Optimizing the heating efficiency of induction-heated asphalt mixtures requires a systematic understanding of multistage energy-conversion mechanisms at the micro- and mesoscales. In this study, three induction media with distinct morphologies, namely steel fibers (SF), steel wool (SW), and steel chips (SC), were investigated. A numerical response chain linking magnetic flux (Φ), induced electromotive force (U), Joule heat (Q), and temperature (T) was established, together with multiphysics experiments involving electromagnetic response, apparent electrical resistance, and induction-heating response, to compare the electromagnetic–thermal characteristics of the different media. The results showed that medium morphology dominated the electromagnetic response. Under ideal non-contact dispersion conditions, SF exhibited the strongest magnetic-flux response, 148.2

To address deterioration of durability and high-brittleness cracking in geopolymers under complex salt erosion, this study designed a mechanical-force/chloride-triggered microcapsule self-healing system that activates within geopolymers under chloride-sulfate wet-dry cycling conditions. Hybrid microcapsules achieve synchronous core hexamethylene diisocyanate (HDI) release through crack-tip stress and chloride-induced shell dissolution. At the optimal dosage (1.5 wt%), the synergistic triggering mechanism enhances impermeability by 8.32 %, reduces pest hole (pores size > 0.1 mu m) proportion by 52.7 %, and decreases compressive strength loss by 13.23 %. After 150 cycles of dry-wet chlorine salt-sulfate exposure, the relative dynamic elastic modulus remains above 60 %, confirming that the healing agent simultaneously reduces ion migration channels and suppresses pest hole expansion. Microscopic experiments and molecular dynamics studies reveal that at the repair product interface-formed by HDI reacting with hydroxyl groups-the binding energy between polyurethane (PU) and sodium aluminosilicate hydrate (N-A-S-H) gel increases by 9.53 % compared to the polyurea (PUA) system. The ester groups in PU coordinate to form an ordered hydrogen-bond network, exhibiting a 398 % increase in O-H bonds. Under salt erosion, PU demonstrates significantly superior interfacial stability with N-A-S-H gel over PUA. The spatial confinement of sodium ions within PU inhibits Cl-/SO2-4 migration. This research establishes a crossscale design paradigm for self-healing geopolymer durability in harsh environments.

Sulfate attack accelerates internal damage in geopolymer concrete (GPC), thereby restricting its long-term application in aggressive environments. To enhance the sulfate resistance of GPC, polyvinyl alcohol fibers (PVAF) were surface-modified with nano-SiO2 to produce nano-SiO2-modified polyvinyl alcohol fibers (NS-PVAF), which were subsequently incorporated into GPC to prepare nano-SiO2-modified polyvinyl alcohol fiber-reinforced geopolymer concrete (NS-PVAFRGPC). A 15-month sulfate exposure test was conducted, integrating macroscopic performance evaluation, pore structure characterization, and sulfate ion (SO42-) transport analysis to elucidate the durability evolution and sulfate resistance mechanisms of NS-PVAFRGPC. Compared with PVAFRGPC, NS-PVAFRGPC exhibited markedly lower deterioration after exposure to 3%, 5%, and 10% Na2SO4 solutions. The mass loss rate and compressive strength loss rate were reduced by 22.67%-26.61% and 42.20%-54.89%, respectively, while the relative dynamic elastic modulus increased by 3.48%-8.36%. Pore structure analysis further demonstrated that NS-PVAFRGPC maintained a more stable pore network, with porosity and mean pore diameter reduced by 38.13%-49.22% and 8.13%-13.39%, respectively, together with a lower fractal dimension and higher sphericity. Among the investigated pore parameters, porosity showed the strongest association with the performance degradation of NS-PVAFRGPC. In addition, increasing sulfate concentration intensified the driving force for SO42- transport, leading to a higher apparent diffusion coefficient. These findings clarify how NS-PVAF enhances the long-term sulfate resistance of GPC by stabilizing the pore structure, restricting SO42- transport, and suppressing internal damage. They also provide a scientific basis for the material design and engineering application of highly durable fiber-reinforced GPC in sulfate-rich environments.

To address the issues of uneven performance recovery, difficulty in balancing high and low-temperature properties, and poor compatibility with asphalt in existing rejuvenators, this study proposes the use of furfural extracted oil (FEO) for asphalt regeneration. However, the research results demonstrate that adding FEO to asphalt reduces its anti-aging ability. Previous studies have shown that the addition of organic bentonite (OBT) to asphalt enhances its anti-aging properties due to the layered structure of the bentonite. Therefore, this study aims to regenerate aged asphalt with FEO and OBT while simultaneously improving the anti-aging performance of the regenerated asphalt. Basic physical properties of the composite regenerated asphalt were compared using penetration, softening point, and ductility tests for three different OBTs: FHGEL-205B, HFGEL-120, and BP-183. The rheological characteristics were tested using dynamic shear rheological tests and bending beam rheological tests. Anti-aging ability was evaluated through residual penetration, softening point difference, and rheological fatigue aging index. Finally, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) experiments were conducted to analyze the regeneration mechanism. The comparative analysis of the experimental results showed that the composite regenerated asphalt with 3

Inductive charging pavements for electric vehicles are limited by pavement electromagnetic properties. This study develops a magnetised asphalt mixture (MAM) using recycled Ni-Zn ferrite as fine-aggregate replacement and evaluates its performance in an 85.5 kHz S-S compensated wireless power transfer system from experiments and simulations. Ferrite incorporation increases effective relative permeability (mu eff) up to similar to 21.84, while efficiency saturates around mu eff approximate to 13. A minimum MAM thickness is required for net efficiency gain across studied gaps, with a maximum gain of similar to 10.4% over a conventional mixture. Under lateral misalignment (i.e. horizontal offset between the transmitter and receiver coil centres, DS = 60 mm), MAM mitigates efficiency loss, increasing coupling coefficient and efficiency by similar to 0.06 and 2.4%. A permeability window mu eff approximate to 7-13 is recommended, and a 1 km WPT lane can reduce annual input energy by similar to 2.3 & times; 104 kWh and CO2 emissions by similar to 10 tons.

Geopolymer is a promising construction cementitious material for a wide range of applications as an alternative to Portland cement. However, their high cracking susceptibility limits their practical engineering applications. In this study, functional hybrid microcapsules were designed for the self-healing of geopolymers, utilizing lead sulfate as a chloride ion trigger, polyethylene wax as the shell material, and hexamethylene diisocyanate as the core material. The encapsulation index, microscopic morphology, chemical structure, mechanical properties, and chloride ion responsiveness of the microcapsules were systematically characterized. The effects of microcapsules on the pore structure, impermeability, mechanical properties and crack repair of geopolymers were evaluated. The results demonstrated that the microcapsules exhibited a rough-surfaced spherical core-shell structure, with the core material successfully encapsulated within the shell. The microcapsules could be triggered in large quantities by mechanical force and chloride ions, and the pore structure of geopolymer could be effectively improved by the successive competitive reaction of the core, increasing the impermeability repair rate by 22.7 % and the compressive strength reserved rate by 50.4 %. The coordination reaction of lead sulfate in chloride ions improves the triggering efficiency of microcapsules in geopolymer, and effectively repairs the crack area, and the maximum width of fully repaired cracks can reach 0.31 mm.

Calcareous silt exhibits a higher concentration of calcium carbonate. Due to its inherently inferior engineering properties, calcareous silt necessitates solidification treatment prior to utilization. The shear strength of calcareous silt serves as a pivotal metric for evaluating the calcareous silt’s capacity to withstand shear deformation, which is of paramount importance for assessing soil stability and engineering performance. To explore the engineering properties of calcareous silt solidified with a fluorgypsum-slag-based(F) binders, this research utilized such an agent to solidify calcareous silt. Direct shear tests were subsequently conducted on the solidified calcareous silt samples to analyze the shear behavior of the silt at varying curing durations and solidifying agent dosages. numerical simulations of the ultimate bearing capacity of foundations were carried out using the Abaqus numerical modeling software. The experimental findings reveal that the F group possesses superior shear characteristics compared to cement group, with a 28-day cohesion value of 1365.36 KPa and a friction angle of 39.62° for the F20 cohort. The F group exhibits a tendency towards brittle failure influenced by aging and dosage, whereas the cement group demonstrates plastic failure traits. The rate of cohesion enhancement in the F group diminishes with aging but escalates with increased dosage. Numerical simulations indicate that the F group exhibits a notably higher ultimate bearing capacity of 5460.75 KPa, underscoring its excellent engineering efficacy.

Geopolymers, a class of synthetic amorphous aluminosilicate materials, have shown significant potential as environmentally friendly and cost-effective adsorbents for heavy metals in aqueous solutions. However, predicting the adsorption capacity of geopolymers poses considerable challenges due to the wide variety of raw materials used for their synthesis and the diversity of heavy metals in solution. To advance the application of geopolymers in heavy metal adsorption, this study employs machine learning (ML) to accurately predict their adsorption capacities. An Extra Trees (ET) model with superior predictive performance was developed, and a web-based graphical user interface (GUI) software was created to facilitate its use by researchers and engineers. Further interpretation and analysis of the ET model revealed the importance of various input features in influencing the adsorption capacity of geopolymers for heavy metals, ranked as follows: curing time (d) > adsorbent dosage (g/L) > n(Na2O/SiO2) > hydrated metal ion radius > initial concentration (mg/L) > pH > n(H2O/Na2O) > specific surface area > heavy metal valence > contact time (min) > n(Na2O/Al2O3) > temperature (degrees C) > n(SiO2/Al2O3) > curing temperature (degrees C). This study provides new insights into the adsorption behavior of geopolymers for heavy metals, enabling the rapid prediction and optimization of their adsorption capacity, and offers innovative ideas for the secondary resource utilization of industrial solid waste, contributing to environmental protection.

Geopolymer materials represent a promising green cementitious material; however, their relatively poor volume stability and higher risk of cracking limit their engineering applications. Therefore, it is necessary to develop geopolymer concrete with self-healing capabilities. This study uses hexamethylene diisocyanate as the core material and polyethylene wax as the wall material to prepare single-component microcapsules suitable for the highly alkaline environment of self-healing geopolymer concrete through a melt dispersion condensation method. The results show that the microcapsules possess a rough-surfaced spherical core-shell structure and appropriate particle size, offering high mechanical properties and reliable thermal stability. The core content of microcapsules can reach 71.6 % with good sealing performance. The addition of a small amount of microcapsules will improve the mechanical properties of geopolymer and improve the pore size distribution, and the compressive strength reserved rate can be increased by 36.6 %, and the crack repair rate can reach 64.2 %. When isocyanate interacts with hydroxyl groups and water molecules on the matrix surface in the cracked area, variations in microcapsule dosages result in the formation of polyurethane-polyurea bonding materials with diverse structures and types, as well as transition layer bonding with the matrix. The reaction of an appropriate amount of isocyanate with water molecules is beneficial to improving the bonding strength, whereas an excessive reaction weakens it.

To achieve dual optimization of the mechanical properties and environmental impacts of geopolymer concrete (GPC), this study proposes a high-strength geopolymer concrete (HSGPC) without coarse aggregate. The mix proportion of HSGPC was optimized using the response surface methodology, targeting compressive strength and splitting tensile strength to determine the optimal mix. Additionally, the carbon emission impact of HSGPC was assessed and compared with ordinary Portland cement concrete, ultra-high-performance concrete, and reactive powder concrete. The results indicate that the optimal mix proportion for HSGPC includes 15% fly ash content, 10.30% silica fume content, alkali activator ratio of 2.5, and a NaOH molar concentration of 10 M. Simultaneously, the carbon emissions of HSGPC are reduced by about 30% compared to ordinary Portland cement concrete. Compared to ultra-high-performance concrete and reactive powder concrete of the same strength, the production of HSGPC respectively reduces carbon emissions by 59.87% and 68.24%. This study not only provides valuable technical support for the practical application of GPC in engineering but also holds significant implications for promoting sustainable development in the construction industry.

Clogging in permeable asphalt pavements compromises their functional properties. Understanding clogging characteristics and developing appropriate maintenance methods is crucial. This study integrates indoor accelerated clogging simulations with Grey Relational Analysis to investigate the factors influencing clogging behavior. Computer tomography scanning and seepage model simulations are utilized to examine the distribution of clogging materials, seepage properties, and changes in pore parameters in permeable asphalt mixtures before and after clogging. Additionally, variable frequency vibration tests are conducted to evaluate the impact of vibration frequency on clog removal efficiency. Findings show that the cementation hardening effect of clay progressively seals pores, with sand particles of 0.15 mm diameter exerting the most significant influence on clogging. Wet-dry cycles lead to an accumulation of clay cementation, resulting in a 26.1 % and 72.4 % decrease in pore channel length and volume, respectively, at depths of 0-4.2 cm. The area within this depth range is most prone to clogging, increasing pore tortuosity. Seepage behavior is primarily determined by several main interconnected pores. Vibration test outcomes indicate that frequencies between 100 and 400 Hz are optimal for disrupting cementation blockages.

This study proposes a method utilizing nano-SiO2 modified polyvinyl alcohol fibers to enhance the interface properties of geopolymer concrete. The surface properties of modified polyvinyl alcohol fibers were analyzed through microscopic characterization. The influence of different dosages of modified polyvinyl alcohol fibers on the mechanical properties of geopolymer concrete was investigated. Molecular dynamics simulations revealed the interfacial toughening mechanism between modified polyvinyl alcohol fibers and geopolymer concrete. Results showed that nanoSiO2 modified polyvinyl alcohol fibers increased surface roughness, thereby enhancing interfacial adhesion and mechanical interlocking between fibers and geopolymer concrete, significantly improving compressive, splitting tensile, and flexural strengths of geopolymer concrete with an optimal fiber dosage of 0.2 %. Relative to unmodified PVA fibers, the modified fibers enhance the compressive, splitting tensile, flexural strength, and elastic modulus by 20.19 %, 15.72 %, 22.34 %, and 30.58 % respectively. KH560 serves as an intermediate medium for nano-SiO2 modified polyvinyl alcohol fibers, generating numerous hydrogen bonds at the interface and tightly adhering nano-SiO2 to the surface of polyvinyl alcohol fibers. Additionally, nano-SiO2 can form ionic bonds and stable Si-O-Si bonds with the hydrated sodium aluminosilicate gel.

The pavement surface sediments are continuously transported into the pore structure of permeable pavement under hydraulic power, resulting in the loss of permeability function. Obtaining the siltation behavior of the permeable asphalt mixture is the key and foundation to achieving siltation prevention and control technology for permeable asphalt pavement. In this paper, a self-developed laboratory accelerated siltation test was designed, and X-ray diffraction (XRD), computed tomography (CT) experiments, intrinsic frequency tests were employed to explore the siltation behavior of permeable asphalt mixture. The test results reveal that the density of pavement surface sediments is approximately 15.2 g/m2 per day, and pavement surface rainwater contains 27.6% clay minerals, which exhibits induration consolidation property with dry-wet cycles. The blockage behavior caused by sand particles is 7.5% higher than that caused by clay. For the siltation contribution of permeable asphalt mixture, sand particles account for 81%, clay particles represent 7%, and the induration consolidation contributes 12% of the siltation. CT test results indicate that the lower 1/3 of permeable asphalt mixture is silted up with continuous adhesive deposition of clay. The dry-wet cycle is one of the key factors of hardening blockage, the hardening blockage primarily experiences three stages: stagnation and hardening, erosion and collapse, and deposition blockage. Intrinsic frequency test explores that the intrinsic frequency of permeable asphalt pavement is between 14,000 Hz and 15,000 Hz, and the intrinsic frequency of pavement surface sediment is 3968.83 Hz. The intrinsic frequency of pavement increases continuously with the transportation of surface sediment, and there is a good correlation between the siltation degree and intrinsic frequency of permeable asphalt mixture.

To prepare economical and environmentally friendly new cementitious composite materials - reactive powder concrete (RPC) that meets the requirements of field construction. In this paper, RPC was prepared by manu-factured sand (MS) as fine aggregate, the compressive strength of MSRPC under natural curing (NC), standard curing (SC) and natural + heat curing (N + HC) were studied, and the microscopic mechanism of MSRPC was analyzed with different curing methods, revealing the relationship between mechanical properties and micro-structure of RPC under different curing methods. It lays an important foundation for the widely used of RPC in practical engineering. The results showed that the MSRPC prepared under the three curing methods can meet the performance standards of the actual engineering components, and the compressive strength of the MSRPC under NC and N + HC could reach 85 %-95 % and 101 %-103 % of the SC, respectively. Hot water curing is helpful to the early hydration reaction and generates a large amount of C-S-H, which reduces the internal porosity of the MSRPC and has a great influence on the early strength.

In order to promote the wide application of reactive powder concrete (RPC) in practical engineering. In this paper, RPC was prepared using conventional and economical natural river sand instead of quartz sand and economical and environmentally friendly basalt fiber (BF) instead of steel fiber, and the macroscopic properties of basalt fiber reactive powder concrete (BFRPC) with different fiber content, such as flowability, failure mode, compressive strength and splitting tensile strength were studied, and the strength calculation formula of BFRPC was established based on the mechanical property results. The microscopic morphology and structure of BFRPC were characterized by scanning electron microscope (SEM) and Image Pro Plus (IPP) image processing software. The results show that BF has a small effect on the compressive strength of RPC, while it has a significant increase on the splitting tensile strength. When BF content is at 2 kg/m3, the 28-day compressive strength reaches 95.2 MPa and splitting tensile strength reaches 7.78 MPa. Compared with the RPC with BF of 0 kg/m3, the BFRPC shows an improvement in its 28-day compressive strength by 25.70% and an increase in its splitting tensile strength by 83.92%. According to the microscopic analysis, reasonable fiber content can optimize the internal microstructure of BFRPC, but excessive BF content will produce agglomeration and overlap, resulting in strength loss. Based on the gray correlation analysis method, it was concluded that the particle area ratio and pore fraction dimension were the most correlated with the mechanical properties of BFRPC. In addition, the feasibility and applicability of the BFRPC strength calculation formula were summarized. This research results of this paper provides a valuable reference for the further research and promotion of BFRPC.

为研究稻壳灰与聚丙烯纤维对使用水泥进行盐渍土加固方法的改良效果,制备水泥掺量为10％、纤维掺量为0.3％、纤维长度为12 mm、稻壳灰掺量为20％ 的稻壳灰纤维水泥加固盐渍土.对稻壳灰纤维水泥加固盐渍土的无侧限抗压强度、劈裂抗拉强度、CBR等力学性能进行了系统的试验,同时基于XRD与化学式分析探究了稻壳灰在水泥加固盐渍土中的改良机理.结果表明掺入稻壳灰与聚丙烯纤维的水泥改性盐渍土的力学性能要优于水泥盐渍土,60 d的无侧限抗压强度提高了31.9％、劈裂抗拉强度提高了49.1％,CBR值提高了16.52,通过XRD和化学式分析认为稻壳灰的掺入抑制了导致水泥加固盐渍土强度下降的Friedel盐的生成,并降低使水泥加固盐渍土膨胀的钙矾石(AFT)和钙硅石(CaSiO3)的浓度,生成了具有组成水泥骨架的水化硅酸钙,从而提高水泥土的力学性能.

The spherical hinge is an important part of rotating bridge construction, but over a long period of time, spherical hinge self-lubricating coating is easily eroded by water vapor. In this paper, the tribological properties and seasonal freezing damage evolution characteristics of a variety of rotating spherical hinge self-lubricating coating materials were studied by means of friction coefficient measurement experiments, friction and wear experiments and shear rheological experiments based on a self-developed indoor spherical hinge rotational friction coefficient tester. The results show that the self-developed indoor spherical hinge rotational friction coefficient tester can effectively and truly represent the working state and tribological properties of self-lubricating coating in practical engineering. A seasonal freezing environment has obvious influence on the tribological properties of spherical hinge self-lubricating coating, which is an irreversible process of deterioration. With the increase in the freezing–thawing cycle, the friction coefficient and viscosity of self-lubricating coating materials increase gradually, and the thixotropy and elastic recovery become worse and worse. When the content of graphene is 0.1%, the performance is the best. At room temperature and in a freeze–thaw environment, the friction coefficient of graphene grease is lower than that of PTFE 0.007 and 0.008, respectively. The diameter of the grinding plate is less than 0.075 mm and 0.001 mm, respectively. The maximum bite load without card is higher than 8.1% and 11.5%. The area of the thixotropic ring is lower than 41% and 42%. Phase transition points were higher than 42% and 64%. The apparent viscosity was higher than 6.6% and 74%. Graphene greases show the greatest bearing capacity, thixotropy and structural strength in conventional and seasonal freezing conditions and exhibit excellent tribological properties.

本工作对泡沫沥青的设计优化和冻融循环后泡沫沥青混合料的路用性能进行了研究.采用自行设计的室内沥青发泡机,结合70#基质沥青最佳发泡条件的发泡温度为159℃,搅拌速率为1156 r/min,研究了发泡用水量对发泡效果的影响,并采用硅烷偶联剂对沥青进行改性,制备了4种沥青混合料.结果表明,泡沫沥青的针入度随着发泡用水量的增加而增大,软化点、延度和粘度均随着用水量的增加而减小;冻融循环30次时,硅烷偶联剂改性泡沫沥青相对于改性前的泡沫沥青的高温稳定性提高了20.63％,低温抗裂性提高了28.51％,水稳定性提高了20.14％;改性泡沫沥青高温性能、低温抗裂性和水稳定性相对稳定;硅烷偶联剂改性泡沫沥青粘结力有所增强,改善了泡沫沥青内部由水导致的粘结力下降的问题.