Case Studies in Construction Materials最新文献

{"title":"Mechanistic influence of water chemistry on cement hydration through acidity–alkalinity interactions governing strength and durability","authors":"Anurag Angoth ,&nbsp;Reddy Babu Gude ,&nbsp;Srinivasulu Vemu","doi":"10.1016/j.cscm.2026.e05758","DOIUrl":"10.1016/j.cscm.2026.e05758","url":null,"abstract":"<div><div>The chemical composition of mixing water plays a critical yet often overlooked role in governing cement hydration, microstructure formation, and long-term durability. This study systematically investigates the influence of water chemistry covering acidic (S2), bicarbonate (S3), hydroxide (S4), and saline (S5) waters against potable control (S1) on the performance of ordinary Portland cement-based mortar and concrete. Experimental evaluation included fresh properties, mechanical strength, pore solution pH evolution, transport properties and microstructural characterization using SEM–EDS. Results revealed that water chemistry significantly altered hydration kinetics and matrix densification. Acidic water (S2) delayed setting and caused strength reductions exceeding 30 % relative to control, whereas hydroxide-rich water (S4) accelerated hydration, yielding the highest 90-day compressive (47 MPa) and flexural (6 MPa) strengths. Pore solution analysis confirmed stable alkalinity for S4 and S1 (pH &gt; 12.3 at 365 days), moderate decline for S3 (12.5 → 12.0), and severe depletion for S2 and S5 (11.9 → 11.1 and 12.1 → 11.4). Correspondingly, carbonation depth increased from 5 mm (S1) to 12 mm (S2), while S4 remained lowest (&lt; 3 mm). Hydroxide alkalinity produced the densest microstructure (porosity &lt; 7 %, absorption 2.3 %), whereas acidic and saline systems exceeded 12 % porosity and 5 % absorption. Chloride profiling further confirmed that S4 limited chloride ingress (&lt; 0.1 % by cement mass at 30 mm depth) compared with S5, which surpassed corrosion thresholds (&gt; 0.45 %). SEM–EDS observations validated these trends: hydroxide-rich mixes exhibited compact C–S–H morphology, while acidic and saline waters induced microcracking, carbonate precipitation, and salt crystallization. Findings confirm that pH alone cannot define water suitability for concrete. Instead, the combined effects of mineral acidity, CO₂ acidity, and hydroxide/bicarbonate alkalinity govern hydration efficiency, pore stability, and long-term durability providing essential criteria for using non-potable or recycled waters in sustainable construction.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05758"},"PeriodicalIF":6.6,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the bonding strength of rebars in seawater sea-sand concrete under chloride erosion and freeze–thaw cycles","authors":"Yao Xiao,&nbsp;Yiwen Qu,&nbsp;Siyuan Wang,&nbsp;Jianghao Liu","doi":"10.1016/j.cscm.2026.e05754","DOIUrl":"10.1016/j.cscm.2026.e05754","url":null,"abstract":"<div><div>This study experimentally investigated the bond behavior between reinforcement and seawater sea-sand concrete (SSC) under the combined actions of chloride-induced corrosion and freeze–thaw (F–T) cycles. The coupled environmental effects were simulated through a slow freezing test and an accelerated electrification corrosion method. In the test program, the number of F–T cycles (0, 15, 25, and 50) and the chloride ion concentrations (3.5 %, 7 %, and 10 %) were used as key environmental variables. The bond–slip behavior between rebars and SSC was then examined by push-out tests, taking into account the F–T cycles, salt solution concentration, rebar type (plain and deformed), and concrete strength grades. The results achieved in this study indicate that the interfacial bond strength between the rebars and SSC decreased with the increase in F-T cycles. After 50 F–T cycles, the bond strength of the specimens was reduced by more than 19 % compared with that of the uncycled specimens. The variation trend of bond properties of specimens under the coupling effect of F-T cycles and chloride corrosion was related to the F-T cycles. The bonding slip strength exhibited a pattern of initial increase followed by a gradual decline with increasing F-T cycles. Finally, A theoretic bond-slip curve between rebars and SSC after chloride salt F-T cycles is proposed and is in good agreement with the experimental results.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05754"},"PeriodicalIF":6.6,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoding Roman construction techniques through a multiproxy study of pozzolanic mortars from the Brick Amphitheater of Nola (Campania, Southern Italy)","authors":"Serena Spadavecchia ,&nbsp;Giovanna Montesano ,&nbsp;Concetta Rispoli ,&nbsp;Martina Mercurio ,&nbsp;Mario Cesarano ,&nbsp;Assunta Campanile ,&nbsp;Barbara Liguori ,&nbsp;Paola Petrosino ,&nbsp;Piergiulio Cappelletti","doi":"10.1016/j.cscm.2026.e05753","DOIUrl":"10.1016/j.cscm.2026.e05753","url":null,"abstract":"<div><div>The long-lasting performance of ancient pozzolanic mortars highlights the advanced expertise of Roman builders. By intentionally mixing lime with specific volcanic materials, like ash or sand, the Romans developed hydraulic mortars and concretes that could harden even underwater and exhibit high mechanical strength. Furthermore, these pozzolanic additives accelerated the setting process via hydraulic reactions, offering a faster alternative to the slow carbonation of pure slaked lime. This study provides the first integrated reconstruction of the technological choices and historical evolution of the Brick Amphitheater of Nola by linking the provenance and compositional variability of volcanic aggregates to its different building phases. Due to the site's complex historical stratigraphy and multiple construction phases, a targeted, non-invasive sampling strategy was adopted. Eighteen bedding mortar samples from the Amphitheater structures and adjoining Late Antique walls were analyzed using an integrated analytical including Polarized Optical Microscopy, X-Ray Powder Diffraction, Field Emission Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy, Mercury Intrusion Porosimetry, Differential Thermal Analysis and Thermogravimetric Analysis. The research aims to distinguish construction phases and trace the evolution of building techniques by i) identifying the geological provenance of raw materials, ii) analyzing the mortar mix design, and iii) reconstructing the site's chronology. Results confirmed that raw materials were locally sourced, employing aggregates from Somma-Vesuvius district, as well as recycled Neapolitan Yellow Tuff, highlighting the Roman builders' expertise in selecting and combining local volcanic aggregates with hydrated lime to produce natural hydraulic mortars. The observed hydraulicity is attributed to the binder-aggregate interaction, evidenced by reaction rims and the formation of calcium-aluminum-silicate-hydrate (C-A-S-H) gels. Mortars from the Amphitheater structures display optimized binder-aggregate ratios and well-compacted pore networks, contrasting with the greater heterogeneity, increased porosity and mixed aggregate origins of mortars from Late Antique walls. These findings reflect intentional and consistent material selection and formulation, also reflecting chronological and functional evolution of the site.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05753"},"PeriodicalIF":6.6,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Manganese zinc ferrite composite graphene oxide improves the macroscopic and microscopic properties of cement paste","authors":"Suhui Yu ,&nbsp;Aoyang Li ,&nbsp;Jian Yuan ,&nbsp;Zhaoguang Li ,&nbsp;Yan Wang ,&nbsp;Shaohui Zhang","doi":"10.1016/j.cscm.2025.e05751","DOIUrl":"10.1016/j.cscm.2025.e05751","url":null,"abstract":"<div><div>Graphene oxide (GO) had great potential in improving the performance of cement-based materials. However, the strong interaction between GO sheets was easy to cause agglomeration, which seriously limited the full play of its enhancement effect. To address this issue, this study proposed a novel strategy using manganese-zinc ferrite (MZF) to assist the dispersion of GO, aiming to solve the key problems of uneven dispersion and poor stability of GO in cement-based materials. In this study, MZF@GO materials with different composite ratios (MZF: GO = 2:1, 5:1, 10:1) were prepared. The dispersion behavior of MZF@GO was discussed. The effects of MZF@GO on the hydration process, macroscopic properties, and microstructure of cement composites were systematically studied. The results showed that MZF formed strong interfacial bonding with GO through chemical coordination, exhibiting excellent dispersion stability in simulated cement pore solution. After adding cement, MZF@GO accelerated the hydration heat release of cement, and the peak heat flow of MZF-5@GO was the highest (2.1 mW/g). Compared with the JZ group (curing 28 days), the compressive strength of MZF-2@GO, MZF-5@GO, and MZF-10@GO samples increased by 9.39 %, 16.18 %, and 8.87 %, respectively, while the flexural strength increased by 22.67 %, 32.86 % and 26.03 %, respectively. Meanwhile, the total porosity of the MZF-5@GO group decreased by about 13.26 %, indicating that the dispersed GO could effectively promote the growth of hydration products and reduce harmful pores, whereas MZF primarily contributed through physical filling. MZF@GO did not significantly reduce the resistivity of cement composites. Overall, MZF served as an effective dispersing medium for GO and provided a new approach for its efficient application in cement-based materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05751"},"PeriodicalIF":6.6,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing tensile strength and microstructural properties of solidified high-moisture dredged sediment through solid waste-based binder stabilization and basalt fiber reinforcement","authors":"Hongwei Wang ,&nbsp;Jiahui Zhang ,&nbsp;Longjun Dong ,&nbsp;Rachid Zentar ,&nbsp;Ying Shi ,&nbsp;Daoyuan Sun","doi":"10.1016/j.cscm.2025.e05752","DOIUrl":"10.1016/j.cscm.2025.e05752","url":null,"abstract":"<div><div>The study of materials with good mechanical properties for backfilling Urban Underground Spaces (UUS), such as abandoned underground spaces and ground subsidence, has important practical significance for achieving urban safety. A binder developed with solid waste materials was employed to solidify dredged sediment, transforming it into a Liquefied Stabilized Backfill Material (LSBM) for UUS. This study investigates the reinforcing effect of Basalt Fibers (BF) on the Splitting Tensile Strength (STS) behavior of solidified dredged sediment treated with a waste-based binder. A comprehensive experimental program was conducted to assess the influence of BF content, BF length, curing time, initial moisture content, and binder dosage on both STS and stress-strain responses. The results indicate that the optimal BF contents for maximizing STS at 3, 7, and 28 days were 0.1%, 0.1%, and 0.2%, respectively. Meanwhile, the corresponding STS values were 182.20 kPa, 191.98 kPa, and 242.74 kPa, representing STS increases of 120.9%, 65.2%, and 31.3% compared to the solidified sediment without BF. A fiber length of 3 mm yielded the best reinforcing effect on the tensile strength behavior of LSBM, with the STS reaching peak values of 104.47 kPa, 183.12 kPa, and 260.89 kPa at the curing times of 3, 7, and 28 days, respectively. Moreover, BF incorporation significantly improved the ductility of the solidified matrix. A regression model with a high coefficient of determination (R²=0.947) was developed, enabling effective analysis and estimation of STS from the given parameters under comparable conditions. Additionally, a strong linear relationship between the STS and Unconfined Compressive Strength (UCS) for the LSBM samples was established. Microstructural analysis revealed that the BF enhances tensile performance by increasing interfacial friction and filling pores via associated hydration products, thereby facilitating a broader stress distribution within the dense matrix. Additionally, a simplified economic and environmental benefit analysis demonstrated that per 100 kPa of STS, the 28d solidified sediment with 0.2% BF exhibited a 7.3% reduction in cost and a 15.7% reduction in CO₂ emissions per ton compared with the solidified sediment backfill material without BF. Overall, the findings of this study demonstrate that BF-reinforced, waste binder-treated dredged sediment presents a technically viable and environmentally sustainable solution for UUS backfilling.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05752"},"PeriodicalIF":6.6,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on the restrained shrinkage of internally cured concrete with combined use of superabsorbent polymers, nanosilica and basalt fibers","authors":"Said Mirgan Borito ,&nbsp;Zhao Bo ,&nbsp;Han Zhu ,&nbsp;Yasser E. Ibrahim ,&nbsp;Sadi Ibrahim Haruna","doi":"10.1016/j.cscm.2025.e05736","DOIUrl":"10.1016/j.cscm.2025.e05736","url":null,"abstract":"<div><div>Superabsorbent polymers (SAP) are widely used in concrete to mitigate autogenous shrinkage by absorbing and releasing water when internal humidity drops. However, SAP can negatively affect concrete's mechanical properties, particularly compressive strength, due to pore formation after water release. To address this issue, this study systematically investigates the effects of superabsorbent polymers (SAP), nanosilica (NS), and basalt fibers (BF) on the mechanical properties, shrinkage behavior, and cracking resistance of concrete. The addition of NS mitigates the pore formation caused by SAP by enhancing hydration and filling voids, while BF improves tensile strength and crack resistance by bridging microcracks, especially under shrinkage restraint conditions. The experimental program focused on analyzing the performance of concrete mixtures with SAP, NS, and BF, specifically addressing restrained shrinkage and its impact on early-age cracking. The results reveal that SAP significantly reduces shrinkage and delays cracking by providing internal curing, thereby mitigating moisture loss during the early curing phase. However, the addition of SAP was found to decrease compressive strength and modulus of elasticity due to pore formation within the matrix. In contrast, the inclusion of NS and BF compensated for the strength reduction, improving both compressive strength and tensile resistance, as well as providing limiting crack propagation under restraint. The combined incorporation of 0.3 % SAP, 0.9 % NS, and 1.2 % BF (NSBF-ICC mix) demonstrated the best overall performance, offering improved shrinkage resistance and cracking behavior while maintaining mechanical integrity. Specifically, the NSBF-ICC mix exhibited an 11.2 % increase in compressive strength and a 16.8 % improvement in tensile strength compared to the control mix, while also showing a 30 % reduction in shrinkage strain relative to the control mix and a 25 % reduction in shrinkage strain compared to the SAP-only mixture. The synergy between SAP, NS, and BF significantly mitigated the negative effects of SAP alone, providing a balanced solution for internally cured concrete. These findings highlight the potential for optimizing the use of hybrid additive systems to improve concrete durability without compromising strength, offering valuable insights for future research into hybrid cementitious mixtures in applications like concrete pavements and bridge decks that require enhanced durability.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05736"},"PeriodicalIF":6.6,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on the mechanical performance of 3D-printed concrete-glued laminated timber composite beams","authors":"Xiaoyue Zhang ,&nbsp;Zhengren Chen ,&nbsp;Xinting Zhou ,&nbsp;Zheng Li ,&nbsp;Xuhong Zhou","doi":"10.1016/j.cscm.2025.e05749","DOIUrl":"10.1016/j.cscm.2025.e05749","url":null,"abstract":"<div><div>This study presents a novel, reinforcement-free prefabricated composite beam system integrating 3D-printed concrete (3DPC) slabs and glued laminated timber (GLT) beams. The system employs an ultra-high-performance concrete (UHPC)-filled notch-screw shear connector to address the interfacial bonding challenge between the two materials. Push-out tests on the connector demonstrated that its load-bearing capacity and slip stiffness increased with notch depth and length, while the shear length ahead of the notch had a minor influence. For the critical 3DPC-UHPC interface, three failure modes were identified, with performance governed by matrix interlayer properties and interface morphology. The X-interface with an original 3DPC surface was optimal, and adding polyoxymethylene fiber further enhanced performance. Connectors with a vertical printing path showed superior performance, with approximately 8 % higher load capacity than those with a horizontal path. Bending tests on composite beams clarified the influence of cross-sectional mesh configuration and printing material. Beams with a transverse mesh exhibited 28.8 % greater initial stiffness than those with a top-surface mesh. Crucially, the system achieved satisfactory structural performance without traditional steel reinforcement, validating the feasibility of the proposed reinforcement-free, prefabricated approach. Finally, predictions for bending stiffness and interface shear capacity based on the gamma method showed good agreement with experimental values.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05749"},"PeriodicalIF":6.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic performance enhancement of precast bridge pier using ultrahigh-performance concrete jacket","authors":"Jiuhong Fan ,&nbsp;Xiuhua Li ,&nbsp;Bowen Xiao ,&nbsp;Ying Lu ,&nbsp;Jin Di ,&nbsp;Fengjiang Qin","doi":"10.1016/j.cscm.2025.e05750","DOIUrl":"10.1016/j.cscm.2025.e05750","url":null,"abstract":"<div><div>The application of precast bridge piers is becoming increasingly widespread due to its significant time-saving advantages. To enhance the seismic performance of the bridge piers, ultrahigh-performance concrete (UHPC) jackets was set in the plastic hinge of the precast bridge piers with socket connection. Quasi-static tests were conducted on five specimens to investigate the influence of the height and thickness of the UHPC jacket on the seismic behavior of precast bridge piers. When the UHPC jacket height was too low or the thickness was too great, the plastic hinge region of the pier shifted upward, reducing the ductility and cumulative energy dissipation of the pier, which adversely affected its seismic performance. Based on the numerical analysis results, a bending moment enhancement coefficient was regressed and the dimension design method of UHPC jacket was proposed. This study provides a reference for designing UHPC jackets to enhance the seismic performance of bridge piers.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05750"},"PeriodicalIF":6.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of the hydration heat, temperature distribution and thermal stress of mass concrete","authors":"Guowen Sun ,&nbsp;Haorui Zheng ,&nbsp;Liguo Wang ,&nbsp;Liang Peng ,&nbsp;Haitao Yang ,&nbsp;Yifan Li","doi":"10.1016/j.cscm.2025.e05748","DOIUrl":"10.1016/j.cscm.2025.e05748","url":null,"abstract":"<div><div>Thermal cracks induced by hydration heat are one of the primary factors affecting the durability of mass concrete structures. To accurately predict the early-age temperature rise and thermal stress of mass concrete, a hydration heat prediction model for Portland cement was established based on the Parrot-Killoh hydration kinetic model, considering the effects of water-cement ratio, cement fineness, relative humidity and temperature. Subsequently, taking the predicted hydration heat as the internal heat source, a finite element analysis model for the temperature and thermal stress fields of mass concrete was constructed. The influence laws of key parameters including water-cement ratio, cement fineness and curing temperature on the core temperature and thermal stress were systematically investigated. The results indicate that reducing the water-cement ratio or using finer cement significantly increases the peak core temperature and peak compressive stress of concrete; an increase in curing temperature accelerates the hydration reaction, raises the peak temperature and reduces the late-age tensile stress. Furthermore, a thermo-mechanical-damage coupled model based on the Mazars damage criterion was employed to simulate the early-age damage evolution process, revealing that damage tends to occur on the surface and edge regions within 24 h after casting. The multi-scale prediction method proposed in this study provides a reliable theoretical tool and engineering reference for temperature control and crack prevention design of mass concrete.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05748"},"PeriodicalIF":6.6,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Creep failure of alkali activated slag concrete in compression: Effect of loading age and stress level","authors":"Ziyang Zhang ,&nbsp;Xianggang Bian ,&nbsp;Jianfei Kang ,&nbsp;Tengfei Xu","doi":"10.1016/j.cscm.2025.e05744","DOIUrl":"10.1016/j.cscm.2025.e05744","url":null,"abstract":"<div><div>With the rapid advancement of 3D printing, concrete is required to bear significant stress loads during its early-age period. The high stress creep failure behavior is directly associated with the structural stability and build ability requirements of 3D printed concrete elements during layer deposition. Nonlinear creep manifests in concrete subjected to high stresses. This process results in the accumulation of damage, which culminates in creep failure of concrete materials. However, limited information exists on this phenomenon in alkali-activated slag concrete. In this study, the creep failure of alkali-activated slag concrete under high uniaxial stress was investigated, and the creep failure characteristics of alkali-activated slag concrete were obtained. Additionally, the effects of loading age and stress ratio were investigated. The failure mechanism, creep coefficient, and nominal Poisson’s ratio of alkali-activated slag concrete specimens were investigated. Findings indicated that as age increases, the influence of loading age on the nonlinear creep of alkali-activated slag concrete progressively diminishes. Stress levels significantly affect the nonlinear creep of alkali-activated slag concrete. Specifically, when the stress level reached 0.95<span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, the alkali-activated slag concrete specimen failed after sustaining the load for a few seconds. During the creep phase, the circumferential creep coefficient and nominal Poisson’s ratio of the specimen exhibited a substantial increase, with the circumferential creep coefficient markedly exceeding the axial creep coefficient. Furthermore, the specimens exhibited significant lateral expansion upon destruction. Non-destructive and crack analyses were conducted to identify the creep-failure mechanism. The creep-failure study indicated that the propagation of microcracks inside the specimen influenced the nonlinear creep and creep-failure characteristics of alkali-activated slag concrete specimens subjected to high sustained compressive stress. The deterioration of the adhesive substance between particles progressively culminated in extensive fractures, which resulted in creep failure.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05744"},"PeriodicalIF":6.6,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}