Case Studies in Construction Materials最新文献

{"title":"Local bearing capacity of steel fiber and spirals reinforced UHPC-CA: Mechanism analysis and calculation method","authors":"Sheng Li ,&nbsp;Shuo Liu ,&nbsp;Weiwei Wu ,&nbsp;Wenzhong Zheng ,&nbsp;Yiwei Zhong ,&nbsp;Weichen Tian","doi":"10.1016/j.cscm.2025.e05706","DOIUrl":"10.1016/j.cscm.2025.e05706","url":null,"abstract":"<div><div>Introducing appropriate coarse aggregate (CA) into ultra-high performance concrete (UHPC) can reduce costs and mitigate early cracking risks, while maintaining mechanical and durability properties. Ultra-high performance concrete with coarse aggregate (UHPC-CA) can demonstrate significant potential for transforming the construction industry. To investigate the local compression behaviors and failure mechanism of UHPC-CA, 9 specimens confined with spirals and steel fibers were tested under local loading conditions. The study focused on load response, failure mechanisms, cracking characteristics, and the relationship between local load and spiral strain. The wedge cleaving theory governed the failure mechanism of UHPC-CA, conceptualized as an arch structure with multiple tie rods under spiral confinement. The study identified two primary failure modes: splitting tensile failure and wedge shear failure, influenced by the middle and top bursting forces. Additionally, the parameter analysis was conducted, leading to the development and verification of a bearing capacity calculation model applicable to UHPC-CA with spirals.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05706"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788610","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":"Nano-C-S-H seeds reinforced UHPC containing silica fume and metakaolin: Mechanism analysis and carbon footprint assessment","authors":"Guanghong Lai ,&nbsp;Zhenghe Sun ,&nbsp;Siya Zhang ,&nbsp;Feiyu Liao ,&nbsp;Shiyu Li ,&nbsp;Jinli Qian ,&nbsp;Zhihong Lin","doi":"10.1016/j.cscm.2025.e05698","DOIUrl":"10.1016/j.cscm.2025.e05698","url":null,"abstract":"<div><div>Decarbonization of ultra-high-performance concrete (UHPC) can be achieved by reducing cement consumption and optimizing the use of supplementary cementitious materials (SCMs). This study investigates the effects of nano-C-S-H seeds on the microstructural evolution mechanisms of ternary phase UHPC, which includes cement, silica fume (SF), and metakaolin (MK), while also quantifying the associated carbon footprint. The results indicate that nano-C-S-H seeds significantly enhance the pozzolanic reactions of SF and MK, reduce the induction period and acceleration period of cement hydration. This acceleration facilitates the formation of a more homogeneous and denser C-(A)-S-H micro-network structure, resulting in improved mechanical performance at 1 d, particularly in the blended SF-MK system. In addition, life cycle assessment results show that the combined effect of nano-C-S-H seeds and SCMs significantly lowers the carbon emissions associated with UHPC production. This study offers critical theoretical insights for developing UHPC with low carbon footprints and high early strength.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05698"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921500","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":"Study on the mechanical behavior of basalt-polypropylene fiber concrete: Insights from experimental testing and numerical simulation","authors":"Shuailong Lian,&nbsp;Jingjing Huang,&nbsp;Wen Wan,&nbsp;Yanlin Zhao,&nbsp;Weijun Wang,&nbsp;Xuan Wang,&nbsp;Qiuhong Wu","doi":"10.1016/j.cscm.2025.e05746","DOIUrl":"10.1016/j.cscm.2025.e05746","url":null,"abstract":"<div><div>This paper takes basalt-polypropylene fiber concrete as the research object, carries out the Brazilian splitting and uniaxial compression test, adopts acoustic emission (AE) monitoring and combines numerical simulation experiments with ABAQUS software to systematically study the effects on the mechanical properties of basalt fiber and polypropylene fiber concrete with different volume admixture. The test results show that the fiber admixture can improve the toughness of the concrete. The tensile strength and compressive strength generally show the trend of increasing first and then decreasing with the increasing volume admixture of fibers. The tensile strength increased maximum when the volume incorporation of basalt fibers and polypropylene fibers was 0.1 % and 0.3 %, respectively. The compressive strength is most highly increased when the volume incorporation of basalt fibers and polypropylene fibers is 0.2 % and 0.1 %, respectively. The AE activity with time could be divided into four stages, which coincided with the stress-time curves of the specimens. The accumulative AE counts reflect the number of cracks produced during the test, and the b-values reflect the crack expansion during the test. The addition of basalt fibers and polypropylene fibers can reduce the generation and expansion of cracks for the specimens and improve the strength of the specimens. Through theoretical analysis and numerical simulation, the addition of basalt fibers and polypropylene fibers helps to improve the peak strength and residual strength of concrete specimens, and the larger the volume admixture of fibers is, the greater the improvement of residual strength of fiber concrete specimens.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05746"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921561","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":"Sustainable production of lightweight geopolymer from mixed fly ash: Effects of alkali activators and surfactants","authors":"Onanong Arjariya ,&nbsp;Suratsawadee Kungsanant ,&nbsp;Tanan Chub-uppakarn ,&nbsp;Sumate Chaiprapat","doi":"10.1016/j.cscm.2026.e05777","DOIUrl":"10.1016/j.cscm.2026.e05777","url":null,"abstract":"<div><div>Upcycling fly ash is a key challenge in supporting the circular energy production of biomass power plants. Using a mixture of palm ash (PA) and rubberwood ash (RA) in the production of lightweight geopolymer offers an innovative pathway for converting industrial waste into a valuable construction material. The study demonstrates that up to 40 % of mixed PA and RA can be utilized for metakaolin (MK) replacement in lightweight geopolymer production. The geopolymer formulation was examined at various mass ratios of MK:PA:RA using sodium hydroxide or potassium hydroxide combined with sodium silicate as alkaline activators. The suitable formulation was further applied for lightweight geopolymer production, comparing two types of surfactants—anionic and nonionic surfactants. Combining anionic and nonionic surfactants at a mass ratio of 1:3 resulted in a more stable foam than using a single surfactant alone. The formulated lightweight geopolymer has a density of 1544 kg/m³ , a compressive strength of 5.41 MPa, and a water absorption rate of 23.61 % by weight, meeting the standard for lightweight non-load-bearing concrete, with a dry density below 1680 kg/m³ and an average net-area compressive strength above 4.14 MPa, as specified in ASTM C129. Its thermal conductivity was 0.741 W/m·K, making it suitable for thermal insulation.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05777"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921722","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":"Study on the interfacial bond behavior of steel fibers embedded in cement-based materials under hot-dry environments","authors":"Pin Liu ,&nbsp;Jie Yang ,&nbsp;Chensen Zuo ,&nbsp;Junhu Shao ,&nbsp;Shengai Cui","doi":"10.1016/j.cscm.2025.e05672","DOIUrl":"10.1016/j.cscm.2025.e05672","url":null,"abstract":"<div><div>In hot-dry environments of high-temperature geothermal tunnels, the severe deterioration of concrete matrix performance significantly weakens the bond between steel fibers and the matrix, thereby compromising the reinforcing efficiency of steel fibers. This study classifies surrounding rock temperatures into four grades and establishes corresponding simulated environments. Through pullout tests, the influence of temperature on the bond-slip behavior of steel fibers is investigated, the degradation mechanism of fiber-matrix interfacial bond properties is analyzed, and numerical simulations are employed to explore the effects of fiber parameters on pullout behavior. The results indicate that: hot-dry conditions reduce the straightening degree of end hooked steel fibers after pullout, accompanied by channel expansion and spalling; above 80°C, excessive initial defects at the fiber-matrix interface inhibit significant plastic deformation of end hooked fibers during pullout, eliminating the second peak in pullout load; the adverse effects of the hot-dry environment on the pullout behavior of steel fibers gradually manifest with increasing curing age, with higher temperatures leading to poorer interfacial bond performance; fiber embedment length, hooked ends, and moderate inclination angles enhance interfacial bond, whereas excessive inclination triggers matrix spalling at the pullout end, diminishing reinforcement effectiveness.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05672"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735770","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":"Optimizing compressive strength in eco-friendly cement composites using CO₂-sequestered precipitated calcium carbonate by particle size and replacement ratio","authors":"Jaegon Lee,&nbsp;Heeyoung Lee","doi":"10.1016/j.cscm.2025.e05690","DOIUrl":"10.1016/j.cscm.2025.e05690","url":null,"abstract":"<div><div>The cement industry accounts for approximately 7–8 % of global CO₂ emissions, emphasizing the urgent need for eco-friendly cementitious materials capable of reducing the sector’s carbon footprint. This study aims to develop sustainable cement composites by incorporating CO₂-sequestered precipitated calcium carbonate (PCC) as a supplementary cementitious material and by optimizing its particle size and replacement ratio to improve mechanical performance while minimizing environmental impact. To achieve this goal, 204 cement paste specimens were prepared using four PCC particle sizes (0.08, 0.1, 1.8, and 2.0 μm) and four replacement levels (5, 10, 15, and 20 %). Mechanical, microstructural, and thermal characteristics were investigated using compressive strength tests (ASTM C109), mercury intrusion porosimetry, digital image correlation, field-emission scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The results reveal that compressive strength generally decreased with increasing PCC replacement. However, the mix containing 1.8 μm PCC at 5 % replacement achieved the highest strength (46.7 MPa, + 18.02 % relative to the control), accompanied by reduced pore volume and a more uniform strain distribution. These findings demonstrate that optimizing PCC particle size and dosage offers a novel, low-carbon pathway for achieving both mechanical improvement and CO₂ reduction. The proposed approach offers significant potential for the large-scale application of CO₂-sequestered PCC in carbon-neutral construction materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05690"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788589","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":"Noise reduction effect and mechanism of ultra-thin friction course with a 3-mm NMAS","authors":"Jiangmiao Yu ,&nbsp;Qitai Weng ,&nbsp;Leidi Xin ,&nbsp;Yuan Zhang ,&nbsp;Yong Deng ,&nbsp;Guilian Zou","doi":"10.1016/j.cscm.2025.e05739","DOIUrl":"10.1016/j.cscm.2025.e05739","url":null,"abstract":"<div><div>To develop durable and low-noise asphalt pavements, this study developed an Ultra-Thin Friction Course with a Nominal Maximum Aggregate Size(NMAS) of 3 mm (UTFC-3) using the Coarse Aggregate Void Filling (CAVF) method, achieving a dense skeleton structure and asphalt film thickness exceeding 15μm. Laboratory tests and 3D laser scanning confirmed that UTFC-3 meets all key performance requirements, including high-temperature stability, moisture resistance, and skid resistance. Through vertical tire-drop noise tests, impedance tube measurements, and dynamic mechanical analyses, UTFC-3 demonstrated a significant noise reduction of 2.9–10.1 dB(A), with pronounced effects in mid-to-high frequency ranges. The noise reduction mechanism is attributed to an optimized surface texture that suppresses mid-to-high frequency tire-pavement interaction noise (250–20000 Hz) and enhanced damping properties that attenuate low-frequency (&lt;250 Hz). Field validation further supports its acoustic efficacy, offering a durable and low-noise pavement solution for urban environments.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05739"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921565","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":"Coupled effects of polymer-to-cement ratio and resting time on cold-joint degradation and interfacial mechanism of PAE cement-based coatings","authors":"Jinyu Ge ,&nbsp;Qingan Li ,&nbsp;Wenxun Qian ,&nbsp;Xuesong Han ,&nbsp;Pengfei Zhu ,&nbsp;Fei Xu","doi":"10.1016/j.cscm.2025.e05731","DOIUrl":"10.1016/j.cscm.2025.e05731","url":null,"abstract":"<div><div>Polyacrylic ester (PAE) latex cement-based coatings were prepared using P·O 42.5 ordinary Portland cement with polymer-to-cement (P/C) ratios ranging from 10 % to 50 %. The effects of P/C ratio and resting time before mortar overlay on the coatings’ crosslinking degree, adhesion strength, bonding performance, and corrosion resistance were systematically investigated. The P/C ratio significantly affected coating compactness and interfacial compatibility, with optimal performance achieved at a P/C ratio of 25 %, where the bonding strength increased by 11 % and the corrosion current density decreased from 9.31 to 0.35 μA·cm⁻², representing a reduction of nearly two orders of magnitude compared with bare rebar. Resting time was identified as a key factor governing interfacial evolution. At 3 h, sufficient migration of water and Ca²⁺ ions from the subsequently cast mortar promoted continuous hydration, yielding a hydration degree of 45.8 % and a dense C–S–H structure. Extending the resting time to 24 h resulted in excessive polymer crosslinking and densification, which restricted hydration-medium transport. Consequently, the hydration degree on the coating side decreased to 40.5 %, the C–S–H fraction dropped to 29 %, while CH content increased to 20 %, leading to an approximately 50 % reduction in bonding strength. This study elucidates the “polymer densification–hydration medium shielding” mechanism responsible for the interfacial cold-joint effect and provides quantitative insight into the coupled influence of P/C ratio and resting time. The findings offer a theoretical basis for optimizing polymer-modified cement-based coatings and controlling on-site construction timing.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05731"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921567","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":"Effect of specimen geometry on the dynamic direct tensile responses of ultra-high-performance fiber-reinforced concrete","authors":"Hyeon Woo Noh ,&nbsp;Van Doan Truong ,&nbsp;Dong Joo Kim","doi":"10.1016/j.cscm.2025.e05732","DOIUrl":"10.1016/j.cscm.2025.e05732","url":null,"abstract":"<div><div>Direct tensile responses of ultra-high-performance fiber-reinforced concrete (UHPFRC) at high strain rates were investigated using a high-rate hydraulic universal testing machine (HR-UTM) with modified cylindrical specimens. The modified cylindrical UHPFRC specimens containing 2 vol% steel fibers exhibited tensile strain-softening behavior even at static strain rates, in contrast to the tensile strain-hardening responses commonly reported in previous studies. The modified cylindrical UHPFRC specimens containing 0.5 and 2 vol% steel fibers exhibited average tensile strengths of 8.8 and 10.0 MPa, respectively, at static strain rate (<span><math><mover><mrow><mi>ε</mi></mrow><mo>̇</mo></mover></math></span>=5.55 ×10⁻⁴ s⁻¹). As the strain rate increased from 5.55 × 10⁻⁴ to 162.96 s⁻¹, the tensile strength of the specimen with 2 vol% steel fibers increased from 10.0 to 17.1 MPa. Moreover, the elastic modulus of UHPFRC in direct tension increased from 59.4 to 124.7 GPa as the strain rate increased from 5.55 × 10⁻⁴ to 99.53 s⁻¹. However, at strain rates exceeding 162.45 s⁻¹, accurately determining the tensile elastic modulus became difficult because of vibrations and early damage to strain gauges. Overall, the results demonstrate that specimen geometry plays a critical role in governing the dynamic tensile response of UHPFRC, emphasizing the need to consider geometric effects in material design and structural applications subjected to high strain rates.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05732"},"PeriodicalIF":6.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921601","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":"2026-07-01","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}