Table of Content

Volume 45 Issue 1
20 January 2026

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Cement and Concrete

Research Status on Basic Mechanical Properties and Engineering Applications of Coral Concrete

WANG Wensheng, LYU Hailong, MA Jiangtao, LIU Qi, NIE Xiaodong

2026, 45(1):  1-20.  doi:10.16552/j.cnki.issn1001-1625.2025.0700

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Coral concrete is a marine engineering material composed of coral sand， reef limestone as aggregates， blended with cementitious materials such as cement， fly ash and admixtures， and mixed with seawater. In marine engineering and island reef construction， it can maximize the use of local materials， save resources and reduce transportation costs， which is of great significance to promote island reef engineering construction. This study systematically introduces the characteristics of coral raw materials， methods for modifying coral concrete， mix proportion design， and research progress in static mechanical performance， dynamic mechanical performance， penetration and explosion resistance. It analyzes the effects of mix proportion design， mineral admixtures and fiber reinforcement technology on improving the mechanical properties of coral concrete. In addition， it discusses and prospects the existing problems in the current research on coral concrete， aiming to provide key technical support for the large-scale application of coral concrete in island reef engineering construction and accelerate the implementation of the maritime power strategy.

New Spraying Construction and Crack Repair Performance of Ultra-Rapid Setting Magnesium Phosphate Cement Coating

YU Qiuchun, LI Wei, LIANG Yun, DENG Yongjie, HUANG Hanhan, LI Weihong, LI Dongwei

2026, 45(1):  21-29.  doi:10.16552/j.cnki.issn1001-1625.2025.0676

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Aiming at the construction problem caused by the rapid setting and hardening of magnesium phosphate cement （MPC） under the condition of no retarder， this study adopted the new mixing-stirring-spraying integrated spraying construction to carry out the mechanized construction of ultra-rapid setting MPC coating， which effectively solved the bottleneck of jet construction of rapid setting cement coating and reduced the cost of raw materials. Based on this， this paper focused on the influence of spraying ultra-rapid MPC coating on the chloride ion penetration resistance of concrete matrix， and evaluated the improvement effect of ultra-rapid MPC coating on the mechanical properties and chloride ion penetration resistance of cracked mortar members. The results show that after 90 d seawater immersion， the chloride ion content of coated concrete in the depth 0~<5 mm is significantly reduced by 24.8% （mass fraction） compared with that of uncoated concrete， and the chloride ion penetration resistance is effectively improved. The permeability behavior of chloride ion in coated concrete obeys the law of decreasing with the increase of structural depth. In the depth 0~<5 mm， the chloride ion content increases with the increase of seawater immersion age， and gradually tends to be saturated， reaching saturation at 454 d， and the content is 0.193 %. The 28 d flexural strength of the cracked concrete members after coating repair is increased by 131.3%， and the chloride ion content in the depth 0~<5 mm is reduced by 12.9%. This study provides a theoretical basis for the application of spraying ultra-rapid MPC coating in the protection， repair and reinforcement of concrete structures in marine environment.

Time-Lag Analysis and Dynamic Accounting of Environmental Benefits of Pavement Cement Concrete Carbon Sequestration

YANG Zhaoning, ZHANG Duan, SUN Boxue, GAO Feng, LI Xiaoqing, NIE Zuoren, CUI Suping

2026, 45(1):  30-39.  doi:10.16552/j.cnki.issn1001-1625.2025.0619

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Cement materials exhibit significant carbon sequestration potential over their life cycle. However， effective accounting methods for their environmental benefits remain underdeveloped. This study established a time-lag analysis model for pavement cement concrete carbon sequestration based on dynamic characterization metrics， enabling a systematic evaluation of the temporal distribution and environmental benefits of carbon sequestration throughout the life cycle of pavement cement concrete. To address the shortcomings of static accounting approaches， two corrective parameters are proposed： the time factor α and the emission offset β. Results show that over a 100 a timeframe， the total carbon sequestration from cement materials accounts for 22.18% of the CO₂ emissions associated with cement production. Compared to the dynamic approach， traditional methods overestimate the environmental benefit of cement carbonation by 53.8%. Moreover， the time-lag analysis reveals that under a 100 a time horizon， α is 0.65 and β is 38 614.79 kgCO₂e. These parameters allow for rapid correction of static carbon accounting outcomes. The findings provide a methodological foundation for the accurate quantification of cement carbon sequestration and offer strategic implications for carbon management in long-lived infrastructure systems.

Influence of Pre-Curing on Macroscopic Properties and Microstructure of Silicon Calcium Slag Composite Autoclaved Aerated Concrete

LIANG Xinxing, ZHANG Jingshen, WANG Chaosheng, LIANG Liguizu, LIU Ze, ZHANG Tong, ZHU Yingcan

2026, 45(1):  40-46.  doi:10.16552/j.cnki.issn1001-1625.2025.0721

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In this paper， silicon calcium slag， slag， and desulfurization gypsum were used as the main raw materials. By adjusting the process parameters such as fresh slurry temperature， pre-curing temperature and pre-curing time， the influence of the preparation process of silicon calcium slag composite autoclaved aerated concrete on dry density， compressive strength， and microstructure was studied. The results show that with the increase of fresh slurry temperature， the compressive strength of the test block shows a trend of increasing first and then decreasing， reaching a peak at 45 ℃， an increase of 96.3% compared to 25 ℃. With the increase of pre-curing temperature， the compressive strength of the test block shows a trend of increasing first and then decreasing. When the pre-curing temperature is 62.5 ℃， the compressive strength increases by 19.6% compared to the 52.5 ℃ group. When the pre-curing time is 8 h， the tobermorite is arranged in a large leaf like orderly manner， and the test block reaches the A05 strength level. If the pre-curing time is too short （<8 h）， it will cause uneven distribution of the main hydration product tobermorite. If the pre-curing time is too long （>8 h）， it will cause interface degradation. By optimizing the process parameters （fresh slurry temperature of 45 ℃， pre-curing temperature of 62.5 ℃， pre-curing time of 8 h）， the mechanical properties and pore uniformity of silicon calcium slag composite autoclaved aerated concrete can be synergistically improved， providing theoretical support for the industrial application of calcium silicate slag building materials.

Effect of Modification on Properties of 3D Printing Rice Straw Fiber Cement-Based Composite

JIANG Demin, HU Siyu, KANG Honglong, LI Yujin, HOU Yuxiang

2026, 45(1):  47-57.  doi:10.16552/j.cnki.issn1001-1625.2025.0622

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To explore the application of plant fibers in 3D printing cement-based materials， this study used rice straw fiber as an additive and investigated the modification effects of boiling treatment and potassium permanganate solution treatment on rice straw fiber， as well as their impact on the performance of 3D printing rice straw fiber cement-based composite. The results show that boiling treatment makes fiber surface clean and rough but increases their water absorption.Potassium permanganate solution treatment reduces water absorption while increasing surface roughness and crystallinity. Both modification methods significantly improve the mechanical properties， the interlayer bonding strength and interstrip bonding strength of 3D printing rice straw fiber cement-based composites， with the potassium permanganate modification superior. This work offers new idea for design and performance optimization of 3D printing rice straw fiber cement-based materials and broadens the application of rice straw fiber in the construction field.

Resistance to Chloride Ion Erosion of Jointed Concrete in Salt Spray Environment

YAN Yongdong, WANG Zonghao, LU Chunhua, WU Keke, JIANG Cheng

2026, 45(1):  58-68.  doi:10.16552/j.cnki.issn1001-1625.2025.0672

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To investigate the chloride ion ingression mechanism in concrete with construction joints in coastal salt spray environment， chloride ion erosion tests were carried out on jointed concrete specimens in a salt spray environment， considered factors such as joint type， erosion time， and material composition， measured the chloride ion mass fraction at jointed and non-joint areas at different ages. The results show that at the same erosion time， the chloride ion mass fraction at the joint area is higher than that at the non-joint area， with the highest mass fraction at the direct wet joint. Along the concrete depth， the chloride ion mass fraction increases first and then decreases， reaching the maximum value at 4 mm deep from the exposed surface of concrete. Addition of crystalline admixture （CA） or a combination addition of CA and UEA expansive agent could both reduce the chloride ion mass fraction at the joint area， thereby mitigating the adverse effects of joints on the durability of concrete. The chloride ion diffusion coefficients at the non-joint area and joint area show the same attenuation trend with the salt spray time， the coefficient value at the joint area is approximately 1.3 times that at the non-joint area.

Temperature Response and Thermo-Mechanical Field Regulation Mechanism of Phase Change Concrete under Freeze-Thaw Cycles

LI Tong, WANG Qinghe, ZHANG Yichao

2026, 45(1):  69-80.  doi:10.16552/j.cnki.issn1001-1625.2025.0799

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China has a wide distribution of severely cold and cold regions， where concrete structures are long-term exposed to freeze-thaw cycles， making them prone to damage and significantly shortening their service life. Leveraging their heat absorption and release properties， phase change materials can effectively regulate the temperature and stress fields within concrete. Based on this， this study first established a mesoscale finite element model of phase change concrete considering different phase change material content and replacement ratios of recycled aggregates， and validated the model’s accuracy through CT scanning tests. Subsequently， the finite element numerical simulation method was employed to analyze the temperature response and the evolution law of the thermal-mechanical field in phase change concrete during freeze-thaw cycles. The results indicate that phase change materials can effectively inhibit the transfer rate of external temperature into concrete， mitigating the temperature fluctuations caused by increased replacement ratios of recycled aggregates. Meanwhile， the incorporation of phase change materials significantly reduces the average thermal stress and the maximum principal stress difference within concrete. When the content of phase change materials increases from 0% to 8% （mass fraction）， the average thermal stress of concrete decreases by 12.6%， and the average maximum principal stress difference in the interfacial transition zone between aggregates and mortar drops by 47.0%. By buffering temperature-induced deformations through their latent heat effects， phase change materials effectively alleviate stress concentration， thereby enhancing the freeze-thaw resistance of concrete.

Load-Bearing Capacity of GFRP Bar Sea Sand Concrete Deep Flexural Members in Chloride Environment

JIN Qingping, YANG Zhenyuan, LIANG Yingqiang, LIU Yundie, SONG Shie

2026, 45(1):  81-91.  doi:10.16552/j.cnki.issn1001-1625.2025.0800

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In coastal and marine engineering， using sea sand to replace river sand can reduce the costs associated with cross-regional transportation of river sand and help protect terrestrial ecosystems. Coupled with the use of glass fiber reinforced polymer （GFRP） bars instead of steel reinforcement， it effectively resolves the issue of chloride ion corrosion in sea sand.For the common bent caps and other deep flexural members in offshore bridges， 30 GFRP bar-sea sand concrete deep flexural members were fabricated， and their load-bearing performance was tested after immersion in a chloride environment for different durations， including failure modes， deflection， cracking， and ultimate load capacity. The results show that chloride salt immersion changes the failure mode of GFRP bar-sea sand concrete deep flexural members from concrete crushing to shear failure. As the immersion time increases， the cracking load of the members increases， the ultimate load capacity of the members decrease， the cracks number of the members gradually reduces， and the maximum deflection value of the members increase. Based on the test results， the existing code formula for calculating the load-bearing capacity of reinforced concrete deep flexural members is modified by introducing the GFRP bar reduction factor index. The modified formula can well predict the ultimate load capacity of GFRP bar-sea sand concrete deep flexural members after immersion in a chloride environment.

Compressive Damage of Basalt Fiber Reinforced Foam Concrete Based on Digital Image Correlation

AN Yangzhuang, YU Hai, LIU Changgeng

2026, 45(1):  92-102.  doi:10.16552/j.cnki.issn1001-1625.2025.0646

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To investigate the compressive damage evolution law of basalt fiber reinforced foam concrete， this paper employed quasi-static compression tests and utilized digital image correlation technology for full-field strain analysis. It explored the effects of matrix density （600~1 200 kg/m³） and basalt fiber volume content （0%~0.5%） on the mechanical properties and damage behavior of basalt fiber reinforced foam concrete. The results indicate that the most significant improvement in the ultimate compressive strength of basalt fiber reinforced foam concrete is achieved when the basalt fiber volume content is 0.3% or 0.4%. The compression process of basalt fiber reinforced foam concrete can be divided into four stages： compaction， linear elastic， plastic， and failure. Furthermore， based on the full-field， full-process strain data acquired via digital image correlation， this study defined a damage degree factor and a damage localization coefficient to quantitatively characterize and analyze the material’s damage extent and localization behavior. The incorporation of basalt fiber effectively increases the initial damage load of basalt fiber reinforced foam concrete， delays the damage evolution process， reduces the degree of damage localization， and alters the material’s failure mode.

Effect of Foaming Pressure on Properties of Magnesium Oxysulfate Cement-Based Ultra-Lightweight Foam Concrete

ZHOU Yutong, ZHOU Zheng, QIU Lyuchao, LU Kuangda, XU Dongmei, ZHANG Shiyuan, ZHANG Shixuan, JIAN Shouwei, TAN Hongbo

2026, 45(1):  103-111.  doi:10.16552/j.cnki.issn1001-1625.2025.0696

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This study proposed a preparation technique for magnesium oxysulfate cement-based ultra-lightweight foam concrete （MOS-ULFC）， in which pressure is applied during the prefabricated foaming and slurry mixing stages， followed by pressure release during molding. The pressure differential induced bubble expansion， thereby increasing porosity and achieving ultra-lightweight characteristics. The effects of different foaming pressures on the density， mechanical properties， thermal conductivity， and pore structure of MOS-ULFC were systematically analyzed. Results show that， within the range of 101~160 kPa， increasing the foaming pressure markedly reduces the density and thermal conductivity of MOS-ULFC. When the foaming pressure increases from 101 kPa to 130 kPa， the dry density decreases from 157.81 kg/m³ to 49.22 kg/m³， with a reduction of 68.81%， while the thermal conductivity decreases from 0.069 8 W/（m·K） to 0.037 1 W/（m·K）， with a reduction of 46.85%. At 160 kPa， both density and thermal conductivity of MOS-ULFC increase slightly but remaine lower than those of the atmospheric-pressure group （101 kPa）. Applying pressure during prefabricated foaming and slurry mixing stages significantly increases the internal pressure of bubbles. Upon returning to atmospheric pressure after molding， the trapped air rapidly expands， leading to a substantial increase in bubble size， and consequently， in average pore size and porosity. Specifically， when the foaming pressure increases from 101 kPa to 130 kPa， the average pore size increases from 78.53 μm to 113.49 μm （an increase of 44.52%）， while the total porosity increases from 91.94% to 96.21%. This work provides a new approach for the ultra-lightweight design and preparation of foam concrete.

Effect of Raw Material Molar Ratio on Macro-Properties of Modified Magnesium Oxysulfate Cementitious

QIU Junfu, ZHANG Ruifeng, WANG Zhenghua, SHU Chunxue, ZHANG Jiayang, HE Xinxin, LI Yuyang

2026, 45(1):  112-122.  doi:10.16552/j.cnki.issn1001-1625.2025.0735

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To investigate the effects of the oxygen-sulfur ratio and water-sulfur ratio on the macro-properties and mechanisms of modified magnesium oxysulfate cementitious， the influence patterns of the raw material oxygen-sulfur ratio （M=n（α-MgO）∶n（MgSO₄）） and water-sulfur ratio （H=n（H₂O）∶n（MgSO₄）） on the hydration products， mechanical properties， and water resistance of MOS were studied through XRF， hydration heat analysis， XRD， and SEM. The results indicate that： with the water-sulfur ratio fixed at 20∶1 and the oxygen-sulfur ratio fixed at 11∶1， the magnesium oxysulfate cementitious exhibits optimal mechanical properties； with the oxygen-sulfur ratio fixed at 8∶1 and the water-sulfur ratio fixed at 18∶1， the mechanical properties of magnesium oxysulfate cementitious are optimized. An increase in oxygen-sulfur ratio promotes the formation of over 80% by mass of the 5·1·7 phase， where needle-like 5·1·7 crystals interweave into a network structure. These crystals， along with unreacted MgO in the system， fill the pores in the sample， resulting in a denser structure and improved mechanical properties. Compared to the magnesium oxysulfate cementitious with an oxygen-sulfur ratio of 7∶1， the 28 d flexural strength and 28 d compressive strength of the cementitious with an oxygen-sulfur ratio of 11∶1 increase by 51.1% and 34.8%， respectively. Conversely， an increase in water-sulfur ratio leads to the hydration of MgO （which originally acts as a filler） into Mg（OH）?， causing volumetric expansion and a reduction in mechanical performance of magnesium oxysulfate cementitious.

Influence of Formwork Surface Roughness on Appearance Quality of Concrete Products

LI Shunkai, DOU Huakang, SUN Fengpin, CHEN Ronghui, LI Jie

2026, 45(1):  123-132.  doi:10.16552/j.cnki.issn1001-1625.2025.0766

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To systematically explore the influence mechanism of formwork surface roughness on the apparent quality of concrete， this study employed image analysis technology to investigate the influence of different formwork surface roughness on the concrete surface porosity， pore distribution， mirror reflection characteristic （gray value）， and color difference （gray level standard deviation value）. XRD and SEM analyses were employed to analyze the formation mechanism of the color difference. The results indicate that as formwork surface roughness increases， the concrete surface porosity shows an upward trend， and the proportion of large pores increases， while the proportion of small pores decreases accordingly. The gray value of the concrete surface decreased with the increase of the formwork surface roughness. Lower formwork surface roughness helps the surface structure of the specimens more compact and enhances the mirror reflection ability， thereby increases the gray value. However， surface color difference （gray level standard deviation value） of the concrete first increases and then decreases with the increase of the formwork surface roughness，and is most pronounced in concrete formed under the lowest formwork surface roughness.Microscopic test results show that when formwork surface roughness is low， the surface of formwork is smooth， the content of Ca（OH）₂ and the microstructure density in adjacent parts of the concrete surface are slightly increased， resulting in the formation of dark areas on the formed surface and causing color differences.

Experimental Study on Nutrient Slow-Release Performance of Nutrient Aggregate Ecological Concrete

LEI Jinsheng, TAN Jiawei, SHI Xiaoyu, LEI Junjie, LIU Jinxin

2026, 45(1):  133-144.  doi:10.16552/j.cnki.issn1001-1625.2025.0716

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Ecological concrete used in riparian environments necessitates needs to enhance nutrient retention capacity， extend fertiliser efficacy cycles， and improve ecological restoration performance. Nutrient slow-release aggregates were prepared using materials containing fertiliser components， which were then substituted for natural coarse aggregates at varying substitution rates of nutrient aggregate to produce nutrient aggregate ecological concrete with different porosities. Tests measured nutrient release amount in aquatic environments， analysing how porosity and nutrient aggregate substitution rates influenced nutrient slow-release performance， mechanical properties， and water permeability of nutrient aggregate ecological concrete. Concurrently， vegetation performance tests were conducted to investigate how slow-release properties of ecological concrete influence vegetation performance. Results indicate that granulated nutrient aggregates effectively reduce nutrient loss through their stable structure. Slurry coating reduces nutrient release rates without blocking nutrient availability， achieving slow-release fertilization and sustain nutrient supply. Nutrient aggregate ecological concrete dynamically regulates nutrient release. Specimens with lower porosity exhibit superior mechanical performance at equivalent substitution rate of nutrient aggregate. Porosity and nutrient aggregate substitution rate can serve as key indicators for regulating the vegetation performance of ecological concrete.

Solid Waste and Eco-Materials

Research Progress on Metakaolin-Based Geopolymers and Their Application in Conservation of Grottoes

YANG Gangliang, MIAO Xiaobin, YAN Shaojun

2026, 45(1):  145-155.  doi:10.16552/j.cnki.issn1001-1625.2025.0606

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The conservation of grottoes， including water damage control and restoration， has extremely high requirements for the compatibility of physical-mechanical properties and weather resistance of materials. Metakaolin （MK）， a highly active pozzolanic material， serves as a raw material for geopolymers that demonstrate exceptional stability and durability. In recent years， these geopolymers have been increasingly applied in grottoes conservation. When the MK precursor is mixed with an alkaline solution， silicon and aluminum tetrahedra polymerize to form an initial polymer with Si—O—Al—O bonds， which further undergoes polycondensation to create a stable， three-dimensional network gel material—known as metakaolin-based geopolymer （MKG）. The properties of MKG are closely related to factors such as the composition of the MK， the type of alkaline activator， and temperature. However， its practical application and effectiveness in cultural heritage conservation are usually constrained by challenges like salt alkali resistance and specific service environments. Therefore， it is imperative to integrate advancements in materials science with the specific needs of cultural relic conservation to enhance the application and performance of MKG in preservation practices.

Mechanical Properties and Carbon Sequestration Capacity of CO₂-Cured Recycled Aggregate Concrete Incorporating Coconut Shell Biochar

HUANG Zhenhui, ZHAO Fei, CHANG Jun, LI Wenzheng, ZHOU Zhi

2026, 45(1):  156-164.  doi:10.16552/j.cnki.issn1001-1625.2025.0724

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To address the dual challenges of construction waste recycling and carbon sequestration in the concrete industry， this study employed CO₂-mineralized recycled coarse aggregates （RCA） and coconut shell biochar （CSB） as sustainable substitutes for natural aggregates. The effects of RCA （0% to 100% by mass replacement） and CSB （0% to 30% by volume replacement） on the mechanical properties， carbon sequestration capacity， and microstructure of CO₂-cured recycled aggregate concrete were systematically investigated. Results indicate that the concrete with optimal mixture （0% RCA + 20% CSB） achieves a compressive strength of 42.1 MPa （a 38.0% increase compared to the control group with normal curing） and a splitting tensile strength of 3.86 MPa （a 23.7% improvement）. This enhancement is attributed to the hierarchical pore structure of CSB， which regulates moisture to promote secondary hydration and facilitates CO₂ diffusion， thereby driving the densification of CaCO₃. Multiscale characterization via thermogravimetric analysis， Fourier transform infrared spectroscopy， and scanning electron microscopy reveals that a 20% CSB substitution rate not only promotes the polymorphic transformation of CaCO₃ but also maintains the stability of calcium silicate hydrate （C-S-H）， resulting in a 100% increase in carbon sequestration capacity. This study demonstrates a synergistic approach to waste valorization and CO₂ utilization， offering an effective strategy for developing high-performance， low-carbon concrete with significant implications for sustainable construction practices.

Influence of Burnt Coal Cinder on Mechanics and Hydration Process of Cement

LIU Shiqi, ZHOU Zichen, HUANG Xiulin, ZENG Ming, ZHANG Bing, ZHANG Jianfeng, SHEN Chunhua

2026, 45(1):  165-176.  doi:10.16552/j.cnki.issn1001-1625.2025.0600

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The low hydration reactivity of burnt coal cinder limits its application as supplementary cementitious material. In this study， the hydration reactivity of burnt coal cinder was activated by mechanical ball milling method， and mechanism of improving the reactivity of burnt coal cinder and its effect on the mechanical properties and hydration process of composite cementitious material were systematically explored. The results show that the layered aluminosilicate structure in burnt coal cinder is destroyed by mechanical ball milling， leading to the changes in the binding energies of Si—O and Al—O. The concentrations of reactive Si and Al increase by 694.55% and 634.27% in ball milling burnt coal cinder compared to burnt coal cinder. When the ball milling burnt coal cinder content is 30% （mass fraction）， the 3 and 28 d compressive strength of composite cementitious material increase by 6.03% and 22.38%， respectively， compared to the basic group， and increase by 49.13% and 82.99%， respectively， compared to the reference group. The incorporation of ball milling burnt coal cinder promotes the consumption of Ca（OH）₂， which results in the increase of hydration products such as calcium silicate hydrate （C-S-H） gel， and the densification of microstructure， thereby improving the mechanical properties of composite cementitious material. The cumulative heat of hydration gradually decreases with the increase of ball milling burnt coal cinder content without affecting the mechanical properties of composite cementitious material.

Effect of Fluorine-Containing Composite Activator on Hydration Products and Properties of Steel Slag-Based Thermal Storage Cement

ZHOU Yelai, MA Huibo, ZHANG Shidong, ZHAO Xianglin, ZHU Chun, KONG Haitao, LI Baorang

2026, 45(1):  177-190.  doi:10.16552/j.cnki.issn1001-1625.2025.0670

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In this study， a fluoride-containing composite activator （Na₂SiO₃·9H₂O/Na₂SO₄/K₂SO₄/KF） was designed for steel slag （SS）-based thermal storage cement and applied to three cementitious systems： SS-Portland cement （PC）， SS-calcium aluminate cement （CAC）， and SS-calcium sulphoaluminate cement （CSA）. The effect of activator dosage on compressive strength， thermal conductivity， and specific heat capacity was systematically evaluated， and the underlying activation mechanisms were investigated using XRD， TG-DTG， and SEM analyses. The results demonstrate that the alkaline environment generated by the activator effectively promotes the depolymerization of mineral phases in the steel slag-cement system， whereas the incorporation of F^- suppresses the formation of ettringite （AFt） and calcium aluminate hydrates. Under the combined action of the activator， the depolymerized ［Al（OH）₄］^- and ［H₂SiO₄］^2- tend to form aluminum-rich calcium silicoaluminate hydrate （C-A-S-H） gel. The excess ［Al（OH）₄］^- is eventually converted into Al（OH）₃. The formation of denser hydration products significantly enhances the mechanical and thermophysical properties of the paste， enabling all three systems to achieve or surpass the performance of pure cement paste. Among them， SS-PC and SS-CAC systems exhibit optimal overall performance at a 3% （mass fraction） activator dosage. However， excessive activator leads to reactions between Al（OH）₃ and F^-， hindering the strength development of the SS-CAC system. This study not only elucidates the mechanism of the fluoride-containing composite activator in SS-based thermal storage cement， but also provides a reference for the resource utilization of SS and the design of high-performance thermal storage cement.

Preparation and Formation Mechanism of Ultra-Early Strength Environmental-Friendly Steel Slag Micro Powder UHPC

TANG Xianyuan, REN Bowen, HU Bingqian, LIU Dacheng, FENG Meijie

2026, 45(1):  191-201.  doi:10.16552/j.cnki.issn1001-1625.2025.0647

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To enhance the rapid repair capability of concrete pavements after damage and strengthen the reuse of solid waste resources， based on the previously developed environmental-friendly steel slag micro powder ultra-high performance concrete （UHPC）， nine groups of ultra-early strength steel slag micro powder UHPC were prepared using an orthogonal experimental design. The influencing factors included the replacement rate of ordinary Portland cement （OPC） for sulphoaluminate cement （SAC）， the content of early-strength agent lithium carbonate， the content of steel fiber， and the content of setting regulator borax. By testing initial setting time， compressive strength， and flexural strength at different ages， the influence patterns of each factor were analyzed， and the optimal mix ratio of ultra-early strength UHPC was determined. Additionally， field emission scanning electron microscopy （SEM） and X-ray diffractometer （XRD） were used to characterize the micro-morphology and phase composition of ultra-early strength UHPC at various ages. The results show that with the increase of OPC replacement rate， the setting time of UHPC decreases first and then increases， and the mechanical properties show a downward trend. The excessively rapid early hydration reaction of the SAC-OPC system leads to incomplete hydration， resulting in lower later-age compressive strength compare to the reference group. At a low OPC replacement rate， the SAC-OPC system UHPC prepared from steel slag micro powder still has relatively low alkalinity. Ettringite（AFt） is present in the hydration products， but calcium hydroxide（CH） is not observed. Moreover， the content of AFt gradually decreases with increasing OPC replacement rate. As hydration reaction proceeds， the pores， voids， and cracks in the matrix of ultra-early strength UHPC gradually reduce， and the structure tends to be dense. Based on the analysis of the influences of various factors on the mechanical properties and construction performance of SAC-OPC system concrete， the ultra-early strength environmental-friendly steel slag micro powder UHPC with initial setting time of 30 min and compressive strength and flexural strength of 39.6 and 11.2 MPa for 3 h under conventional curing conditions is prepared.

Application of Fine-Grained Phosphorus Slag in Highway Base

CAI Yin, LI Rui, BAO Tianpeng

2026, 45(1):  202-211.  doi:10.16552/j.cnki.issn1001-1625.2025.0738

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To promote the high-value utilization of phosphorus slag， improve the mechanical properties and road performance of highway base， this paper used fine-grained phosphorus slag to replace part of the gravel aggregate to prepare a highway base mixture. The factors affecting the unconfined compressive strength， compressive resilient modulus， water stability， and crack resistance of the mixture were comprehensively analyzed. The results show that the cement dosage， phosphorus slag dosage， and curing age have a significant effect on the unconfined compressive strength and compressive resilient modulus of the mixture. The unconfined compressive strength and compressive resilient modulus of the mixture decrease with the increase of phosphorus slag dosage. The water stability of the mixture increases first and then decreases with the increase of phosphorus slag dosage. When the phosphorus slag dosage is 25% （mass fraction）， the water stability coefficient of the mixture reaches 93%. Compared with the control group without phosphorus slag， with the increase of phosphorus slag dosage， the early dry shrinkage strain and dry shrinkage coefficient of the specimens are larger， but the later dry shrinkage strain and dry shrinkage coefficient are smaller， which improves the crack resistance of the mixture. The engineering application of phosphorus slag in the highway base material of a secondary road in Yunnan Province was carried out. The qualified rate of the highway is 100%， which verifies the feasibility of the application of phosphorus slag in the highway base material.

Mechanical and Thermal Properties of Gypsum-Based Self-Leveling Mortar Incorporated with Brick Slag-Based Energy Storage Particles

WANG Qingpei, LI Hui, ZHENG Wukui, YUAN Wenbin, CHANG Ning, ZHOU Zhou

2026, 45(1):  212-226.  doi:10.16552/j.cnki.issn1001-1625.2025.0702

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To promote the integrated development of solid waste resource utilization and building energy efficiency industry. This study prepared composite energy storage particles （ESPs） using paraffin wax and brick slag （BS）， and partially replaced sand with gypsum-based self-leveling mortar to prepare a new type of gypsum-based self-leveling phase change energy storage mortar （NGSESM）. The adsorption rate of BS and leakage rate of ESPs， as well as the microstructure， thermal properties， and mechanical properties of NGSESM were studied using mass change method， XRD， FT-IR， SEM， DSC， mechanical and thermal performance testing methods. Results show that various the adsorption conditions and particle size of BS affects the adsorption rate of BS and leakage rate of ESPs. The incorporation of ESPs significantly affects the morphology of gypsum crystals of adjacent regions， and deteriorates the mechanical properties of NGSESM. When ESPs substitute 75% （mass fraction） of sand， the mechanical properties and fluidity of NGSESM can meet the requirements of “Gypsum based self-leveling compound for floor” （JC/T 1023—2021）. In addition， the phase transition temperatures of NGSESM during heating and cooling processes are 17.2~27.3 ℃ and 14.9~22.4 ℃， with latent heating values of 4.1 and 4.3 J/g. This study provides key technical support for the application of energy-saving materials in solid waste based buildings.

Effects of PAM Flocculants on Dewatering Performance of Waste Pile Foundation Slurry

XUE Nanbo, CHEN Weiwei, YAN Weijie, XIA Libin

2026, 45(1):  227-236.  doi:10.16552/j.cnki.issn1001-1625.2025.0703

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Large amounts of waste pile foundation slurries generated from bridge and road construction exhibit high water content and fine particle size， making direct disposal prone to causing severe environmental pollution. Flocculation and dewatering represent a crucial step for the efficient treatment and resource utilization of the waste pile foundation slurry. In this study， polyacrylamide （PAM） flocculants were employed to investigate the dewatering performance of waste slurry， which is derived from a bridge pile foundation project in Jiangxi Province， China. Comparative analyses were conducted on the changes in slurry structure， morphology and particle size before and after flocculation. The results indicate that anionic PAM （APAM）， cationic PAM （CPAM） and non-ionic PAM （NPAM） all achieve optimal dewatering effectiveness at a concentration of 0.2% （mass fraction）. 3%， 4% and 7% （volume fraction） of these flocculants can induce rapid flocculation and dewatering within 10 s， significantly reducing the water content by 29.5%， 24.3% and 19.5%， respectively. Among them， APAM demonstrates the best treatment performance， yielding a supernatant turbidity of only 20 NTU after 2 h. APAM effectively agglomerates fine particles into larger flocs， markedly enhancing the crystallinity of slurry. The characteristic particle size values （D₁₀， D₅₀， D₉₀） all increase substantially， particularly the D₉₀， which surges from 15.10 μm to 25.50 μm （an increase of 68.9%）. In conclusion， APAM exhibits excellent flocculation and dewatering capabilities， showing promising application potential for the environmentally sound treatment of waste pile foundation slurry.

Preparation and Performance Optimization of Shield Mud-Based Non-Sintered Ceramsite

WANG Panpan, SUN Jinjin, ZHANG Peiran, YANG Qi, WAN Xing, FENG Xu, WANG Zhihua, DING Jianwen

2026, 45(1):  237-245.  doi:10.16552/j.cnki.issn1001-1625.2025.0739

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Based on the shield mud sampled from landfill yard in Nanjing， the shield mud-based non-sintered ceramsite was prepared using the full-process wet materials and wet operation modes， where the injection molding and standard curing technology were adopted. Through the bulk density， water absorption rate and cylinder pressure strength tests， the influence laws of sulfate activator （gypsum）， alkaline activator （sodium silicate） and modifier （sodium sulfate + triethanolamine， calcium sulfoaluminate， polypropylene fiber） on the physical and mechanical properties of non-sintered ceramsite were investigated. The results indicate that the optimal proportion （mass fraction） of gypsum and sodium silicate is 2%~6% and 5%~7%， respectively， and the optimal modifier proportion （mass fraction） is 1.0% sodium sulfate + 0.050% triethanolamine. The high-strength shield mud-based non-sintered ceramsite is prepared by reducing the soil-to-cement ratio and foam volume ratio with the optimal proportion of additives （7% gypsum， 4% sodium silicate， and 1.0% sodium sulfate + 0.050% triethanolamine）. The bulk density of the high-strength non-sintered ceramsite is 821 kg/m³， the cylinder pressure strength approaches 9.6 MPa， and the water absorption rate within 1 h is only 4.2%， which meets the standard of high-strength lightweight coarse aggregate with a density grade of 900. The microscopic analysis shows that calcium silicate hydrate/calcium aluminosilicate hydrate gels and expansive ettringite are generated inside the high-strength non-sintered ceramsite， which are the main source of the strength. This study can provide theoretical and technical support for the resource utilization of shield mud.

Research of Cement-Based Grouting Materials of Calcium Aluminate Cement-Gypsum-Lime Ternary System

YANG Maosheng, ZHANG Haibo

2026, 45(1):  246-255.  doi:10.16552/j.cnki.issn1001-1625.2025.0627

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The formation of metastable phases during calcium aluminate cement （CAC） hydration results in mechanical property instability， which restricts its application in grouting reinforcement engineering. This study proposed a composite system incorporating CAC with gypsum and lime to optimize its hydration behavior and enhanced the mechanical properties and stability of the grouting material. The evolution patterns and mechanisms of hydration product types， contents， and morphology of CAC-gypsum-lime ternary system were revealed through hydration temperature testing， XRD， TG-DTG， and SEM methods. The experimental results indicate that the optimal composition range for achieving early high strength corresponds to 55%<m（CAC）<65%， 5%<m（lime）<15%， m（gypsum）<30%. When maintaining constant CAC dosage within this optimal range， the compressive strength initial increase and then decrease with the reduction of the mass ratio of gypsum and lime. With the reduction of gypsum content， the plate-type dicalcium aluminate hydrate （2CaO·Al₂O₃·8H₂O， C₂AH₈） transitions from a stacked distribution to an interlocked distribution with ettringite crystals， resulting in a decrease in structural compactness， flexural and compressive strength of specimens. These findings provide both theoretical foundations and technical support for the application of calcium aluminate cement-based grouting materials in complex engineering environments.

Ceramics

Effect of Nano-TiO₂ on Sintering Characteristics of Al₂O₃ Ceramics

CHEN Youmei, LI Yicheng, HE Ting, LIU Yingshou, LI Yang, XIAO Hanning, YUAN Mouyun, ZHANG Weiqun

2026, 45(1):  256-263.  doi:10.16552/j.cnki.issn1001-1625.2025.0641

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Al₂O₃ ceramics were prepared by compression molding and pressureless sintering using calcined α-Al₂O₃ powder as raw material， nano-TiO₂ as sintering aid and carboxymethyl cellulose as binder. The effects of sintering temperature and nano-TiO₂ addition on microstructure， linear shrinkage， phase structure， bulk density， porosity， flexural strength and whiteness of Al₂O₃ ceramics were studied， and the sintering characteristics were evaluated. The results show that the addition of appropriate amount of nano-TiO₂ can significantly improve the sintering performance of Al₂O₃ ceramics， while excessive nano-TiO₂ will cause the abnormal growth of Al₂O₃ grains， which will lead to the decrease of shrinkage and bulk density and the increase of porosity. When the addition amount of nano-TiO₂ is 0.7% （mass fraction） and the sintering temperature is 1 500 ℃， the properties of Al₂O₃ ceramics are excellent. The flexural strength reaches the maximum value of （188.89 ± 5.87） MPa， and the bulk density， porosity and whiteness are 3.45 g·cm^-3， 7.78% and 76.6.

Glass

Influences of Raw Material Types on Reaction of OLED Substrate Glass Batch During Heating Process

TIAN Yingliang, WANG Zhongyu, LI Zhifeng, ZHAO Zhiyong

2026, 45(1):  264-274.  doi:10.16552/j.cnki.issn1001-1625.2025.0644

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OLED substrate glass batches exhibit a relatively high melting temperature. Rational selection of raw material types can significantly enhance the melting rate， reduce production energy consumption， and improve glass melting quality. This study investigated the influence of introducing different source materials for different quartz sand from different origins， aluminum raw material， and magnesium raw material on the batch behavior during heating. The results demonstrate that under identical conditions： when using quartz sand from three different origins （denoted as B sand， Q sand， and F sand）， the batch utilizing B sand shows 0.97% and 3.52% reduction in energy consumption compared to batches using Q sand and F sand， respectively. However， the F sand batch exhibits the fastest melting rate. The energy consumption of batches using Al₂O₃ is 13.77% lower than that of batches using Al（OH）₃， yet the decomposition process of Al（OH）? promotes the melting process. The energy consumption of batches materials using MgO is 7.36% lower than that of batches using MgCO₃. The research findings provide a reference for industrial production of OLED substrate glass in raw material selection. When using sand B sand， Al（OH）?， and MgO as raw material sources， the produced OLED substrate glass exhibits advantages of a higher melting rate and lower energy consumption.

Physical Simulation of Bubble Movement in Ascending Section of Platinum Channel for Electronic Display Glass

HE Feng, ZHI Jiayao, ZHAO Zhilong, ZHANG Kejian, XIE Junlin, ZHAO Zhiyong, TIAN Yingliang

2026, 45(1):  275-287.  doi:10.16552/j.cnki.issn1001-1625.2025.0763

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Platinum channel is one of the most critical pieces of equipment in the production of electronic display glass. This paper studied the influence of inclination angle changes in ascending section of platinum channel structure on movement behavior of bubbles in molten glass. A physical simulation experimental platform with a model-actual geometric ratio of 1∶4 was constructed through structural and dimensional design. Polydimethylsiloxane was used as the simulated liquid， combined with similarity criteria （Reynolds number， Galileo number）， the movement characteristics and distribution laws of bubbles were systematically analyzed under three inclination angles of the ascending section of platinum channel： 23°， 30°， and 45°. The results show that the measured kinematic viscosity of the simulated liquid has good similarity with the theoretically calculated kinematic viscosity. Changes in the inclination angle of ascending section of platinum channel have a significant impact on the flow of molten glass and the movement of bubbles. When the inclination angle of ascending section of platinum channel changes from 23° to 45°， the bubbles at its outlet are more concentrated in upper part of the pipe cross-section， and the lifting effect on bubbles is obvious. After comprehensive analysis， it is found that the effect of a 30° inclination angle is optimal.Within the scope of this study， an increase in the inclination angle of ascending section of platinum channel strengthens the synergistic effect between bubble buoyancy and fluid dynamics.

Effect of Single-Step Heat Treatment Temperature on Structure and Properties of Transparent Li₂O-Al₂O₃-B₂O₃-La₂O₃ Glass-Ceramics

HU Sijia, XIE Hailei, ZHOU Kun, DUO Shuwang, SHI Jiang

2026, 45(1):  288-298.  doi:10.16552/j.cnki.issn1001-1625.2025.0612

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A novel SiO₂-free aluminoborate glass demonstrates outstanding cracking resistance and shows considerable potential for application as cover glass. In this work， La₂O₃-containing aluminoborate glass-ceramics were successfully fabricated via high-temperature melt-casting method. The effect of one-step heat treatment temperature on the structural and functional was systematically investigated. The results reveal that increasing the heat treatment temperature from 585 ℃ to 630 ℃， ［BO₃］ units in the glass network gradually convert into ［BO₄］ tetrahedral coordination. Simultaneously， LiAl₇B₄O₁₇ and Li₂AlB₅O₁₀ crystalline phases precipitate in progressively greater quantities. Grain size increases， and morphology evolves from a purely granular particles form to a microstructure where granular particles and short-rod crystals coexist. The crystallinity degree rises markedly from 49.6% to 88.9%， accompanied by a reduction in visible light transmittance from 87.28% to 57.75%. With increasing heat treatment temperature， Vickers hardness continuously increases. Under 600 ℃ heat treatment condition the specimen exhibits optimum comprehensive properties， achieving a Vickers hardness of 6.24 GPa， a fracture toughness of 1.12 MPa·m^1/2， a visible light transmittance of 87.28%， and a cracking resistance of 19.1 N. These findings demonstrate that optimizing the heat treatment temperature enables a synergistic enhancement of hardness， transparency， and damage resistance. This study offers a novel pathway for designing high-performance， transparent glass-ceramics cover glass materials.

Interfacial Structure and Hermeticity of Kovar Alloy-Glass Seals via Pre-Oxidation Temperature Control

NIE Zhijian, WANG Qiang, YANG Xiufu, MA Xing, SHI Lei, LI Shixin

2026, 45(1):  299-308.  doi:10.16552/j.cnki.issn1001-1625.2025.0694

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This study systematically investigated the influence mechanism of pre-oxidation temperature on the interfacial microstructure and mechanical properties of 4J29 Kovar alloy-borosilicate glass seals. 4J29 Kovar alloy samples were pre-oxidized at 550， 700， 850， and 1 000 ℃ in a wet nitrogen atmosphere using a continuous mesh belt oxidation furnace. The research investigated the formation mechanism of the oxide film on the surface of 4J29 Kovar alloy at different pre-oxidation temperatures， the evolution of phase composition， and the impact on the bending resistance and sealing heameticity of electronic component sealing base pins. The results show that the pre-oxidation temperature is a key factor in regulating the interface bonding mechanism： at the lower temperature range of 550~700 ℃， fewer oxides are formed， which are mainly distributed at grain boundaries， with the primary component being Fe₃O₄. In contrast， at higher temperatures of 850 and 1 000 ℃， a dense oxide film forms on the alloy surface， primarily composed of FeO and Fe₃O₄ phases， promoting the formation of a chemical bonding structure with a distinct iron diffusion zone at the sealing interface. Mechanical performance tests testing indicates that samples pre-oxidized at 850 ℃ retain good hermeticity after enduring 10 N bending force for 3 cycles， demonstrating excellent interface bonding strength. However， high-temperature treatment at 1 000 ℃ causes the formation of numerous bubbles at the sealing interface， along with glass climbing phenomenon， which compromises interface integrity and long-term reliability.

Road Materials

Research Progress on Composition and Performance Evaluation of Fiber-Modified Micro-Surfacing for Road

ZHANG Shaobo, MA Jianyun, ZHANG Xinyong, GAO Xinwen, CHEN Qian

2026, 45(1):  309-324.  doi:10.16552/j.cnki.issn1001-1625.2025.0630

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Fibers exhibit excellent strength and deformation capacity. When incorporated fiber into micro-surfacing mixtures， they can serve as reinforcement and provide waterproofing functions， thereby addressing issues such as easy cracking and poor durability in traditional micro-surfacing， and significantly enhancing the service quality of micro-surfacing. In this paper， the composition and proportion of fiber-modified micro-surfacing materials were systematically reviewed. The enhancement mechanisms of physical and chemical surface modification methods on fiber dispersion and interfacial bonding were revealed. The effects of fiber type， content， and binder type on improving the construction performance， abrasion resistance， water damage resistance， and rutting resistance of micro-surfacing were comparatively evaluated. Additionally， the limitations of existing evaluation methods for low-temperature crack resistance were analyzed. The optimal fiber type and content for fiber micro-surfacing were recommended. The performance enhancement mechanisms of fiber-modified micro-surfacing were elucidated. Finally， an outlook on future research trends in fiber micro-surfacing was provided. The aim is to promote the high-quality development and application of fiber-modified micro-surfacing.

Rheological and Mechanical Properties of Polybutyl Acrylate-Acrylic Acid/Water Glass Composite Modified Sludge

LU Yiping, HUANG Xiulin, ZHOU Zichen, LIU Shiqi

2026, 45(1):  325-335.  doi:10.16552/j.cnki.issn1001-1625.2025.0784

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This paper used butyl acrylate （BA）， acrylic acid （AA）， and water glass as main raw materials， and sodium dodecyl sulfate （SDS） and polyoxyethylene alkylphenol （OP-10） as composite emulsifiers， composite soil curing agent （PBA） was synthesized through pre-emulsification and semi-continuous seed emulsion polymerization. The effects of water glass modulus， curing agent content， and water-soil ratio on the unconfined compressive strength of the PBA-cured soil were investigated through orthogonal experiments. FT-IR analysis indicates that all three monomers， BA， AA， and water glass， participate in the reaction. When the modulus of water glass is 2.2， the content of curing agent is 4%（mass fraction）， and the water-soil ratio is 0.44， the performance of the PBA-cured soil is optimal， with a fluidity of 132 mm and an unconfined compressive strength of 1.37 MPa after 7 d.

Strength and Microscopic Mechanism of Fly Ash-Slag-Red Mud-Based Cementitious Materials Solidified Soil

YUE Pengfei, GUO Sibiao, DING Xiujuan, WANG Yusong, WANG Dazhou, HU Yue, ZHANG Rongrong, ZHANG Gang, DING Jinmeng

2026, 45(1):  336-345.  doi:10.16552/j.cnki.issn1001-1625.2025.0758

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In order to solve the problems of high cost and high carbon emission in the production process of traditional cementitious materials in subgrade reinforcement engineering， and to realize the recycling and high-value utilization of industrial solid waste， sodium hydroxide was used as alkali activator to prepare fly ash-slag-red mud ternary composite cementitious materials. Through the unconfined compressive strength （ UCS ） test， the effect of mix ratio of solid waste-based cementitious materials and sodium hydroxide content on the 7 d UCS of solidified soil was studied. The correlation analysis of UCS results was carried out by SPSS software， and the solidification mechanism of solid waste-based cementitious materials on soil was discussed by means of SEM-EDS and XRD. The results show that the solidified soil specimens with different mix ratios show three types of splitting failure， shear failure and tensile-shear composite failure. The interaction between solid waste-based raw materials and alkali activator has a significant effect on the UCS of solidified soil. When the mass ratio of fly ash， slag， and red mud is 1∶3∶1， the 7 d UCS of solidified soil is the highest， up to 1.795 MPa. There is a significant positive correlation between sodium hydroxide content and UCS， and the correlation coefficient reaches 0.76. With the hydration reaction in the solidified soil， a large number of hydrated calcium silicate and hydrated calcium aluminate gel phases is generated to wrap the soil particles and fill the pores between the particles， thereby significantly improving the strength of solidified soil. With the increase of sodium hydroxide content， its promotion effect on the hydration reaction is more significant. The proportion of the sum of micropores and small pores in solidified soil gradually increases， and the proportion of the sum of mesopores and macropores gradually decreases.

Performance and Strength Formation Mechanism of High Dosage Phosphogypsum-Cement-Curing Agent Stabilized Crushed Stone Base Layer Material

HE Zhaoyi, ZOU Meng, YAO Qiwen, CAO Dongwei, QIN Meng

2026, 45(1):  346-358.  doi:10.16552/j.cnki.issn1001-1625.2025.0660

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This study investigated the use of high dosages of phosphogypsum in combination with cement and a self-developed curing agent for the stabilization of graded crushed stone， with the objective of preparing pavement base layer material. The study encompassed a comprehensive investigation into the effects of varying dosages of cement， phosphogypsum and curing agent on the unconfined compressive strength and pavement performance of base layer material at various ages. The hydration mechanism and microscopic properties of the materials were investigated by XRD， FTIR， SEM-EDS and other testing method， and its leaching toxicity was also tested. The results indicate that increasing the mass ratio of cement to phosphogypsum enhances the mechanical properties of the base layer material. Moreover， the mechanical properties of the base layer material are further optimised through the incorporation of a geopolymer curing agent， self-developed， replacing 20%（mass fraction， the same below） of the cement. The 7 d unconfined compressive strength is selected as the evaluation index， and the optimal mix ratio of high dosage phosphogypsum-cement-curing agent stabilized crushed stone base layer material is determined by combining this with the actual engineering requirements. The proposed optimal mix ratio is 35% phosphogypsum + 4% cement + 1% ternary alkali activated curing agent + 60% graded crushed stone， and the ratio of 7， 28 and 60 d unconfined compressive strengths increases by 69.2% （reaches 6.6 MPa）， 106.7% （reaches 9.3 MPa） and 88.3% （reaches 11.3 MPa）， respectively， in comparison with the control group without a curing agent. The primary hydration products are calcium silicate hydrate （C-S-H） gel and ettringite （AFt）， which are formed by the hydration of cement. The alkaline curing agent not only activated the cement but also reacted with the Ca²⁺ from the phosphogypsum via a pozzolanic reaction， further promoting the formation of C-S-H and calcium silicate （aluminate） hydrate （C-（A）-S-H） gels， the collective formation of these gels contributes to the overall strength of the base layer material. In addition， the toxic leaching concentrations of F^-， PO{}_{\mathrm{4}}^{\mathrm{3}-}， and heavy metal elements in base layer material are in accordance with the current standards established by China for sewage discharge.

Experimental Study on Road Performance of Cement Stabilized Macadam Incorporating Recycled Aggregate

HUANG Zhengtao, GUAN Junxiao, NIU Yapeng, CUI Yicheng, HE Xiongfei

2026, 45(1):  359-366.  doi:10.16552/j.cnki.issn1001-1625.2025.0765

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In response to the demand for the resource utilization of construction waste， and taking the promotion and application of recycled aggregates prepared from waste concrete in road engineering materials as the background， the road performance and effect of cement stabilized macadam incorporating recycled aggregate were discussed. By controlling the cement content in the mixture and the replacement rate of recycled aggregates， laboratory tests such as heavy compaction test， unconfined compressive strength test and splitting tensile strength test were carried out to study the road performance of cement stabilized macadam incorporating recycled aggregate. Subsequently， a field test of abutment backfilling was conducted to verify the compaction effect and engineering applicability of cement stabilized macadam incorporating recycled aggregate. The results show that the addition of recycled aggregates significantly reduces the road performance of cement stabilized macadam incorporating recycled aggregate. When the cement content in the mixture is 3% to 5%（mass fraction）， as the replacement rate of recycled aggregates increases from 0% to 100%（mass fraction）， the optimal moisture content of cement stabilized macadam incorporating recycled aggregate gradually rises， with a maximum increase of 85.04%， and the maximum dry density gradually decreases， with a maximum reduction of 11.89%. Both the unconfined compressive strength and the splitting tensile strength gradually decline. The maximum reduction rates for the two are 51.98% and 50.42% respectively. Cement stabilized macadam incorporating recycled aggregate not only meets the compaction standards and has good uniformity， but also has a dense and stable core sample， which can be used for abutment backfilling. These findings provide experimental support for the application and promotion of recycled concrete aggregates in cement stabilized macadam incorporating recycled aggregate used for abutment backfilling.