We optimized the gradation of cold recycled mixture (CRM) based on low-temperature performance. Firstly, the low-temperature crack resistance of CRM with different gradation and emulsified asphalt content was studied by indirect tension (IDT) and semi-circular bending (SCB) test. Thereafter, the low-temperature performance evaluation index suitable for CRM was put forward. Then, the triangular coordinate statistical chart was used to analyze the optimal proportion of three grades of aggregate which are 2.36 – 4.75 mm, 0.075 – 2.36 mm and below 0.075 mm. The results showed that the W_f and G_f could distinguish the low-temperature performance of CRM with different mixtures and emulsified asphalt dosage. For cold recycled fine aggregate, 2.36 – 4.75 mm, 0.075 – 2.36 mm and less than 0.075 mm account for 20% – 25%, 74.3% – 80% and 5% – 8%, respectively. The CRM with lower void fraction, higher W_f and G_f could be obtained. Based on the reported findings, it was suggested that the sieve passing percentage of 4.75, 2.36, and 0.075 mm of CRM is 45% – 55%, 27% – 52% and 1.5% – 5%, respectively.

The fracture behaviours and notch effects of single-edge-notched (SEN) and double-edge-notched (DEN) 2D carbon fibre reinforced carbon matrix composites (C/Cs) were discussed and compared. The fracture behaviours of DEN and SEN were performed by tensile and bending load-displacement relationships, and the effects of notch depth on notch sensitivity were determined by DEN specimens. The results from mechanical tests indicated that the SEN exhibited a brittle behaviour with linear elasticity, while the DEN exhibited a ductile behaviour with nonlinearity. It was also found that increasing notch depth and decreasing ligament width can lead to a higher ultimate tensile strength of DEN. On the other hand, the digital image correlation (DIC) method and acoustic emission (AE) system were also applied during the mechanical tests to study the local mechanical characteristics of shear damage, strain concentration and fracture behaviour of 2D C/Cs. The results revealed the mechanisms of notch insensitivity and explained the differences in fracture behaviours between SEN and DEN.

Nano-scale CuF₂ with superior electrochemical activity was successfully prepared by a mixed solvent co-precipitation method. The SEM and TEM analyses demonstrated that the methanol concentration had a pronounced effect on both the particle size and the extent of agglomeration. With the increase in methanol content, the particle size and agglomeration of CuF₂ decreased first and then increased. When the volume ratio of methanol to deionized water was 1:1, the CuF₂ particles exhibited the smallest size and the lowest degree of agglomeration. CuF₂ synthesized with 50% methanol exhibited superior electrochemical performances with a voltage plateau above 3 V and a 1st discharge capacity of 525.8 mAh·g⁻¹ at 0.01 C due to the synergistic influence of the particle size and dispersion. The analysis results using electrochemical impedance spectroscopy (EIS) and constant current intermittent titration technique (GITT) affirmed the addition of methanol was beneficial for promoting Li⁺ diffusion and accelerating electrochemical reaction kinetics of CuF₂.

Corn starch was used as a templating agent, and an oxide mixture containing alumina, magnesia, zirconia and yttria was added in the sol-gel state. After slip casting, curing at 85 °C, drying and sintering, high-performance porous alumina ceramics were obtained. The properties of the porous alumina ceramics were analyzed by means of SEM, XRD, flexural strength and porosity. The research findings showed that, when the starch content was 1 wt%, the prepared ceramic mainly consisted of four phases: α-Al₂O₃, MgAl₂O₄, ZrO, and YSZ. The flexural strength reached 157.27 MPa, the flexural strength of the green body was about 3 MPa, and the porosity was around 30%.

Iron phosphate based glass-ceramics with deliberately added Ce as an active nuclide simulant were prepared by microwave sintering. The sintering characteristics, including phases and structural evolution, and chemical durability were investigated. XRD showed that NaZr₂(PO₄)₃ and FePO₄ became the main crystalline phases of glass-ceramics with increasing sintering temperature. SEM revealed the glass-ceramics compactness increased first and then decreased as sintering temperature increased. Raman spectrum showed that, as sintering temperature increased, the network structure of glass-ceramics changed from mainly containing orthophosphate and pyrophosphate to a single orthophosphate. After immersion for 28 days, LR_Na, LR_Zr and LR_Ce of the glass-ceramics prepared at 1 000 °C were as low as 3.64×10⁻⁵, 0.25×10⁻⁹ and 5.70×10⁻⁹ g/m²/d respectively. The results indicate that iron phosphate based glass-ceramics can be prepared by rapid microwave sintering of glass powders and there is a potential of employing such microwave sintering technique in processing of glass-ceramics nuclear waste form.

The surface of MoSi₂-SiB₆ / phenolic resin matrix composites was modified by mica, and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied. The results showed that the mica improved the thermal properties of the composites, the thermal expansion coefficient decreased, and the liquid phase formation caused the composites to shrink and increase the density. The flexural strength of mica surface modified composites not only increased to 78.64 MPa after thermal treatment at 800–1 200 °C, but reached 83.02 MPa after high temperature treatment at 1 400 °C. The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo₂C and MoB, and the improvement of the shear strength of the composites by the mica. The shear strength of MBm5-2 at room temperature reached 33.08 MPa, indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.

Focusing on the ultralow expansion functionality of the crystalized glass containing the cordierite crystal phase with the molar composition 20.7MgO·20.7Al₂O₃·51.6SiO₂·7.0TiO₂, we systematically investigated impacts of thermal treatment protocols on T dependence of coefficients of thermal expansion (CTE). Except for the phase compositions, morphology is identified as another important factor to control the T dependence of CTE. By using X-ray diffraction and scanning electron microscope, various modes of T dependence of CTE for crystallized glasses are ascribed to their different phase compositions and microstructure with finely dispersed nanoparticles. These understanding contributes to the further modification of CTE of the crystalized glass by altering their thermal treatment scenarios.

The viscosity of anti-irradiated glass was quantitatively characterized using beam bending viscometry (BBV), parallel plate viscometry (PPV), and rotational viscometry (RV). The Vogel-Fulcher-Tammann (VFT) equation was determined to be the most suitable for representing the viscosity-temperature characteristics of anti-irradiation glass by comparing the fitting effects and accuracy of different equations within different test ranges. The fragility index m of anti-irradiation glass was 47.5, as calculated using an Angell plot, and the cause of the appropriate fit of the VFT equation was analyzed. The effects of different heating temperatures and loading rates on the tensile properties of glass were studied using a universal testing machine. The results indicated that, at a tensile rate of 10 mm/s, the heating temperature increased from 903 to 1 023 K, and the deformation process of anti-irradiation glass transitioned from unstable to stable. When the tensile rate increased from 10 to 30 mm/s at 1 023 K, the deformation process of the glass was extremely unstable. This work provides theoretical guidance for the large-size preparation of flexible anti-irradiation glass.

The effects of different Al₂O₃/SiO₂ (Al/Si) ratios on the structure and tensile strength of Na₂O-CaO-MgO-Al₂O₃-SiO₂ glass fiber were investigated by Raman, tensile strength tests and molecular dynamics simulation. The results showed that Al³⁺ mainly existed in the form of [AlO₄] within the glass network. With the increase of Al/Si ratio, the Si-O-Al linkage gradually became the main connection mode of glass network. The increase of bridging oxygen content and variation of Qⁿ indicated that a higher degree of network polymerization was formed. The tensile strength of the glass fibers obtained through experiments increased from 2 653.56 to 2 856.83 MPa, which was confirmed by the corresponding molecular dynamics simulation. During the stretching process, the Si-O bonds in the Si-O-Al linkage tended to break regardless of the compositional changes, and the increase of fractured Si-O-Al and Al-O-Al linkage absorbed more energy to resist the destroy.

The influence of FT (freeze-thaw) cycles and average strain rate on the dynamic impact performance, energy evolution characteristics, and failure behavior of sandstone was studied through dynamic impact tests. Results displayed that the FT damage process of samples can be divided into three stages based on the changes in weight, porosity, and P-wave velocity. The dynamic peak strength, dynamic elastic modulus, and strength ratio decreased with increasing FT cycles, and increased with increasing average strain rate. Moreover, the average strain rate reduced the influence of FT cycles on dynamic peak strength. In general, the incident energy, reflected energy and dissipated energy increased with increasing average strain rate, the transmitted energy was negligibly affected by the average strain rate, and the energy dissipation ratio decreased with increasing average strain rate. In addition, the influence of FT cycles on each type of energy and energy dissipation ratio during sample failure was smaller than that of average strain rate. The average size of fragments can accurately demonstrate the impact of FT damage and average strain rate on dynamic peak strength and failure mode, and quantitatively evaluate the sample’s fragmentation degree. Fractal dimension varies with FT cycles and average strain rate, and the threshold is between 148.30 and 242.57 s⁻¹. If the average strain rate is in the threshold range, the relationship between the fractal dimension and dynamic peak strength is more regular, otherwise, it will become complicated. The results reveal the dynamic failure mechanism of white sandstone samples, providing assistance for dynamic rock-breaking and disaster prevention in cold regions.

Ag-doped alkali borosilicate glasses with different TiO₂ contents were prepared by the melting method. The viscosity-temperature curves of the glass samples were fitted using the MYEGA equation, and it was found that the viscosity of the glass showed a gradual decrease with the increase of TiO₂ content in the interval of the crystallization temperature of the glass. The results of XPS analysis show that TiO₂ mainly enters the glass network in the form of [TiO₄] before the heat treatment of the glass samples. In contrast, after the heat treatment, the contents of [TiO₄] and [TiO₅] in the glass decreased significantly, and the content of [TiO₆] increased, which led to the separation of TiO₂ from the glass network. The microhardness of glass shows the same pattern. Raman spectral analysis shows that the introduction of TiO₂ promotes phase separation in glass. The reduction of glass viscosity facilitates the movement of particles within the glass, while the creation of phase separation promotes heterogeneous nucleation of grains. FE-SEM analysis reveals that the silver halide grains in the heat-treated glass are dispersed in the matrix in a spherical shape, and the average size of the silver halide grains tends to increase with the increase of TiO₂ content.

This article investigated the factors and mechanisms that affected the workability and mechanical properties of cement paste incorporating nano-TiO₂. The findings indicated that, for nano-TiO₂ aqueous solution concentrations of 3%, 6%, 9%, and 12%, the optimal dispersion effect was achieved with an ultrasonic dispersion time of 20 minutes. Specifically, at a 6% nano-TiO₂ content, both the workability and mechanical performance of the cement paste were enhanced. Furthermore, while nano-TiO₂ did not alter the types of hydration products present in the cement paste, it did increase the amount of C-S-H gels. This enhancement was attributed to a higher number of nucleation sites for hydration products, which promoted hydration and reduced the porosity of the cement paste.

This study aims to investigate the failure modes at the interface of semi-flexible pavement (SFP) materials. The cohesive and wetting properties of asphalt materials, as well as two types of grout (early strength cement grout - ELS and high strength cement grout - CHS), were evaluated through pull-out tests and contact angle experiments. The rheological properties of the grout/asphalt mortar were assessed using dynamic shear rheometer (DSR) testing. The interaction coefficient, complex shear modulus, and complex viscosity coefficients of the grout/asphalt mortar were calculated to analyze the interaction between the grout and asphalt. Failure modes were identified through image analysis of semi-circular bending test (SCB) specimens. Results indicate that ELS specimens exhibit a lower grout/asphalt interface failure ratio compared to CHS specimens, due to the superior wettability and interaction of ELS grout. As the temperature increases, the proportions of cement fracture and aggregate failure decrease, while the proportion of asphalt cohesive failure surfaces increases. Furthermore, the bonding strength of SBS-modified asphalt with the grout exceeds that of pure asphalt.

Three typical toughening components (i e, emulsion asphalt, waste tire rubber particles, and polyethylene fibers) were employed to prepare self-compacting concrete (SCC). The fracture behaviors of these prepared SCC were investigated through the three-point bending test of notched beams, in which the accompanying acoustics emissions (AE) were also recorded. The test results showed that although incorporating a single toughening component reduced the fracture strengths and fracture toughness of SCC, the combination of multiple toughening components could diminish this negative effect. In addition, introducing toughening components could enhance the fracture energy and ductility index of SCC, with an improvement up to 10 times or more when PE fibers and other toughening components were involved. Based on the results of AE characteristics, SCC exhibited a progressive damage process with mitigated crack propagation after the addition of toughening components. Overall, this study could advance the understanding of the influence mechanisms of toughening components on concrete fracture behavior and further instruct the improvement in the fracture performance of concrete.

Fluidized solidified soil (FSS) is an innovative backfill material that offers benefits such as easy pumping and straightforward construction. This study examined how varying the water-soil ratio and the curing agent dosage affect the properties and microstructure of FSS. The strength development mechanism was investigated when composite solidification agents were used. The findings show that both the water-solid ratio and the curing agent dosage can affect the microstructure of FSS, thereby affecting its performance. When the water-solid ratio increases from 0.52 to 0.56, the unconfined compressive strength (UCS) and flexural strength of the FSS decrease by 34.1% and 39.3% after 28 d. Conversely, the curing agent dosage increasing from 10% to 30% will increase both UCS and flexural strength by 11.2 times and 11.1 times. As the curing age increases, the number of cracks at failure point in the FSS will increase and lead to a more complete failure. Numerous needle-like AFt, C-S-H gel, and C-(A)-S-H gel create a three-dimensional network by adhering to soil particles.

This study applied machine learning methods to predict the durability performance (specifically shrinkage and freeze-thaw resistance) of solid waste-activated cementitious materials. It also offered insights for optimizing material formulations through feature impact analysis. The study collected a total of 130 sets of shrinkage data and 106 sets of freeze-thaw data, establishing various models, including BP, GA-BP, SVM, RF, RBF, and LSTM. The results revealed that the SVM model performed the best on the test dataset. It achieved an R² of 0.935 8 for shrinkage prediction, with MAE and RMSE values of 0.464 4 and 0.625 4, respectively. Regarding freeze-thaw quality loss prediction, the R² was 0.917 8, with MAE and RMSE values of 0.313 9 and 0.532 8, respectively. The study analyzed the impact of different features on the outcomes using the SHAP method, highlighting that the alkaline activator dosage, Al₂O₃, SiO₂, and water glass modulus were critical factors influencing shrinkage, while CaO, water-cement ratio, water, and Al₂O₃ were crucial for freeze-thaw resistance. By investigating feature interactions through single-factor and two-factor analysis, the study proposed recommendations for optimizing material formulations. This research validated the efficacy of machine learning in predicting the durability of solid waste cementitious materials and offered insights for material optimization through feature impact analysis, thereby laying the groundwork for the development of related materials.

This study evaluates and optimizes the comprehensive property of desulfurization gypsum-based composites (DGCs). The water-gypsum ratio (A), ratio of dihydrate to hemihydrate desulfurization gypsum (B), and dosage of silica fume (C) were selected as multifactorial factors to design the three-level response surface methodology (RSM) experiments. Additionally, X-ray powder diffraction and scanning electron microscope (SEM) were used. The results indicate that the interactions of factor AC, BC and AB have the most significant effect towards the mechanical performances, thermal insulation as well as water resistance of DGCs, respectively. The water-gypsum ratio has the greatest influence on the overall performance of DGCs. In addition, the relative errors between the RSM test values and the model predictions do not exceed 5%, indicating that the RSM optimization models are highly accurate and well-fitted.

To address the issues of low strength, poor economic efficiency, and high carbon emissions associated with traditional sludge solidifiers, this study employs coal gangue (CG), a byproduct of coal production, and granulated blast furnace slag (GBFS) to prepare geopolymer cementitious materials for sludge solidification. The effects of the solidifier mix ratio, coal gangue calcination temperature, and alkali activator modulus on the unconfined compressive strength of the stabilized soil after 7 and 28 days of curing were investigated. Electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) tests were conducted on the stabilized soil to explore the relationship between strength, electrochemical parameters, and microstructure. The results indicate that when the ratio of coal gangue to slag is 2.5:7.5, the calcination temperature of coal gangue is 750 °C, and the modulus of water glass is 1.1; meanwhile, the stabilized soil exhibits high strength. The electrochemical parameters were used to qualitatively characterize the ionic concentration in the pore solution as the degree of soil adhesion and the hydration level during the solidification process. Stabilized soil with higher hydration and strength exhibited a distinct capacitive arc, with deeper hydration resulting in a rightward shift of the curve’s intercept on the horizontal axis. This study demonstrates the applicability of electrochemical impedance spectroscopy in evaluating the solidification effectiveness of alkali-activated calcined coal gangue-blast furnace slag sludge.

This study aims to investigate the intrinsic repair behavior of asphalt using molecular dynamics simulation. The Materials Studio software was employed to construct a virgin asphalt and SBS modified asphalt. The evaluation of the two types of asphalt included diffusion coefficient, activation energy of diffusion, and pre-exponential factor. The self-healing performance of both virgin asphalt and SBS modified asphalt was then analyzed and verified through fatigue shear-healing tests. The molecular dynamics results indicate that the self-healing properties of both asphalts improve with increasing temperature. The time required for the cracked area to be filled was found to be shorter than the time needed for the asphalt material to recover its mechanical properties. Furthermore, the activation energy of diffusion for SBS modified asphalt was slightly higher compared to that of virgin asphalt, as observed in the experimental results. The self-healing speed and collision frequency of SBS modified asphalt were both faster than those of virgin asphalt, indicating that the self-healing performance of SBS modified asphalt is superior overall.

Although the stabilising properties of single microorganism-modified steel slag can meet the specification requirements, its f-CaO content is still high, which limits its further application. To overcome this limitation, this paper proposes the use of multivariate microorganisms to synergistically pre-dispose steel slag to further reduce the f-CaO content in steel slag. Firstly, the synergistic growth and propagation pattern of multivariate microorganisms and their mineralisation ability were investigated, and then the effect of different microorganism dosages on the stability and physical properties of steel slag was studied. The results of the study show that the optimum ratio of Bacillus pasteurus, yeast and carbonic anhydrase bacteria is 5:2:3, at which time the amount of precipitation is 1.81 g. Among the three, Bacillus pasteurus plays the main role, and yeast and carbonic anhydrase bacteria play a synergistic role. When the dosage of multifunctional microorganisms is 60%, the f-CaO content of steel slag disposed of by multifunctional microorganisms is 1.85%, which meets the requirement that the f-CaO content of steel slag be less than 3.0% (specification). The basic properties of water absorption and crushing index of steel slag disposed by multi-functional microorganisms have been improved to different degrees, and compared with the undisposed steel slag, the water absorption and crushing index have been reduced by 27.43% and 4.17%, respectively, and the water-immersed expansion rate has been reduced by 84.27%.

To investigate the effect of recycled sand on the compressive properties of recycled coarse aggregate concrete with different strength grades, an experimental study on the stress-strain curve under uniaxial compression was conducted. The failure processes and modes of recycled sand concrete (RSC) were studied, and the peak stress, peak strain, elastic modulus, ultimate strain, and toughness of RSC with different strength grades were studied. The interfacial transition zone (ITZ) of RSC was studied using microhardness and SEM, and its failure mechanism was studied. The results indicate that the addition of recycled sand has a significant impact on the descending segment of the stress-strain curve for the same strength grade. Based on Chinese standards, the relationship between the parameters of the descending segment and the peak stress of RSC was determined. A constitutive relationship for the stress-strain behavior of RSC under uniaxial compression was proposed. The microhardness of the ITZ increases with the decrease in the water-binder ratio and first increases and then decreases with the replacement ratio. This is due to the gelation activity of recycled powder, which reacts with hydration products to fill pores. However, when the content of recycled powder is excessive, the alkaline environment that maintains the stability of the C-S-H gel is disrupted, leading to a decrease in microhardness.

To address the negative impact of an internal curing agent on strength while preserving its ability to resist autogenous shrinkage, we investigated the incorporation of triethanolamine and triisopropanolamine as early-strength components. These additives were combined with an internal curing agent to prepare a compound early-strength internal curing agent so as to investigate how compound early-strength internal curing agents affect the mechanical characteristics and volume stability of mortar. This was assessed using a battery of tests, including strength, autogenous shrinkage, internal relative humidity, mercury intrusion porosimetry, X-ray powder diffraction, and scanning electron microscopy. These results indicate that the compound early-strength internal curing agent effectively maintains the volume stability of the mortar without compromising its early mechanical properties. The compressive strength ratios of the mortar mixed with the compound early-strength internal curing agent were 109.45% at 3 days and 119% at 7 days, indicating significant improvement compared with the internal curing agent. Furthermore, the 7-day autogenous shrinkage rate of the mortar was −56.78 µm/m. The proportion of hazardous-grade pores larger than 100 nm was reduced to 3.54%, and the pore distribution was uniform. This study introduces innovative ideas and methods for mitigating the adverse effects of internal curing agents on the early strength of mortar.

To investigate the feasibility of applying electrolytic manganese residue (EMR) in cementitious materials, an approach combining high-temperature activation (200, 400, 600, 800 and 1 000 °C) and mechanical grinding (5 min) was adopted to stimulate the EMR activity. We analyzed the effect of calcination temperature on the performance of EMR with the aid of X-ray diffraction (XRD), specific surface area test (BET) and pozzolanic activity test, explored the effects of EMR activation temperature and content (0%, 10%, 15% and 20%) on the setting time, soundness, drying shrinkage, compressive strength, hydration products of cement-EMR mixed slurry, and assessed the effect of cement hydration on the solidification of harmful NH₄⁺-N and Mn²⁺ in EMR. The research results show that high-temperature calcination can lead to the dehydration, decomposition or crystalline phase transformation of the inert sulfate and other substances in EMR, mechanical grinding can improve its particle distribution, and the coupling of the two can effectively enhance the pozzolanic activity of EMR. The decomposition and recombination of aluminum-silica phase at 800 C optimized the EMR activity, and the strength activity index (SAI) of EMR at 28 d reached up to 95%. Appropriate calcination temperature and EMR content can ensure the workability of the mixed slurry, and when the EMR calcination temperature was 400 – 1 000 °C, the setting time of the mixed slurry under different EMR contents satisfied the specification requirements. When the calcination temperature was 600 – 1 000 °C and EMR content was less than 20%, the soundness of the mixed slurry satisfied the specification requirements. The compressive strength of the mixed slurry increased and then decreased with the increase of activated EMR content, when the EMR content was 10%, the compressive strength of all specimens was optimal and higher than the baseline group; when the activation temperature was 800 °C, the C-S-H gel in the mixed slurry interconnected with the rod-like Aft and blocked Ca(OH)₂, and the 28 d compressive strength was increased by 14% compared with that of the baseline group. The solidification rate of Mn²⁺ in EMR by cement hydration was higher than 99%, and that of NH₄⁺-N was higher than 97%. The leaching toxicity after solidification can meet the requirements of toxic emission. The results of the study may provide theoretical basis for the feasibility of the application of EMR in cementitious materials.

In order to improve the efficient and high-value recycling utilization rate of waste red bricks from construction waste, this study crushed and ground the waste red bricks to produce recycled brick powder (RBP) with different fineness, used the Andreasen model to explore the influence of RBP on the compact filling effect of cementitious material system based on the basic characteristics of RBP. The influence of grinding time (10, 20, 30 min) and content (0%, 5%, 10%, 15%, 20%) of RBP on the macroscopic mechanical properties of cementitious materials was investigated. We analyzed the significant impact of RBP particle characteristics on the compressive strength of the specimen with the aid of grey entropy theory, and revealed the influence mechanism of RBP on the microstructure of cementitious materials by scanning electron microscope (SEM) and nuclear magnetic resonance (NMR). The results show that the fineness of RBP after grinding is smaller than that of cement. The fineness of recycled brick powder increases gradually with the extension of grinding time, which is manifested as the increase of <3 µm particles and the decrease of >18 µm particles. Compared with the unitary cement cementitious material system, the particle gradation of the RBP-cement binary cementitious material system is closer to the closest packing state. With the increase of RBP content and grinding time, the compactness of the binary cementitious system gradually decreases, indicating that the incorporation of RBP reduces the mechanical strength of the specimen. The results of grey entropy show that the specific surface area D(0.1) and <45 µm particles are the significant factors affecting the mechanical properties of cementitious materials mixed with RBP. RBP mainly affects the macroscopic properties of cementitious materials by affecting the internal compactness, the number of hydration products and the pore structure. The results of SEM show that when the RBP content is less than 15%, the content of C-S-H in cement paste increase, and the content of Ca(OH)₂ decreases, and the content of C-S-H decreases and the content of Ca(OH)₂ increases when the RBP content is more than 15%. The NMR results show that with the extension of grinding time, the pore size of micropore increases gradually, that of middle-small pores decreases gradually, and that of large pores remains unchanged. With the increase of RBP content, the micropores first decrease and then increase, and the middle-small pores and large pores gradually decrease. In summary, the compactness of cementitious material system can be improved by adjusting the fineness of RBP. Considering the performance of cementitious materials and the utilization rate of RBP, it is recommended that the grinding time of RBP is 20 min and the content is 10%–15%.

By using the phased characteristics summarizing method of the existing research on magnesium slag, this study investigates the hydration reaction, alkali activation reaction and CO₂ mineralization reaction processes and mechanisms, and then explores its high-value utilization. The results show that physical and chemical activation can improve the mechanical properties of the gelled material system by increasing the crystal phase defects and surface energy and by reconstructing a new gelling system by depolymerizing glass. The CO₂ mineralization reaction of magnesium slag can be used to construct a new gelling system for CaCO₃ and calcium-modified silica gel. Magnesium slag can also be used to enhance the dry shrinkage and carbonation resistance of concrete owing to its expansibility and high alkali reserves. The mechanism and existence form of heavy metal ions in magnesium slag have been clarified. The study proposed a production system for magnesium slag and highlighted the potential research value in the field of wet carbonation to promote the application of magnesium slag.

To examine the influences of waste polypropylene fiber (PPF) on the strength and internal pore structure of recycled aggregate concrete incorporating iron ore tailings, both the cubic compressive strength and axial compressive strength of the concrete were measured. Additionally, the microstructure was analyzed using scanning electron microscopy. The evolution of pore structure parameters, including pore size distribution, pore type distribution, and nuclear magnetic resonance spectral area in the concrete, was investigated through nuclear magnetic resonance (NMR) analysis. A model correlating the concrete’s pore structure with its macroscopic performance was subsequently developed based on fractal theory. The results demonstrate that an appropriate amount of PPF created a bridging effect that decelerated the progression of macro cracks, enhanced the ductility of the concrete’s failure mode, and increased both cubic compressive strength and axial compressive strength, with the most effective dosage being approximately 0.6%. An appropriate amount of PPF (ranging from 0.3% to 0.6%) facilitated the formation of harmless pores and shifted the pore size distribution towards medium and small sizes. Specifically, a fiber content of 0.6% resulted in the most significant reduction in the T2 spectral area. Furthermore, the pore structure of concrete exhibits distinct fractal characteristics. As the PPF content increased, the fractal dimension initially rose and then declined, demonstrating a strong correlation with the mechanical properties.

Low-carbon alkali-activated slag (AAS) is among the most common alkali-activated materials (AAMs). To further lower CO₂ emissions and optimize the material system, we proposed a scheme of using phosphorous slag (PS) to substitute ground granulated blast-furnace slag (GGBS) in sodium carbonate (NC) activated slag system. we conducted a systematic study on the mechanical properties of the NC-activated slag/PS blends at normal temperature and examined the influences of different substitution amounts of phosphorus slag and NC equivalents on the performance of the material system. The hydration process was analyzed using hydration flow and chemical shrinkage. The hydration products were characterized via XRD and TGA. Moreover, the pore structure and pH value were also analyzed. When the substitution dosage of PS was not greater than 30%, the 3 d compressive strength of the systems was improved to a certain degree. However, in the medium and later periods, the compressive strength of the systems was slightly lower than that of the control group. The 90 d compressive strength of the control group 4SC-0% was 47.6 MPa, which was 4.0 MPa lower than the 28 d one of itself, presenting a strength retrogression phenomenon, while all the test groups demonstrated a continuous growth law. When the substitution dosage of PS was not more than 30%, the hydration reaction of the AAS system was facilitated, whereas when the substitution amount was 50%, the hydration of the system was conspicuously slowed down. The incorporation of phosphorous slag was capable of enhancing the volume stability of the material system. The hydration products of this system were likely to be manasseite, calcite, and C-S-(A)-H. When the incorporation amount of phosphorous slag increased, the quantity of the hydration products reduced, which might result in the generation of C-N-S-A-H. The study proposed the methodology for designing weak base-activated slag/PS.

The effects of various fly ash (FA) contents on the durability and mechanical properties of recycled fine aggregate high ductility cementitious composites (RFA-HDCC) prepared with recycled fine aggregates (RFA) to fully replace natural fine aggregates was investigated. The results indicated that a 50% FA content significantly increased the compressive strength of RFA-HDCC by 13.93%. However, a further increase in FA content led to a drastic decrease. The increased fly ash content substantially reduced the flexural and tensile strength; however, it markedly increased the matrix strain capacity, resulting in a 53.73% increase in the peak strain when FA was raised to 70%. Regarding durability, the increase in FA content negatively affected the chloride ion permeability and carbonation resistance. However, the increase in FA content initially improved the frost resistance of RFA-HDCC, peaking at 50% FA and deteriorating at 60% and 70% FA content.

We proposed a microscopic mechanical model for the effective elastic modulus of resin mineral composites based on the Mori-Tanaka method and equivalent inclusion theory to predict the elastic modulus of these materials. The model-predicted values were compared with the experimental results. The results show that when the resin dosage is lower than 10 wt%, the predicted value is lower than the measured value, and the decrease in porosity is obvious; when the resin dosage is higher than 10 wt%, the predicted value is higher than the measured value, the maximum error is 7.95%, and the decrease of porosity is not obvious. The model can predict the trend of the change of elastic modulus. The elastic modulus of resin mineral composites decreases with the increase of porosity. Therefore, the resin dosage should be controlled within 10 wt% when designing the experiments, which provides a guiding direction for the mechanical properties of resin mineral composites to be improved afterward.

Semisolid ZL101 aluminum slurry was prepared by a micro fused-casting process. The nozzle temperature has great effects on the microstructure and mechanical properties, which are primarily influenced through changing cooling conditions of the fused-casting area. With the decline of nozzle temperatures, the microstructure of semisolid ZL101 aluminum slurry tends to be more homogeneous, delivering smaller grains. Temperatures of liquids and solids were measured by differential scanning calorimetry (DSC). Distribution and characteristics of microstructure were examined by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and optical microscope (OM). It is found that uniform shape and good grain size are observed for semisolid samples fabricated by micro fused-casting under conditions including nozzle temperature of 592 °C, bucket temperature of 600 °C, stirring velocity of 600 r/min and channel diameter of 3 mm. Due to the smaller average grain size of 53 µm and shape factor of 0.71 for the fine grains, the ultrahigh average tensile strength and Vickers hardness can reach (181±1.25) MPa and (87.95±1.18) HV for the optimized semisolid ZL101 aluminum slurry, respectively.

To improve the controlled release ability, we prepared attapulgite into microspheres by spray drying. This research began with a thorough thermogravimetric analysis to optimize attapulgite’s heat treatment for drug loading. By advanced spray drying, attapulgite was transformed into microspheres, refining its drug release characteristics. Various parameters were examined, achieving optimal particle size and morphology at 25% solid content, 2.5% dispersant, and 3% binder. Attapulgite microspheres demonstrated exceptional encapsulation efficiency, exceeding 95% for doxorubicin hydrochloride, highlighting their versatility in drug delivery. FTIR and XRD were used to predict changes in material properties after spray drying. Notably, cytotoxicity tests confirmed the high biocompatibility of attapulgite microspheres, devoid of cell death induction. Attapulgite microsphere loaded with doxorubicin enable sustained drug release and maintain killing ability against tumor cells. This study confirms the viability of spray dried attapulgite microspheres for efficient drug loading and delivery and provides insights for innovative drug delivery systems that utilize the unique properties of attapulgite to advance therapeutics.

The detection of circulating tumor DNA (ctDNA) with high sensitivity and specificity is crucial for the early diagnosis and monitoring of tumors, as well as for drug therapy. In this study, a simple and highly sensitive biosensor was specifically designed for the identification of targeted ctDNA. For the first time, a three-dimensional polyvinylidene fluoride-graphene oxide-chitosan (PVDF/CS/GO) nanofiber mesh was fabricated on a polydimethylsiloxane (PDMS) micropillar substrate using electrospinning technology, and the nanofibers were functionalized with peptide nucleic acids probe-gold nanoparticle (PNA-AuNP) complexes, which served as affinity molecules for detecting the methylation of the E542K variant of the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA) gene in the peripheral blood of cancer patients. Additionally, an anti-5-Methylcytosine monoclonal antibody - multi-walled carbon nanotubes-COOH complex (Anti-5-mC-MWCNTs-COOH) complex was incubated to result in significantly amplified electrochemical signals for the accurate quantification of the E542K variant of the PIK3CA gene. Detectable signal responses were observed only when both molecules were simultaneously present, greatly enhancing the accuracy of the analysis. The biosensor exhibits high capture sensitivity for the methylation level of the E542K variant of the PIK3CA gene across a concentration range of 50 to 10 000 fmol/L, with the lowest detection limit of 10 fmol/L. The ctDNA nanobiosensor has been shown to be both feasible and valuable for quantifying ctDNA concentrations in clinical blood samples. Consequently, this 3D nanofiber biosensor shows significant potential for clinical applications in cancer diagnosis and personalized medical treatments.