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        <title>Frontiers in Materials | Structural Materials section | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/materials/sections/structural-materials</link>
        <description>RSS Feed for Structural Materials section in the Frontiers in Materials journal | New and Recent Articles</description>
        <language>en-us</language>
        <generator>Frontiers Feed Generator,version:1</generator>
        <pubDate>2026-10-24T16:27:52.750+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1950801</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1950801</link>
        <title><![CDATA[EPD-grounded carbon-resilience allocation for low-carbon concrete supply: decision fidelity, route validation, and correlated-disruption stress testing]]></title>
        <pubdate>2026-10-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Xin Yang</author><author>Yong Xiang</author><author>Yao Wei</author>
        <description><![CDATA[IntroductionGreen construction teams need a defensible way to convert product-specific concrete carbon declarations into supply decisions that recognize delivery and disruption exposure. Prediction-to-optimization workflows can obscure a critical evidence boundary: verified environmental product declaration (EPD) values can support formal supplier comparison, whereas machine-learning estimates require decision-level validation before allocation.Methods We introduce an evidence-aligned framework that separates observed EPD attributes, model-estimated screening outputs, scenario-derived A4 transport, and assumption-based disruption stress and assigns each a specific decision role. Model transportability was audited using plant, company, temporal, and geographic holdouts, followed by a direct comparison of predicted and EPD-observed rankings and allocations. Formal strength-constrained optimization minimized observed EPD A1–A3 plus scenario A4 under plant-share caps.ResultsAfter harmonization and deduplication, the analysis contained 45,739 EPD records from 663 plants. A prospective external cohort added 22 declarations from 14 plants and seven derivation-unseen companies; the frozen model reduced record-level MAE by 6.6% relative to the frozen training median, while the supplier-ranking gate retained the EPD-grounded path. Across nine city-strength cases, a 40% cap produced three-plant allocations with a mean Herfindahl–Hirschman Index of 0.36. Under a 10% independent plant-disruption stress rate, it reduced the probability of losing at least half of supply from 0.100 to 0.027; mean and median A1–A4 premiums were 14.57% and 7.76%, respectively. The benefits remained measurable across disruption probabilities of 5%–30% and pairwise correlations of 0–0.50. An OpenStreetMap routing check covered 79 plant–project pairs: median distance error was 6.39%, 17 of 18 allocation decisions were unchanged, and the remaining case had 0.026% route-evaluated objective regret.DiscussionThe contribution is a transparent carbon-concentration frontier with an empirical decision-fidelity gate: prediction supports early screening, whereas EPD values anchor formal allocation. The framework provides extensible planning evidence while preserving clear boundaries between comparative scenarios and operational procurement.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1978854</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1978854</link>
        <title><![CDATA[Performance enhancement of concrete with alkali-conditioned fly ash lightweight aggregate]]></title>
        <pubdate>2026-10-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Xiaozhong Zheng</author><author>Tao Han</author><author>Zhuang Wang</author><author>Tingting Luo</author><author>Guangfei Liu</author><author>Bing Xue</author><author>Peihe Yu</author><author>Yongsheng Ji</author>
        <description><![CDATA[Lightweight concrete serves as an effective means of minimizing the dead load of shaft walls. In the present work, spherical lightweight aggregates produced from fly ash were employed as a substitute for conventional sand and gravel in wellbore concrete mixtures. A series of alkaline immersion curing experiments and material characterization tests were carried out to evaluate the effects of alkali type and concentration on the fundamental properties of non-sintered fly ash lightweight aggregates, including unconfined compressive strength and water resistance. The investigation also examined how aggregate grading and water-to-cement ratio influence the mechanical behavior and impermeability of fly-ash lightweight aggregate concrete. Scanning electron microscopy combined with microhardness testing was utilized to characterize the modifications in the interfacial transition zone induced by alkaline curing. A mechanistic model was proposed to explain the improvements in mechanical properties and impermeability under alkali treatment. Experimental results demonstrate that alkaline immersion promotes more complete hydration of fly ash, thereby directly enhancing both the unconfined compressive strength and impermeability of FLBA concrete. In alkali-activated FLBA concrete, the microhardness across the ITZ is considerably higher than that of the bulk cement paste matrix; the microhardness values increase as the aggregate surface is approached, and this gradient exhibits a strong correlation with the degree of improvement in mechanical strength and impermeability.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1954367</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1954367</link>
        <title><![CDATA[Mechanical behaviors of weathered coal gangue filled concrete pavement based on surface solidification]]></title>
        <pubdate>2026-10-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yingsong Li</author><author>Wei Guo</author><author>Xinge Miao</author><author>Xiangling Tao</author><author>Qingtao Wang</author><author>Jiangyi Zhang</author><author>Weichi Chen</author><author>Ziyao Wei</author>
        <description><![CDATA[Weathered coal gangue (WCG) is a solid waste formed by the long-term accumulation and weathering of coal gangue. Its low strength and poor stability prevent direct use as a concrete aggregate, limiting large-scale utilization. To overcome this, a consolidation treatment was developed and the treated WCG was evaluated as a replacement aggregate for concrete pavement in mining areas. The physical properties of the WCG before and after treatment were first measured. Then, the failure modes and stress changes of WCG concrete under different replacement intervals were evaluated by compressive strength, splitting tensile strength, flexural strength, shear strength tests and numerical simulation. The results showed that the Los Angeles wear rate, Vickers hardness and impact value of WCG after consolidation treatment were 19.88%, 141.43 kgf/mm2 and 5.66%, respectively, indicating improved wear resistance, hardness, and impact resistance after consolidation treatment. Under the condition of meeting the requirements of secondary road strength, the maximum substitution range of WCG replacement gravel was 2.36–19.0 mm. At this time, the flexural strength of concrete was 4.67 MPa, the compressive strength was 27.81 MPa, the splitting tensile strength was 2.13 MPa, the cohesion was 2.93 MPa, and the internal friction angle was 66.20°. The simulation results showed that the failure mode was of the ‘X’ type when no aggregate was replaced by coal gangue, whereas after full replacement the failure initiated at the outermost large aggregate and propagated inward, with the cracks propagating along the interfacial transition zone (ITZ) and through the aggregate. When the replacement interval was 2.36–19.0 mm, the interval contributing most to the stress bearing capacity of WCG concrete was 19.0–31.5 mm, with a contribution rate of 58.31%. These findings provide a theoretical basis for the application of WCG in concrete pavement.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1947456</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1947456</link>
        <title><![CDATA[Non-linear analysis of composite steel-concrete beam with web openings using finite element method and design of experiments]]></title>
        <pubdate>2026-10-14T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Mastan Sheik</author><author>M. Vishnu Priyan</author><author>Ramesh Kothapali</author><author>S. Aishwarya</author>
        <description><![CDATA[In structural engineering, composite beams with web openings are essential for accommodating ducts and pipes while maintaining floor-to-floor height. However, web openings can reduce the load-carrying capacity and alter the structural response of composite beams. This study investigates the effects of web-opening shape, opening area, and spacing-to-diameter ratio on the structural behaviour of composite steel–concrete beams using nonlinear finite element analysis and design of experiments. Five opening shapes, three opening areas of 7,853, 31,415, and 125,663 mm2, and spacing-to-diameter ratios ranging from 1.08 to 3 were investigated using ABAQUS v6.14, resulting in a total of 330 finite element models. The finite element results were analysed using a design of experiments framework with an L27 orthogonal array, response surface methodology, and analysis of variance using MINITAB 20 and Design-Expert 13. The results showed that circular openings exhibited the highest load-bearing capacity among the investigated opening shapes, while opening area and spacing-to-diameter ratio were the dominant parameters influencing the ultimate load. The response-surface analysis identified an opening area of 31,415 mm2 and a spacing-to-diameter ratio of 1.50 as the highest-response combination within the investigated parameter range. The findings demonstrate the added value of integrating validated nonlinear finite element modelling with DOE-based response surface analysis to systematically evaluate and optimise web-opening configurations in composite steel–concrete beams.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1967974</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1967974</link>
        <title><![CDATA[Mesoscopic crack evolution and cracking resistance of recycled asphalt mixtures with different RAP contents using discrete element method]]></title>
        <pubdate>2026-10-13T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Hao Li</author><author>Haiqi Zhang</author><author>Yimin Huang</author><author>Qiuwei Liu</author><author>Jiumou Zhan</author><author>Yongkang Lin</author>
        <description><![CDATA[To reveal the mesoscopic mechanism underlying the deterioration of macroscopic cracking resistance in recycled asphalt mixtures, this study constructed discrete element models that finely characterize virgin aggregates, RAP, aged asphalt, and new asphalt binder, while considering aggregate breakage and aged asphalt coating layers of different thicknesses. The mesoscopic parameters are calibrated using indoor splitting test results. On this basis, the influence of RAP content on mesostructural damage and cracking behavior of the mixtures was investigated, and quantitative relationships between mesoscopic damage indicators and macroscopic mechanical properties were established. The results indicate that microcracks preferentially initiate in the loading axis region, while the lateral regions experience lower stresses and serve as buffer zones. The splitting failure is essentially a tensile failure induced by tensile stress exceeding the material limit, with tensile microcracks accounting for more than 97% of the total. As the RAP content increases from 15% to 60%, the crack development pattern gradually evolves from a linear primary crack to branch-like and eventually network-like propagation. Aggregate breakage is mainly concentrated at the two ends of the loading axis and along the crack propagation paths, with the total breakage index ranging from 4% to 10%. A clear negative correlation exists between mesoscopic damage indicators and macroscopic mechanical responses. Mesoscopic damage ultimately leads to the degradation of macroscopic performance through two pathways, namely, microcrack coalescence and skeleton weakening. The findings of this study can provide a theoretical basis for the design optimization of recycled asphalt mixtures.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1979048</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1979048</link>
        <title><![CDATA[Characteristics of fume components and dynamic emission behavior of crumb-rubber-modified asphalt]]></title>
        <pubdate>2026-10-09T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Liaoliang Luo</author><author>Jiasheng Dai</author><author>Wenqiang Zhu</author><author>Changfeng Li</author><author>Long Yu</author><author>Yu Liu</author><author>Binqian Li</author><author>Zhenghao Zhang</author>
        <description><![CDATA[IntroductionCrumb-rubber-modified asphalt (CRMA) facilitates the recycling of end-of-life tires but may release complex fumes during high-temperature processing. This study characterized the dynamic fume evolution and representative organic components of CRMA.MethodsAn integrated system combining controlled fume generation, real-time monitoring, and offline collection was developed. Volatile organic compound (VOC) responses from four asphalt binders were monitored at 120–200 °C. The H₂S and SO₂ responses of CRMA were quantified, and the detectable organic components in fumes from CRMA and its corresponding base asphalt were analyzed using gas chromatography–mass spectrometry.ResultsThe VOC concentration–time profiles were reproducible, with relative deviations below 10% during the principal response stages. VOC responses increased with temperature, generally peaking before gradually approaching a slowly varying stage. At 200 °C, the peak VOC concentration of CRMA reached 3,719.1 mg/m³, approximately 5.5 times that of the base asphalt. As the temperature increased from 120 to 200 °C, the cumulative responses of H₂S and SO₂ increased from 265 to 1,035 ppm·min and from 3,785 to 5,715 ppm·min, respectively. CRMA also exhibited more resolved chromatographic peaks, with isoprene-related compounds, benzothiazole derivatives, benzothiophene, and dibenzothiophene forming representative crumb-rubber-associated signals.DiscussionElevated temperatures intensified CRMA fume responses through the combined effects of volatilization, enhanced thermal desorption of rubber-bound components, and mass transfer, providing a basis for processing-temperature optimization and targeted fume control. The reported concentrations are laboratory-specific sensor-equivalent values intended for comparative assessment rather than direct estimation of field emissions or occupational exposure.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1930537</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1930537</link>
        <title><![CDATA[Study on the influence of matrix asphalt mixture air voids on the performance of semi-flexible pavement materials]]></title>
        <pubdate>2026-10-09T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Jie Chen</author><author>Zhiyu Yang</author><author>Hui Huang</author><author>Jiechao Lei</author><author>Weian Xuan</author>
        <description><![CDATA[In practical applications, semi-flexible pavement materials need to achieve a balance between mechanical properties, high-temperature stability, cracking resistance, and water stability. However, these performance requirements are strongly influenced by the void content of the matrix asphalt mixture, which determines the grouting space and the composite structure of semi-flexible pavement materials. In this study, matrix asphalt mixtures with three different void contents (20.6%, 24.9%, and 29.2%) were prepared. The effects of the matrix void content on the perfusion characteristics and overall performance of semi-flexible pavement materials were systematically evaluated through perfusion tests, Marshall stability and splitting tests, three-point bending tests, rutting tests, and freeze–thaw splitting tests. Subsequently, the impact of the void ratio on each parameter was analyzed. The findings indicate that, within the tested void content range (20.6%–29.2%), increasing the void ratio of the matrix asphalt mixture continuously improved the mechanical properties of the semi-flexible pavement material: the Marshall stability was enhanced by a factor of up to 4.8, and the splitting strength by up to 1.4 times. Results from the trabecular three-point bending test reveal a more pronounced effect of void fraction on the crack resistance of semi-flexible pavement materials with rising temperatures. At 15 °C, lower void fractions lead to superior crack resistance. Conversely, when the void fraction reaches 24.9% at −10 °C, semi-flexible pavement materials exhibit enhanced crack resistance. Rut dynamic stability and freeze–thaw splitting tests demonstrate that higher void ratios in the matrix correlate with superior resistance to high-temperature deformation and water stability. When the void ratio falls below 24.9%, increasing it significantly enhances resistance to high-temperature deformation, with an improvement range of up to 63.6%. Therefore, 24.9% is identified as the recommended balanced air-void content of the matrix asphalt mixture, at which the semi-flexible pavement material achieves the most balanced comprehensive performance in terms of mechanical properties, high-temperature deformation resistance, water stability, and cracking resistance.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1973453</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1973453</link>
        <title><![CDATA[Hydration, mechanical, and environmental performance of blended cements incorporating ground granulated blast furnace slag, ground waste bottle glass, and metakaolin]]></title>
        <pubdate>2026-10-08T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Saule Mergenbayeva</author><author>Nuray Abdullayeva</author><author>Aliya Abzal</author><author>Kassym Talgatuly</author><author>John L. Provis</author><author>Chang-Seon Shon</author><author>Zhanar Zhakiyeva</author>
        <description><![CDATA[This study investigates the effect of incorporating 20 wt% ground granulated blast furnace slag (GGBFS), ground waste bottle glass (GWBG) and metakaolin (MK) on the hydration behavior, mechanical and environmental performance of blended cements cured at 23 °C ± 2 °C for 7, 28, and 90 days. Mechanical performance was evaluated using the strength activity index (SAI), while environmental performance was assessed through heavy metal leaching and a preliminary sustainability screening. The tested mortars achieved SAI values greater than 80% at all curing ages, consistent with the observed development of hydration products and microstructural evolution. Heavy metal leaching tests showed Pb and Zn below the limit of detection, while Cr release ranged from 0.70 to 1.15 mg/kg, which is substantially below the non-hazardous waste acceptance limit. The preliminary sustainability screening showed reductions of 10.9%–17.2% in calculated binder-production embodied energy and 12.9%–18.9% in calculated binder-production CO2 emissions compared to a plain Portland cement benchmark. These findings demonstrate the potential of these SCMs for producing blended cements with satisfactory mechanical performance, limited trace-metal release, and lower calculated binder-production CO2 indicators compared with the plain Portland cement benchmark.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1957042</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1957042</link>
        <title><![CDATA[Sustainable valorization of phosphogypsum solid waste as composite filler in asphalt mastic: rheological behavior and construction benefits]]></title>
        <pubdate>2026-10-08T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Liangchao Li</author><author>Baoan Li</author><author>Lu Yang</author><author>Xingjun Liu</author><author>Xinran Gu</author><author>Haowen Li</author><author>Yixiang Li</author><author>Jiufu Yang</author><author>Wenju Peng</author>
        <description><![CDATA[Massive phosphogypsum (PG) stockpiles bring persistent environmental risks in China, while heavy-duty channelized traffic increasingly causes premature rutting and fatigue cracking in asphalt pavements. To reconcile engineering requirements with environmental pressures, PG was used as a filler for high-value applications. In this study, asphalt mastic was prepared using Grade A 70# road asphalt, with mineral powder and PG as a single filler, and a PG–mineral powder composite filler. Temperature–frequency scanning, multiple stress creep recovery (MSCR), and linear amplitude scanning (LAS) tests were subsequently conducted using a dynamic shear rheometer (DSR). The influence of filler type, filler–asphalt ratio, and blend proportions on the mechanism of viscoelastic behavior evolution in mastic was analyzed. It was found that PG filler enhanced the high-temperature deformation resistance of asphalt mastic compared with mineral powder. At high filler–asphalt ratios, the transition of the viscoelastic structure could be delayed, and weak shear thickening characteristics were exhibited under heavy shear loading. A filler–asphalt ratio threshold was observed for the fatigue resistance of PG mastic. At a filler–asphalt ratio of 1.0, its fatigue life was found to surpass that of mastic with mineral powder. For the composite system, a performance-to-blend-ratio threshold was demonstrated. At a 50% PG blend ratio (filler–asphalt ratio was 1.0), optimal fatigue resistance was achieved while maintaining excellent high-temperature stability. Furthermore, a quantitative assessment confirmed that this optimal blend reduces filler processing carbon emissions by 42.9%. These findings provide core theoretical support and key design parameters for the sustainable, large-scale application of PG solid waste in green highway construction.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1964302</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1964302</link>
        <title><![CDATA[Protocol-dependent aging responses of polyurethane-bound pavement composites under thermo-oxidative, hygrothermal, and UV exposure]]></title>
        <pubdate>2026-10-05T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Leilei Han</author><author>Zhengxin Wu</author><author>Zhiqing Zhu</author>
        <description><![CDATA[Polyurethane-bound pavement composites offer high mechanical performance, but accelerated durability rankings can depend on how aging is imposed and which material response is measured. This study compared a moisture-curing methylene diphenyl diisocyanate-based polyether polyurethane binder and dense PC-13 composite under thermo-oxidative, hygrothermal, continuous ultraviolet (UV), intermittent UV, and intermittent UV–immersion exposure. A 20 h thermo-oxidative group enabled duration-matched comparison with 20 h hygrothermal aging, and replicated mixture testing at 480 h supported Welch tests with Holm correction across the three UV protocols. At 20 h, thermo-oxidative aging reduced binder tensile strength to 13.52 MPa versus 18.13 MPa after hygrothermal aging and also produced lower elongation at break and splitting strength. Gel permeation chromatography and tetrahydrofuran-insoluble measurements showed that soluble-fraction molecular-mass changes did not reproduce the mechanical severity ranking. At 480 h, intermittent UV–immersion produced the lowest mean dynamic stability, flexural strain, and splitting strength, with retentions of 38.31%, 25.59%, and 52.57%, respectively. Flexural strain distinguished all three UV protocols, while the matched intermittent comparison showed a significant additional loss of dynamic stability when water immersion replaced 1 h of dark conditioning. Because continuous and intermittent schedules accumulated different UV-on times, those comparisons are interpreted only as whole-protocol contrasts. The results demonstrate that durability assessment of polyurethane-bound pavement composites requires protocol-specific, multi-indicator interpretation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1861716</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1861716</link>
        <title><![CDATA[Influence of alkali activator modulus on mechanical properties and microstructure of slag-fly ash geopolymer-solidified dredged sludge]]></title>
        <pubdate>2026-10-05T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yulin Wang</author><author>Yan Tian</author><author>Sisi Fang</author><author>Xianding Guo</author><author>Yating Fan</author><author>Jun Wang</author><author>Daohe Wu</author><author>Yinghua Cui</author><author>Xuexian You</author><author>Zipeng Qin</author>
        <description><![CDATA[This study investigates the solidification of dredged sludge using a slag-fly ash geopolymer to promote its resource-oriented reuse as a sustainable construction material. Moving beyond approaches that primarily vary activator dosage, this study treats the alkali activator modulus (SiO2/Na2O molar ratio) as an independent chemical-control parameter. The effects of nominal modulus (0.6–1.4) and activator dosage (6%–10% relative to the total slag-fly ash precursor mass) on unconfined compressive strength, cohesion, and internal friction angle (φ) were systematically evaluated. X-ray diffraction and scanning electron microscopy were used to characterize phase-related and morphological changes and to support interpretation of the reaction mechanisms. The intermediate nominal modulus levels of 1.0 and 1.2 exhibited comparatively favorable mechanical performance, with M = 1.0 producing the highest values among the tested modulus levels. For the representative C = 8% specimens examined by SEM and XRD, M = 1.0 exhibited the most continuous and dense gel-like matrix among the three moduli investigated, consistent with more extensive reaction. At M = 1.0, the M10C10 mixture reached the peak 28-day unconfined compressive strength of 1.63 MPa, while the M10C8 mixture reached a 28-day cohesion of 499.11 kPa. At the lower modulus of M = 0.6, later-age strength regression and crystalline precipitation indicate an unfavorable low-modulus reaction environment; alkali migration and efflorescence-related processes are treated as possible contributing mechanisms rather than demonstrated causes. At M = 1.4, the lower effective alkalinity was associated with less extensive activation and lower strength. Considering the limited additional 28-day strength gain when the activator dosage increased from 8% to 10% at M = 1.0, M = 1.0 with an 8% dosage may be considered a dosage-efficient candidate when activator-use efficiency is prioritized over maximum short-term strength. The 28-day mechanical performance indicates potential for embankment and backfill applications, but long-term durability and environmental performance require further verification. These findings show that controlling activator modulus is important for tailoring the mechanical response and microstructure of slag-fly ash geopolymer-solidified dredged sludge.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1927109</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1927109</link>
        <title><![CDATA[Stability analysis of surrounding rock during excavation unloading-reloading based on the Hoek-Brown criterion]]></title>
        <pubdate>2026-10-02T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Xu-Hai Feng</author><author>Zeng-Lun Guan</author><author>Hou-Wei Sun</author><author>Zhi-Qiang Liu</author><author>Hai-Yang Huang</author><author>Pin-Qiang Mo</author>
        <description><![CDATA[The stability of surrounding rock in underground excavations is fundamentally governed by the stress evolution induced by excavation unloading and subsequent reloading processes, such as support installation, lining, or internal pressure recovery. However, existing studies have mainly focused on excavation-induced unloading, while the mechanical response of surrounding rock subjected to subsequent reloading remains insufficiently understood. To address this issue, an analytical framework based on the Hoek–Brown strength criterion is proposed to investigate the elastoplastic behavior of surrounding rock during the excavation unloading–reloading process. The proposed framework consists of two complementary components: a limit equilibrium analysis of the overlying rock mass to evaluate the global stability of underground openings, and an elastoplastic analytical solution for a circular cavern to characterize local stress redistribution, plastic zone evolution, and failure mode transition. Based on these solutions, the upper and lower limit pressures associated with tensile and shear failure mechanisms are derived. The results demonstrate that the stress path induced by unloading and reloading plays a critical role in controlling the mechanical response of surrounding rock. Subsequent reloading modifies the stress state around the excavation boundary and may lead to a transition from tensile-dominated instability to shear-controlled failure. Parametric analyses further reveal that burial depth, lateral pressure coefficient, and rock mass quality significantly affect the stability limits and failure characteristics. The proposed method provides an analytical basis for determining allowable pressure ranges and evaluating the stability of underground excavations.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1964867</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1964867</link>
        <title><![CDATA[Experimental study on strain redistribution and peak-load degradation of reinforced concrete lattice beams under localized beam-bottom support loss]]></title>
        <pubdate>2026-10-02T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Chungen Wei</author><author>Shengfeng He</author><author>Zirong Huang</author><author>Sheng Liu</author><author>Cheng Yang</author><author>Biao Nie</author><author>Qingqing Zhang</author><author>Yuhang Wu</author><author>Qingyuan Liu</author><author>Yashen Gu</author>
        <description><![CDATA[Localized beam-bottom support loss can alter deformation compatibility within reinforced concrete lattice beams and reduce their load-carrying capacity, yet the associated spatial response remains insufficiently quantified. This study conducted staged central-node loading tests on 1:10 square-grid lattice-beam models under complete support and three prescribed support-loss conditions (η = 0.2, 0.4, and 0.6). Optical-frequency-domain-reflectometry distributed sensing provided continuous longitudinal strain fields on the upper and lower beam surfaces. Response evolution was evaluated from strain-field patterns, signed longitudinal-profile correlation, and the recorded system-level peak load. Increasing η produced progressively stronger strain localization around Horizontal Beam 2 and the orthogonally connected vertical beams, accompanied by relative unloading of peripheral parallel beams. At η = 0.6, the upper-surface correlation coefficient of Horizontal Beam 2 decreased to −0.59 to −0.77 at 200–400 kg, indicating substantial reorganization of the longitudinal strain distribution. The recorded peak load decreased from 1235 kg under complete support to 978, 782, and 604 kg, corresponding to reductions of 20.8%, 36.7%, and 51.1%, respectively. The observations demonstrate that localized support loss changes grid-level deformation sharing while progressively degrading the model-scale peak load. These results provide an experimental basis for identifying support-loss-sensitive regions and designing distributed monitoring layouts for lattice-beam slope-protection systems.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1951523</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1951523</link>
        <title><![CDATA[Impact of the surrounding ambient temperature on the fresh and hardened properties of one-part alkali-activated materials incorporating recycled brick powder and aggregate]]></title>
        <pubdate>2026-10-01T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yazeed A. Al-Noaimat</author><author>Mazen J. Al-Kheetan</author><author>Mehdi Chougan</author><author>Ayah A. Alkhawaldeh</author><author>Seyed Hamidreza Ghaffar</author>
        <description><![CDATA[This study investigates the influence of the combined effect of mixing and curing temperatures on the flowability, slump height reduction, flexural and compressive strengths, water absorption, and microstructural performance of one-part alkali-activated materials (AAM), providing insight into the in situ efficiency and applicability of these materials. The effect of temperature was evaluated for two different mix designs: one prepared with 100% natural aggregates (NA) and the other with 50% brick aggregates (BA). Four different surrounding temperatures were selected: 35, 20, 10, and 0 °C, and the temperatures were varied together at 0, 10, 20, and 35 °C; consequently, the results describe the combined exposure condition and do not isolate the individual effects of mixing temperature and curing temperature. The workability of both mix designs was found to be dependent on the surrounding temperature, with lower flowability and a reduction in slump height as temperature increased. At the same time, increasing the surrounding temperature was found to increase the 3-day strength performance of the mixture. Nevertheless, 28-day mechanical strength performance was better for ambient-prepared mixtures, indicating that high temperature might initially boost AAM performance, but does not allow it to reach its maximum mechanical strength performance at later ages. Similarly, the water absorption capacity of the mixture was found to depend on the surrounding temperature, with the lowest value for the mixture prepared at 35 °C. Scanning electron microscopy (SEM) analysis revealed that aggregates in both mixtures (100% NA and 50% BA) delaminated from the cement paste at 0 °C. The results presented in this study provide an insight into the efficiency and performance of AAM under varying environmental conditions.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1890188</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1890188</link>
        <title><![CDATA[Long-term skid and abrasion resistance of limestone aggregate asphalt mixtures]]></title>
        <pubdate>2026-09-29T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Liangfa Jiang</author><author>Shengyi Huang</author><author>Liuyuan Lan</author><author>Chengli Zhao</author><author>De Yang</author><author>Yuanfeng Chen</author><author>Junlin Liang</author>
        <description><![CDATA[To reveal the evolution trend of long-term skid resistance and abrasion resistance of limestone when applied in the surface layer of asphalt pavement, this study systematically investigated the coupling effects of temperature, loading speed, and aggregate particle size on the evolution of long-term skid resistance and abrasion resistance of asphalt pavement using a self-developed laboratory accelerated abrasion test device. Meanwhile, the degradation mechanism of pavement surface morphology and its internal correlation with performance decay were analyzed. The results show that the developed device can well simulate the abrasion process of asphalt pavement and realize the accurate acquisition of abrasion depth and friction coefficient. The skid resistance of limestone asphalt pavement mainly presents two distinct evolution modes: a rapid initial decline followed by stabilization, or a short-term initial increase followed by continuous decline. The abrasion resistance of the pavement exhibits three stages, namely, slow decline, rapid decline, and stabilization. Pavements with smaller aggregate particle size are more prone to overall structural deterioration, resulting in a faster decline in abrasion resistance and skid resistance. Meanwhile, increases in temperature and loading speed both accelerate the attenuation of skid resistance and abrasion resistance of the pavement. Under low-temperature conditions, the failure mode of pavement surface morphology is single, with relatively slow performance attenuation. In contrast, under high-temperature conditions, the failure modes of pavement surface morphology are more diverse, accompanied by faster performance attenuation. The research results can provide a theoretical basis for the rational application and durability design of limestone in the surface layer of asphalt pavement.]]></description>
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        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1950426</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1950426</link>
        <title><![CDATA[Performance regulation of porous vegetation ecological concrete using carbonated recycled coarse aggregate and fly ash-silica fume blends]]></title>
        <pubdate>2026-09-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Rijin Hu</author><author>Neng Xiong</author><author>Jin Li</author><author>Xinen Pan</author><author>Bo Liu</author><author>Junlin Tang</author><author>Linjian Wu</author>
        <description><![CDATA[Pores, microcracks, and alkaline calcium-bearing phases in the adhered old mortar of recycled coarse aggregate (RCA) limit its application in porous vegetation ecological concrete (PVEC). To simultaneously satisfy PVEC requirements for load-bearing performance, connected porosity, and reduced alkalinity, this study combined gaseous accelerated carbonation of RCA with the addition of the fly ash-silica fume (FA-SF) blend. The effects of parent concrete strength, RCA carbonation duration, and the FA-SF replacement ratio on the compressive strength, connected porosity, and leachate pH of PVEC were investigated. The evolution of calcium-bearing phases and the aggregate-paste interfacial transition zone (ITZ) was analyzed using thermogravimetric and derivative thermogravimetric (TG/DTG) analysis, X-ray diffraction (XRD), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The results showed that, as the strength grade of the parent concrete increased from C30 to C50, the compressive strength of recycled-coarse-aggregate porous vegetation ecological concrete (R-PVEC) increased from 3.96 MPa to 5.15 MPa, whereas the leachate pH increased from 12.14 to 12.62. When RCA derived from C40 concrete was carbonated for 5 days at 20 °C, 70% relative humidity, and a CO2 concentration of 20%, the compressive strength of carbonated recycled coarse aggregate porous vegetation ecological concrete (CR-PVEC) reached 5.63 MPa, equivalent to 98.4% of the compressive strength of CR-PVEC in the 7 days carbonation group. In addition, after accelerated carbonation for 5 days, the connected porosity of CR-PVEC remained at 27.99%, while its leachate pH decreased to 11.68. The addition of the FA-SF blend further improved the overall performance of CR-PVEC. At a FA-SF replacement ratio of 25%, CR-PVEC exhibited the highest compressive strength, at 6.56 MPa. When the replacement ratio was increased to 30%, the compressive strength, connected porosity, and leachate pH of the specimens were 6.32 MPa, 28.55%, and 10.51, respectively. Microstructural analyses showed that RCA carbonation and the addition of the FA-SF blend reduced the estimated Ca(OH)2 content from 1.21% to 0.70%, increased the CaCO3 content from 21.89% to 25.66%, and reduced the ITZ thickness from 36 μm to 15 μm. RCA carbonation primarily regulated the calcium-bearing phases and local defects in the adhered old mortar, while the addition of the FA-SF blend further optimized the new paste and interfacial structure. Together, these two measures enhanced the load-bearing capacity of the CR-PVEC skeleton and reduced the leachate pH.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1949496</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1949496</link>
        <title><![CDATA[Effects of TiO2 activating flux concentration on A-TIG welding characteristics of inconel 738LC nickel-based superalloy]]></title>
        <pubdate>2026-09-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Linggen Ren</author><author>Dong Zhang</author><author>Xudong Wen</author><author>Qinghe Xu</author>
        <description><![CDATA[To improve the weldability of Inconel 738LC nickel-based superalloy, TiO2 was employed as an activating flux for activated tungsten inert gas (A-TIG) welding, and the effects of different TiO2 concentrations on weld geometry, microstructure, cracking behavior, and mechanical properties were systematically investigated. Optical microscopy, scanning electron microscopy, real-time arc imaging, and surface-tension measurements were employed for characterization. The results showed that TiO2 concentration significantly affected weld formation and microstructural evolution. Among the investigated conditions, 1.00 g/mL TiO2 provided the most favorable overall performance, increasing the penetration depth by approximately 68.6% and the molten-pool area by 63%, while reducing the heat-affected-zone width by approximately 22%. This condition also produced a higher equiaxed dendrite fraction, and improved tensile strength and elongation, although liquation cracking was not completely eliminated. The penetration enhancement is attributed primarily to the TiO2-induced modification of the surface-tension gradient, which promotes inward Marangoni convection and downward heat transport within the molten pool. TiO2 concentration also altered the visible arc morphology, which may additionally contribute to heat redistribution. These results demonstrate that appropriate control of TiO2 addition can improve the overall welding performance of Inconel 738LC during A-TIG welding.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1936820</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1936820</link>
        <title><![CDATA[Structural behaviour of bent angle-steel joints embedded in transmission tower foundations: full-scale testing and finite element modelling]]></title>
        <pubdate>2026-09-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Qi-Chun Wang</author><author>Hai-Yun Ma</author><author>Da-Gang Han</author><author>Xing Huang</author><author>Song-Yang He</author><author>Xiao-Chuan Guo</author><author>Shao-Bo Kang</author>
        <description><![CDATA[Bent angle-steel joints embedded in concrete foundations are commonly used as load-transfer components between transmission tower legs and foundations. Due to their bent geometry and bolted connections, these joints are subjected to complex stress states under vertical loads and auxiliary inclined or horizontal loads. To investigate the structural behaviour of bent angle-steel joints embedded in concrete foundations of transmission towers, full-scale tension and compression tests were conducted on Q420 high-strength steel joints. The specimens were subjected to vertical loads together with auxiliary inclined or horizontal loads, and the corresponding load-strain responses, stress development and failure modes were recorded. Finite element models were also developed to evaluate the stress distribution of the joint and the strength reserve of the gusset plate. The test results showed that, under tensile loading, the joint ultimately failed at a vertical tensile load of 1100 kN after local yielding developed near the upper loaded end of the angle member and tearing of steel occurred in the top loading plate. Under compressive loading, local bending first occurred on the compressive side of the angle member, and the joint eventually failed by flexural yielding at a vertical compressive load of 1989 kN. The numerical results indicated that the maximum von Mises equivalent stresses under tensile and compressive loading were 254.2 MPa and 264.1 MPa, respectively, both lower than the nominal yield stress of Q420 steel. The observed failures were mainly associated with yielding or bending of the angle member rather than yielding of the gusset plate. Under the investigated loading conditions, the joint satisfied the required load-transfer capacity.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1910600</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1910600</link>
        <title><![CDATA[Foundation backfill prepared from inferior desulfurization gypsum and fly ash: laboratory evaluation and field application]]></title>
        <pubdate>2026-09-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Jingjing Liu</author><author>Bing Bai</author><author>Qingke Nie</author>
        <description><![CDATA[While standard desulfurization gypsum is widely utilized, the application of long-term stockpiled inferior desulfurization gypsum remains limited due to its inherent compositional instability. To bridge this research gap, this study investigated the feasibility of utilizing inferior desulfurization gypsum combined with fly ash to form a geopolymer as a factory foundation fill material. Through a comprehensive approach incorporating microstructural analysis, shear strength testing, water stability evaluation, and in-situ field validation, the study evaluated the material’s macroscopic performance and discussed the hypothesized underlying reaction mechanisms. Microstructural and calorimetric analyses suggest that a polymeric network serves as the primary structural framework, which appears to be reinforced by ettringite interlocking and micro-aggregate filling and encapsulation by desulfurization gypsum and fly ash. When mixed at a mass ratio of DG:FA = 50:50 and incorporating 3% sodium hydroxide by mass, the resulting geopolymer exhibits favourable load-bearing capacity, excellent water stability, and negligible expansion effects. The plate load test results revealed a bearing capacity of 150–200 kPa and a deformation modulus of 52.7–56.5 MPa, satisfying the load-bearing and deformation requirements of the investigated project conditions.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fmats.2026.1928488</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fmats.2026.1928488</link>
        <title><![CDATA[Mechanical properties and normal-incidence sound absorption performance of crumb-rubber-modified porous asphalt mixtures]]></title>
        <pubdate>2026-09-18T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Wenhua Wang</author><author>Kaidi Liu</author><author>Jiaxiang Fang</author><author>Xufeng Wang</author><author>Yizhe Han</author><author>Guangyong Wang</author><author>Xu Wang</author>
        <description><![CDATA[IntroductionPorous asphalt mixtures provide effective drainage and acoustic-energy absorption, but their mechanical durability under thermal and moisture exposure remains an important engineering concern. This study evaluated the effects of wet-process crumb rubber (CR) dosage on the mechanical, volumetric, moisture-related, and normal-incidence sound absorption performance of OGFC-13 mixtures.MethodsCR dosages of 0%, 10%, 15%, 20%, and 25% by mass of the base asphalt were investigated, and the corresponding mixtures were designated R-0, R-10, R-15, R-20, and R-25. Paired specimens were evaluated before and after accelerated laboratory aging at 85 °C for 120 h to compare their relative aging susceptibility. A comprehensive performance index (CPI) and weight-sensitivity analysis were further used to evaluate the overall performance of the mixtures under different engineering priorities.ResultsR-15 exhibited the highest unaged dynamic stability of 5450 cycles/mm and the lowest Cantabro loss, whereas R-20 provided the highest low-temperature deformation capacity and normal-incidence sound absorption, with a peak absorption coefficient of 0.79 and an average coefficient of 0.50. Under the baseline engineering weighting scenario, the CPI values of R-15 and R-20 were 76.42 and 76.22, respectively. Weight-sensitivity analysis showed that the preferred dosage varied between 15% and 20% as the engineering priorities changed.DiscussionThe results indicate that a CR dosage of 15–20% provides a stable high-performance range for OGFC-13 mixtures. Approximately 15% CR is recommended for heavy-traffic applications in which rutting resistance and aging durability are prioritized, whereas approximately 20% CR may be preferred where low-temperature, moisture, or acoustic performance is given greater importance.]]></description>
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