bridge, achieving alignment with its design objectives. • An algorithm accurately simulates the continuous combination of double-layer elements and the shrinkage and creep effects. • The computational efficiency of the algorithm is enhanced using an exponential function recursion method. • The algorithm is integrated into a self-developed FEM software and its correctness has been validated. • The algorithm has been applied to calculate the construction process of several composite cable-stayed bridges. [ABSTRACT FROM AUTHOR]

Styrene-butadiene-styrene block copolymer (SBS) modified bitumen (SMB) is unable to meet usage requirements after being exposed to sun-light, heat and oxygen. The researches show that it is difficult to restore bitumen effectively when the penetration of the aged bitumen is below 20 dmm. Therefore, the penetration of 20 dmm is taken as the dividing line in this paper. Higher than 20 dmm is considered as mild-moderate aging, while lower than 20 dmm is considered as severe aging. The traditional rotating thin-film ovens (RTFO) and pressure aging vessels (PAV) methods are similar to simulate the aging behavior of the upper layer of bitumen pavement, but they are difficult to simulate the aging in the depth direction of bitumen pavement. In this paper, the aging of the modified bitumen is simulated by extending the aging time and deepening the depth of the aging mold, and then it is graded according to the penetration. We aimed to investigate the differences in physical, microscopic and rheological properties of SMB with including 0 wt%, 1.5 wt%, 2.5 wt%, 3.5 wt%, 4.5 wt% and 5.5 wt% SBS content before and after aging. Through the physical performance, such as penetration, softening point, ductility and elastic recovery, it was observed that a high SBS content leads to strong anti-aging ability. Fourier Transform Infrared (FTIR), fluorescence microscopy (FM), scanning electron microscopy (SEM) and atomic-force microscope (AFM) revealed that a good network structure can be formed through absorbing light components when the SBS exceeds 3.5 wt%. After that, it was found that there is a positive correlation between aromatic index and penetration, as well as a positive correlation between butadiene index and softening point. Additionally, rheological frequency scanning and temperature scanning indicated that the modulus was increased and the phase angle was decreased with increasing SBS content or aging. After aging, the rutting resistance of SMB was enhanced but the cracking resistance was weakened. This research can establish a theoretical support and foundation for the regeneration of the mild-moderate aged SMB. [Display omitted] • The simple method for judging SMB aging degree is further improved. • The physical properties, microscopic properties and rheological properties of mild-moderate SMB are systematically studied. • The aging mechanism of SMB with mild-moderate aging is obtained, which provided a theoretical basis for regeneration. [ABSTRACT FROM AUTHOR]

This paper delves into the innovative realm of vascularization within concrete, a technique that embeds channel networks into the concrete matrix, mirroring the vascular systems found in living organisms. This approach facilitates the flow of diverse substances throughout the material, significantly expanding the functionalities of concrete beyond its traditional use. The work studies the core principles behind optimizing vascular networks in cementitious materials, from established methods like Constructal Law and Murray's Law to computational approaches and lesser-known theories like Percolation Theory and Darcy's Law. The discussion extends to fundamental fluid dynamics principles - Hagen-Poiseuille, Bernoulli's, Continuity, and Navier-Stokes Equations - and their significance in vascular network design. Additionally, the paper outlines various strategies to construct these vascular networks, addressing the evolution of fabrication methods over time and the challenges encountered. While most existing research focuses on self-healing and thermal regulation capabilities, this paper also explores the potential of vascular networks for a broad spectrum of applications. Through this review, the paper underscores vascularization's transformative potential in shaping concrete technology's future. • An innovative realm of nature-inspired vascularization within concrete was reviewed. • Core principles behind optimizing vascular networks in cementitious materials were summarized. • Fundamental fluid dynamics principles and their significance in vascular network design were reviewed. • Various strategies to construct vascular networks and the challenges encountered were reviewed. • Applications of vascularization in concrete such as self-healing and thermal regulation were discussed. [ABSTRACT FROM AUTHOR]

This paper conducted a full-scale experiment on a PCCP with an inner diameter of 1400 mm and a length of 6000 mm. A finite element model was established on the basis of this experiment, and the influence of different recovery stresses, Fe-SMA bar diameters, and material types on the strengthening effect was investigated. The simulation results indicated a notable enhancement in the strengthening effect upon employing Fe-SMA bars with recovery stresses of 0 MPa, 175 MPa, 330 MPa, and 382 MPa, respectively. With the increased recovery stress, the micro-cracking pressure enhanced 33.8 %, 51.5 %, 72.1 %, and 80.9 % and the visible cracking pressure enhanced 12 %, 24.8 %, 31.6 %, and 33.1 %, respectively, compared to the non-strengthened PCCP. Finally, this paper proposed a design concept for a short-duration, micro excavation PCCP strengthening method based on the self-prestressing of the Fe-SMA. • Conducted a full-scale experiment about PCCP with broken wires strengthened by Fe-SMA bars. • Investigated the influence of distinct Fe-SMA bar diameters and recovery stresses on the strengthening effect. • Innovatively conducted simulation study of PCCP with broken wires strengthened by Fe-SMA strips. • Proposed the concept design of a micro excavation or non-excavation strengthening technique for PCCPs. [ABSTRACT FROM AUTHOR]

The use of cementitious piezoelectric composite enables structure monitoring of concrete construction, while its piezoelectric and mechanical performance are relatively low. This paper developed a novel high-performance piezoelectric composite through carbonation of calcium and magnesium-based binder (including Ca(OH) 2 and Mg(OH) 2). The influence of PZT volume, forming regime, and polarization condition on compressive strength and piezoelectric strain coefficient (d 33) of the two piezoelectric composites was investigated. Results showed that the use of PZT volume from 20 % to 80 % led to a 6-fold and 3-fold greater d 33 value for Ca(OH) 2 and Mg(OH) 2 piezoelectric composites, respectively. While, such change in PZT volume reduced the compressive strength by 50 % and 55 % for the two piezoelectric composites. This is due to the significantly increased porosity and decreased carbonation degree as indicated by microstructural analysis. The use of a higher forming pressure from 25 to 100 MPa resulted in 60 % and 105 % increases in d 33 values for the two piezoelectric composites. Such improvements in compressive strength were 120 % and 135 %, respectively. The d 33 values were increased by 45 % and 60 % with the polarization voltage increasing from 1.5 to 3.5 kV/mm for the two piezoelectric composites. Such increases in d 33 were 64 % and 94 % when polarization duration extended from 5 to 25 min. This study determined the optimal preparation regime of the two piezoelectric composites that can ensure the best overall performance considering the trade-off among piezoelectric, mechanical, and microstructural properties of the composites. The results of this paper can facilitate the application of novel and high-performance of piezoelectric sensor in smart concrete structures. • Piezoelectric composites were developed through carbonation of Ca(OH) 2 and Mg(OH) 2. • The d 33 of the two piezoelectric composites reached 55 and 35 pC/N, respectively. • The compressive strength of the two piezoelectric composites easily exceeded 40 MPa. • The developed piezoelectric composites can enable monitoring of concrete construction. [ABSTRACT FROM AUTHOR]

To explore the potential of magnesite adopted as supplementary cementitious material (SCM) in cement industry, the authors of this paper investigated the hydration characteristics of ternary slag cement mixtures containing magnesite or limestone. All cement pastes were formulated with a water-to-binder ratio of 0.4, and a total of 50 % substitution level was applied across the blends, with varying slag and magnesite/limestone contents. Experimental results confirmed that adding limestone to slag cement can promote the hydration of cement clinker through the nucleation effect, while not for magnesite addition. As the substitution ratio of magnesite increased, there was a notable increase in both the critical pore diameter and cumulative pore volume, leading to a continuous decrease in the compressive strength of cement pastes. Compared to limestone-containing blends, the incorporation of magnesite was more beneficial to the compressive strength at 7 and 28 days. Additionally, limestone facilitated the precipitation of hemi- and mono-carboaluminate, whereas no hemicarbonate was observed in mixtures containing magnesite. The addition of magnesite promoted the formation of hydrotalcite-like phase, and the quantitative analysis revealed that the dissolution of magnesite primarily occurred in the first 7 days. The authors believed that the results obtained in this paper proposed new perspectives on utilizing magnesite as SCM in cement industry. • The hydration characteristics of cement-slag-magnesite ternary systems. • The differences with respect to hydration characteristics with magnesite or limestone addition. • The correlation of porosity and chemically bound water content vs. compressive strength of ternary pastes. [ABSTRACT FROM AUTHOR]

Engineered cementitious composites (ECCs), renowned for their crack resistance and tensile properties, are extensively employed in restoration work. However, research on the interfacial bonding properties between ECC and existing concrete exposed to high temperatures (ECC-HTC) is limited. Factors such as exposure temperature, substrate moisture, and curing conditions significantly influence the properties of ECC-HTC. This paper investigates the effects of these factors on the macro-mechanical properties, microstructure, and physical phase changes of ECC-HTC. This paper reveals that elevated exposure temperatures from 20 °C to 600 °C increase substrate damage, reducing compressive strength from 50.9 MPa to 29.9 MPa, increasing interfacial porosity from 2.7 % to 8 %, and increasing pore structure complexity, with the fractal dimension rising from 1.11 to 1.3. This results in a decrease in interfacial bonding strength from 3.48 MPa to 2.54 MPa. High substrate humidity adversely affects bonding strength at 20 °C due to increased interfacial porosity from a higher water-cement ratio. Conversely, at 600 °C, it favors the formation of C-S-H, enhancing bonding strength. Water-cured (20 °C water soaking) substrates exposed to 600 °C improve interfacial bonding strength by 0.3 MPa compared to those subjected to standard condition curing (20 °C, RH > 95 %). This is attributed to the moisture availability, which favors the formation of C-S-H with a lower Ca/Si ratio in the interfacial transition zone (ITZ). Better pre-curing conditions help recover strength of substrate exposed to high temperatures but do not improve interfacial bond strength because healing of substrate pores and cracks hinders ECC hydration product penetration. These findings offer valuable theoretical insights and practical guidance for repairing and reinforcing fire-damaged concrete structures. • Higher temperatures increase substrate damage and interfacial porosity, reducing interfacial bonding strength. • Compared to dry substrates, SSD substrates lower interfacial bonding strength at room temperature but enhance it at 600 °C. • Compared to standard conditions curing, water soaking of substrates exposed to 600 °C enhances interfacial bonding strength. • For high-temperature concrete, better pre-curing conditions improves substrate strength but not interfacial bonding strength. [ABSTRACT FROM AUTHOR]

Using seawater and sea sand to prepare concrete could effectively alleviate the shortage of freshwater and river sand resources and promote the sustainable development of concrete. However, the current research on the setting process, hardened properties, and sustainability of ultra-high-performance seawater sea sand concrete (UHPSSC) remain considerably limited. In this paper, the UHPSSC was designed to mitigate the autogenous shrinkage and enhance the sustainability, and the effect of seawater, untreated and desalinated sea sand on the setting process, mechanical properties, durability, and sustainability was explored by various tests. Results show that the abundant ions (e.g., Cl- and SO 4 2-) in seawater and untreated sea sand promote the dissolution and nucleation of cement, accelerating the hydration process, and seawater provides a high pH hydration environment, which enhances the pozzolanic reaction activity of silica fume and fly ash. This leads to the enhanced flexural and compressive strengths at early age, reduced flowability, and increased autogenous shrinkage. Although the seawater and untreated sea sand considerably alleviate the natural raw materials consumption, the mechanical performance at 28 d and durability are reduced, thereby decreasing the sustainability index by 7.8 %. The desalination treatment of sea sand decelerates the hydration process of UHPSSC with untreated sea sand due to the lower ion content in desalinated sea sand. The application of desalinated sea sand mitigates the adverse impact of untreated sea sand on the workability, mechanical properties, and durability. However, this desalination process requires more energy and freshwater consumption, thereby decreasing sustainability index. The fly ash incorporation could improve the workability of UHPSSC, and decrease the autogenous shrinkage value by 17.9 %. Moreover, it mitigates the environmental effect without compromising the mechanical properties and durability, leading to an impressive 42.8 % improvement in sustainability. Durability assessment reveals that the prepared UHPSSC specimen maintains outstanding mechanical properties even after 360 d of exposure to severe marine environment, indicating its excellent durability. This paper provides novel insights for achieving a cleaner and more sustainable concrete production. • A comprehensive assessment of the sustainability of UHPSSC is performed. • The sustainability of designed UHPSSC is increased by 42.8 %. • The correlation between the autogenous shrinkage values and IRH is established. • 360 d of marine exposure test implies the excellent durability of prepared UHPSSC. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of steel reinforcement configured with different strengths after different high temperatures on the shear performance of the test beams, a total of 20 reinforced concrete (RC) beams, through experiments, numerical analyses and theoretical studies, in order to understand the key factors affecting the shear performance of the beams. The test revealed that the mechanical properties of concrete and steel reinforcement showed a trend of increasing and then decreasing after high temperatures. Increasing the stirrup ratio and stirrup strength can significantly improve the crack resistance and shear capacity of the beams, as well as the deformation performance of the beams. The residual shear strengths of test beams with high-strength stirrups after exposure to high temperatures are significantly greater than those of ordinary reinforced concrete beams. Specifically, the shear capacity of beams with high-strength stirrups after exposure to 800°C increased by 23.7 % compared to ordinary beams, and the mid-span deflection performance increased by 28.7 %. The stresses in the shear span region of the test beams after high temperature were more concentrated at the diagonal and the number of cracks was significantly reduced. In this paper, a simplified formula for calculating the residual shear capacity of RC beams after room and high temperatures is proposed, which can well predict the test results. • Analyzed the effect of high temperature on the shear performance of high strength steel RC beams. • Revealed the effect of the strength of stirrups on the RC beams after high temperatures was revealed. • Proposed a simplified model to evaluate the residual shear capacity of theRC beams after high temperature. [ABSTRACT FROM AUTHOR]

A composite anti-aging rejuvenator for road asphalt was studied and prepared. Asphalt samples with different aging degrees and modifier dosages were prepared by RTFOT(rolling thin film oven) and PAV(pressure aging vessle)， and the viscoelastic, high temperature, low temperature and fatigue properties of the modified asphalt were comprehensively characterised based on their rheological properties. The test results showed that the composite anti-aging rejuvenator improved the fatigue performance and low temperature performance of aging asphalt. Among them, the creep rate m value at −18°C was recovered to 99.2 % of the unaged level, and the G-R(Glover-Rowe) parameter was reduced to more than 90 %. After long term aging of the composite anti-aging reclaimed mixtures were still able to maintain the water stability and low temperature performance higher than the level required by the specification. The paper found the better effect of adding same ratio of rejuvenator and anti-aging agent to aging asphalt. The reason was that the same ratio of rejuvenator and anti-aging agent could have synergistic effect and enhance each other. This paper verified the road value of the composite anti-aging rejuvenator from asphalt and asphalt mixtures, which provides technical support and reference for the promotion of old pavement reclamation and long-life pavement. • A composite anti-aging rejuvenator was designed. • The composite anti-aging rejuvenator showed greater recovery effects than basic rejuvenator. • The optimal ratio of composite anti-aging rejuvenator was determined. • Water stability and low-temperature cracking resistance of asphalt mixtures was improved. [ABSTRACT FROM AUTHOR]

Epoxy resin (EP) is used in construction materials due to its low curing shrinkage, excellent chemical stability, and mechanical properties. However, its flammability limits applications in the field of construction. Co-precipitation method with sodium hydroxide as the alkali source and hydrothermal method with urea as the alkali source are the common ways to prepare MgAl-LDH. In this study, MgAl-LDH1 (abbreviated as LDH1) was prepared by using NaOH as the alkali source at 65 ℃ for 12 h, MgAl-LDH2 (abbreviated as LDH2) by using urea as the alkali source at 120 ℃ for 12 h, and MgAl-LDH3 (abbreviated as LDH3) was prepared by using triethanolamine as the alkali source at 100 ℃ for 2 h. Then, LDH1, LDH2, LDH3 were compounded with ammonium polyphosphate (APP) to synergistically enhance the flame retardant properties of EP (Composite material abbreviated as LDH1-APP-EP, LDH2-APP-EP, LDH3-APP-EP). The results showed that the best flame retardant effect was achieved after compounding APP (5 wt%) with LDH3 (5 wt%) prepared with triethanolamine as the alkali source. Compared with Pure-EP, the peak exothermic rate and peak smoke production rate of LDH3-APP-EP prepared with triethanolamine as the alkali source decreased by 74.54 % and 67.44 %, respectively. Compared with LDH prepared with NaOH and urea as the alkali source, LDH prepared with triethanolamine as the alkali source has a larger layer spacing and a higher weight loss percentage which releases more gases, moisture, and carbon layers formed by triethanolamine during the combustion process to reduce the heat release from the fire. It's evident that LDH3-APP-EP prepared with triethanolamine as the alkali source has higher residual carbon densities and the lowest residual carbon values based on SEM and Raman test results. This result proves that the LDH3 with triethanolamine as the alkali source has a good effect on EP flame retardation in this paper which provided a new way to design new efficient flame retardants. [Display omitted] • Three kinds of MgAl-LDH were prepared in this paper by three alkali sources. • MgAl-LDH and APP had a significant synergistic retardant effect for EP. • LDH3 were firstly compounded with APP had the best flame retardant effect. • LDH3 prepared with triethanolamine effectively reduce the heat release from the fire. [ABSTRACT FROM AUTHOR]

In this work, two types of sandwich structures were fabricated to develop sustainable building materials using renewable and waste resources. The chopped jute fiber reinforced perlite-filled gypsum composite was used as the core and the brown paper and the woven jute fiber reinforced epoxy composite (JFRC) were used as skins to manufacture the sandwiches. The effect of jute fiber content (10 g - 20 g) in the core on the flexural properties was studied. The flexural test was conducted to determine the flexural strength, modulus, energy absorption, and the load-bearing capacity of brown paper skin-based sandwiches (BPSS) and JFRC skin-based sandwiches (JFSS). The results of this study show that the flexural properties of both BPSSs and JFSSs are improved significantly with increasing jute fiber content up to 17.5 g indicating the optimum fiber content. The flexural strength and modulus of BPSS at 17.5 g jute fiber content are respectively 8.44 % and 30.16 % greater than those at 10 g jute fiber content. On the other hand, the JFSSs show 30.24 % and 60.36 % increase in flexural strength and modulus respectively at 17.5 g jute fiber content compared to those at 10 g fiber content. The flexural energy absorptions of BPSS and JFSS are also increased by 45.40 % and 22.90 % respectively when jute fiber content in the core is increased from 10 g to 17.5 g. The specific load-bearing capacity of JFSSs is 130.38 % - 216.56 % greater than BPSSs depending on the fiber content in the core. [Display omitted] • Two types of sandwich structures were developed using gypsum/perlite composite core. • Flexural properties of sandwiches increased with increasing jute fiber content. • The optimum jute fiber content in gypsum/perlite composite core is 17.5 g (4.22 %). • JFRC skins significantly improved the specific load bearing capacity and toughness. • Distinct failure mechanisms observed for BPSSs and JFSSs. [ABSTRACT FROM AUTHOR]

This paper aims to propose a generalizable parameter calibration framework for discrete element method (DEM) and to develop the refined dynamic compaction DEM (RDCD) model for red-bed soft rocks (RBSR), which is used to investigate the contribution of tamping weight (W) and drop distance (H) to dynamic compaction quality control. Firstly, the linear model (LM) and the linear parallel bond model (LPBM) were selected to accurately represent the dynamic behavior of RBSR based on dynamic compaction characteristics. A generalizable calibration framework for LM and LPBM contact models was further proposed. Secondly, based on the calibration framework, a series of DEM simulations, parameters significance analysis, and physical tests were conducted to accurately calibrate the contact parameters of RBSR. Finally, the RDCD model for RBSR was developed, which was used to investigate the contribution of W and H to dynamic compaction quality control from a micro perspective. All results indicated that the proposed generalizable calibration framework could provide an accurate determination of RBSR contact parameters for dynamic compaction simulation. Specially, the lightweight inversion model for LPBM parameters was developed, enabling the rapid acquisition of contact parameters for RBSR. The LM parameters of RBSR were determined directly and indirectly, which could be directly applied to various RBSR. Moreover, the shockwaves generated by a heavier tamper with a lower drop distance had longer durations and larger propagation, enhancing the compactness of the overall specimen and generating larger and more uniformly distributed strong force chains. The dynamic compaction simulation results indicated that increasing the W could enhance dynamic compaction quality control. This paper contributes to the theoretical refinement of the contribution of W and H on-site dynamic compaction quality control. • A generalizable parameter calibration framework for discrete element method. • The refined dynamic compaction DEM model for red-bed soft rocks is developed. • The contribution of W and drop distance H to dynamic compaction is investigated. • The shockwaves generated by a heavier W have longer durations and propagation. [ABSTRACT FROM AUTHOR]

After the CO 2 mineralization reaction of cement-based materials, on the one hand, the microstructure of the materials is improved, and the hardening performance is improved. On the other hand, CO 2 is effectively stored and good environmental benefits are generated. This paper reviews the thermodynamic and kinetic models of mineralization of cement-based materials. Secondly, the variation of pore structure and the durability of cement-based materials after CO 2 mineralization were reviewed. Then, the factors influencing mineralization degree in ordinary Portland cement system, non-hydrated silicate system, active magnesia system and recycled concrete waste were reviewed. On this basis, the fundamental problem of limiting the degree of mineralization of cement-based materials was identified, i.e., the CO 2 mineralized product layer limits the dissolution of Ca2+ and the diffusion of CO 2. • The present paper reviewed the existing methods for evaluating the mineralization degree of cement-based materials and applicability. • The factors affecting the mineralization degree of each cement system are reviewed. • Two possible solutions to improve the mineralization degree of cement system are proposed. [ABSTRACT FROM AUTHOR]

The rapid solidification and significant shrinkage of alkali-activated slag cement are key issues that restrict its practical engineering application. This paper explores the composition design of alkali-activated cements (AAC) with slow coagulation and shrinkage reduction. This paper adjusts the proportion of slag (SG) and calcined coal gangue powder (CCGP), regulates the content of Na 2 O·2.4SiO 2 -NaOH-Na 2 CO 3 ternary activator components, and uses calcium carbonate whiskers (CW) instead of SG to prepare AAC with slow coagulation and shrinkage reduction. When the activator is composed of (66 %) Na 2 O·2.4 SiO 2 -(2 %) NaOH-(32 %) Na 2 CO 3 mixed composition, the CO 3 2- and Ca2+ in the system react preferentially to produce CaCO 3. The decrease of Ca2+ concentration delays the formation of C-(A)-S-H, resulting in the initial and final setting time of AAC reaching 334 min and 346 min, respectively. When the CW substitution rate is 3 %, the 28d compressive strength of AAC reaches 102.2 MPa. The 49d drying shrinkage of the AAC is 7020μm/m and the 49d autogenous shrinkage is 2387μm/m. This is attributed to the combined effect of enhancement mechanisms such as whisker bridging, crack deflection, whisker pullout, whisker–matrix coalition pullout and whisker breakage. This study establishes the relationship between the composition and performance of high performance AAC, which is significance for the resource utilization of coal gangue and the practical engineering application of AAC. • The composition of Na 2 O·2.4SiO 2 -NaOH-Na 2 CO 3 ternary mixed activator was designed. • Calcium carbonate whisker (CW) was used to reduce the shrinkage of AAC. • The retarding mechanism of Na 2 CO 3 was clarified. • The microscopic enhancement mechanisms of CW were explored. [ABSTRACT FROM AUTHOR]

The acoustic emission (AE) technique allows monitoring damage in (reinforced) concrete in a non-destructive way by means of piezoelectric sensors attached to the material surface. This approach has disadvantages such as a decrease of the sensor coupling over time, high attenuation of AE waves in concrete, and difficulties in terms of sensor placement. Embedded AE sensors, so-called 'smart aggregates' (SA), can be a valuable addition or alternative to surface-mounted AE sensors. However, the embedment of sensors brings its own challenges. In this paper, the use of SA is investigated to monitor cracking of fiber reinforced concrete during a three-point bending test, and corrosion and related concrete cracking of reinforced concrete during an accelerated corrosion test. The novelty of the paper is the application of SA for passive AE monitoring during concrete degradation processes with a varying cracking behavior and crack orientation. Special emphasis is put on data filtering and localization of AE sources. The results show that, despite a higher level of wide-band noise for the SA sensors, they are able to detect and localize concrete cracking after dedicated filtering. Furthermore, the potential of SA sensors in early-stage detection of corrosion damage is demonstrated, offering enhanced possibilities for predictive maintenance of concrete structures. • Feasibility of smart aggregates for passive acoustic emission monitoring is studied. • Smart aggregates enable to detect and localize concrete cracks after post-filtering. • Potential of smart aggregates for rebar corrosion damage detection is demonstrated. [ABSTRACT FROM AUTHOR]

Salt-erosion effect can significantly deteriorate the serviceability of asphalt pavements in salt-rich regions. This paper aims to analyze the creep characteristics and the evolution mechanism of asphalt binder/mastic under salt-erosion conditions. The multi-stress creep recovery (MSCR) test and bending beam rheology (BBR) test were conducted to investigate the creep evolution of salt-eroded asphalt binder/mastic under different temperatures. The gel permeation chromatography (GPC) and scanning electron microscopy (SEM) were employed to analyze the creep evolution mechanism of salt-eroded asphalt binder/mastic. Furthermore, the Burgers model and Schapery model were adopted to study the viscoelastic characteristic evolution of salt-eroded asphalt binder/mastic. Results indicated that the proportion of small molecules in asphalt binder was declined, and the mineral filler coated with asphalt binder was exposed, after salt erosion. The nonrecoverable deformation of asphalt binder/mastic at high- and medium-temperature were reduced after salt erosion. Meanwhile, the percentage of recoverable strain increased with the salt freeze-thaw cycles. The low-temperature performance of asphalt binder/mastic was deteriorated after salt erosion. Following 20 times of salt erosion, the stiffness modulus of asphalt binder/mastic increased by 59.77 % and 16.47 %, respectively. Meanwhile, salt erosion can decrease the viscous components in asphalt binder/mastic, the comprehensive compliance (J c) of asphalt binder/mastic increased by 59.65 % and 16.93 %. Furthermore, the asphalt binder-mineral filler interaction was weakened after salt erosion, the Einstein coefficient decreased by an average of 18.52 %. The design and construction of asphalt pavement in salt-rich regions might be benefited from this paper. • Evaluate the creep characteristics of salt-eroded asphalt binder/mastic. • Investigate the evolution of salt-eroded asphalt binder-filler interaction. • Clarify the creep evolution mechanism of salt-eroded asphalt binder/mastic. [ABSTRACT FROM AUTHOR]

Coating mortars are essential for passive fire protection (PFP) in structures, preventing spalling. The present study explored the factors that affect the performance of mortars under fire or high temperatures through a systematic literature review. We used the Scopus database, and surveyed articles published in the past 15 years (2008–2023) resulting in 102 papers that were read completely. Most works investigated the effects of carbon nanotubes (CNTs), supplementary cementitious materials (SCMs), fibers, and phase change materials (PCMs) on the residual mechanical properties of mortars after elevated temperatures. We summarized the influence of these materials, with most results indicating that they are promising strategies to improve the fire resistance of mortars. More specifically for coating mortars, few studies have been conducted on their physical and mechanical characterization, with gaps being observed primarily in terms of thermal characterization and performance with a curing age greater than 90 days. Thus, this research contributes to the advancement of more reliable and efficient construction materials, while ensuring the safety of buildings and people. ● We reviewed 102 papers on the physicochemical behavior of mortars under high temperature. ● Coating mortars provides relevant passive fire protection. ● Carbon nanotubes (ideally less than 0.4 %) can improve mortar performance. ● Research gaps: performance with curing age > 90 days, behavior of post-fire curing. [ABSTRACT FROM AUTHOR]

Glued-in rods technique (GiR) is an attractive, yet a relatively new, option to effectively connect structural timber members. With timber buildings accounting for almost 90 % of single-storey residential buildings in developed countries, this technique could be an effective answer for the rehabilitation of aging existing timber beams, thus serving to enhance sustainability and circularity in timber construction. Compared to steel rods, the use of fibre reinforced polymer (FRP) rods could provide additional benefits due to lower weight, better corrosion resistance and lower thermal conductivity. Research on the behaviour of members bonded with Basalt FRP glued-in rods is limited. Nevertheless, until now, there is still no guidance for fabrication and design of such members with any type of FRP rods. The present paper reports an experimental programme on the ultimate performance of glued laminated (glulam) timber beams bonded with glued-in BFRP rods. The article's research significance lies in the type, rod arrangement and material of the glued-in rods connection. In particular, the article examines experimentally four connection types, with the key studied parameters being the rod diameter (8 mm and 10 mm) and the rod arrangement (D1: two rows of 2 rods each over the cross-section, one row on the tensile zone and one row on the compression zone; D2: four rods aligned vertically across the beam's depth). Four replicates were tested for each connection type, leading to a total of 16 test specimens. A four-point bending arrangement with a 2300 mm span was adopted to determine the moment capacity of the connections. Load-displacement response and failure mechanisms were monitored and evaluated. The prominent failure mode observed was bar pull-out and tensile splitting of timber. Design D1 connections with 10 mm bars exhibited the best performance in terms of moment capacity and maximum displacement at failure. The article also offers insights into the observed strain and FRP-adhesive-timber bond behaviour of GiR rods via the use of strain gauges attached to the embedded rods. Addressing the absence of design guidance for such members, the paper proposes theoretical models capable of predicting their moment capacity and the rotational stiffness. In particular, the proposed models achieved mean values of 1.15 for the moment resistance and of 0.99 for the rotational stiffness compared to the experimental data. • Glulam timber beams bonded with glued-in BFRP rods. • 16 tests under four-point bending, examining 2 rod arrangements and 2 diameters. • Proposed theoretical model for bonded timber members. [ABSTRACT FROM AUTHOR]

Engineered cementitious composite (ECC), also known as strain-hardening cementitious composite (SHCC), is attracting increasing interest in the construction industry because ECC has unique mechanical properties, crack resistance, damage tolerance, and durability. The properties of ECC have originated from the unique design philosophy for tuning the cementitious matrix, fibers, and fiber-matrix interface. To facilitate the applications of ECC in the construction industry, this paper aims at clarifying the specification, characterization, and quality control methods for ECC materials. The specification includes raw materials, processing and production methods, and key properties such as the fresh and hardened properties as well as durability. A two-stage quality control approach is presented to elucidate the quality control efforts before and during construction events. The representative ranges of ECC properties are introduced, and the methods for evaluating ECC properties and representative applications are reviewed. This paper provides guidelines for practicing engineers and facilitates the applications of ECC in the construction industry. • The specification, characterization, and quality control methods for ECC materials are reviewed. • The specification includes raw materials, processing and production methods, and key properties. • A two-stage quality control approach is presented for the construction industry. • The processing and production methods largely impact the fresh and hardened properties of ECC. • This review provides guidelines to practicing engineers for applications of ECC in construction. [ABSTRACT FROM AUTHOR]

In May 2024, this journal published the paper "Experimental and a dual-scale analysis of the influence of coating on humidity control ability of hygroscopic materials with different porosity", in which a series of hygrothermal properties of foamed concretes are primarily measured, and subsequently used in a interior-humidity-levels performance evaluation via hygrothermal simulation and buffering correlations. This post-publication discussion voices concerns on the sorption isotherm and vapour permeability measurements performed on the foamed concretes. Concerning the sorption isotherms, it is established that these differ from other results on the same materials, and their overly high 75 %RH moisture contents are doubtful. Regarding the vapour permeabilities, the execution and interpretation of the cup tests differ from the relevant standard, and plausibly an incorrect element of the set-up has been weighed. As these hygroscopic properties are the crucial factor in the hygrothermal performance simulations, the findings on that front are equally jeopardised. • This post-publication critique expresses concerns on a previously published paper. • The paper's sorption isotherm measurements deviate from other literature results. • They furthermore bring about an excessively high moisture content at 75 %RH. • The paper's vapour permeability measurements deviate from the relevant standard. • They moreover are based on weighing of the wrong element of the cup set-up. [ABSTRACT FROM AUTHOR]

Gypsum wallboards are widely used as a building material, but limitations exist in their weight and brittleness. The incorporation of various fillers in the gypsum makes them lightweight, stiff, and capable of resisting catastrophic failure but with the cost of strength. Sandwiching the filled gypsum using a low-cost material as skin may be an innovative approach to improve the flexural properties. In this work, sandwich structures were fabricated using jute fiber reinforced and unreinforced perlite-filled gypsum as cores and low-cost brown paper as skins. The density, flexural strength, modulus, and toughness of the resulting sandwich structures were investigated. It is found that the increase in perlite content in pure gypsum and jute fiber-reinforced gypsum significantly enhances the flexural strength, modulus, and toughness of the sandwich structures. However, previous research on jute fiber-reinforced and unreinforced gypsum/perlite composite panels (without skin) showed a decrease in flexural strength due to an increase in perlite content. The maximum flexural strengths of unreinforced sandwich (URS) and jute fiber reinforced sandwiches (JRS) at a perlite content of 15 g are found to be 13.29 % and 40.79 % greater than the control sandwich with pure gypsum core. The maximum flexural toughness of the JRS at a perlite content of 20 g and that of the URS at a perlite content of 15 g are respectively 118.31 % and 79.14 % greater than the control sandwich. A significant difference in load-displacement curves between JRSs and URSs is noticed despite the similar failure sequence i.e. core cracking→skin yielding→skin tearing. [Display omitted] • Sandwich structures were fabricated using gypsum/perlite composite and paper skin. • Flexural strength increased due to the addition of perlite & jute fiber in the core. • The optimum perlite contents in URS and JRS cores are 3.53 % and 3.61 % respectively. • Flexural strength and toughness of JRSs are greater than those of URSs. • URSs and JRSs showed unique load-deflection curves despite identical failure modes. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced polymer (CFRP) tendons possess significant potential for applications in civil engineering, owing to their exceptional mechanical properties. Achieving effective anchoring of CFRP tendons is a crucial factor in promoting their engineering applications. In this paper, a novel mechanical integrated wedge-type anchorage system consisting of two components, a single-channel integrated sleeve-wedge and a steel barrel, has been proposed to achieve the anchorage of CFRP tendons. The internal stress distribution and anchoring performance of the proposed anchorage system were analyzed using the finite element (FE) method. Furthermore, this paper focused on the transverse damage of CFRP tendons caused by the wedges, proposing a design method based on transverse damage control. The effects of the slope angle of the integrated sleeve-wedge, the presetting force, anchorage length, and the differential angle on the slip behavior of the anchorage system and the degree of transverse damage to CFRP tendons were investigated. Ultimately, the anchoring performance of the optimal design was experimentally validated. The results show that the design of the proposed anchorage system necessitates careful consideration of damage to CFRP tendons induced by stress concentration around wedge slits. The matrix failure index F I FT of the LaRC05 failure criteria proves effective in evaluating transverse damage under complex stress conditions. The average tensile strength of the anchorage system for the 5 mm CFRP tendons was 2565 MPa, exceeding the guaranteed tensile strength value of 2513 MPa. The anchorage system successfully achieved the desired explosive failure mode for CFRP tendons. This attests to the feasibility of the design concept of the proposed anchorage system and underscores the necessity of incorporating transverse damage control in the design approach. • A novel mechanical integrated wedge-type anchorage system (NMIWTAS) for CFRP tendons was designed. • The design concept of NMIWTAS was validated through finite element (FE) method and anchorage test. • The matrix failure index of Larc05 failure criteria can be used to evaluate the damage degree of CFRP tendons. • The NMIWTAS based on the damage control method can achieve the anchor efficiency of 102 %. [ABSTRACT FROM AUTHOR]

A novel strengthening scheme of high-strength stainless steel wire rope (HSSSWR) meshes reinforced engineering cementitious composite (ECC) jacket was used to strengthen the reinforced concrete (RC) short columns in this paper. The seismic performance of short columns after being strengthened was investigated, considering the changes in the strengthening scheme, and the spacing of lateral HSSSWRs. The failure mode, hysteresis behavior, envelope curve, ductility, energy dissipation, stiffness degradation, and strength degradation were introduced specifically based on the analysis of six full-scale short columns. The test results show a significant enhancement in the seismic performance of the strengthened short columns, especially in ductility and energy dissipation, which were increased by 49.4–98.4 %, and 149.3–713.2 %, respectively. The placement of HSSSWRs in ECC jacket proved to be effective in enhancing the strengthening effect of the jacket. A prediction model for the shear capacity of the strengthened columns was proposed using the Modified Compression Field Theory (MCFT), and the predicted results were in good agreement with the test results presented in this paper and in relative study. • The RC short columns were strengthened by different ECC jacket and corresponding cyclic loading tests were conducted. • The influence of different ECC jackets on seismic improvement of short columns was revealed. • The prediction model based on the MCFT was proposed to predict the shear capacity of strengthened columns. [ABSTRACT FROM AUTHOR]

Self-heating electrically conductive cementitious composites (ECCCs) represent an innovative advancement in civil engineering materials, offering a variety of functionalities including deicing, electrical curing, and facilitating concrete casting in cold weather. This paper presents a comprehensive review of self-heating ECCCs, focusing on electrical/ohmic curing and deicing. After an in-depth review of previous research, effective dispersion techniques, such as combinations of surfactants and admixtures, were found to be critical for establishing robust electrical conductivity and self-heating performance in ECCCs. The study also shows that the self-heating performance of ECCCs is influenced by several factors, such as filler properties, mixture design, moisture content, temperature, and curing conditions. The effects of moisture are controversial; while some studies suggest it improves self-heating, others indicate that it may disrupt conductive pathways through unwanted hydration. Generally, this paper presents an overall review of self-heating ECCCs research ranging from the raw materials, fabrications, mechanisms, and test methods to case studies on their performances. Finally, remaining issues and future directions for the advancements of ECCCs to extend their applicability are discussed. • The use of self-heating ECCCs for deicing and electrical curing was discussed. • Effective filler dispersion is crucial for electrical and self-heating performance. • Percolation thresholds, contact resistance, and tunneling enable resistive heating. • Optimizing combinations of surfactants and admixtures is essential for effective dispersion. • Various factors influencing self-heating performance were examined. [ABSTRACT FROM AUTHOR]

Uniaxial compressive strength (UCS) is of great importance for building stone. Index tests have been widely used to quickly predict UCS due to the cumbersome and expensive measurement of UCS. The paper presents a state-of-the-art review of the current understanding of those index tests. Emphasis is placed on recording the four frequently used point load, Schmidt hammer, sound velocity and Brazilian test. In particular, those four index tests are initially introduced by exhibiting experimental apparatus and standard testing methods. This is followed by a review of various corresponding methods (including regression analysis, machine learning, and numerical simulation) for correlating UCS to index tests. Subsequently, the paper provides a summary of validity studies of index tests in the UCS estimation by eliminating the effects of rock heterogeneity. Also, how index tests and their correlations with UCS respond to the rock heterogeneities is examined to know the reliability of estimated UCS. Then, the possibility of unifying the numerous correlations for predicting UCS via index tests is explored based on the previous mass data. Throughout the presentation, the current overall gaps in understanding four index tests are identified by the research community in an attempt to stimulate further research in these promising directions. • A State-of-the-art review on the studies of index tests for predicting UCS is presented. • Emphasis is placed on the correlations between UCS and index tests, as well as validity and reliability of index tests. • Possibility of unifing the numerous correlations between UCS and index tests is explored. • Limitations of current understanding of predicting UCS via index tests are discussed. • Recommendations are presented for future research. [ABSTRACT FROM AUTHOR]

Grouting is one of the most commonly used methods in water disaster treatment in fractured rock mass under high temperature. When slurry with normal temperature diffuses in fractured rock under high temperature, slurry rheological properties actually undergo complex changes under the combined effects of time and heat exchange. This is especially true for quick setting slurry, whose rheological properties vary with time dramatically. However, most of the studies on slurry rheological properties are based on normal temperature or constant high temperature and there are few reports considering heat exchange, which cannot provide a scientific basis for effective grouting control in deep buried tunnel engineering. Therefore, study on rheological properties of quick setting slurry considering heat exchange was conducted in this paper. Firstly, time-varying equations of slurry temperature during grouting process were derived. Secondly, a characterizing method of slurry rheological properties considering heat exchange was proposed. Finally, a stepwise algorithm was developed and a grouting simulation test under high temperature was carried out to verify the proposed method. Here we show that heat exchange between slurry and surrounding rock has a significant influence on the rheological properties of quick setting slurry, which in turn affects the grouting pressure as well as the distribution of slurry pressure. Ignoring the influence of heat exchange process and calculating the slurry rheological parameters under constant high temperature would lead to an overestimation of grouting pressure. The calculation error was as high as 48 %. On the other hand, ignoring the influence of heat exchange process and calculating the rheological parameters under constant low temperature would lead to an underestimation of grouting pressure, with an error of 38 %. Comparison results show that experimental slurry temperature corresponded well with theoretical values, which verified the reliability of time-varying equations of slurry temperature. Theoretical curves of slurry pressure and grouting pressure considering heat exchange were in good agreement with the experimental values. The errors were within 10 %, which verified the accuracy of characterizing method proposed in this paper. • Time-varying equation of slurry temperature considering heat exchange was derived. • A characterizing method of slurry rheology under high temperature was proposed. • A grouting simulation test under high temperature was carried out. [ABSTRACT FROM AUTHOR]

The repeated failure of repaired interface in steel bridge deck pavement (SBDP) under complex service environment makes SBDP maintenance challenging. The primary objective of this paper was to figure out the impact of seepage on repaired interface failure, addressing the secondary damage on SBDP after distresses maintenance. A uni-body bi-material structure (UBS) specimen was fabricated to simulate the repaired interface. Besides, a simulation experimental device of hydrodynamic scouring action was put forward to evaluate the effect of cycle numbers on failure behavior of repaired interface during an indirect tensile test. In addition, numerical simulation analysis was conducted to determine the tensile stress characteristics of repaired interface under load-seepage coupling effect. Findings revealed that the failure state of repaired interface may change from brittle fracture to large deformation damage under seepage effect. The longer the duration of hydrodynamic scouring action, the more serious damage of the repaired interface, with 540 cycles resulting in an approximately 25 % reduction in interface strength. Furthermore, the stress condition of repaired interface is significantly worse when consider the coupling effect of load and seepage, approximately 40 % greater than that of a single load action. And it is closely related to its relative position with the orthotropic steel bridge deck and the actual stress conditions. The research findings presented in this paper can serve as a theoretical foundation for SBDP maintenance. • The interface failure is affected by the properties of materials on both sides. • The seepage effect results in the failure state from brittle to large deformation. • The seepage effect may lead to a sharp decline in repaired interface strength. • The interface suffers from much severe stress condition under seepage effect. [ABSTRACT FROM AUTHOR]

Compaction construction is one of the most critical factors affecting road performance and durability. To improve the construction quality and service life of road, intelligent compaction (IC) technology has received continuous attention. In contrast to traditional compaction construction, IC improves the compaction quality and uniformity of each road layer through real-time monitoring and adjustment of the compaction process. Intelligent compaction measurement values (ICMVs) were proposed to provide quantitative indexes for compaction quality monitoring and basis for dynamic regulation of compaction conditions. However, the current ICMVs have problems such as low accuracy and stability, and poor applicability under different working conditions, which limit the application of IC technology. To address these shortcomings, this paper conducts a state-of-the-art review of ICMVs, outlining the past research achievements and discussing future development directions. In this paper, the vibrating dynamical models of compaction was firstly summarized and the future research directions are proposed. Next, the existing calculation models of ICMVs are systematically investigated and the significant factors that affected ICVMs calculations are summarized. Solutions to eliminating influences from those factors are discussed in further, e.g., by a combined effort in improving calculations models for ICMVs and advancing the multiple regression analysis method. • The article reviews the dynamical models of intelligent compaction. • The review article compares the calculation methods of five different ICMV models. • The review article examines significant factors that affect the ICMVs and their influcial mechanisms. • Suggestions for future research on ICMVs in subgrade and pavement construction are drawn. [ABSTRACT FROM AUTHOR]

In this paper, the anchorage mechanism and bearing capacity of the special type of pawl bolt anchored in concrete under uplift load were studied. Static tests were carried out on two typical pawl bolts, namely 135° and 180° pawl bolts, and the effects of anchorage depth and pawl type on their failure modes were studied. The experimental results show that the uplift bearing capacity of pawl bolt is improved more effectively than that of smooth bolt. The two typical failure modes of pawl bolts under uplift load are concrete breakout failure and bolt yield failure. The concrete breakout failure exclusively occurs with anchorage depth of 5 d , while the failure mode could change from concrete breakout failure to bolt yield failure with the increase of anchorage depth. The finite element model was established to elucidate the failure mechanism of anchorage bolt and concrete. The crack propagation and diffusion angle distribution of anchorage concrete can be directly judged by concrete tensile damage and stress vector in simulation analysis. Additionally, a calculation method to accurately predict the uplift bearing capacity of pawl bolt was proposed, which considered the effect of diffusion angle θ i on the uplift bearing capacity and further discusses the change law of cone diffusion angle θ i and concrete crack propagation. The calculated results exhibited a concordance with the experimental and numerical results, which shows that the formula presented in this paper can be considered reliable and can guide the practical engineering design. ● Studied design params' impact on pawl bolts force transfer mechanism and concrete cone diffusion angle. ● Examined concrete crack behavior under uplift load for pawl bolts. ● Proposed spatial angle-variation elliptic concrete cone calculation model for pawl bolts based on cone diffusion angle. [ABSTRACT FROM AUTHOR]

Currently available permafrost protection techniques do not pay enough attention to the properties of asphalt pavement, and the problem of strong heat-absorbing asphalt pavement and permafrost constraining each other is a global challenge that needs to be urgently addressed. Phase change materials (PCMs) can regulate the operating temperature of pavement structures by storing and releasing large amounts of heat during phase changes. In this paper, composite shaped phase change material (CSPCM) was applied to the permafrost region of Qinghai-Tibetan Plateau, and a new method of phase-change pavement structures with gradient low-thermal conductivity was proposed to reduce the heat absorption of the pavement and realize the active protection of permafrost. The structures were designed based on finite element software, and the heat flux and temperature distribution within the structure were analyzed and verified with indoor and outdoor thermal regulation tests. Results showed that the preferred gradient low-thermal conductivity structure reduced the annual net heat absorption at the top of the pavement by 8.18 %, the heat absorption in summer by 7.65 %, and the heat release in winter by 6.75 % compared with the control group. The heat flux and the temperature distribution within the pavement structures were significantly altered by the phase-change asphalt pavement structures with gradient low-thermal conductivity, and the simulation results of the finite element model agreed well with the results of the indoor and outdoor thermal regulation tests. The temperature regulation factor (RT) was proposed as an evaluation index to quantitatively analyze the temperature regulation performance of CSPCM on the pavement structure, and the results showed that the flexible base layer had the greatest influence on the temperature regulation performance of the pavement structure. The phase-change asphalt pavement structures with gradient low-thermal conductivity proposed in this paper is a structure that has an efficient cooling effect on the interior of the pavement, and provides a new idea for improving the stability of permafrost subgrade and the integrated design of materials and structures in permafrost regions. • CSPCM and thermal induction can be combined to protect permafrost in permafrost regions. • Finite element model is established, and the regulation ability of phase-change pavement structure is studied. • Finite element numerical simulation analysis agreed with the experimental test. [ABSTRACT FROM AUTHOR]

Historical masonry arch bridges constitute the backbone of many existing transportation networks in different countries in Europe and worldwide. They represent valuable cultural heritage assets and play an essential social and economic role. Since construction, old masonry bridges have accumulated structural damage from traffic and environmental actions. Furthermore, depending on their geometrical and mechanical characteristics, they may be particularly vulnerable to extreme events like earthquakes. Thus, accurate structural assessment under different loading conditions is critical for the conservation of these structures. Realistic assessment requires suitable numerical models to represent the characteristic 3D behaviour. The complexity of this task is further compounded by the practical difficulty in obtaining essential information on the internal bridge structure and the masonry mechanical parameters, which are vital to achieve accurate response predictions against service and extreme actions. This paper presents an advanced calibration procedure for a refined macroscale bridge model, allowing for the anisotropic nature of the masonry material. The proposed calibration approach is applied to an actual multi-span masonry viaduct, where sonic, ultrasonic, and ground penetrating radar tests are conducted to investigate the internal structure of the viaduct and determine the elastic properties of the masonry materials. In addition, the dynamic characteristics of the bridge are evaluated through in-situ measurements under environmental vibrations and used for model validation. The results from a standard simplified model calibration and an enhanced calibration are compared considering the vibration modes of the bridge. Simplified calibration is carried out using the results from in-situ tests, while a statistic inference procedure and numerical optimisation are adopted in the refined calibration to achieve improved accuracy. Although the paper focuses on a specific case study, the adopted methodology can be easily applied to studying other masonry bridges and cultural heritage masonry structures. • An advanced calibration procedure for a refined bridge macroscale model is presented. • The proposed calibration approach is applied to a multi-span masonry viaduct. • In-situ non-destructive tests are used to evaluate the internal structure of the bridge and the elastic material parameters. [ABSTRACT FROM AUTHOR]

In this paper, a new model for chloride diffusion in cracked concrete is presented. The model was developed within a standard continuum damage mechanics framework but newly considers both an irreversible damage variable and a strain field, gaps identified through a literature review, offering a more comprehensive description of the diffusion-like processes in concrete with small and moderate cracks than current models. The model utilizes a realistic dependence for the diffusion coefficient on the damage state and employs a bi-logistic mapping function or an S-curve mapping function to effectively describe the non-linear effects of cracks on diffusion in concrete. The dependence on the strain field introduced by this model not only allows examination of diffusion in opening cracks, it also enables the process of crack closing to be simulated, whatever the irreversible damage variable may be. This paper also proposes a novel calibration procedure for experimental testing involving the use of the Brazilian splitting test on samples enclosed in a steel ring. This innovative approach simplifies the process of creating a portfolio of cracks with varying widths. In the calibration tests described here, samples were subjected to natural diffusion while chloride content was monitored in inlet and outlet chambers attached to the samples, eliminating the need for laborious chloride profiling. Our in-depth examination of chloride diffusion in cracked concrete is applicable to analyses of corrosion in steel-reinforced concrete structures worldwide, with the new calibration procedure offering a straightforward method for populating the model with realistic material parameters, thus providing a valuable tool for accurately predicting chloride penetration in real-world scenarios. • Development of a new continuum model for diffusion in damaged concrete. • Modeling of increased diffusion in cracks and the decrease during crack closure. • Constructing a non-linear mapping function for damage and equivalent strain. • Developing new calibration based on natural diffusion in cracked samples. • Identifying the bi-logistic function as the best candidate for solving real-world scenarios. [ABSTRACT FROM AUTHOR]

In March 2024 Construction and Building Materials published "Water distribution characteristics of capillary absorption in internally cured concrete with superabsorbent polymers", which claims to present a water distribution model characterising the spatiotemporal moisture content evolution in internally cured concrete with superabsorbent polymers during capillary absorption. This discussion, considered a post-publication critique, establishes that the paper's water distribution model conflicts with the paper's capillary absorption tests. While the model is based on the premise of the square-root-of-time behaviour of capillary absorption, the tests do not demonstrate that square-root-of-time behaviour. This critique in addition questions the paper's forthright application of the power-law diffusivity expression with exponent 4, given that its validity for the paper's materials has not been verified. It is shown that different but equivalent diffusivity expressions lead to different moisture diffusivities at lower moisture contents. • This post-publication review formulates concerns on a previously published paper. • The paper's water distribution model and capillary absorption tests are in conflict. • The paper's adoption of an unverified moisture diffusivity expression is doubtful. [ABSTRACT FROM AUTHOR]

Recycled Aggregate Concrete (RAC) has attracted considerable attention for its potential to conserve natural resources and mitigate carbon emissions. Nevertheless, the widespread adoption of RAC in the construction industry faces challenges associated with its inherent performance deficiencies, including the formation of pores and microcracks in the recycled aggregate (RA) generated during the crushing process, as well as the presence of dual interfacial transition zones (ITZ) within the internal structure of RAC. The incorporation of fibres as reinforcement offers a promising solution to improve the performance of RAC. The paper begins with a comprehensive examination of various fibre properties and recycled aggregates. Then, summarizing the impact of fibres on RAC's performance. Special emphasis is placed on analyzing the influence of mixed fibres on the mechanical properties of RAC. The introduction of a blend of low-strength and high-strength fibres demonstrates the potential for further improving the mechanical properties of RAC beyond the benefits offered by individual fibres. This blending strategy also enhances the multiscale crack resistance of RAC, attributed to the collaborative effects of various fibres at different load stages. The reinforcing mechanism at the micro-scale of RAC is also discussed. Finally, the paper outlines perspectives for future research. [Display omitted] • A comprehensive review of hybrid fibre reinforced recycled aggregate concrete. • The effects of a single type of fibre on mechanical properties and microstructure. • Combining high-strength and low-strength fibres shows positive effects. • Blended fibres induce a dense C-S-H gel phase, enhancing cracking resistance. • The economic and environmental impacts are discussed. [ABSTRACT FROM AUTHOR]

This paper presents a series of experimental investigations into the flexural fatigue performance of rubberised concrete (RuC). A detailed account of fatigue response of reference conventional concrete materials (CCM) and RuC under flexural loading is presented. The experimental arrangement is described as well as the constituent materials, and the volumetric rubber replacement ratio of both fine and coarse aggregates varies between 0 % and 20 % in this study. The effect of three different stress ratios (R = 0.1, 0.3 and 0.5) on the flexural fatigue response are studied. It is found the static flexural strength of RuC with the rubber contents (ρ rv) of 10 % and 20 % show a reduction of 12 % and 24 % compared to their counterpart of CCM, respectively. A stress level of 0.9 is embedded in this study while despite the uncertainty of fatigue life of concrete materials, the increase of stress ratio from 0.1 to 0.5 lead to an increase of fatigue life of RuC in general. It is notable that the inclusion of rubber in concrete increases the fatigue life uncertainty whereas significantly increases the fatigue life of RuC at the same time, i.e. the average fatigue life of RuC with 20 % rubber content shows an increase of 170 % compared to its counterpart of CCM when R = 0.5. Based on the experimental results in this study, a series of three-parameter Weibull distribution models are proposed to describe the failure probability of RuC under fatigue flexural loadings, which consider the effects of ρ rv , stress ratio, stress level, and loading frequency on the probability of failure (PF) of RuC. This paper presents the attempt to investigate the possibility distribution of fatigue life of RuC, and all numerical calculation curves are in good agreement with the experimental results carried out in this study. • Flexural strength and fatigue behaviour of conventional and rubberised concrete were tested. • Cyclic flexural tests at different stress ratios were carried out. • The fatigue life probabilistic model of rubberised concrete is established. • The three-parameter Weibull distribution is introduced as a cumulative failure model. • Effect of stress ratio and rubber content is included. [ABSTRACT FROM AUTHOR]

During coal preparation, a substantial volume of coal gangue (CG) is generated, leading to severe environmental and health concerns stemming from its massive accumulation. Comprehensive research has been conducted on the utilization of CG in various engineering applications. Transforming it into supplementary cementitious material (SCM), geopolymer, and concrete aggregate holds pivotal significance in engineering applications, aligning with the imperatives of sustainable development. However, there are notable deficiencies in current research related to the grading, categorization, and standardization of CG for its optimal utilization based on its basic properties, which need to be addressed for further study and development. This paper takes the mineral composition of CG as a starting point, delving into an analysis of physical and chemical characteristics determined by the composition. Based on these characteristics, the effects of five main activation methods including mechanical, chemical, thermal, microwave, and composite treatments are comprehensively reviewed with a focus on their interaction mechanisms with CG. Subsequently, the fresh properties, mechanical properties, and durability of cementitious materials and aggregates prepared by CG were summarized and analyzed. Research suggests that contingent upon the degree and purpose of treatment (activation), CG can be applied in SCM (partially replacing cement), geopolymer (completely replacing cement), and concrete aggregate, with distinct treatment conditions influencing its engineering characteristics. This paper offers a systematic perspective and insights into the high-capacity utilization and value-added applications of CG. It highlights the issues encountered in the utilization of CG while further providing novel perspectives for its scaled utilization in engineering. [Display omitted] • Utilization of coal gangue in engineering is an ecological and sustainable way. • The pretreatment intensity varies across different utilization methods. • Progressed coal gangue exhibits excellent engineering utilization effect. • Numerous issues were identified, and some suggestions were proposed. [ABSTRACT FROM AUTHOR]