Table of Content

Volume 45 Issue 2
20 February 2026

Previous Issue 　

Cement and Concrete

Research Progress on Applications of Seawater and Sea-Sand Engineered Cementitious Composites for Offshore Construction

CHEN Yu, QIU Siyuan, CHEN Xusheng, ZHANG Yamei

2026, 45(2):  367-379.  doi:10.16552/j.cnki.issn1001-1625.2025.0814

Asbtract ( 82 )   HTML ( 10)   PDF (3174KB) ( 49 )  

Figures and Tables | References | Related Articles | Metrics

Under the strategic background of accelerating the construction of a strong marine country， the development and application of seawater and sea-sand engineered cementitious composites （ECC） are of great significance for the construction of marine infrastructures in coastal and island areas. Seawater and sea-sand ECC not only inherits the excellent toughness， ductility and crack control performance of traditional ECC， but also shows a stronger ability to resist corrosive medium erosion and frequent natural disaster impact in the marine environment in actual projects， which has a broad application prospect. The influences of inorganic salt ions in seawater as well as the particle morphology and mineral composition of sea-sand on the mechanical properties of ECC are systematically sorted out， the additive manufacturing technology based on 3D printing of seawater and sea-sand ECC is discussed， and its typical application scenarios in engineering are summarized. On this basis， the key scientific issues and technical difficulties in the current research of seawater and sea-sand ECC are further analyzed， and the opportunities and challenges for future development are envisioned.

Effect of Calcium Nitrate on Performance of Ferroaluminate Cement at -10 ℃

XU Kaiqin, LIAO Yishun, ZHANG Pu, ZHANG Dong, QI Dongyou

2026, 45(2):  380-389.  doi:10.16552/j.cnki.issn1001-1625.2025.0876

Asbtract ( 60 )   HTML ( 10)   PDF (1833KB) ( 33 )  

Figures and Tables | References | Related Articles | Metrics

This study systematically investigated the effect of calcium nitrate content on the mechanical properties and microstructure of ferroaluminate cement under the curing condition of -10 ℃， aiming to address the issues of slow hydration and limited strength development of cement-based materials under sub-zero temperatures conditions. A series of tests were conducted to evaluate the fluidity， setting time， freezing point， and compressive strength at -10 ℃ of cement pastes with different calcium nitrate content. Microstructure was characterized by X-ray diffraction （XRD）， scanning electron microscopy （SEM） and mercury intrusion porosimetry （MIP）. The results show that as the calcium nitrate content increases， the fluidity of the cement paste gradually improves and the setting time shortens. When the calcium nitrate content increases from 0% to 12% （mass fraction）， the fluidity of the cement paste increases from 159 mm to 181 mm， the initial setting time shortens from 53 min to 18 min， and the final setting time shortens from 74 min to 23 min. Moreover， the content of calcium nitrate effectively lowers the freezing point of the ferroaluminate cement paste， ensuring continuous hydration under sub-zero temperatures. Under curing conditions of -10 ℃， the content of calcium nitrate promotes the early hydration reaction of cement and improves the compressive strength of the paste. At 28 d， the compressive strength exhibits a trend of increasing first and then decreasing with the increase in calcium nitrate content， reaching a maximum value of 47.2 MPa at a calcium nitrate content of 8%， which is about 11.4 times higher than the control group. Microstructural analysis reveals that an appropriate amount of calcium nitrate refines the pore structure， enhances the compactness of the system， and thereby improves mechanical properties. However， when the content exceeds 8%， microcracks are prone to form within the paste， and the morphology of ettringite （AFt） crystals is disrupted， leading to decreased structural compactness and a subsequent reduction in mechanical properties of the paste.

Adsorption Characteristics and Action Mechanism of Na-Montmorillonite on Polycarboxylate Superplasticizer

LI Meng, KONG Desong, HUANG Teng, HE Zhihao, WANG Enwen, WEI Yunlong

2026, 45(2):  390-403.  doi:10.16552/j.cnki.issn1001-1625.2025.0720

Asbtract ( 57 )   HTML ( 3)   PDF (3942KB) ( 18 )  

Figures and Tables | References | Related Articles | Metrics

The competitive adsorption between the mud （mainly clay minerals such as bentonite） of concrete aggregate and polycarboxylate superplasticizer （PCE） adversely affects the performance of cement and concrete. The purpose of this paper was to explore the effect of Na-montmorillonite on the adsorption behavior of three kinds of PCE （JSJ-1， JSJ-2， JSJ-3） and cement performance. The molecular structure and parameters of PCE were characterized by Fourier transform infrared spectroscopy （FT-IR）， nuclear magnetic resonance hydrogen spectroscopy （¹H-NMR） and gel permeation chromatography （GPC）. The fluidity and setting time were measured by cement paste test. The structural changes and adsorption mechanism of Na-montmorillonite after adsorption were analyzed by X-ray diffraction （XRD） and simultaneous thermal analysis （TG-DSC）. The results show that the presence of large molecular groups in PCE makes the cement paste completely lose fluidity when the Na-montmorillonite content is 5% （mass fraction）. The adsorption kinetics study shows that the adsorption of three types of PCE by Na-montmorillonite conforms to the pseudo-second-order kinetic model （R²>0.99）， mainly chemical adsorption， and the maximum adsorption capacity is 338.98 mg/g （JSJ-1）， 294.12 mg/g （JSJ-2）， 280.90 mg/g （JSJ-3）. The Langmuir isotherm fitting results show that the adsorption process is uniformly covered by a monolayer （R²>0.99）. The structure analysis of Na-montmorillonite after adsorption confirms that the PCE side chain is embedded in the interlayer of Na-montmorillonite to form a stable intercalation structure， which delays the decomposition temperature range of PCE to 200 ~ 450 °C.

Process Optimization and Action Mechanism of Dimethyl Maleate Polycarboxylate Superplasticizer Synthesized by Microwave-Assisted Method

WANG Tianyi, GU Yue, SUN Rui, WANG Dongmin

2026, 45(2):  404-412.  doi:10.16552/j.cnki.issn1001-1625.2025.0698

Asbtract ( 16 )   HTML ( 3)   PDF (1612KB) ( 10 )  

Figures and Tables | References | Related Articles | Metrics

Polycarboxylate superplasticizer （PCE） was synthesized by microwave-assisted method and conventional water bath method using terminal alkenyl polyoxyethylene polyoxypropylene ether and dimethyl maleate as raw materials. Taking the dispersion performance of PCE as the main evaluation index， the optimal ratio of raw materials and process conditions were determined by single factor experiment. The results show that the microwave-assisted method can greatly shorten the reaction time and show better reaction efficiency. Compared with conventional water bath method， microwave-assisted method can significantly improve the dispersion performance and time retention ability of PCE. The infrared spectrum analysis show that the products obtained by the two synthesis methods have the same molecular structure. The adsorption isotherm fitting results show that the adsorption behavior of PCE synthesized by two methods on the surface of cement particles conforms to the Langmuir monolayer adsorption model， and the PCE synthesized by microwave-assisted method has stronger adsorption capacity. PCE synthesized by microwave-assisted method has a significant effect on delaying the hydration process of cement， and increasing the dosage of PCE can effectively reduce the total hydration heat of cement.

Optimization of Component Mix Proportion and Performance Study of Ceramic Sand Lightweight Mortar

KONG Xin, WU Jiaming, SONG Benteng, WANG Zhenxing, YE Zhengmao

2026, 45(2):  413-425.  doi:10.16552/j.cnki.issn1001-1625.2025.0783

Asbtract ( 21 )   HTML ( 4)   PDF (4024KB) ( 13 )  

Figures and Tables | References | Related Articles | Metrics

This study systematically investigated the influence pattern and underlying mechanism of component mix proportion on mortar properties， addressing the contradiction between density and strength in ceramic sand lightweight mortar. It focused on revealing the synergistic optimization effects of the water-to-binder ratio and mineral powder content. The results indicate that as the water-to-binder ratio increases， the dry density of the mortar continuously decreases， the drying shrinkage value continuously increases， and anti-chloride ion erosion ability of the mortar exhibit a trend of decreasing first and then increasing. When the water-to-binder ratio is 0.24， the water absorption and open porosity of mortar are the lowest， the 28 d compressive strength is the highest， and the degree of cement hydration degree and porosity achieve an optimal balance. The increased content of hydration product calcium hydroxide （CH） and amorphous phase （C-S-H gel） enhances the matrix compactness.Based on this， when the mineral powder content is increased to 12% （mass fraction）， the mechanical and durability properties of the mortar are significantly improved. The dry density reaches 1 465.44 kg/m³， the 28 d compressive strength is 51.6 MPa， the water absorption rate is 6.66%， the open porosity is 9.76%， the chloride ion migration coefficient is the lowest， and the 90 d drying shrinkage rate decreases by 22.88%. Mineral powder fills the pores through secondary hydration reactions and the micro-aggregate effect， thereby reducing the porosity. This study provides a reference for the mix proportion design of ceramic sand lightweight mortar.

Effect of Recycled Brick Aggregate Loaded with Microorganisms on Crack Self-Healing of Cement-Based Materials

ZHAO Xiaomeng, ZONG Xudong, YANG Yijie, WANG Jie, DU Mingxing, FENG Chunhua

2026, 45(2):  426-436.  doi:10.16552/j.cnki.issn1001-1625.2025.0871

Asbtract ( 22 )   HTML ( 4)   PDF (5025KB) ( 13 )  

Figures and Tables | References | Related Articles | Metrics

Microbial-induced mineralization precipitation （MICP） is applied in cement-based materials primarily by utilizing microorganisms to react with calcium sources to generate calcium carbonate， thereby achieving the self-healing of cracks in cement-based materials. However， practical application of MICP is limited by the living environment of microorganisms. In this study， recycled brick aggregate （RBA） was used as the carrier material to investigate the crack self-healing effect of microorganisms on cement-based materials under the induction of Ca2?/Mg2? loaded on RBA. Modern testing methods such as inductively coupled plasma （ICP）， X-ray diffraction （XRD）， and scanning electron microscope （SEM） were adopted to systematically explore the effect mechanism. The results show that the addition of Mg²⁺ increases mineralization rate of microorganisms within a certain range. When the RBA content is 60% （mass fraction）， it has little effect on the strength of cement-based materials. The crack healing rate of the crack initial width 110.98 μm specimen reaches 97.7%， and the water absorption rate decreases by 63.6%. The crack healing rate of the crack initial width 167.61 μm specimen can reaches 96.4%， and the water absorption rate decreases by 76.4%. When cement-based material generates cracks， the calcium carbonate precipitation generated by the induced mineralization of microorganisms can effectively fill the cracks， ultimately realizing the self-healing of cracks in cement-based materials.

Prediction of Concrete Compressive Strength by GA-BP Neural Network Based on Mortar Film Thickness

YU Hanzhi, ZHOU Li’an, LIU Yu, ZHOU Wenjuan, LIANG Yunjian

2026, 45(2):  437-448.  doi:10.16552/j.cnki.issn1001-1625.2025.0825

Asbtract ( 50 )   HTML ( 5)   PDF (3518KB) ( 10 )  

Figures and Tables | References | Related Articles | Metrics

To achieve more precise predictions of modern concrete compressive strength， mortar film thickness was employed as the key parameter in mix design， replacing the quantities of individual concrete constituents. Through theoretical calculations and experimental studies， the influence of mortar film thickness on concrete compressive strength was analysed. Two compressive strength prediction models were constructed： one based on traditional concrete mix proportion and another based on mortar film thickness， utilising a backpropagation optimised by a genetic algorithm （GA-BP） neural network. Results indicate that mortar film thickness is jointly determined by the total volume of cement mortar and coarse aggregate parameters. As film thickness increases， the quality of the interfacial transition zone initially improves before deteriorating， while the skeletal support function of coarse aggregates progressively weakens. This leads to an overall decline in concrete compressive strength. Compared to the traditional prediction model， the mortar film thickness-based model achieves a 19.7% improvement in accuracy， a 50.4% reduction in root mean square error， an average relative error of 2.8%， and a determination coefficient of 0.935. Regression evaluation metrics indicate this model provides more precise predictions of concrete compressive strength.

Numerical Simulation Study of Transport Mechanism of Chloride Ions in Concrete Mesostructure under Water Pressure

YU Aiping, LI Zhengkang, CHENG Zichen, YANG Yuhan, LIU Yongqi, CHEN Xuandong

2026, 45(2):  449-460.  doi:10.16552/j.cnki.issn1001-1625.2025.0883

Asbtract ( 15 )   HTML ( 4)   PDF (7079KB) ( 8 )  

Figures and Tables | References | Related Articles | Metrics

In marine environment， water pressure promotes the transmission of chloride ions in concrete， accelerating the deterioration of reinforced concrete structures. This study established a theoretical model of chloride ion transport considering the diffusion-convection coupling effect and implemented numerical solutions at the mesoscopic scale of concrete using the finite element method. It simulated the chloride ion transport process in the mesoscopic structure of concrete under different water pressures and investigated the influence mechanisms of water pressure existence， erosion time， and hydrostatic pressure on the chloride ion transport behavior. The research shows that the existence of water pressure not only promotes the transport of chloride ions but also changes the chloride ion transport mechanism. When there is no water pressure， the chloride ion transport mechanism is mainly diffusion， while under water pressure， the transport mechanism shifts from diffusion-dominated to diffusion-convection coupling. Moreover， the promoting effect of the interface transition zone （ITZ） on chloride ions weakens with increasing water pressure， and the chloride ion transport becomes more directional. Additionally， even after long-term exposure， the chloride ion concentration in the deep regions of concrete can continue to accumulate to the critical concentration due to the water pressure effect. More importantly， when the water pressure increases from 0.10 MPa to 1.00 MPa， the chloride ion concentration in the deep regions shows an exponential growth. Based on the chloride ion concentration changes at the 60 d measurement point， the chloride ion concentration at 0.30 MPa is approximately 2.11 times that at 0.10 MPa， about 3.98 times at 0.50 MPa， and reaches approximately 14.22 times at 1.00 MPa. The promoting effect of water pressure on chloride ion transport cannot be ignored. This study quantitatively reveals the chloride ion transport laws under water pressure， providing a theoretical basis for the durability design and life prediction of pressure-bearing concrete structures such as submarine tunnels and hydraulic structures.

Shrinkage and Prediction Model of High-Performance Micro-Fine Steel Fiber Reinforced Sulphoaluminate Cement Concrete

LI Xiaopeng, ZHAO Jun, CHEN Zhehan, LIANG Mengyang

2026, 45(2):  461-470.  doi:10.16552/j.cnki.issn1001-1625.2025.0791

Asbtract ( 15 )   HTML ( 3)   PDF (2136KB) ( 10 )  

Figures and Tables | References | Related Articles | Metrics

Sulphoaluminate cement （SAC） has the characteristics of micro-expansion and low shrinkage. Therefore， Using SAC-based composite materials as the connection material for precast structural joint， is expected to reduce the risk of shrinkage cracking. This study revealed the variation law and mechanism of the shrinkage of steel fiber reinforced sulphoaluminate cement concrete （SFRSC） through shrinkage tests， hydration heat tests and SEM tests. The results indicate that decreasing binder-aggregate ratio， sand ratio and fly ash content， or increasing steel fiber volume fraction， can restrain the shrinkage of SFRSC. The inhibitory effect of steel fiber plateaus when its volume exceeds 3.0%. The shrinkage of SFRSC is significantly lower than that of steel fiber reinforced ordinary Portland cement concrete. Micro-structural observations indicate that the transformation of ettringite （AFt） into calcium monosulfoaluminate hydrate （AFm） is accompanied by substantial bound-water release and a reduction in solid volume， jointly contributing to SFRSC shrinkage. The shrinkage of SFRSC arises from the combined effects of SAC hydration， self-desiccation， and steel fiber constraint. The synergistic action among AFt， AFm and steel fiber establish a multi-level shrinkage-suppression system in SFRSC， characterizing by expansion compensation-shrinkage inhibition-mechanical restraint. Finally， a predictive model for SFRSC shrinkage is proposed based on ACI code and CEB-FIP code.

Acoustic Emission Parameter Calibration and Source Localization Accuracy in Steel Fiber Reinforced Concrete

GUO Yongmin, ZHANG Longjiao, AN Xinzheng, LI Weizhi, AN Shuhao, JI Mengqi, WANG Yan

2026, 45(2):  471-481.  doi:10.16552/j.cnki.issn1001-1625.2025.0873

Asbtract ( 44 )   HTML ( 1)   PDF (3875KB) ( 12 )  

Figures and Tables | References | Related Articles | Metrics

A systematic experimental study was conducted to address the issues of parameter calibration and insufficient source localization accuracy in acoustic emission （AE） testing of steel fiber reinforced concrete （SFRC）. Three types of steel fiber—end-hook type， shear type， and corrugated type—were incorporated into specimens at volume fractions of 0%， 0.5%， 1.0%， and 1.5%， followed by pencil lead break tests and loading AE tests. The results show that under identical conditions such as water-cement ratio， the steel fiber content significantly influences AE sound velocity and signal rise time： for every 0.5 percentage points increase in steel fiber content， the average sound velocity decreases by approximately 4.3%， while the rise time shortens by about 5.4%. In contrast， the differences among fiber types have minimal effect on these parameters. Among the sensor layout schemes， a four-sensor spatial diagonal arrangement exhibits the smallest localization error and the best stability. Uniaxial compression tests verify the effectiveness of the proposed parameter settings and layout scheme， with source localization results closely matching actual crack positions. This study proposes a practical method for AE parameter calibration and sensor layout scheme in SFRC， providing technical support for damage monitoring and health assessment of SFRC structures， with significant engineering application value.

A New Mechanism for Inhibiting Alkali Efflorescence Dominated by Ettringite

LI Lang, ZHANG Yuwei, GAO Yuhui, LIU Yue, CHENG Yan, ZHENG Weiguo

2026, 45(2):  482-489.  doi:10.16552/j.cnki.issn1001-1625.2025.0772

Asbtract ( 17 )   HTML ( 4)   PDF (1991KB) ( 18 )  

Figures and Tables | References | Related Articles | Metrics

Efflorescence poses a critical challenge to the stability of cement-based decorative materials. Traditional methods have limitations such as low efficiency and strength damage. This study proposed and verified a new hypothesis： through the regulation of exogenous Ca²⁺， ettringite （AFt） can be transformed from an efflorescence promoting phase to an efficient efflorescence inhibition phase. Using sulphoaluminate cement （SAC） as the matrix and adding CaCl₂ as calcium sources， the efflorescence inhibition mechanism of AFt was systematically studied by multi-scale characterization methods such as XRD， SEM， TG-DSC and MIP. The results show that the optical density （OD） value of the SAC sample with 10% CaCl₂ （mass fraction） admixture is reduced by 39.2% compared to the sample without CaCl₂， indicating that it can significantly reduce the degree of efflorescence. The core mechanism lies in： 1） AFt crystal structure （3CaO·Al₂O₃·3CaSO₄·32H₂O） fixes free Ca²⁺， reducing the source of migratory ions. 2） AFt crystals can bind a large amount of crystalline water， reducing the carrier of ion migration. 3） A large amount of AFt interlaced growth forms a dense skeletonon， total porosity as low as 2.78%， blocking the ion migration channels. The three work together to achieve the "fixed ion source， bound migration carrier， and blocking migration channel" alkali inhibition effect. This study reveals the new function of AFt in active alkali inhibition and provides a new idea for the design of long-lasting anti-alkali efflorescence cement-based decorative materials.

Solid Waste and Eco-Materials

Research Progress on Basic Mechanical Properties of Crumb Rubber Concrete

WANG Boxin, YUN Weilong, LI Jiacheng, LIU Taiyuan, DUAN Siyu

2026, 45(2):  490-502.  doi:10.16552/j.cnki.issn1001-1625.2025.1008

Asbtract ( 32 )   HTML ( 5)   PDF (4325KB) ( 14 )  

Figures and Tables | References | Related Articles | Metrics

The global cumulative amount of waste tires is increasing year by year. Replacing part of the fine aggregate in concrete with crumb rubber particle （CR） produced from crushed waste tires to prepare crumb rubber concrete （CRC） is an important approach for large-scale consumption and high-value utilization of waste tires. Meanwhile， this modification can enhance the toughness， frost resistance， thermal insulation， and noise reduction properties of concrete. However， the basic mechanical properties of CRC are often lower than those of ordinary concrete， which directly restricts its popularization and application， failing to give full play to its performance advantages. Focusing on domestic and international studies related to the basic mechanical properties of CRC， this paper adopted the literature clustering method to analyze the research focus in the CRC field. It systematically sorted out the influence regularities of CR replacement rate， particle size， and modification treatments on the compressive strength， splitting tensile strength， and flexural strength of CRC. The deterioration mechanism of its mechanical properties was analyzed by combining with the characteristics of microstructure. In addition， the research progress of mesoscale numerical simulation was summarized， and a comprehensive review framework covering macroscale， mesoscale， and microscale was established. The results indicate that a 10% （volume fraction） CR replacement rate is the critical threshold to ensure the mechanical properties and engineering applicability of CRC. Composite modification methods can effectively improve the mechanical strength of CRC， while the thickness of the interfacial transition zone （ITZ） and the proportion of harmful pores are the core indicators linking microstructure to macro-mechanical properties.

Review on Solidification Mechanism and Performance Regulation of Fluidized Solidified Soil

SHU Chang, CHEN Zhenzhong, WANG Wei, MEI Youjing, WANG Ningning, ZHANG Yamei

2026, 45(2):  503-516.  doi:10.16552/j.cnki.issn1001-1625.2025.0815

Asbtract ( 21 )   HTML ( 4)   PDF (2414KB) ( 20 )  

Figures and Tables | References | Related Articles | Metrics

In recent years， fluidized solidified soil has become a research hotspot in the domestic and international building materials field due to its advantages of high fluidity， high efficiency and low cost. This paper reviews the commonly used solidification agents and solidification mechanisms of fluidized solidified soil， with a focus on evaluating the potential of utilizing various industrial wastes to partially replace traditional Portland cement in the preparation of fluidized solidified soil. From the perspective of fluidity regulation， the water-to-solid ratio is a key indicator affecting fluidity. It can be specifically regulated by the liquid limit of soil and the water demand for standard consistency of cementitious materials. The incorporation of polycarboxylate superplasticizer and fly ash can significantly improve fluidity. From the perspective of mechanical properties regulation， the addition of early strength agent such as CaCl₂ or industrial wastes like red mud and carbide slag can effectively promote the hydration reaction of cementitious materials and fill pores. Meanwhile， inducing the formation of ettringite in the system can accelerate water consolidation and enhance hydration efficiency. From the perspective of bleeding regulation， optimizing particle gradation and incorporating red mud can effectively inhibit the bleeding phenomenon. In the long term， it is necessary to comprehensively evaluate the solidification agent scheme and its comprehensive benefits from the aspects of regionality of materials， soil source properties， solidification effect， economy， low-carbon and safety.

Preparation of Calcium Silicate Hydrate from Fly Ash by Alkali Fusion Method and Its Silicon Slow-Release Performance

ZHANG Mengtian, WANG Xuekai, XU Zifang, HU Shuangyue, LI Zheng, LI Jiawei

2026, 45(2):  517-527.  doi:10.16552/j.cnki.issn1001-1625.2025.0861

Asbtract ( 11 )   HTML ( 2)   PDF (3625KB) ( 6 )  

Figures and Tables | References | Related Articles | Metrics

This study utilized coal fly ash （CFA） as raw material to achieve the extraction of highly reactive soluble silicon and the controllable synthesis of nano-sized calcium silicate hydrate （CSH） through an alkali fusion-hydrothermal method， providing a feasible pathway for the high-value utilization of coal-based solid waste. The specific procedure included： using Na₂CO₃ as an activator and calcining at 850 ℃ for 2 h. The calcined product was dissolved in water at a solid-liquid ratio of 1∶10. After 90 min in an 80 ℃ water bath， solid-liquid separation yielded a silicon extraction solution. This process achieves a silicon extraction rate of 45.7%. The silicon extraction solution was then reacted with CaCl₂ in an 80 ℃ water bath for 3 h to successfully synthesize CSH. Slow-release studies demonstrate that the silicon release behavior of the as-prepared CSH in citric acid solution follows the Higuchi diffusion model， with a maximum silicon slow-release concentration of 350 mg/L. It also exhibits continuous release characteristics under different pH conditions， at pH value of 6 and 8， the silicon slow-release concentration reached 150 and 100 mg/L， respectively， on the third day. This research achieves the low-cost resource conversion of CFA， and the prepared CSH holds promise for promoting the green resource utilization of solid waste and the sustainable development of agriculture.

Optimization Methods and Activation Mechanisms for Enhancing Activity of Coal Gangue Powder

CUI Yingbin, LIAN Haikun, LIU Fangfang, WANG Zhen, FAN Taotao, SI Chundi, LI Zixuan

2026, 45(2):  528-539.  doi:10.16552/j.cnki.issn1001-1625.2025.0851

Asbtract ( 40 )   HTML ( 4)   PDF (4771KB) ( 15 )  

Figures and Tables | References | Related Articles | Metrics

The activity of coal gangue determines its potential and application scenarios for resource utilization in the building materials sector. To investigate methods for enhancing coal gangue activity， coal gangue powder from the Shijiazhuang metropolitan area was selected as the subject. Compressive strength， flexural strength， and reactivity index were adopted as evaluation metrics. The study compared the activity of coal gangue powder after single and combined treatments of mechanical activation， thermal activation， and chemical activation， along with the corresponding changes in the mechanical properties of mortar. Additionally， laser particle size analysis， XRD， and SEM were employed to analyze the mechanism of enhancing gangue powder activity at the microscopic level. Results indicate that mechanical activation-thermal activation-chemical activation synergistic treatment yields the most significant enhancement in both reactivity of coal gangue powder and mechanical properties of mortar， followed by thermal activation. The effectiveness of chemical activation depends on the type of activator， with CaO demonstrating the best activation effect. The recommended composite activation parameters are 60 min mechanical grinding， calcination at 650 ℃， and 4% （mass fraction） CaO. The corresponding coal gangue powder reactivity index， 28 d mortar compressive strength， and 28 d flexural strength are 108.20%， 46.2 MPa， and 8.1 MPa， respectively. Mechanical grinding and high-temperature calcination enhance the hydration reactivity of coal gangue powder by regulating its particle size distribution and phase composition ratio. Chemical activation primarily promotes the formation of hydration products like calcium silicate hydrate （C-S-H） gel through alkaline environment adjustment， achieving simultaneous improvement in both the reactivity of coal gangue powder and the mechanical properties of mortar.

Effect of Microwave Curing on Strength and Microstructure of Incense Stick Ash-Cement Composite Cementitious Materials

WANG Yijiang, LI Zijun, HE Zhihai, LU Jun

2026, 45(2):  540-548.  doi:10.16552/j.cnki.issn1001-1625.2025.0683

Asbtract ( 9 )   HTML ( 3)   PDF (4906KB) ( 9 )  

Figures and Tables | References | Related Articles | Metrics

As a biomass ash， the large-scale disposal of incense stick ash （ISA） remains a major challenge. Partially replacing cement with ISA is an effective strategy to achieve resource recovery and reduce the carbon footprint of cement-based materials. However， the low early-age activity of ISA easily leads to low early mechanical properties of cement-based materials. To solve this problem， microwave can be used to stimulate the early reactivity of ISA， thereby improving the mechanical strength of composite cementitious materials. In this study， composite cement pastes containing 0%~20% ISA by mass were prepared and were cured under two conditions： microwave （M） curing and microwave followed by water （MW） curing. The effects of ISA content and curing condition on the compressive strength， mineral composition， pore structure， and nanomechanical properties of cement pastes were systematically investigated. The results show that both M and MW curing can improve the early compressive strength of cement pastes with ISA. Moreover， M and MW curing significantly refine the pore structure of samples and densify the microstructure. At the nanoscale， M and MW curing promote the formation of calcium silicate hydrate （C-S-H） gel and the transformation of low density （LD） C-S-H gel to high density （HD） C-S-H gel. This study aims to promote the application of ISA and microwave curing in cement-based materials and provide theoretical support for the performance optimization and sustainable design of green building materials.

Mix Proportion Optimization Design and Performance Study of All-Solid Waste Cementitious Materials Based on Response Surface Methodology

ZHANG Xiaolong, SUN Weiguo, WANG Wei, WANG Zhaohui, YAN Maohao, LIU Hongqiang, YANG Junhong

2026, 45(2):  549-561.  doi:10.16552/j.cnki.issn1001-1625.2025.0849

Asbtract ( 24 )   HTML ( 4)   PDF (2517KB) ( 16 )  

Figures and Tables | References | Related Articles | Metrics

To enhance the resource utilization rate of industrial solid waste， this study systematically investigated the synergistic regulation of ground granulated blast furnace slag （GGBFS）， steel slag （SS）， and desulfurization gypsum （FGD） on the workability and mechanical performance of all-solid waste cementitious materials， based on the Mixture-Optimal （Custom） Design method in the Design-Expert software. The results indicate that the ternary solid waste system exhibits significant regulation of fluidity and setting performance. When the content of GGBFS is 50.75% （mass fraction， the same below）， SS content is 40.00% and FGD content is 9.25%， the mortar fluidity reaches a maximum of 205 mm， while the initial setting time and final setting time shorten to 170 and 490 min， respectively. This effect is primarily attributed to the synergistic action between the skeletal effect of SS particles and the setting acceleration of \mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-} in FGD. Furthermore， when GGBFS content is not less than 70%， the SS content is controlled below 30%， and FGD content is maintained within 4%~5%， the 28 d compressive and flexural strength reach maximum value of 45.3 and 8.6 MPa， respectively， This validates the performance enhancement mechanism of “ground granulated blast furnace slag dominant，steel slag synergy gypsum， and desulfurization gypsum activation”. Through response surface model optimization analysis reveal that an optimal balance of material properties is achieved when the content of ground granulated blast furance slag， steel slag， and desulfurization gypsum are 63.6%， 34.9%， and 1.5%， respectively， the comprehensive performance of materials achieve the optimal balance， the measured value of each response indicator deviate from their predicted value by less than 5%， confirming the accuracy and reliability of the established regression model. In addition， the carbon emission and economic analysis reveal that， compared with ordinary Portland cement， the optimized all-solid waste cementitious materials reduce the global warming potential （GWP） by approximately 86% and save about 100 yuan/t， highlighting its application potential in promoting low-carbon building materials and sustainable development.

Synergistic Carbonation-Hydration Mechanisms and Microstructural Evolution in Low-Heat Cement and Steel Slag Mortars

WEN He, ZHANG Xiaoxiang, GU Lei, DENG Jiaxin

2026, 45(2):  562-572.  doi:10.16552/j.cnki.issn1001-1625.2025.0810

Asbtract ( 11 )   HTML ( 4)   PDF (6967KB) ( 8 )  

Figures and Tables | References | Related Articles | Metrics

The carbonation of ordinary cementitious material has been extensively studied， whereas the carbonation behavior of low-heat Portland cement combined with steel slag remains insufficiently explored. Steel slag， rich in free CaO and latent hydraulic activity， can promote carbonation reactions when incorporated into low-heat cement systems. In this study， the effects of binder-sand ratio， water-binder ratio， and steel slag dosage on compressive strength， pore structure， and phase evolution under different carbonation durations and curing regimes were investigated. Results show that appropriate pre-curing regulates the residual water-binder ratio， enhances CO₂ diffusion， and improves carbonation efficiency. At a binder-sand ratio of 3∶5 with a low water-binder ratio， specimens nearly completely carbonized within 48 h， with calcite as the main carbonation product. The formation of aragonite depending on the carbonation rate. Compressive strength correlates well with carbonation degree， reaching up to 68.8 MPa after 48 h of carbonation. Pore structure analysis indicate that carbonation and subsequent hydration can significantly refine the pore size and improve the density of samples. XRD， TG-DTG， FT-IR， and SEM-EDS reveal that CaCO₃ generated by carbonation interacted with hydration products to form a three-dimensional cross-linked structure， markedly enhancing microstructural compactness and mechanical performance.

Influence of Molybdenum Tailings Sand Substitution Amount on Mechanical Properties and Microstructure of Manufactured Sand Cement Mortar

RUI Zhenhua, LYU Xiangyu, GUO Can, HUANG Shan, NIU Dongyu

2026, 45(2):  573-581.  doi:10.16552/j.cnki.issn1001-1625.2025.0708

Asbtract ( 21 )   HTML ( 5)   PDF (1767KB) ( 10 )  

Figures and Tables | References | Related Articles | Metrics

To alleviate the shortage of sand resources and achieve resource utilization of industrial solid waste， this study investigated the effect of substituting manufactured sand with molybdenum tailings sand on mechanical properties and microstructure of cement mortar. Five types of cement mortars with different substitution rates of molybdenum tailings sand were designed， and their workability， mechanical properties， and drying shrinkage properties were systematically tested. The microstructure and hydration products were analyzed using SEM and XRD. The results indicate that the saturated content point of water-reducing agent for both molybdenum tailings sand mortar and manufactured sand mortar is 5‰ of the total mass of cementitious materials， and the water retention of molybdenum tailings sand mortar is poorer. The compressive strength of mortar reaches its peak at a mass substitution rate of 50% for molybdenum tailings sand， while the flexural strength is optimal at a substitution rate of 25%. The drying shrinkage value increases significantly with the substitution rate， reaching a drying shrinkage value of 1 223×10^-6 at a substitution rate of 100% after 90 d. Microscopic analysis shows that an appropriate amount of molybdenum tailings sand can enhance the compactness through micro-aggregate filling effect and nucleation effect， but excessive substitution leads to grading deterioration and increased porosity. Molybdenum tailings sand can partially replace manufactured sand in cement mortar， and the recommended substitution rate is not more than 50% to balance mechanical properties and volume stability.

Mechanical Properties of Silty Clay Stabilized with GGBS-Carbide Slag-Desulfurization Gypsum Based on Response Surface Methodology

WANG Dongdong, ZHANG Shuaiwei, SONG Xinjiang, XU Haibo, YIN Xiang, QIAO Leixin

2026, 45(2):  582-591.  doi:10.16552/j.cnki.issn1001-1625.2025.0889

Asbtract ( 11 )   HTML ( 3)   PDF (3814KB) ( 12 )  

Figures and Tables | References | Related Articles | Metrics

Silt clay is widely distributed in China， yet its high water content and low bearing capacity make it unsuitable for direct use in engineering. To enhance its properties， this study employed ground granulated blast furnace slag （GGBS）， carbide slag， and desulfurization gypsum as stabilizers. Using the Box-Behnken design （BBD） within the response surface methodology， the influence of the dosages of these three stabilizers on the mechanical properties of silt clay was investigated， and the optimal mix proportion was determined. The effectiveness of this optimal proportion was verified by comparing the strength and mass loss rate of clay stabilized with xanthan gum under dry-wet cycles. Furthermore， scanning electron microscopy （SEM） was utilized to elucidate the curing mechanism. The results indicate that under 7 d curing， the unconfined compressive strength （UCS） of the silt clay initially increases and then decreases with increasing dosages of GGBS and carbide slag. Under 28 d curing， with the increase in the admixture amounts of carbide slag and desulfurization gypsum， the UCS of silt clay first increases and then decreases. The optimal dosages are determined as 18.43% （mass fraction） for GGBS， 9.13% for carbide slag， and 4.06% for desulfurization gypsum. Under this optimal proportion， the strength and durability are superior to those of clay stabilized with xanthan gum. The incorporation of the stabilizer leads to the formation of gel products such as calcium silicate hydrate （C-S-H）， calcium aluminosilicate hydrate （C-A-S-H）， and ettringite. The sample particles are cemented and encapsulated， which drives the optimization of pore structure and the enhancement of compactness， thereby promoting the improvement of soil strength and durability at the macro level.

Ceramics

Research Progress on High-Temperature Oxidation Behavior of SiOC Ceramics and Their Composites

LI Dan, PENG Linwei, MA Qingsong, GUO Lei

2026, 45(2):  592-602.  doi:10.16552/j.cnki.issn1001-1625.2025.0795

Asbtract ( 30 )   HTML ( 7)   PDF (6086KB) ( 23 )  

Figures and Tables | References | Related Articles | Metrics

Owing to the excellent properties， including high-temperature resistance， low density， low thermal conductivity and cost-effectiveness， SiOC ceramics show significant potential for applications in thermal insulation materials for aerospace. However， SiOC ceramics are prone to structural damage and performance degradation under high-temperature oxidizing conditions， making it essential to gain an in-depth understanding of their oxidation behavior and to optimize their oxidation resistance to meet increasingly demanding service requirements. This paper systematically reviews the oxidation behavior of SiOC ceramics， summarizing recent advances in three antioxidant strategies： element doping modification， composite material design， and surface coating. It reveals the relationship between microstructural evolution and macroscopic properties in high-temperature， and provides developmental recommendations for subsequent research and application of oxidation-resistant composite materials.

Preparation and Properties Regulation of Tubular Halloysite Doped Cordierite Ceramics

PAN Honghai, ZHANG Wen, WANG Honglei, ZHOU Xingui

2026, 45(2):  603-612.  doi:10.16552/j.cnki.issn1001-1625.2025.0816

Asbtract ( 57 )   HTML ( 2)   PDF (2810KB) ( 9 )  

Figures and Tables | References | Related Articles | Metrics

Cordierite ceramics are ideal materials for lithography square mirrors and laser reflectors due to their low thermal expansion coefficient， excellent chemical stability and high mechanical properties. In order to meet the more stringent application requirements in related fields， it is necessary to modulate the key parameters such as thermal expansion coefficient and elastic modulus by means of doping modification. Tubular halloysite has excellent thermal stability and mechanical properties due to its unique tubular structure， showing its good potential as a dopant. In this paper， cordierite ceramics doped with tubular halloysite were prepared by solid phase sintering with tubular halloysite powder as dopant. The effect of tubular halloysite doping on the composition， microstructure， mechanical properties and thermal expansion properties of cordierite ceramics was studied. The results show that doping tubular halloysite can promote the densification of cordierite ceramics to a certain extent. With the increase of tubular halloysite doping mass fraction， the density of cordierite ceramics increases and the open porosity decreases. The 10.0% tubular halloysite-doped cordierite ceramics have the highest elastic modulus， and the 20.0% tubular halloysite-doped cordierite ceramics have the highest hardness. Compared with pure cordierite ceramics， the average thermal expansion coefficient of cordierite ceramics doped with 2.5% tubular halloysite decreases from 1.40×10^-6 K^-1 to 0.65×10^-6 K^-1 at room temperature （25 ℃） to 160 ℃.

Selective Adsorption of Different Flavors by Waste Porcelain Powder/Glass Composite Porous Ceramics

ZENG Yingzi, DENG Tengfei

2026, 45(2):  613-624.  doi:10.16552/j.cnki.issn1001-1625.2025.0840

Asbtract ( 11 )   HTML ( 5)   PDF (2281KB) ( 3 )  

Figures and Tables | References | Related Articles | Metrics

By adjusting the ratio of waste porcelain powder and glass powder， porous ceramics with different porosities were sintered at a series of temperatures gradients from 910 ℃ to 990 ℃. Porous ceramics with different porosities were used as adsorbents to evaluate their adsorption/desorption performance for six flavors. The retained components within the porous ceramics were elucidated， and a release model for these flavors from the porous ceramics was established. The results indicate that the porous ceramics with 40% porosity exhibits the highest specific surface area， reaching 2.33×10⁶ mm²/g， along with the greatest adsorption capacity （223.98~301.82 mg/g） and the shortest adsorption time （2.68~9.90 s） for all six flavors. The dense pore network of the high porosity porous ceramics effectively shortens the diffusion path of the flavors， facilitating a faster adsorption rate. In the flavor release experiments， the release rate of the three alcohol-soluble flavors approach 100%， whereas those of three water-soluble flavors all remain below 70%. The main retained components of the three water-soluble flavors in the porous ceramics are DL-glyceraldehyde， L-lactic acid， and 5-hydroxymethylfurfural， respectively. These retained components contain two types of polar functional groups from among hydroxyl group （—OH）， aldehyde group （—CHO）， and carboxyl group （—COOH）， and they form a strong hydrogen-bonding network with the hydroxyl group on the surface of porous ceramics， which enhances the adsorption efficacy of the porous ceramics towards them.

Preparation of SiO₂-Coated Cu₂O via Hydrolysis Method and Study on Its Oxidation Resistance

YANG Yue, MIAO Lifeng, JIANG Xinmin, LIAO Lingchen, BAO Zhenhong

2026, 45(2):  625-633.  doi:10.16552/j.cnki.issn1001-1625.2025.0870

Asbtract ( 20 )   HTML ( 4)   PDF (3477KB) ( 7 )  

Figures and Tables | References | Related Articles | Metrics

This study successfully prepared the SiO₂ coated Cu₂O samples （Cu₂O@SiO₂） with a core-shell structure via a hydrolysis method， using Cu₂O as the core material and tetraethyl orthosilicate （TEOS） as the silicon source. The microstructure and oxidation resistance of the samples were systematically characterized by X-ray diffraction （XRD）， transmission electron microscopy （TEM）， energy dispersive spectroscopy （EDS）， Fourier transform infrared spectroscopy （FT-IR）， and simultaneous DSC-TG analysis. The results indicate that the Cu₂O@SiO₂ prepared under the conditions of a reaction temperature of 45 ℃， NH₃·H₂O concentration of 3.96% （mass fraction）， and TEOS concentration of 3.84% （mass fraction） retained Cu₂O as the primary crystalline phase even after heat treatment at 380 ℃ in an oxidizing atmosphere. Compared to uncoated pure Cu₂O， the initial oxidation temperature of the Cu₂O@SiO₂ increases from 230 ℃ to 385 ℃， representing an improvement of 155 ℃.

Preliminary Analysis of Microstructure and Physicochemical Composition of Ancient Porcelain from Huozhou Kiln in Shanxi Province

YANG Yuanqing, WANG Tian, GUO Rui, ZHU Jianfeng, LI Qiang, WANG Fen, LUO Hongjie

2026, 45(2):  634-645.  doi:10.16552/j.cnki.issn1001-1625.2025.0848

Asbtract ( 21 )   HTML ( 6)   PDF (5317KB) ( 5 )  

References | Related Articles | Metrics

To investigate the raw material characteristics of the body and glaze from Huozhou kiln ancient porcelains （white porcelain， white and black porcelain， and black porcelain）， this study utilized ultra-depth-of-field optical microscopy （OM）， X-ray fluorescence spectrometry （XRF）， X-ray diffractometer （XRD）， and ultraviolet-visible-near-infrared spectrophotometry （UV-Vis-NIR） to analyze the microstructure and physicochemical composition of the body and glaze. Comparative analysis was conducted with white porcelain from Ding kiln and white and black porcelain， from Cizhou kiln， Pacun kiln， and Xin’an kiln. The results indicate that in Huozhou kiln body， the Al₂O₃ content decreases in the following order： fine white porcelain， coarse white porcelain， black glaze porcelain， and white and black porcelain. While the SiO₂ content is similar in white porcelain and white and black porcelain bodies， it is lower in black porcelain bodies. The black porcelain body shows significant fluctuations in Al₂O₃， SiO₂， CaO and other components. Mullite constitutes the primary phase in the Huozhou kiln body， with minor quantities of quartz and cristobalite. There is a significant difference in the chemical composition of the matrix between Huozhou kiln and Ding kiln white porcelain. The former contains higher Al₂O₃， SiO₂， Na₂O and Fe₂O₃ content in the body， and higher Al₂O₃， K₂O and TiO₂ content in the glaze. There are also obvious differences in the chemical composition of the body and glaze between the white and black porcelain of Huozhou kiln and the porcelain of Cizhou kiln， Pacun kiln and Xin’an kiln. The former glaze contains higher MgO， Al₂O₃ and Fe₂O₃ content. The white porcelain body of Huozhou kiln is pure white， the white and black porcelain is gray white， and the black glaze porcelain body is dark brown， which is related to the concentration of coloring elements in the body. The average value of the acidity coefficient of the chemical elements of the glaze decreases in the order： white porcelain， white and black porcelain， and black glaze porcelain， reflecting that the firing temperature of the three types of products decreases in turn. UV-Vis-NIR reflectance spectroscopy shows that Huozhou kiln white porcelain and white and black porcelain have multiple reflection peaks at 400~800 nm， and the main reflection peak is located at 420~500 nm， while black glaze porcelain has no obvious reflection peak.

Glass

Reaction Mechanism of Methane-Flue Gas Thermochemical Reforming

ZENG Hongjie, ZHOU Wencai, GUAN Min, SHEN Zhongjie, HE Guinan, CHEN Shuyong, CHEN Jiarui, LI Hongqiang, WANG Wei, ZUO Zefang

2026, 45(2):  646-654.  doi:10.16552/j.cnki.issn1001-1625.2025.0886

Asbtract ( 12 )   HTML ( 2)   PDF (2373KB) ( 4 )  

Figures and Tables | References | Related Articles | Metrics

Studying the mechanism of methane-flue gas thermochemical reforming reaction is crucial for a deeper understanding of the interactions between methane-flue gas reforming reactants， optimizing methane-flue gas reforming reaction conditions and parameters， and improving the reaction yield and purity of methane-flue gas reforming reaction products. Experimental studies were conducted on dry reforming of methane and steam methane reforming reactions under different experimental conditions using an atmospheric pressure tube furnace. The effects of different experimental parameters on the reaction processes， reaction activity， and selectivity of dry reforming of methane and steam methane reforming reactions were analyzed. The results indicate that the methane-flue gas reforming reaction process is accompanied by the occurrence of methane cracking reaction. At temperatures below 1 100 ℃， methane cracking tends to generate carbon black and hydrogen gas. At temperatures above 1 100 ℃， methane cracking tends to generate acetylene ［C₂H₂］ and hydrogen gas. Under the same reaction conditions， the activity of steam methane reforming reaction is greater than that of dry reforming of methane. The increase in reforming reaction temperature is beneficial for the progress of methane-flue gas reforming reaction.

Refractory Materials

Erosion Behavior of Refining Slag with Different Basicities on Magnesia-Carbon Refractories

YE Yukui, LEI Changkun, LIAO Jiaming, ZHANG Xin, HU Tianzeng, REN Bo, WANG Enhui, HOU Xinmei

2026, 45(2):  655-662.  doi:10.16552/j.cnki.issn1001-1625.2025.0832

Asbtract ( 16 )   HTML ( 3)   PDF (2679KB) ( 7 )  

Figures and Tables | References | Related Articles | Metrics

Three types refining slag with different basicities （R = 0.8， 1.0， and 1.2） were prepared. The influence of basicity on resistance to slag erosion of MgO-C bricks was systematically investigated using thermodynamic calculations， surface tension measurements and dynamic anti-slag test. The results show that with the increase of basicity， the viscosity of slag decreases and the surface tension increases significantly. In refining slag S1 （R=0.8）， higher solubility of MgO results in more severe erosion of MgO-C refractories. For refining slag S3 （R=1.2）， increased CaO content causes reduced viscosity and elevated surface tension， which enhances slag penetration by 69.14% compared to refining slag S1 （R=0.8）. However， the structural integrity of refractory is relatively well-preserved. This study demonstrates that moderately increasing refining slag basicity can extend the service life of MgO-C refractories. However， in practical application， it is necessary to comprehensively consider its influence on inclusions in steel.

Functional Materials

Current Status of Tobermorite Crystal Structure, Synthesis-Modification, and Adsorption Applications

QIN Juan, CAO Guoyi, SHI Jiayu, JI Qiang, LYU Jiarui, GU Xiaomin, SHI Jian

2026, 45(2):  663-674.  doi:10.16552/j.cnki.issn1001-1625.2025.0833

Asbtract ( 22 )   HTML ( 2)   PDF (1529KB) ( 13 )  

Figures and Tables | References | Related Articles | Metrics

Tobermorite （TOB） is a layered calcium silicate hydrate with a high specific surface area. Its research and applications have expanded from traditional building materials to functional fields such as environmental remediation， owing to its unique crystal structure. This paper provides a comprehensive review of recent advances in TOB research and compares the differences between two common synthesis techniques （traditional hydrothermal and microwave-assisted hydrothermal methods）. It further introduces various modification strategies， including ion doping， thermal activation， acid washing， and loading， which are employed to enhance the adsorption performance of TOB. The underlying mechanisms and current applications of TOB for removing nitrogen/phosphorus， heavy metals， and organic dyes from wastewater are also systematically summarized. Although TOB has demonstrated high adsorption potential， its large-scale applications still face a series of challenges. This paper aims to provide a theoretical foundation and technical reference for the functional development and sustainable utilization of TOB. Prospects for future research on TOB are also proposed， encompassing the development of efficient synthesis routes， optimization of modification techniques， and exploration of synergistic applications in multiple fields.

Influence of Polyvinyl Alcohol Modification on Lithium-Magnesium Separation of Two-Dimensional Montmorillonite Channel Membrane

WANG Jierui, ZHAO Yunliang, WANG Zhenlei, ZHANG Tingting, ZHANG Xin, LI Ying

2026, 45(2):  675-683.  doi:10.16552/j.cnki.issn1001-1625.2025.0875

Asbtract ( 10 )   HTML ( 3)   PDF (2845KB) ( 4 )  

Figures and Tables | References | Related Articles | Metrics

Lithium is a key strategic resource to support the new energy revolution， and the total amount of China’s salt lake lithium resources holds a dominant position globally. However， Chinese salt lakes commonly suffer from a high magnesium-lithium ratio， which poses a significant challenge for the efficient separation of lithium and magnesium. This study proposed the use of polyvinyl alcohol （PVA）-modified montmorillonite nanosheets. By precisely controlling the gradient amount of PVA， the channel height of montmorillonite nanosheets was regulated， enabling the highly efficient separation of lithium and magnesium. Furthermore， this work elucidated the mechanism by which PVA modulates the channel height of montmorillonite nanosheets. It is found that PVA can be connected to montmorillonite nanosheets through hydrogen bonds， and enters the montmorillonite layers through intercalation， regulating the channel height of two-dimensional montmorillonite membranes， and achieving efficient separation of lithium and magnesium ions. The separation factor of lithium and magnesium in the simulated brine of the modified membrane can reach up to 92.61， which is 20 times higher than that of the unmodified membrane. The modified membrane demonstrates excellent lithium and magnesium separation capability in brine with high salt concentrations and coexisting multiple cations. The magnesium ion rejection rate remains stable at approximately 97%， and the flux is consistently maintained at a level of approximately 30 L·m^-2·h^-1 after 48 h of long-term stable operation.

Synthesis of Nitrogen-Doped TiO₂ and Its Photocatalytic Performance in Tetracycline Degradation

YANG Shuai, LI Xia, YAO Mengqin, LIU Fei

2026, 45(2):  684-694.  doi:10.16552/j.cnki.issn1001-1625.2025.0798

Asbtract ( 25 )   HTML ( 2)   PDF (5333KB) ( 8 )  

Figures and Tables | References | Related Articles | Metrics

Photocatalysis is an effective method for degrading tetracycline （TC）， with photocatalytic materials serving as the core component of this process. Titanium dioxide （TiO₂） is a highly efficient and environmentally friendly photocatalytic material. However， it suffers from rapid recombination of photogenerated carriers and a narrow ultraviolet light response range. To address these limitations， this study employed a gradient nitrogen （N）-doping strategy to modify sea-urchin-like TiO₂. An in situ hydrothermal method was utilized to construct N-doped TiO₂ materials， systematically elucidating the regulatory effects of N-doping concentration on the structure and performance of photocatalyst. Experimental result indicate that when the nitrogen-to-titanium ratio （n_N∶n_Ti） is 5， the prepared photocatalyst （5N-TiO₂） exhibits the best photocatalytic performance， achieving a 64% degradation rate for TC under 120 min of visible light irradiation. This represents a 137% enhancement compared to undoped TiO₂. Characterization analysis reveals that 5N-TiO₂， rich in Ti³⁺ and oxygen vacancies， synergistically narrows the band gap of TiO₂ from 3.07 eV to 2.60 eV， and significantly improves the separation rate of photogenerated carriers. However， further increasing the N-doping concentration level shows that excessive N forms electron-hole recombination centers， thereby reducing carrier lifetime. Consequently， the photocatalytic performance of 10N-TiO₂ （n_N∶n_Ti=10） decrease to 41% of that of undoped TiO₂.

Road Materials

Mix Ratio Optimization of Slag-Fly Ash Geopolymer Grouting Materials

LIU Meifang, LIU Jianzheng, HU Liqun, GAO Shengfa, LIU Jiahong, LI Guochao

2026, 45(2):  695-711.  doi:10.16552/j.cnki.issn1001-1625.2025.0812

Asbtract ( 23 )   HTML ( 5)   PDF (3082KB) ( 57 )  

Figures and Tables | References | Related Articles | Metrics

In order to provide mix ratio design references and theoretical support for the promotion and application of geopolymer grouting materials in road trenchless grouting reinforcement and other projects， for slag-fly ash geopolymer grouting materials （SFGGM）， the influences of water-to-binder ratio， alkali equivalent， sodium silicate modulus and fly ash content on multiple key indicators such as fluidity， setting time， drying shrinkage rate and mechanical property were obtained through range analysis and analysis of variance by using four-factor and four-level orthogonal experiments. On this basis， a comprehensive weight analysis of multiple indicators was conducted with AHP-entropy method to select the optimal mix ratio scheme that takes into account workability， volume stability and mechanical property. The results show that the water-to-binder ratio has the most significant impact on fluidity. As the water-to-binder ratio increases， the fluidity of slurry improves significantly. The alkali equivalent is the dominant factor controlling the setting time and drying shrinkage rate. If alkali equivalent is too high， it will lead to shorten setting time and increased drying shrinkage rate. The fly ash content is a key factor affecting compressive strength and flexural strength. Excessive content leads to a decrease in compressive strength and flexural strength. Moderately increasing the alkali equivalent and sodium silicate modulus is conducive to promoting strength development. The main influencing factors of each performance index obtained from range analysis and analysis of variance are consistent. The optimal ratio for comprehensive performance is as follows： water-to-binder ratio 0.6， sodium silicate modulus 1.6， alkali equivalent 6%（mass fraction）， and fly ash content 0.4（the proportion of total mass of silicon and aluminum source ash）.

Characteristics of Deformation and Energy Evolution of Roadbed Medium-Grained Sandstone under Differential Fatigue Loading

LIU Gaoxi, WU Yunfeng, LIU Yongliang, LIU Yong

2026, 45(2):  712-724.  doi:10.16552/j.cnki.issn1001-1625.2025.0773

Asbtract ( 13 )   HTML ( 3)   PDF (6755KB) ( 14 )  

Figures and Tables | References | Related Articles | Metrics

In order to reveal the mechanical response mechanism of medium-grained sandstone under differential fatigue load， this paper studied the deformation characteristics and energy evolution law of sandstone under three loading modes （slow loading and rapid unloading， constant speed loading and unloading， rapid loading and slow unloading） through laboratory tests. The dynamic changes of peak strain， residual strain and energy dissipation of the samples were analyzed by MTS 322 rock mechanics test system. The results show that under varying loading modes， the strain exhibited by sandstone remains consistent， with the residual strain approximating the deformation discrepancy between successive cyclic stages. The peak strain is observed to be largest in the slow and fast unloading mode， and smallest in the fast and slow unloading mode. Furthermore， the residual strain exhibits a logarithmic growth at the initial stage due to the compression and density of the internal defects， and increases linearly with the maximum cyclic stress in subsequent stages. The input energy and elastic energy increase stepwise with the number of cycles， and the dissipation energy increase rate is significantly higher in the slow-plus-slow unloading mode than in the other modes. The dissipation energy of the first cycle of a single cyclic stage is elevated， and the mean dissipation energy is exponentially associated with the maximum cyclic load. The dissipated energy ratio fluctuates and converges with the number of cycles， a phenomenon that is closely related to the internal damage inhomogeneity of material damage and the fluctuation of loading stress. The present study elucidates the influence mechanism of loading rate on the fatigue performance of sandstone， thereby providing a theoretical basis for the selection of road base layer materials and structural optimization.

Strength and Dry-Wet Cycle Resistance of Magnesium Oxide-Activated Ground Granulated Blast Furnace Slag-Basalt Fiber Stabilized Shield Residues

CAO Wei, LI Xinyang, LIU Fuyou

2026, 45(2):  725-734.  doi:10.16552/j.cnki.issn1001-1625.2025.0449

Asbtract ( 19 )   HTML ( 3)   PDF (1596KB) ( 8 )  

Figures and Tables | References | Related Articles | Metrics

In this paper， the shield residues solidified by magnesium oxide （MgO）-activated ground granulated blast furnace slag （GGBS）-basalt fiber （referred to as “modified samples”） were studied， aiming to explore the improvement effect of this curing agent （MgO-activated GGBS-basalt fiber） on the engineering properties of shield residues. The dosage of the curing agent accounts for 8%， 15% and 30% of the dry mass of shield residues， and the dry mass ratio of MgO to GGBS （m（MgO）∶m（GGBS）） ranges from 1∶9 to 1∶3. The strength and dry-wet cycle resistance of the modified samples were evaluated via unconfined compressive strength tests and modified dry-wet cycle tests （under acidic sulfate condition， pH=5.0）， with cement stabilized shield residues serving as the control group. The results show that： after 120 d of standard curing， the unconfined compressive strength of the modified sample with m（MgO）∶（GGBS）=1∶7 is 4%~24% higher than that of modified samples with other ratios. The pH value of the modified samples is 4%~7% lower than that of the control group. The mass variation and cumulative mass variation of both the modified samples and the control group increase gradually with the increase in the number of dry-wet cycles. After 10 dry-wet cycle tests， the unconfined compressive strength of the modified samples decreases by 22%， while that of the control group decreases by 52%. In conclusion， the shield residue samples solidified by MgO-activated GGBS-basalt fiber （modified samples） exhibit superior strength and dry-wet cycle resistance.