Concrete, as a widely used construction material, suffers from performance degradation due to chloride penetration and sulfate attack in harsh environments. Conventional performance-enhancing methods are costly and emit high levels of carbon dioxide. This study modified graphene oxide (GO) with polycarboxylate superplasticizer (PCE) alone or PCE synergized with a rubber viscosity reducer, optimized dispersion (50 degrees C water bath for 1 h), and prepared C50 modified concrete (500 kg/m3 cementitious materials, w/b = 0.33). GO contents were 0%, 0.001%, 0.003%, 0.005%; a group with 8% reduced cementitious materials (460 kg/m3) was also tested. Results showed PCE-viscosity reducer synergy better dispersed GO, improving concrete workability. GO accelerated cement hydration via nucleation, refining C-S-H gel and reducing porosity. At 0.005% GO, 56 d drying shrinkage dropped by 29.3% vs. the blank, and 56 d chloride penetration electric flux was 586 C, meeting 100-year service life. Sulfate resistance also improved with higher GO content. Even with 8% less cementitious materials, modified concrete outperformed the blank. This provides support for GO's application in cement-based materials.

In-situ polymerization is an effective approach to enhance the toughness of cementitious materials; however, the associated hydration retardation often leads to significant compressive strength loss. In this study, low-dosage nano-silica (NS) was incorporated into in-situ polymerization-modified cement systems (IPMCs) to regulate hydration kinetics and strengthen the polymer-cement interaction. Calorimetry, phase analysis, polymerization characterization, and microstructural observations revealed that 0.2% NS markedly accelerated hydration and increased the overall reaction degree. Consequently, the 28-day compressive and flexural strengths increased to 50.17 MPa and 17.73 MPa. These enhancements stem from the synergistic effects of NS, including its nucleationinduced hydration acceleration, pozzolanic production of additional C-S-H, and refinement of pore structure. Moreover, hydrogen bonding between NS and polymer chains increased the polymer network's crosslink density, while C-S-H formed from NS-driven rehydration bridged with polymer chains via Ca2+, reinforcing the organicinorganic interface. This coupled mechanism effectively offsets the hydration inhibition caused by polymerization and provides new insights for designing high-performance polymer-cement composites.

Gas-liquid cyclone separators are widely used in various industrial processes. To reduce energy loss in traditional cyclone separators and enable their application in chemical absorption-based CO2 capture systems for recovering liquid droplets from flue gas, this paper proposes a slot-type outflow pipe cyclone separator. Building upon existing research on slotted outflow pipes, this study optimizes the slot configuration and investigates how different slot angles affect separator performance. An innovative control group was established to determine whether the presence of a through-hole at the bottom of the outflow pipe impacts the separator's applicability. The RSM model simulates the gas-phase flow field, while the DPM model, within the multiphase framework, tracks droplet particles. Results show that the slotted outflow pipe structure not only reduces static pressure appropriately but also optimizes pressure distribution and turbulence intensity, enhances flow field stability, and suppresses the short-circuit flow phenomenon. When the bottom of the outflow pipe is unsealed and the groove angle is 90 degrees, cutting particle size and Critical particle size reach optimal values, with reduction rates of approximately 20 % and 23 %, respectively, compared to the Lapple-type. The pressure drop reduction is about 3.3 %. At a constant liquid concentration of 8.1 g m-3, the intake volume reaches 22.56 m3 h-1, yielding a separation efficiency of 80 %. At an intake volume of 34.21 m3 h-1, the separation efficiency increases to 89.35 %, with a lower pressure drop than for the other two outflow pipe configurations.

The widespread use of Portland cement (OPC) has driven a continuous rise in CO2 emissions within the construction sector, posing a significant threat to the global climate. Low-carbon cements enriched in C3S2 and CS hold promise for drastically reducing CO2 output in the cement industry; however, the inherent lack of hydraulic reactivity in C3S2 and CS limits their practical application. Carbon capture, utilization, and storage (CCUS) technologies can rapidly enhance the mechanical performance of C3S2 and CS, thereby unlocking new avenues for low-carbon cement utilization. In this study, we evaluate the degree of carbonation and the post-curing compressive strength of low-calcium sulfoaluminate cements (C3S2/CS-C4A3 S) with varying C3S2 and CS contents under CO2 curing. The carbonation products, carbon sequestration capacity, micro-structural features, and pore architecture are characterized by XRD, TGA, SEM, and MIP analyses. The results indicate that when the C3S2 and CS contents reach 80 wt %, both the C3S2-C4A3 S (C1.5-80) and CS-C4A3 S (C-80) cements exhibit high carbonation rates and excellent mechanical performance. Specifically, the compressive strengths (CO2 sequestration capacities) of C1.5-80 and C-80 reach 46.64 MPa (0.16 g CO2/g) and 44.72 MPa (0.16 g CO2/g), respectively. XRD and SEM analyses reveal that the CaCO3 polymorph distribution strongly depends on the Ca/Si molar ratio of the silicate clinker: in the C3S2-C4A3 S system, aragonite and vaterite coexist with aragonite predominating, whereas in the CS-C4A3 S system vaterite is dominant, with only minor aragonite. This study thus provides valuable insights into the formulation, property tuning, and carbonation-curing efficiency of C3S2/CS-based cements, offering a practical reference for advancing carbon-neutrality in the cement industry.

Lead–zinc tailings (LZT), a low-value mining waste, pose significant environmental and health risks due to their massive accumulation. This study addresses the need for harmless and efficient treatment of LZT by successfully producing lightweight aggregates (LWA) from 100

Mixed ionic-electronic conductor (MIEC) materials have widespread applications in fuel cells, all-solid-state battery electrode interface modification materials, and memory devices. Here, we reveal the two-dimensional superionic conduction between graphene-like B-C layers in the Ca-B-C (Ca2BC11, CaBC5, CaB2C4, and CaB3C3) compounds. Through molecular dynamics simulations driven by high-precision machine learning potentials, which can be tuned within the range of 900-2100 K with defect concentrations as high as 4.8 %. We discovered that the vacancy mechanism between the hexagonal prism drives its superionic diffusion. The ratio of B and C within the framework can modify the covalent (ICOHP) and ionic (Bader) interactions between the compound and Ca2+, along with the interlayer spacing, thereby significantly influencing the superionic transition temperature. Furthermore, the superionic behavior across multiple phases obviates the need for synthesizing pure-phase materials. With excellent thermal and mechanical stability, these compounds of varying compositions are prospective candidates for high-temperature-resistant electrodes and interface enhancement materials and possess potential applications in many extreme conditions.

The alkali-activated slag (AAS) system faces challenges due to its heavy reliance on commercial alkaline activators and the necessity of utilizing 100 % slag as precursor. Additionally, the substantial annual quantity of corn stalks limits disposal options for the corn stover ash (CSA) residues. This study investigates the feasibility of using CSA as a partial substitute for slag in AAS pastes. The effects of CSA calcination temperature, CSA dosage and alkali equivalent on the workability, hydration, shrinkage, and mechanical properties of AAS system with CSA are evaluated. The study indicates that incorporating CSA reduces the fluidity of AAS paste and prolongs the final setting time. Replacing 10 % ground granulated blast-furnace slag (GGBS) with CSA calcined at 600 degrees C enhances hydration and strength development, at a 4 % alkali equivalent. The 72 h cumulative heat release and the 28 d compressive strength increase by 19.9 % and 16.9 % respectively at this case. However, excessive CSA incorporation negatively impacts the hydration process of AAS system, leading a reduction of overall performance. CSA calcined at 600 degrees C exhibits the highest pozzolanic activity, providing the most significant improvements in hydration and mechanical properties of AAS paste with CSA. The results indicate that the CSA can be utilized as slag replacement in AAS paste and provides a feasible solution for the resource utilization of agricultural waste.

Ordinary Portland cement (OPC) is one of the most widely used building materials, but its hydration and setting are challenging to control on demand. In this article, phase change material (PCM) was successfully coated on the surface of sodium silicate (SS) using a facile vibration coating method to fabricate thermo-sensitive SS@PCM (SP) microcapsules. The microcapsules were utilized to accelerate the hydration and setting of cement paste using heat as a trigger on demand. The results showed that PCM powder can be melted and uniformly coated on the surface of SS to form a core-shell structure, and the heat-triggering temperature of SP microcapsules reached 60 degrees C. Before heat triggering, the PCM acts as a barrier preventing SS from reacting with OPC so that a long setting time, high fluidity and extremely low dynamic yield stress could be realized. After heat triggering, the PCM shell disintegrated, followed by the release of SS, the accelerator. SS and residual heat accelerated the hydration of OPC, as evidenced by the rapid increase of storage modulus, the rising of loss modulus, and the decrease of loss factor in several minutes. This led to the setting time decreasing from hours to minutes, losing fluidity, and gaining high static yield stress. The PCM usage of 15 % is beneficial for early hydration within 2-4 h and early compressive strength development. A 3D printing test verified that the paste could achieve the goal of setting on demand by simple addition of SP microcapsules and application of heating.

This study presents a novel cement-based composite exhibiting dual functionality for both absorbing electromagnetic waves and storing thermal energy. The composite was fabricated by incorporating nano-silica-encapsulated phase change microcapsules (n-OD@SiO2, MPCM) and a carbonyl iron powder/amorphous carbon composite absorber (CIP@SiO2@C). Its workability, hydration kinetics, electromagnetic properties, thermal behavior, mechanical performance, and internal microstructure were systematically characterized using isothermal calorimetry (TAM), a microwave vector network analyzer (VNA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and three-dimensional X-ray microtomography (Micro-CT). The results show that the combined addition of MPCM and CIP@SiO2@C markedly enhances both thermal regulation and electromagnetic wave absorption. The composite containing 20 vol% MPCM and 10 wt% CIP@SiO2@C achieved optimal electromagnetic performance, with absorption rates exceeding 80 % across nearly the entire 2-18 GHz and surpassing 85 % within 8-18 GHz. This formulation also demonstrated outstanding thermal regulation, reducing the heating rate by 73 % compared with ordinary cement. Although its mechanical strength was slightly lower than that of plain cement, the optimized composite maintained a 28-day compressive strength of 42.6 MPa, indicating satisfactory structural integrity. The findings underscore the success of the proposed cement-based composite in electromagnetic wave attenuation and thermal management, highlighting its strong potential for applications in electromagnetic pollution mitigation and energy-efficient building materials.

The utilization of aeolian sand (AS) as a substitute for river sand (RS) in ultra-high-performance concrete (UHPC) offers a sustainable solution to address natural sand resource shortages while enhancing AS utilization. This study systematically evaluates the influence of AS content (0-100% RS replacement by mass) on the workability, mechanical properties, and microstructure of UHPC under different curing regimes. All mixtures incorporate 0.65% by volume of straight steel fibers to ensure adequate fiber reinforcement. The results reveal that the spherical morphology, smooth surface nature, and fine particle size of AS enhance the matrix fluidity and reduce the early autogenous shrinkage of UHPC. By employing steam curing at 90 °C for 2 d followed by standard curing for 7 d (M3), UHPC samples with a 60% and 80% AS substitution achieve a compressive strength of 132.4 MPa and 130.8 MPa, respectively; a flexural strength exceeding 18 MPa; a porosity below 10%; and a gel pore content exceeding 60%. The steel fiber reinforcement contributes significantly to the flexural performance, with the fiber-matrix interface quality maintained even at high AS replacement levels. These findings highlight the feasibility of AS as an alternative fine aggregate in UHPC.

Concerns regarding cost and safety have prompted an investigation into the feasibility of Ag+ ion batteries as a promising alternative to lithium-ion batteries. In this work, machine-learned force fields (MLFF) were employed to elucidate the diffusion mechanism of Ag+ ions in delafossite AgAlO2. The demonstration was made through analysis of atomic trajectories, mean squared displacement (MSD), and radial distribution function (RDF), we demonstrated that Ag+ ions diffuse through channels formed by a novel [AlO2]-sublattice. The Madelung energy analysis indicates that electrostatic interactions within the sublattices are stronger than those between the sublattices and Ag+, enabling Ag+ ions to overcome these constraints and achieve free diffusion at elevated temperatures. By introducing defects, the energy barrier was reduced from 0.547 eV to 0.337 eV, leading to a superionic transition temperature of 700 K. This work has discovered an interesting phenomenon of superionic state in delafossite AgAlO2, adding new vitality to the delafossite family.

Preparing clinker-free cementitious materials by using lithium slag (LS) as silica-alumina precursors is an effective means to address environmental issues caused by LS emission. This paper attempted to explore the feasibility of preparing LS-based supersulfate cement (SSC) and the effect of phosphogypsum type (hemihydrate phosphogypsum (HPG) and dihydrate phosphogypsum (DPG)) on the early reaction characteristics of LS-based SSC was systematically investigated. The results showed that the setting time of LS-based SSC decreased with the increase of HPG content, while increased as DPG was dosed. HPG series behaved like Herschel-Bulkley fluid, whereas DPG series fitted well with Bingham mode. In comparison with DPG, an increase in HPG dosage led to a reduction in plastic viscosity and yield stress of LS-based SSC, and consequently, a decreasing tendency in fluidity was observed. HPG could more efficiently activate the hydration of LS than DPG thus leading to a higher compressive strength. At the age of 7 d, the strength exhibited an increasing trend with the increase of phosphogypsum dosage and the maximum value of the HPG series and DPG series could reach 26.8 MPa and 16.6 MPa, respectively. It is technically feasible to prepare SSC using LS and phosphogypsum.

The thermal reactions among the decomposition phases of the hardened Portland cement paste and the TiB2 micron powders result in the surface micro-ceramization of the matrix. Since the thermal oxidation temperature of TiB2 (about 500 degrees C) overlaps with the temperature range of the main hydrates, there should be a suitable temperature interval to apply the surface micro-ceramicization effect. This study investigates the physicochemical and mechanical properties of Portland cementitious materials containing TiB2 subjected to heating protocols with maximum temperatures ranging from 300 degrees C to 900 degrees C. The compressive strength values of all samples decrease when the maximum temperature is below 300 degrees C, attributed to reduced mesopore porosity and increased macropore porosity. When the maximum temperatures exceed 600 degrees C, the compressive strength change ratios of samples containing TiB2 become positive. Compared with the original values, the compressive strength values increase by 35.3 % at 750 degrees C and 55.20 % at 900 degrees C. Both the mass ratios of TiB2 to cement and the maximum temperatures of the heating protocols jointly dominate the extent of the thermal reactions among the decomposed hydrates and TiB2 micron powders.

This study develops innovative cement-based composites with integrated electromagnetic wave absorption and thermal energy storage capabilities by incorporating Fe3O4/n-OD@SiO2@C core-shell microcapsules. These microcapsules feature a hierarchical structure consisting of a Fe3O4/n-octadecane (n-OD) composite core, an intermediate amorphous SiO2 layer, and an outer carbon coating. Structural and functional characterization using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and vector network analysis (VNA) confirmed the structural integrity and multifunctionality of Fe3O4/n-OD@SiO2@C. The results demonstrate that the incorporation of Fe3O4/n-OD@SiO2@C significantly enhances both electromagnetic wave absorption and thermal energy storage in cement-based materials. The composite containing 50 vol% expanded polystyrene (EPS), 10 wt% Fe3O4/n-OD@SiO2@C, and 5 wt% adhesive exhibits optimal electromagnetic wave absorption performance, dissipating 80 % of electromagnetic wave absorption rate across the 8.5-18 GHz frequency spectrum. Simultaneously, this formulation demonstrates exceptional thermal regulation capabilities, decreasing the heating rate by 90.6 % compared to conventional Portland cement. While the addition of EPS and micro-capsules leads to a reduction in compressive strength, the composite still meets non-load-bearing structural requirements while enabling simultaneous electromagnetic wave absorption and thermal energy regulation. These findings highlight the potential of this material for advanced building envelopes in energy-efficient infrastructure, offering dual electromagnetic and thermal management capabilities.

This work aims to develop a green, cost-effective ultra-high performance concrete [UHPC] by utilizing titanium slag. The impact of ultra-fine titanium slag on the hydration process, mechanical properties, and microstructure of UHPC was systematically investigated by employing various testing methods including hydration heat and mechanical property assessments, along with microscopic analysis techniques such as XRD, TG, microhardness and pore structure analysis. The findings indicate that substituting granulated blast furnace slag with ultra-fine titanium slag accelerates the reaction in UHPC, accelerating the formation of hydration products. The ultra-fine titanium slag demonstrates exceptional performance in optimizing the pore structure, enhancing the interfacial transition zone of UHPC, and increasing the paste microhardness. UHPC mixed with ultra-fine titanium slag exhibits superior mechanical properties compared to the control sample, with these properties initially increasing and then decreasing as the content of ultra-fine titanium slag increases.

Oily sludge, a hazardous byproduct of oil processes, poses significant environment and human health when improperly managed. This study examines the thermal behavior and gaseous emissions during co-combustion of oily sludge modified with waste tire powder (OS7-T3) and coal, using an automatic calorimeter and along with kinetic modeling. Additionally, the synergistic effects of co-combustion, as well as the gas emissions under varying oxygen concentrations, heating rates, and the influence of additives, were thoroughly examined. The results indicate that an increase in OS7-T3 content leads to a reduction in the performance of mixed fuel. When the OS7-T3 content reaches 30 %, the calorific value of combustion exceeds 20 MJ/kg, with no substantial decrease in the combustion index. The application of additives effectively mitigates pollutant gas emissions. Increasing the heating rate from 5 degrees C/min to 20 degrees C/min significantly enhances combustion performance, improving it by 4.19 times. Likewise, an increase in oxygen concentration from 10 % to 100 % results in a 2.97fold increase in the combustion index. Montmorillonite reduces the emissions of pollutant gases by absorbing polar molecules. BaO and CaO effectively mitigate H2S and SO2 emissions but have limited influence on the control of NO and NO2 emissions. These findings strongly support the co-processing of oily sludge in cement kilns, facilitating its environmentally friendly disposal and promoting efficient resource utilization.

Materials that effectively facilitate the transport of ionic and electronic charges are crucial for advancing technological innovations in next-generation energy storage devices. This work proposed a new class of high-performance mixed ionic-electronic conductors (MIECs) in graphite intercalation compounds with the composition XC6 (X = {Ca, Sr, and Ba}) using molecular dynamics based on machine learning force fields combined with first-principles calculations. The calculated mean squared displacement and radial distribution functions indicate that CaC6, SrC6, and BaC6 transition to the superionic state at temperatures of 1500, 1800, and 2100 K, respectively. Alkaline earth metal cations can diffuse through two pathways via the vacancy migration mechanism: they can either move across carbon-carbon covalent bonds or migrate to the position above a carbon atom, subsequently diffusing to the center of an adjacent carbon hexagon. Additionally, these materials exhibit high ionic conductivity and excellent thermal and mechanical stability. The results suggest that the introduction of defects effectively regulates the superionic transition temperature, and CaC6 with 10% defects achieves a conductivity of approximately 0.05 S cm-1 at 550 K. We provide a new prospect from the perspective of ion dynamics to design advanced MIECs as high-temperature-resistant electrodes and interface improvement materials.

Viscosity modifier admixtures (VMAs) are essential for 3D printing materials, but commonly used organic VMAs often compromise the mechanical properties of gypsum-based materials. To address this, three inorganic VMAs-attapulgite (ATP), sodium bentonite (NB), and nano-silica (NS)-were systematically compared with hydroxypropyl methyl cellulose ether (HPMC) to evaluate their applicability in 3D printing gypsum building materials. The results showed that ATP, NB, and HPMC reduced slurry fluidity, while NS enhanced it at low dosages. All VMAs significantly increased yield stress but inorganic VMAs had minimal impact on plastic viscosity. Although the addition of VMAs reduced 2-h wet strength and compressive strength, inorganic VMAs caused significantly less reduction than HPMC. NS and HPMC lowered the hydration exotherm peak, with NS accelerating its occurrence. At 1 % dosage, NB and ATP reduced the maximum exothermic peak, but higher dosages caused earlier and higher peaks. Microstructural analysis revealed that 5 % NS resulted in short, thick gypsum crystals, while 0.5 % HPMC led to curly flaky structures. Compared to HPMC, NS excelled in enhancing mechanical properties, NB improved workability and mechanical performance, and ATP demonstrated superior workability, mechanical properties, and printing performance. These findings highlight the potential of inorganic VMAs for developing high-performance 3D printable gypsum materials.

Nanowire composites have attracted much interest recently owing to the experimental demonstrations of many tempting potential applications based on the excellent electrical, thermal and mechanical properties. The critical role of interfacial resistance in nanowire composites has long been recognized, as evidenced by experimental studies dating back several decades showing its dependence on filler size and contact density. While the importance of these effects is well established, many modeling approaches still simplify the problem by assuming ideal nanowire contacts or treating interface resistance through empirical corrections. In this study, we propose a physically consistent model that incorporates interfacial electrical and thermal resistances based on transport physics at nanoscale junctions, and examine their influence on percolation-driven transport. In this study, we develop a physics-based framework that explicitly models interfacial electrical and thermal resistances and reveals their critical role in percolation-controlled transport. However, in the present study, we show that calculated electrical and thermal conductivities are orders of magnitude higher than experimental results when interfacial resistances are ignored. These resistances are not purely contact resistances but stem from rough nanowire junctions, suppressed tunneling, and local potential barriers. By modeling these effects through a square potential barrier approach, we introduced interfacial resistances into the calculations, we find the obtained electrical and thermal conductivities match well with experiments in a wide range of nanowire concentration. Our study evaluated and modeled the effect of interfacial thermal resistance in nanowire composites, and the results demonstrated a dominant role of interfaces on electrical and thermal properties.

The application of a single internal curing material is incapable of effectively balancing shrinkage inhibition and strength development. This paper investigated the effect of nano SiO2-modified superabsorbent polymer (SAP-n) synergized with rice husk ash (RHA) on the shrinkage and mechanical properties of cement pastes. The water desorption process of the SAP-n/RHA composite within cement pastes was characterized using 1H NMR, isothermal calorimetry, and internal relative humidity. Moreover, the hydration kinetics and microstructure of internally cured pastes were revealed. The results demonstrated that the addition of RHA reduced the amount of water released from hybrid system before the final set, and accelerated the desorption rate of SAP afterward, effectively mitigating self-desiccation. A "three-stage" gradient water release model of SAP-n/RHA composite driven by osmotic pressure and humidity differences was proposed. The porous RHA was uniformly distributed in the matrix, especially around the SAP, contributing to internal curing at later ages while providing extra silica to repair voids and densify the pore structure. Compared to pastes containing commercial SAP, the 91-day dry shrinkage of specimens with 0.2 wt% SAP-n and 3.6 wt% RHA was reduced by 16.1 % without compromising autogenous shrinkage inhibition efficiency, and the 28-day strength was increased by 20.6 %.