Materials and Structures最新文献

{"title":"The colloidal nature and osmotic potential of alkali-silica reaction products and their role for the ASR expansion mechanism","authors":"Colin Giebson,&nbsp;Katrin Seyfarth","doi":"10.1617/s11527-024-02542-4","DOIUrl":"10.1617/s11527-024-02542-4","url":null,"abstract":"<div><p>The chemical basics of the ASR are largely revealed and widely accepted, but the nature of the expansion mechanism is still not yet sufficiently well understood. Recent observations showed that ASR products could be considered as colloidal systems. In order to clarify if and to what extent this is the case and whether it could help to better understand the nature of the ASR products and the mechanism of ASR expansion in concrete, 10 ASR products of different composition, water content and synthesised at two temperatures (40 and 60 °C) were investigated over a period of 1.5 years. The ASR products were studied by means of NTA, SEM, ²⁹Si NMR, XRD and an osmotic cell test. The results show that ASR products contain particles of colloidal size, mainly between 50–600 nm and of different shape. The particles are unable to pass pores with a size smaller than themselves what represents a mechanism of semi-permeability in all concrete constituents with respective pore sizes, resulting in the <span>Donnan</span> effect and osmosis. The particles are irreversibly linked by the addition of Ca, which leads to a decrease in the particle concentration, the formation of crystalline phases and thus to a decrease in the osmotic potential of the ASR products. Based on the colloidal nature of the ASR products, expansion caused by ASR in concrete can be explained osmotically.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-024-02542-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798465","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":"Effect of accelerated carbonation on long-term water absorption behavior of cement-based materials","authors":"Fangzhou Ren,&nbsp;Chunsheng Zhou,&nbsp;Zhidong Zhang,&nbsp;Christopher H. Dreimol,&nbsp;Ueli Angst","doi":"10.1617/s11527-024-02533-5","DOIUrl":"10.1617/s11527-024-02533-5","url":null,"abstract":"<div><p>Concrete carbonation has been proven to be a potential path for reducing the carbon footprint of cement industry. However, since carbonation reaction significantly alters the chemical composition and microstructure of cement-based materials, it is necessary to carefully assess its effects on the transport properties and durability of concrete materials. The goal of this work is to clarify the effects of accelerated carbonation on both the pore structure and long-term water absorption behavior of cement-based materials using CEM II/B-M (T-LL) as the binder. Experimental results show that exposure to <span>(text {CO}_{2})</span> at a concentration of over 65% for 90 days leads to substantial carbonation of <span>(text {Ca(OH)}_{2})</span> and other calcium-bearing phases including C–S–H gels. Accelerated carbonation results in a refined pore structure of cement paste, marked by decreased porosity but increased specific surface area accessible to both <span>(text {N}_{2})</span> and <span>(text {H}_{2}text {O})</span>. The long-term capillary absorption of non-carbonated mortar observes the square root of time law in the initial stage and then markedly deviates down, which can be well captured by the modified Richards equation accounting for water sensitivity. In contrast, the long-term absorption into carbonated mortar consistently follows the square root of time law, which could be quantified using the conventional Richards equation. This suggests that after accelerated carbonation, the pore structure of cement mortar is less sensitive to water regain, potentially attributed to the changes in the nanostructure of C–S–H gels caused by carbonation. Additionally, carbonated mortar exhibits lower sorptivity and inherent permeability than non-carbonated mortar, indicating that accelerated carbonation decelerates the water transport in cement-based materials.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798466","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":"Bond strength and flexural performance of repair composites incorporating nanofibrillated cellulose (NFC) modified mortar","authors":"Obinna Onuaguluchi,&nbsp;Shen Wang,&nbsp;Ricky Ratu,&nbsp;Nemkumar Banthia","doi":"10.1617/s11527-024-02534-4","DOIUrl":"10.1617/s11527-024-02534-4","url":null,"abstract":"<div><p>This study investigates the influence of Plain and 0.1% NanoFibrillated Cellulose (NFC) modified repair mortar mixtures on the bond strength and flexural performance of composite and monolithic beam specimens. First, the effect of the NFC on the slant shear and flexural bond strength of repair mortar overlays was assessed. Thereafter, repair mortar thicknesses ranging from 25 to 50 mm were overlaid on concrete substrates, and flexural strength and toughness of specimens were evaluated. Furthermore, the effect of hybrid combination of the NFC and steel macro fiber on the flexural toughness and strain evolution of monolithic Fiber Reinforced Concrete (FRC and FRC + 0.1% NFC) beams were also evaluated. Test results showed that the NFC enhanced the slant shear and flexural bond strengths of repair mortar by about 35% and 43%, respectively. Flexural strength capacity of composite beams generally increased as the repair mortar thickness was raised from 25 to 50 mm. Relative to the single-layer FRC beam, concrete substrate overlaid with 50 mm thick Plain + 0.1% NFC mortar showed about 56% increase in flexural strength. However, a post-crack toughness superior to that of the single-layer FRC beam was only achieved using 25–35 mm thick Plain + 0.1% NFC repair mortar as overlays. Furthermore, with the combination of NFC and steel fiber as discrete reinforcements in FRC, the bending strength, static modulus and toughness of beams were also enhanced.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798451","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":"Thoroughgoing sustainability indices to support the development of a forward-looking market for innovative construction materials","authors":"Davide di Summa,&nbsp;Esteban Camacho,&nbsp;Liberato Ferrara,&nbsp;Nele De Belie","doi":"10.1617/s11527-024-02503-x","DOIUrl":"10.1617/s11527-024-02503-x","url":null,"abstract":"<div><p>In response to the ever-evolving demands of end-users within the construction sector, also due to the heightened global awareness regarding the pivotal role of the construction industry in sustainability ramifications, it has become imperative to wield strategic tools to steer the market toward farsighted choices. A notable example is represented by innovative cementitious materials, which are progressively captivating market interest due to their potential for enhanced overall sustainability performance. Henceforth, a crucial role is played not only by sustainability evaluation tools like Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) analyses but also by the integration of the latter into a more comprehensive approach able to promptly gauge the ecological and economic performance of the intended structural application. Some investigations have started exploring this opportunity, positing novel approaches that proffer immediate evaluations. These methods center around a range of indices that pivot upon ecological implications, along with performance indicators such as compressive strength. In light of this, the current study introduces a pair of novel indices with a more inclusive purview, encompassing not only environmental considerations but also costs and durability performance. One index, aimed at evaluating the feasibility of utilizing advanced construction materials as an alternative to traditional and consolidated options includes the aforementioned parameters on a cubic meter scale. In pursuit of this objective, part of the investigation is focused on the comparison between the mix designs of Ordinary Portland Cement Concrete (OPCC) and Ultra High Performance Concrete (UHPC), with CEM I or CEM III alternatively. The outcome revealed the limits of this first approach as it does not include some essential parameters, and OPCC performed better than UHPC in general. On the other hand, a complementary index has been proposed, seeking to optimize the mix design to be used to build structural elements or components and scale up to the level of the structural application. Thus, to check the consistency of the latter, UHPC roof panels, constructed by employing CEM I or CEM III alternatively, are then compared to panels made with ordinary reinforced concrete. The option containing CEM III registered better results in terms of holistic sustainability. The overall scope of this study is to encourage a more comprehensive, immediate, and all-encompassing evaluative approach, favouring the spread of advanced construction materials within the entire supply chain of the construction industry.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798507","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":"Compressive stress–strain relationships of laminated bamboo under service temperature","authors":"Shanyue Guan,&nbsp;Jiucheng Zhao,&nbsp;Liya Tian,&nbsp;Shizhong Zhang,&nbsp;Hongwei Zhao","doi":"10.1617/s11527-024-02515-7","DOIUrl":"10.1617/s11527-024-02515-7","url":null,"abstract":"<div><p>Laminated bamboo is a novel green building material, understanding its mechanical properties at service temperatures is essential for structural safety and optimal design. However, currently there is no constitutive model capable of effectively predicting the compressive stress–strain relationship of laminated bamboo under the influence of service temperatures. This paper examines the influence of service temperature on the compressive stress–strain relationship in laminated bamboo. The compressive properties of laminated bamboo severely decreased as the temperature rises. Based on the fundamental form of the Weibull cumulative distribution, a constitutive model is proposed. Additionally, four constitutive models previously successfully applied to laminated bamboo or other bamboo composites were modified and analyzed for their capability to predict the compressive stress–strain relationship of bamboo-based materials under different temperature. Among all the models, the proposed Weibull model and the modified RA mode have higher accuracy, and both can simulate strain hardening and thermal softening characteristics of laminated bamboo. The findings of this study not only guide the application of bamboo-based engineered materials in actual engineering structures, enhancing the precision and safety of structural designs but also provide valuable references for the research and application of other bamboo composite materials.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798508","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":"8-storey CLT building dynamical properties analysis and monitoring from construction to operating phase","authors":"Dorian Janot,&nbsp;Florent Vieux-Champagne,&nbsp;Philippe Gueguen,&nbsp;Clement Boudaud,&nbsp;Axel Jung","doi":"10.1617/s11527-024-02540-6","DOIUrl":"10.1617/s11527-024-02540-6","url":null,"abstract":"<div><p>Driven by climate change and the quest for new low-carbon construction, there is an urgent need for full-scale, real-time observations in buildings to calibrate and validate behavior and design models. The science related to timber structure design could be improved by processing the vast amount of data on actual responses in real wooden buildings. One of the first 8-storey timber buildings in France was equipped with four three components sensors for permanent instrumentation, from its construction phase through to operation, i.e., once the occupants had moved in. First, the modal analysis of the building was obtained using temporary network, then the modal parameters (frequency and damping) were monitored over several months to observe the dynamic response of this type of buildings. The results show a significant fluctuation in parameters as a function of increasing stiffness, but above all as a function of mass during the construction and moving in phases, due to the lightweight of this type of building compared with more conventional structures (e.g. reinforced concrete or masonry structures). Once the building was in full operation, significant variations appeared depending on weather conditions (temperature, humidity, wind speed), with high sensitivity to wind, especially for damping, revealed by the nonlinear elasticity response observed. Finally, the amplitude of the vibrations was compared with the ISO10137 standard for admissible mechanical vibration, thus validating the design and opening new perspectives for a longer monitoring phase.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798512","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":"Study on pore structure characteristics of circulating fluidized bed fly ash-based lightweight foamed filler based on X-ray computed tomography","authors":"Jingchao Yang,&nbsp;Xingyi Wang,&nbsp;Xi Huang,&nbsp;Yansen Pei,&nbsp;Xiaoyuan Wang,&nbsp;Pengju Han,&nbsp;Xiaohong Bai","doi":"10.1617/s11527-024-02543-3","DOIUrl":"10.1617/s11527-024-02543-3","url":null,"abstract":"<div><p>As the main solid waste of coal-fired power plants, circulating fluidized bed fly ash (CFBFA) has a huge emission, but its resource utilization in the field of construction materials is limited due to the generation of volume-expanding substances such as caliche and gypsum during the hydration process. A lightweight foamed filler (LFF) was prepared by taking CFBFA as the main material and mixing the foam produced by mechanical foaming to obtain a LFF, which utilizes its internal porosity to alleviate the expansion. The pore structure characteristic parameters such as porosity, homogeneity, pore size distribution, fractal dimension, sphericity, etc. of LFF specimens with different foam doping amounts were investigated from the three-dimensional level using X-CT tomography and other technical means. As the foam doping increases, the phenomena of foam rupture and dissipation and merger and fusion were frequent, which led to the deterioration of the consistency of the morphology of the pores in the LFF materials, and the inhomogeneity of the pore size and the average pore size increased, but the distribution of the pore size conformed to the log-normal distribution. The parameters of the LFF such as the porosity, the homogeneity of the pore distribution, the pore size, etc., were exponentially related to the compressive strength, and relationships of the sphericity with the pore size and homogeneity were quasi-linear.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789176","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":"Study on the shrinkage and restrained cracking of concrete with different surface curing methods","authors":"Jiahe Wang,&nbsp;Huajian Li,&nbsp;Yanbin Tan,&nbsp;Jiaxuan Wang,&nbsp;Yu Gao","doi":"10.1617/s11527-024-02541-5","DOIUrl":"10.1617/s11527-024-02541-5","url":null,"abstract":"<div><p>The shrinkage of concrete cured with plastic film, controlled permeability formwork liner (CPFL) and moisture retention curing film (MRCF) were experimentally measured using the designed test devices. The compressive strain on the inner surface of steel ring was also studied during the steel ring restrained test. The correlation between the development of shrinkage and strain on the steel ring was analyzed from the perspective of concrete creep. The results show that: The surface curing method has a significant impact on the shrinkage deformation and restrained cracking process of concrete. The curing method should be adapted to the characteristics of the concrete body (w/b), otherwise there will be negative effects. CPFL can effectively reduce the drying shrinkage and the risk of restrained cracking of concrete by reducing the local w/b on the surface of concrete. It has a better effect on the low and medium strength grade concrete (C30 and C50), but has adverse effects on high-strength concrete (C80); MRCF can effectively reduce the shrinkage deformation and the risk of restrained cracking through the water supplement effect of the pre-absorbent materials. It has a better effect on the high-strength concrete, while its effect on low and medium strength grade concrete is relatively small. The creep capacity of concrete is closely related to the relative humidity level. It is stronger during the humidity saturation period, and weaker during the humidity decline period.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789177","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":"Early-age compressive behavior and stress–strain relationship of high -strength SSP-cement mortar","authors":"Guohua Sheng,&nbsp;Huiyu Tian,&nbsp;Shengji Jin,&nbsp;He Liu,&nbsp;Jingtao Xiu,&nbsp;Zheng Wei","doi":"10.1617/s11527-024-02538-0","DOIUrl":"10.1617/s11527-024-02538-0","url":null,"abstract":"<div><p>Steel slag powder-cement composite mortar (SSP-cement mortar), a low-carbon building material with industrial solid waste can effectively utilize SSP. However, the low hydration activity of SSP has a significant adverse effect on its early-age behavior. In this study, the early-age compressive behavior and stress–strain relationship of a high-strength SSP-cement mortar at the first curing period of 7 days were comprehensively studied. The mix proportion parameters include the replacement ratio of SSP <i>R</i>_s, cement strength grade <i>f</i>_ce, mesh of SSP <i>ν</i>, and water-binder ratio <i>W</i>/<i>B</i>. The curing temperature was set at <i>T</i> = 20℃ and <i>T</i> = 80℃. The results indicate that: firstly, at <i>T</i> = 20℃ and <i>T</i> = 80℃, the optimal values for cube compressive strength <i>f</i>_cu are 71.2 MPa and 112.4 MPa, respectively, axial compressive strength <i>f</i>_c are 50.1 MPa and 85.4 MPa, respectively. Secondly, with the increase of <i>R</i>_s, the <i>f</i>_c, elastic modulus <i>E</i>_c, and toughness <i>U</i>, showed decreasing trends, the peak strain <i>ε</i>_cp shows an increasing trend. The trends have weakened at <i>T</i> = 80 ℃. With the increase of <i>f</i>_ce and <i>ν,</i> all the indexes (<i>f</i>_c, <i>ε</i>_cp, <i>E</i>_c, and <i>U</i>) show an upward trend. With the increase of <i>W</i>/<i>B,</i> all the indexes show a decreasing trend and are more pronounced at <i>T</i> = 20℃. Finally, an early compressive stress–strain relationship of SSP-cement mortar was established. Based on the given parameters and curing temperatures, a compressive strength prediction model is provided to guide engineering applications.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789239","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":"Cementitious versus alkali-activated textile reinforced mortars for combined energy and seismic upgrade of masonry panels","authors":"Panagiotis Kapsalis,&nbsp;Paraskevi D. Askouni,&nbsp;Catherine G. Papanicolaou,&nbsp;Thanasis C. Triantafillou","doi":"10.1617/s11527-024-02537-1","DOIUrl":"10.1617/s11527-024-02537-1","url":null,"abstract":"<div><p>Masonry retrofitting systems combining seismic with energy upgrading features are increasingly gaining popularity in the scientific community during the past years since they simultaneously address two of the most pressing needs related to the existing building stock. This is commonly realized by applying textile reinforced mortar (TRM) overlays combined with thermal insulation boards on building envelopes. At the same time, the urge for eco-friendly and environmentally sustainable interventions calls for low-cement or even cement-free solutions. This study aims to combine these requirements by experimentally investigating an integrated seismic/energy retrofitting system that incorporates alkali-activated materials (AAM) based on industrial waste. The system is compared to a counterpart one comprising conventional cementitious materials. The relative position of the strengthening and the thermal insulation layers is yet another parameter of this study. The latter includes tests performed on retrofitted masonry specimens aiming to assess their mechanical performance in terms of masonry-to-overlay bond and flexural capacity. This is achieved by shear bond tests, and in-plane and out-of-plane bending tests, respectively. The results show that the replacement of cementitious binders by alkali-activated ones in TRM jackets is a promising alternative, eliminating cement consumption while ensuring comparable load bearing capacities with ‘conventional’ TRM systems. It is also indicated that the effectiveness of the AAM-based system is improved when the strengthening layer is applied externally, i.e., on top of the insulating boards. However, further research is needed for the optimization of the system’s mechanical and long-term performance.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789241","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}