Materials and Structures最新文献

{"title":"Durability assessment of bio-modified geopolymer concrete in simulated sewage environments","authors":"Mehrdad Ameri Vamkani,&nbsp;Zarina Yahya,&nbsp;Michaela Gkantou,&nbsp;Maria Ferentinou,&nbsp;Yangming Gao,&nbsp;Ana Bras","doi":"10.1617/s11527-026-03183-5","DOIUrl":"10.1617/s11527-026-03183-5","url":null,"abstract":"<div><p>Sewer infrastructure worldwide is ageing beyond its designed lifespan, rendering it increasingly vulnerable to biogenic sulphuric acid corrosion, cracking, and structural collapse. Geopolymer concrete represents a promising sustainable alternative to ordinary Portland cement in such aggressive environments; however, its durability under acidic conditions remains insufficiently characterised, particularly when combined with microbial modification. This study evaluated the sulphuric acid resistance and microstructural integrity of two fly ash-based geopolymer concrete formulations—a control mixture and a <i>Shewanella oneidensis</i> species-enhanced bio-modified mixture (Bio)—subjected to 1% H₂SO₄ immersion at 30 °C for 10 days to simulate sewer conditions. A multi-technique analytical framework comprising mechanical testing, capillary water absorption, SEM–EDS, XRF, FTIR, and XRD was employed to elucidate degradation mechanisms and quantify the effect of bacterial modification. Bio-modified specimens exhibited a denser, more homogeneous microstructure and markedly superior acid resistance, including an 82% increase in splitting tensile strength following acid exposure, in contrast to a 13% decrease recorded in control specimens. SEM–EDS analysis confirmed reduced cracking and enhanced retention of Ca and Fe in bio-modified specimens. XRD revealed the preservation of acid-resistant crystalline phases, including quartz and andradite, in bio-modified specimens, whereas the control specimens showed greater phase decomposition and decalcification. FTIR analysis indicated greater stability of Si–O–T bonds in bio-modified specimens, consistent with reduced silicate depolymerisation. These findings confirm that <i>Shewanella</i>-based bio-modification significantly enhances the durability of geopolymer concrete under sulphuric acid attack, supporting its application as a resilient and sustainable material for sewer infrastructure.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03183-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148838067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Behaviour and design of rebar-free ultra-high-performance concrete columns under combined compression and bending","authors":"Haoqin Luo,&nbsp;Zhi Fang,&nbsp;Jianqun Wang,&nbsp;Xuhong Zhou","doi":"10.1617/s11527-026-03249-4","DOIUrl":"10.1617/s11527-026-03249-4","url":null,"abstract":"<div><p>This study presents an investigation on the compressive behaviour of rebar-free ultra-high-performance concrete (UHPC) columns under concentric and eccentric loading. An experimental program was conducted on 42 column specimens with three fibre volumetric contents and seven load eccentricities. A numerical model was developed and validated against the experimental results and then employed in parametric studies covering key design variables, including fibre characteristic parameters, slenderness ratios, and load eccentricities. On the basis of the combined experimental and numerical results, a design methodology for rebar-free UHPC columns is proposed. The approach defines applicable ranges of load eccentricity and slenderness ratio and provides recommendations for fibre use to ensure adequate ductility. Finally, a simplified yet practical equation is established for predicting the load capacity of such members.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-point bend test analysis using digital image correlation: from elasticity to damage","authors":"Sylvain Langlois,&nbsp;François Hild,&nbsp;Maroua Maaroufi,&nbsp;Fikri Hafid,&nbsp;Farid Benboudjema,&nbsp;Amélie Fau","doi":"10.1617/s11527-026-03256-5","DOIUrl":"10.1617/s11527-026-03256-5","url":null,"abstract":"<div><p>Three-point bend tests give access to analytical solutions for identifying mechanical parameters of constitutive models, making it a widely used method for analyzing the behavior of cementitious materials. However, a lack of knowledge regarding the kinematics, such as the Dirichlet boundary conditions, may bias the parameter identification. This paper proposes a methodology to analyze the kinematics of a three-point bend test, from elasticity to damage, and to explicitly compute the mechanical parameters without any kinematic assumptions. The kinematic fields are measured using Global Digital Image Correlation, employing a kinematic basis derived from Timoshenko–Ehrenfest beam theory for the elastic stage, and T3 shape functions for the post-peak stage. Using such bases allows for the direct calculation of the Young’s modulus, tensile strength, and fracture energy. The identified material parameters are close to those obtained through Finite Element Model Updating (FEMU) using a simple elastodamage model.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adhesion between geopolymer matrix and vegetable fibers: effect of matrix composition and fiber treatment","authors":"Henrique Almeida Santana,&nbsp;Paulo Roberto Lopes Lima,&nbsp;Cleber Marcos Ribeiro Dias","doi":"10.1617/s11527-026-03229-8","DOIUrl":"10.1617/s11527-026-03229-8","url":null,"abstract":"<div><p>Seeking to promote sustainable composites composed of a low-carbon matrix and a renewable reinforcement, this study evaluated the fiber–matrix adhesion of sisal fibers used as reinforcement in geopolymeric matrices produced by the alkaline activation of fiber cement waste, in combination with metakaolin. Natural, hornified, and sodium hydroxide–treated fibers were exposed for 28 days to matrices with different free alkali contents and subsequently characterized by thermogravimetric analysis, electron microscopy, and tensile and pull-out tests. Thermogravimetric analysis revealed reductions in the cellulose decomposition peak for all exposed fibers, with more pronounced shifts in more aggressive matrices (up to − 63 °C), indicating structural degradation and decreased thermal stability. Microstructural observations showed increased surface roughness, partial fiber disintegration, and the precipitation of geopolymeric and carbonate phases, with severe alkaline hydrolysis identified in hornified fibers, particularly in potassium-activated systems. Mechanical tests indicated significant losses in tensile strength and reliability after matrix exposure, with hornified fibers exhibiting the highest susceptibility to degradation and, in extreme cases, complete loss of mechanical integrity. In contrast, sodium hydroxide–treated fibers demonstrated improved strength retention, especially when embedded in matrices with lower free alkali content. Pull-out results highlighted that fiber–matrix adhesion is strongly governed by matrix alkalinity and fiber treatment, showing apparent pull-out behavior associated with reduced fiber integrity in less aggressive matrices and premature fiber rupture in highly alkaline environments. Overall, the results demonstrate that careful design of waste-based geopolymer matrices, including matrix composition, associated physicochemical properties, and free alkali concentration, is essential to enhance interfacial bonding and durability in vegetable fiber–reinforced composites.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03229-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uniaxial and triaxial performance of concrete incorporating oxygen plasma-modified recycled plastic particles","authors":"Jernej Karničnik,&nbsp;Gregor Kravanja,&nbsp;Andrej Ivanič,&nbsp;Alenka Vesel,&nbsp;Rok Zaplotnik,&nbsp;Miran Mozetič,&nbsp;Samo Lubej","doi":"10.1617/s11527-026-03246-7","DOIUrl":"10.1617/s11527-026-03246-7","url":null,"abstract":"<div><p>The increasing accumulation of plastic waste and the depletion of natural mineral aggregates have driven interest in the use of recycled plastic particles as alternative aggregates in concrete. However, weak interfacial bonding between hydrophobic plastic particles and the cement matrix remains a critical limitation. This study investigates the effect of oxygen plasma surface modification on the mechanical performance of concrete incorporating recycled polypropylene flakes (PPF) and polyethylene agglomerates (PEA). Compressive and flexural strength tests, together with triaxial tests under confined conditions, were performed. Surface wettability was evaluated using contact angle measurements, and interfacial morphology was analysed by scanning electron microscopy (SEM). Although plastic particles reduced compressive strength compared to reference concrete, plasma treatment improved mechanical performance, particularly for PEA mixtures, with compressive strength increasing by up to 33% relative to untreated counterparts. Under triaxial loading, concrete specimens containing plasma-treated PEA particles exhibited reduced deformations and improved elastic recovery, indicating enhanced pressure transfer under confinement. SEM analysis confirmed improved interfacial bonding in treated specimens. The results demonstrate that oxygen plasma treatment effectively enhances interfacial properties and multiaxial mechanical performance of concrete incorporating plastic particles, providing novel insights into its behaviour under triaxial loading.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03246-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moisture-induced degradation of clay-bearing sandstone","authors":"You Wang,&nbsp;Falk K. Wittel","doi":"10.1617/s11527-026-03233-y","DOIUrl":"10.1617/s11527-026-03233-y","url":null,"abstract":"<div><p>Clay-bearing sandstones used in the construction of historic monuments, churches, and castles are highly susceptible to contour scaling, which manifests as fractures parallel to the exposed facades. Repeated wetting–drying cycles accelerate material degradation through stiffness reduction and hygric deformation induced by swelling clays. This in turn alters the hygro-thermal (HT) properties of the stone. In this study, a scalar damage variable is employed within the framework of continuum damage mechanics to characterize the evolving damage state under the influence of moisture fields. The most critical climatic conditions that lead to degradation are first identified through hygro-thermal simulations. Subsequently, a fully coupled hygro-thermo-mechanical (HTM) model is developed to account for both moisture transport and material degradation. The results demonstrate that contour scaling can occur solely due to moisture cycling, even in the absence of freezing or salt crystallization effects. As such, subsurface zones of damage localization and a water-accumulation layer emerge that align well with on-site observations, pointing at potential damage mechanisms such as contour scaling.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03233-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining microwave healing and permeability testing in porous asphalt mixtures for blue-green infrastructure pavements","authors":"Andres Silva-Balaguera,&nbsp;Jose L. Concha,&nbsp;Jose Norambuena-Contreras,&nbsp;Luis Á. Sañudo-Fontaneda","doi":"10.1617/s11527-026-03244-9","DOIUrl":"10.1617/s11527-026-03244-9","url":null,"abstract":"<div><p>Porous Asphalt Mixtures (PAMs) are widely used in permeable pavement systems for Blue–Green Infrastructure (BGI) applications to manage and treat surface runoff in urban and transport infrastructures. However, their hydrological and structural performance can be compromised by compaction-induced anisotropy and cracking. In this context, the valorisation of industrial by-products and the implementation of heating-based self-healing technologies can improve the performance of the PAMs. This study investigates the combined effects of Blast Furnace Dust (BFD) and microwave heating on crack-healing and vertical permeability in Superpave-compacted PAM for BGI applications. Asphalt mixtures containing 0%, 4%, and 8% BFD (i.e., as a fine-aggregate replacement) were characterised in terms of bulk air-void content, surface-connected voids via 3D scanning, and vertical permeability measured using a falling-head permeameter. The novelty of this study lies in inducing crack damage under controlled low-temperature fracture conditions, subjecting specimens to repeated microwave heating cycles within the bitumen softening range, and measuring permeability before and after cracking, as well as following healing. The main results indicate that BFD modifies the conductive pore network, reducing permeability and decreasing face-to-face anisotropy. Microwave heating promotes mechanical recovery, with hydraulic changes governed primarily by pore-network conductance rather than bulk void content alone. Overall, the PAMs containing 4% BFD exhibited the most balanced multifunctional performance, combining stable healing, lower energy demand, reduced permeability anisotropy, and more predictable vertical drainage behaviour, making it the recommended design for BGI applications.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03244-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation of hardwood shear strength using an asymmetric four-point bending test","authors":"Martin Pilon,&nbsp;Matthieu Lagarrigue,&nbsp;Guilhem Greffier,&nbsp;Laurent Bléron","doi":"10.1617/s11527-026-03235-w","DOIUrl":"10.1617/s11527-026-03235-w","url":null,"abstract":"<div><p>Europe’s abundant hardwood resources are primarily used for energy rather than for timber construction. The lack of precise mechanical characterisation limits their use as structural elements. With regard to shear strength, the current normative European test (EN 408) has drawbacks and is difficult to perform with hardwood. This study aims to develop an asymmetric four-point bending test setup to characterise the shear strength of hardwoods. A numerical model was used to analyse the shear stress distribution under the proposed test setup. Experimentally, three European hardwoods (ash, beech and oak) were tested and the shear strength was retrieved using the stress distribution from the numerical model. Twin tests were also performed with softwood for comparison with the normative test setup. The numerical model confirmed a homogeneous shear stress distribution in the central beam zone, as well as low undesirable other stresses. Experimentally, 80% of hardwood specimens exhibited a correct shear failure, with shear strength consistent with that reported in the literature. The influence of growth ring orientation, density and bending strength was studied. Twin tests demonstrated higher shear strength with the proposed test setup. The asymmetric four-point bending test developed offers an alternative for characterising shear strength, addressing the limitations of EN 408, and demonstrates the mechanical potential of hardwood.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment tools for the environmental performance of concrete – European classification systems and a novel approach","authors":"Tobias Schack,&nbsp;Macielle Deiters,&nbsp;Bastian Strybny,&nbsp;Konrad Bergmeister,&nbsp;Michael Haist","doi":"10.1617/s11527-026-03240-z","DOIUrl":"10.1617/s11527-026-03240-z","url":null,"abstract":"<div><p>In addition to the technological properties of concrete, ecological requirements will become increasingly important in the production of concrete in the future. In recent years, numerous international assessment and classification systems have been developed to transparently communicate and classify the environmental impact of concrete using quantitative parameters. These systems define corresponding classes or levels based on the specific CO₂-emissions of concrete. Such systems for measuring and classifying CO₂-emissions of concrete are becoming increasingly important in the planning, tendering, and execution of future construction projects. It is therefore crucial to provide generally applicable methods and classification systems for the assessment of CO₂-emissions of concrete. This study compares nine recently developed classification systems for evaluating CO₂-reduced concrete, describing their specific features, limitations and potential. On this basis, a novel approach was developed that combines the international systems into a single concept for compressive strength classes from C20/25 to C50/60. The proposed approach provides a simple and transparent framework that combines existing European classification systems and can therefore support the future implementation of uniform standardized international CO₂-classes for concrete. In addition, the current practical availability of such CO₂-reduced concretes is described in relation to the reduction classes of the individual systems.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03240-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural performance of bolted beam-to-beam connections between precast reinforced concrete members: experimental and numerical investigation","authors":"Wael Hameedi,&nbsp;István Völgyi","doi":"10.1617/s11527-026-03245-8","DOIUrl":"10.1617/s11527-026-03245-8","url":null,"abstract":"<div><p>This study evaluates the structural behavior of hybrid bolted beam-to-beam connections for precast reinforced-concrete members through coupled testing and nonlinear simulation. Six full-scale assembled beams were tested in monotonic four-point bending, with three anchor-bolt diameters (16, 20, 24 mm) and two assembly conditions: perfectly aligned joints and intentionally imperfect joints with 1.2° face rotation. Global load-deflection response, and local moment-rotation response, crack evolution, and failure mechanisms were documented. All specimens displayed an initial quasi-linear regime followed by stiffness degradation and a ductile post-yield phase governed by anchor-bolt plasticity. The imposed imperfections mainly penalized pre-yield stiffness, resulting in reductions of ~31% for the largest bolts, while peak resistance and deformation capacity were essentially preserved. A three-dimensional finite-element model was developed in ATENA–GiD and closely captured both the global and local responses. Manufacturing imperfections were captured by embedding the measured wedge-shaped gap at the washer–plate interface via inclined geometry and open-gap contact, enabling the seating effect of the connected surfaces. This modeling method yielded close agreement with the tests; conversely, assuming perfect contact overestimated elastic stiffness by ~12% and ~25% for A20 and A24, respectively. The validated model supported a parametric assessment of grout thickness (10–50 mm), grout compressive strength (45–95 MPa), and bolt yield strength (480–900 MPa). Grout thickness and bolt yield strength governed ultimate resistance, whereas grout strength primarily shifted the governing failure mode. Overall, the connection system provides a ductile load path for precast assemblies when imperfections and grout configuration are accounted for in analysis and design.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"59 7","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-026-03245-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148783148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}