Pub Date : 2025-12-20DOI: 10.1016/j.cscm.2025.e05722
Jun Zhang , Xinyu Zhang , Shouxin Wang , Shufang Li , Wuju Wei
Tensile strength is a crucial parameter for assessing the pavement performance of asphalt mixtures. However, the methods currently commonly used to test the tensile strength of asphalt mixtures usually encounter issues related to operational convenience and testing theory, which significantly impact the accuracy and ease of conducting tensile strength tests. Therefore, this paper proposed a novel testing theory and methodology that utilizes the actual tensile stress–strain relationship of asphalt mixtures and the measured neutral axis height of asphalt mixture bending beams of four-point bending test to determine the tensile strength of the mixture. Furthermore, a series of four-point bending beam tests and direct tension tests at various loading rates were conducted to validate this method. The results demonstrated that this method effectively overcomes the limitations of conventional testing method, and the tensile strength determined by this approach is aligned well with that obtained from direct tension tests, their percent error is only −30 %∼20 %. Additionally, this method better reflects the tensile performance of the mixture over a broad section of the beam, ensuring representative and reliable test results.
{"title":"Theory and methodology for testing asphalt mixtures’ tensile strength by four-point bending","authors":"Jun Zhang , Xinyu Zhang , Shouxin Wang , Shufang Li , Wuju Wei","doi":"10.1016/j.cscm.2025.e05722","DOIUrl":"10.1016/j.cscm.2025.e05722","url":null,"abstract":"<div><div>Tensile strength is a crucial parameter for assessing the pavement performance of asphalt mixtures. However, the methods currently commonly used to test the tensile strength of asphalt mixtures usually encounter issues related to operational convenience and testing theory, which significantly impact the accuracy and ease of conducting tensile strength tests. Therefore, this paper proposed a novel testing theory and methodology that utilizes the actual tensile stress–strain relationship of asphalt mixtures and the measured neutral axis height of asphalt mixture bending beams of four-point bending test to determine the tensile strength of the mixture. Furthermore, a series of four-point bending beam tests and direct tension tests at various loading rates were conducted to validate this method. The results demonstrated that this method effectively overcomes the limitations of conventional testing method, and the tensile strength determined by this approach is aligned well with that obtained from direct tension tests, their percent error is only −30 %∼20 %. Additionally, this method better reflects the tensile performance of the mixture over a broad section of the beam, ensuring representative and reliable test results.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05722"},"PeriodicalIF":6.6,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921437","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}
Pub Date : 2025-12-19DOI: 10.1016/j.cscm.2025.e05719
Yichao Wang , Zeen Hu , Sisi Feng , Yayun Qin , Haitao Yang , Guowen Sun , Yao Zhang
To meet the micro-mechanical design guidelines for achieving strain hardening and steady-state cracking behavior, the coarse aggregates are conventionally excluded from engineered cementitious composite materials. The absence of coarse aggregates leads to challenges, including enormous carbon emissions, elevated drying shrinkage, and reduced compressive strength. To overcome these limitations, this study explored the development of a novel ultra-high ductile concrete (UHDC) incorporating coarse aggregates, with the particular focus on the recycled coarse aggregates. The effects of coarse aggregate content (16 %, 20 % and 24 %) on the workability, drying shrinkage, and basic mechanical properties of UHDC were systematically investigated through the physical and mechanical tests. The results demonstrated that all the UHDC mixtures, both with natural and recycled coarse aggregates, consistently exhibited strain-hardening behavior and multiple micro-cracking characteristics. All the mixtures achieved the average tensile strains exceeding 5 %, while maintaining crack width below 150 μm. As the coarse aggregate content increased, the workability, drying shrinkage, tensile strength, and tensile strain exhibited progressive reduction, whereas the compressive strength demonstrated significant enhancement. Notably, compared to the mixture without coarse aggregates, UHDC containing 24 % coarse aggregates markedly reduced the 28-day shrinkage strain by 65.83 % to 450.56 µε, while simultaneously enhancing the compressive strength by 28.4 %, reaching 38.9 MPa. Furthermore, scanning electron microscopy and X-ray computed tomography (CT) tests were conducted to analyze the micro-structural and pore structure characterization, respectively. In addition, the study demonstrated that compared to the mixture without coarse aggregates, UHDC containing 24 % recycled coarse aggregates significantly reduced the energy consumption and carbon emissions by 18.38 % and 25.25 %, respectively. It was preliminary verified that the incorporation of coarse aggregate effectively enhanced the mechanical performance and promoted sustainability through waste concrete utilization.
{"title":"Enabling recycled coarse aggregates in ductile ECC: A synergistic enhancement of mechanical and sustainability properties","authors":"Yichao Wang , Zeen Hu , Sisi Feng , Yayun Qin , Haitao Yang , Guowen Sun , Yao Zhang","doi":"10.1016/j.cscm.2025.e05719","DOIUrl":"10.1016/j.cscm.2025.e05719","url":null,"abstract":"<div><div>To meet the micro-mechanical design guidelines for achieving strain hardening and steady-state cracking behavior, the coarse aggregates are conventionally excluded from engineered cementitious composite materials. The absence of coarse aggregates leads to challenges, including enormous carbon emissions, elevated drying shrinkage, and reduced compressive strength. To overcome these limitations, this study explored the development of a novel ultra-high ductile concrete (UHDC) incorporating coarse aggregates, with the particular focus on the recycled coarse aggregates. The effects of coarse aggregate content (16 %, 20 % and 24 %) on the workability, drying shrinkage, and basic mechanical properties of UHDC were systematically investigated through the physical and mechanical tests. The results demonstrated that all the UHDC mixtures, both with natural and recycled coarse aggregates, consistently exhibited strain-hardening behavior and multiple micro-cracking characteristics. All the mixtures achieved the average tensile strains exceeding 5 %, while maintaining crack width below 150 μm. As the coarse aggregate content increased, the workability, drying shrinkage, tensile strength, and tensile strain exhibited progressive reduction, whereas the compressive strength demonstrated significant enhancement. Notably, compared to the mixture without coarse aggregates, UHDC containing 24 % coarse aggregates markedly reduced the 28-day shrinkage strain by 65.83 % to 450.56 µε, while simultaneously enhancing the compressive strength by 28.4 %, reaching 38.9 MPa. Furthermore, scanning electron microscopy and X-ray computed tomography (CT) tests were conducted to analyze the micro-structural and pore structure characterization, respectively. In addition, the study demonstrated that compared to the mixture without coarse aggregates, UHDC containing 24 % recycled coarse aggregates significantly reduced the energy consumption and carbon emissions by 18.38 % and 25.25 %, respectively. It was preliminary verified that the incorporation of coarse aggregate effectively enhanced the mechanical performance and promoted sustainability through waste concrete utilization.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05719"},"PeriodicalIF":6.6,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921490","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}
Pub Date : 2025-12-19DOI: 10.1016/j.cscm.2025.e05718
Jun Yan, Zhaoxi Li, Jun Wang
This study investigates the utilization of municipal solid waste incineration bottom ash (IBA), pretreated via simple co-grinding and sieving, in ecological cement mortar (ECM) designed with a modified Andreasen–Andersen particle-packing model and an ultra-low water-to-binder ratio (w/b = 0.16). Mortars with 0–15 % IBA by mass replacing natural river sand were evaluated for mechanical, microstructural, and environmental performance. Strength improved at 5–10 % IBA, with the 10 % mix reaching a 28-day compressive strength of 127.6 MPa. XRD/TGA confirmed pozzolanic reactivity, showing ∼42.9 % consumption of Portlandite (Ca(OH)2) and additional C–A–S–H formation. SEM and MIP revealed a densified matrix and refined pore structure. Leaching concentrations of Cu, Zn, Pb, and Cr were below regulatory thresholds, and mixes with 5–10 % IBA exhibited lower values than the control. Life-cycle assessment indicated that 15 % IBA reduced global warming potential by ∼9.8 % and yielded net benefits in ecotoxicity and human-toxicity categories due to avoided-burden credits. Overall, 10 % IBA provided the best balance between mechanical performance and environmental safety, whereas 15 % maximized environmental benefits, supporting the large-scale, low-cost use of IBA in sustainable construction materials.
{"title":"Valorization of municipal solid waste incineration bottom ash in ecological cement mortar: Mechanical enhancement, effective immobilization of hazardous heavy metals, and life cycle environmental benefits","authors":"Jun Yan, Zhaoxi Li, Jun Wang","doi":"10.1016/j.cscm.2025.e05718","DOIUrl":"10.1016/j.cscm.2025.e05718","url":null,"abstract":"<div><div>This study investigates the utilization of municipal solid waste incineration bottom ash (IBA), pretreated via simple co-grinding and sieving, in ecological cement mortar (ECM) designed with a modified Andreasen–Andersen particle-packing model and an ultra-low water-to-binder ratio (w/b = 0.16). Mortars with 0–15 % IBA by mass replacing natural river sand were evaluated for mechanical, microstructural, and environmental performance. Strength improved at 5–10 % IBA, with the 10 % mix reaching a 28-day compressive strength of 127.6 MPa. XRD/TGA confirmed pozzolanic reactivity, showing ∼42.9 % consumption of Portlandite (Ca(OH)<sub>2</sub>) and additional C–A–S–H formation. SEM and MIP revealed a densified matrix and refined pore structure. Leaching concentrations of Cu, Zn, Pb, and Cr were below regulatory thresholds, and mixes with 5–10 % IBA exhibited lower values than the control. Life-cycle assessment indicated that 15 % IBA reduced global warming potential by ∼9.8 % and yielded net benefits in ecotoxicity and human-toxicity categories due to avoided-burden credits. Overall, 10 % IBA provided the best balance between mechanical performance and environmental safety, whereas 15 % maximized environmental benefits, supporting the large-scale, low-cost use of IBA in sustainable construction materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05718"},"PeriodicalIF":6.6,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921493","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}
Pub Date : 2025-12-19DOI: 10.1016/j.cscm.2025.e05717
Dong Tang , Hailin Wang , Naitian Zhang , Jin Ran , Yongli Zhao , Jing Li
Reflection cracking is a critical issue affecting the durability of semi-rigid base asphalt pavements, primarily caused by the high shrinkage and limited crack resistance of conventional cement-stabilized macadam (CSM). To address this, a filling-type large-size cement-stabilized macadam (F-LSBC) base was developed, yet its interfacial weakening mechanism and corresponding impact on energy evolution remain unclear. This study combines micro- and macro-scale investigations to elucidate the crack resistance mechanism of F-LSBC compared with CSM. Nanoindentation testing was employed to quantify the micromechanical properties of the interfacial transition zone (ITZ), while splitting load–unload tests were conducted to analyze the releasable elastic strain energy and surface-layer energy evolution of the two materials. Results show that the ITZ in F-LSBC exhibits significantly lower elastic modulus (60 %–75 %) and hardness (55 %) than in CSM, along with higher porosity and a 1.5-fold larger volume fraction, confirming a pronounced interfacial weakening structure. Correspondingly, the dissipated energy proportion in F-LSBC reaches about 75 %, notably higher than the 60 % observed in CSM, leading to a 50 % reduction in its energy storage limit and a surface-layer energy less than 40 % that of CSM. These findings indicate that the intentional interfacial weakening in F-LSBC effectively reduces the transmission of shrinkage strain energy to the surface layer, thereby suppressing the formation of reflection cracks. This study provides the first quantitative nanoindentation-based confirmation of ITZ weakening in F-LSBC and provides quantitative evidence supporting the linkage between ITZ weakening and the reduction of surface-layer energy peak, offering theoretical guidance for the design of anti-cracking semi-rigid base materials.
{"title":"Interfacial weakening mechanism and energy evolution of filling-type large-size cement-stabilized macadam for reflection crack mitigation","authors":"Dong Tang , Hailin Wang , Naitian Zhang , Jin Ran , Yongli Zhao , Jing Li","doi":"10.1016/j.cscm.2025.e05717","DOIUrl":"10.1016/j.cscm.2025.e05717","url":null,"abstract":"<div><div>Reflection cracking is a critical issue affecting the durability of semi-rigid base asphalt pavements, primarily caused by the high shrinkage and limited crack resistance of conventional cement-stabilized macadam (CSM). To address this, a filling-type large-size cement-stabilized macadam (F-LSBC) base was developed, yet its interfacial weakening mechanism and corresponding impact on energy evolution remain unclear. This study combines micro- and macro-scale investigations to elucidate the crack resistance mechanism of F-LSBC compared with CSM. Nanoindentation testing was employed to quantify the micromechanical properties of the interfacial transition zone (ITZ), while splitting load–unload tests were conducted to analyze the releasable elastic strain energy and surface-layer energy evolution of the two materials. Results show that the ITZ in F-LSBC exhibits significantly lower elastic modulus (60 %–75 %) and hardness (55 %) than in CSM, along with higher porosity and a 1.5-fold larger volume fraction, confirming a pronounced interfacial weakening structure. Correspondingly, the dissipated energy proportion in F-LSBC reaches about 75 %, notably higher than the 60 % observed in CSM, leading to a 50 % reduction in its energy storage limit and a surface-layer energy less than 40 % that of CSM. These findings indicate that the intentional interfacial weakening in F-LSBC effectively reduces the transmission of shrinkage strain energy to the surface layer, thereby suppressing the formation of reflection cracks. This study provides the first quantitative nanoindentation-based confirmation of ITZ weakening in F-LSBC and provides quantitative evidence supporting the linkage between ITZ weakening and the reduction of surface-layer energy peak, offering theoretical guidance for the design of anti-cracking semi-rigid base materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05717"},"PeriodicalIF":6.6,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921494","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}
Vibration is a critical procedure in the production of cementitious materials to reduce porosity and improve compaction. However, the vibration energy of poker (inserted-type) vibrators exhibits spatial attenuation, which leads to pore distributive heterogeneity and results in uneven mechanical behavior of the material. The current study experimentally investigates the heterogeneity issue and quantifies the relevant efficient compaction zone (ECZ) for a single poker vibrator. Experimental results demonstrate that energy transmission of poker vibration becomes stable at 20 s and forms the ECZ with only 53.9 % coverage. The study confirms that certain difference of insertion depths between two adjacent vibrators can effectively improve the ECZ coverage and solve the corresponding heterogeneity problem. Subsequently, it formulates equations to determine the optimal depth difference and to develop a modified vibration mode. Compared to the conventional operation modes, the presented mode reduces the vertical porosity deviation from 2.46 % to 0.90 % and decreases the overall specimen porosity from 4.27 % to 2.47 %. And it achieves over 95 % ECZ coverage. The findings and the proposed method have applications in promoting the precise vibration control for the on-site cementitious material production.
{"title":"Pore distributive heterogeneity of cementitious materials by poker vibration: Quantification and modification","authors":"Zhiming Yu, Yimiao Huang, Wei Dong, Xiaokuan Zhao, Fang Wang, Guowei Ma","doi":"10.1016/j.cscm.2025.e05720","DOIUrl":"10.1016/j.cscm.2025.e05720","url":null,"abstract":"<div><div>Vibration is a critical procedure in the production of cementitious materials to reduce porosity and improve compaction. However, the vibration energy of poker (inserted-type) vibrators exhibits spatial attenuation, which leads to pore distributive heterogeneity and results in uneven mechanical behavior of the material. The current study experimentally investigates the heterogeneity issue and quantifies the relevant efficient compaction zone (ECZ) for a single poker vibrator. Experimental results demonstrate that energy transmission of poker vibration becomes stable at 20 s and forms the ECZ with only 53.9 % coverage. The study confirms that certain difference of insertion depths between two adjacent vibrators can effectively improve the ECZ coverage and solve the corresponding heterogeneity problem. Subsequently, it formulates equations to determine the optimal depth difference and to develop a modified vibration mode. Compared to the conventional operation modes, the presented mode reduces the vertical porosity deviation from 2.46 % to 0.90 % and decreases the overall specimen porosity from 4.27 % to 2.47 %. And it achieves over 95 % ECZ coverage. The findings and the proposed method have applications in promoting the precise vibration control for the on-site cementitious material production.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05720"},"PeriodicalIF":6.6,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921441","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}
Pub Date : 2025-12-18DOI: 10.1016/j.cscm.2025.e05714
Mohamed Inayathulla , Shamsad Ahmad , Tuba Iqbal , Mohammed A. Al-Osta , Syed K. Najamuddin , Asad Hanif
In this paper, red mud (RM), a highly alkaline waste material from aluminum production rich in alumina, iron, and silica, is used as a supplementary cementing material in developing high-strength self-compacting concrete (HS-SCC). The resulting fresh and hardened-state properties were determined. RM was added to HS-SCC in varying amounts to replace the cement. The results indicate that replacing cement with RM enhances the cohesiveness and flowability of SCC with improved mechanical and durability properties, due to its finer gradation and pozzolanic activity. The in-depth microstructural analysis by SEM showed enhanced packing density, densified pore structure, and interfacial strengthening. The optimal dosage of RM was determined as 10 %, leading to the 28-day compressive strength of the developed SCC > 57 MPa. The RM replacement at 30 % also significantly improved resistance against acid attack and water penetration, while the corresponding drying shrinkage was lower with improved stress-strain behavior. The enhanced properties are primarily due to greater strength and elastic modulus. These findings highlight the use of RM as a viable, sustainable cement substitute that can help resource conservation and environmental remediation in producing high-strength, high-performance self-compacting concrete.
{"title":"High-strength self-compacting concrete incorporating red mud: Development and comprehensive performance evaluation","authors":"Mohamed Inayathulla , Shamsad Ahmad , Tuba Iqbal , Mohammed A. Al-Osta , Syed K. Najamuddin , Asad Hanif","doi":"10.1016/j.cscm.2025.e05714","DOIUrl":"10.1016/j.cscm.2025.e05714","url":null,"abstract":"<div><div>In this paper, red mud (RM), a highly alkaline waste material from aluminum production rich in alumina, iron, and silica, is used as a supplementary cementing material in developing high-strength self-compacting concrete (HS-SCC). The resulting fresh and hardened-state properties were determined. RM was added to HS-SCC in varying amounts to replace the cement. The results indicate that replacing cement with RM enhances the cohesiveness and flowability of SCC with improved mechanical and durability properties, due to its finer gradation and pozzolanic activity. The in-depth microstructural analysis by SEM showed enhanced packing density, densified pore structure, and interfacial strengthening. The optimal dosage of RM was determined as 10 %, leading to the 28-day compressive strength of the developed SCC > 57 MPa. The RM replacement at 30 % also significantly improved resistance against acid attack and water penetration, while the corresponding drying shrinkage was lower with improved stress-strain behavior. The enhanced properties are primarily due to greater strength and elastic modulus. These findings highlight the use of RM as a viable, sustainable cement substitute that can help resource conservation and environmental remediation in producing high-strength, high-performance self-compacting concrete.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05714"},"PeriodicalIF":6.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788419","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}
Pub Date : 2025-12-17DOI: 10.1016/j.cscm.2025.e05693
Jian Gong , Jiaxuan Zhang , Shuren Wang , Aichi Ma , Zhenzhen An
To address the drawbacks of magnesium oxychloride cement (MOC), phosphoric acid was employed to modify MOC cement. MOC cement exhibits poor water resistance, and in cold regions, it is subjected to a complex, multi-stress environment that significantly exacerbates its poor water resistance. Modifying MOC cement can improve its water resistance and thereby enhance its stability in cold regions. This experiment adopted a multi-scale design to simulate temperature variations in cold regions and investigated the effects of dry-wet-freeze-thaw (DWFT) cycle coupling on MOC cement. Mechanical strength, mineral composition, microstructural changes, and pore distribution were analyzed through uniaxial compressive strength (UCS) testing, X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). Damage analysis was conducted on the test specimens based on the test results. The findings revealed that the strength loss of unmodified MOC exceeded 50 % after 20 DWFT cycles, whereas the strength of modified MOC increased by approximately 40 %. The addition of phosphoric acid prevented the dissolution of phase 5 crystals in the MOC system, and the porosity of the modified MOC cement decreased by about 50 %. A damage equation for specimens under DWFT cycles was derived and validated, enabling quantitative analysis of the impact of modifiers on MOC cement performance. The research findings hold significant importance for studying the durability and modification of MOC cement.
{"title":"Coupled mechanical-microstructural damage behavior of phosphoric acid-modified MOC under dry-wet-freeze-thaw cycling","authors":"Jian Gong , Jiaxuan Zhang , Shuren Wang , Aichi Ma , Zhenzhen An","doi":"10.1016/j.cscm.2025.e05693","DOIUrl":"10.1016/j.cscm.2025.e05693","url":null,"abstract":"<div><div>To address the drawbacks of magnesium oxychloride cement (MOC), phosphoric acid was employed to modify MOC cement. MOC cement exhibits poor water resistance, and in cold regions, it is subjected to a complex, multi-stress environment that significantly exacerbates its poor water resistance. Modifying MOC cement can improve its water resistance and thereby enhance its stability in cold regions. This experiment adopted a multi-scale design to simulate temperature variations in cold regions and investigated the effects of dry-wet-freeze-thaw (DWFT) cycle coupling on MOC cement. Mechanical strength, mineral composition, microstructural changes, and pore distribution were analyzed through uniaxial compressive strength (UCS) testing, X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). Damage analysis was conducted on the test specimens based on the test results. The findings revealed that the strength loss of unmodified MOC exceeded 50 % after 20 DWFT cycles, whereas the strength of modified MOC increased by approximately 40 %. The addition of phosphoric acid prevented the dissolution of phase 5 crystals in the MOC system, and the porosity of the modified MOC cement decreased by about 50 %. A damage equation for specimens under DWFT cycles was derived and validated, enabling quantitative analysis of the impact of modifiers on MOC cement performance. The research findings hold significant importance for studying the durability and modification of MOC cement.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05693"},"PeriodicalIF":6.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921442","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}
The semi-rigid base pavement in the Jiayuguan area experiences significant challenges, particularly rutting deformation resulting from the combined effects of high-temperature weather and vehicle loads. By collecting meteorological data from the Jiayuguan area and inputting 24-hour temperature and solar radiation values during summer high-temperature periods, a solid heat transfer physical field and a surface radiation physical field were established to analyze the temperature distribution within the pavement structure. Two typical pavement materials, AC-16 and SMA-16, were selected as asphalt surface materials, with numerical simulations performed using the finite element software COMSOL Multiphysics to study asphalt pavement under combined environmental and vehicle loading conditions. Considering the temperature-dependent properties of asphalt mixtures (e.g., elastic modulus, creep coefficient), solid mechanical physical fields and vehicle load models were developed to estimate the mechanical response and rutting deformation of asphalt pavement under continuous temperature and load coupling conditions. The results indicate that the daily road surface temperature variation reaches 33.89°C, significantly impacting the material properties of asphalt mixtures. Under the combined effects of temperature and load, the mechanical response trends for pavements with AC-16 and SMA-16 surface materials are similar. Maximum vertical deformation, shear creep, and compressive creep all occur within the top 0–4 cm pavement depth, alternating between positive and negative across the transverse direction of the pavement. Compared to AC-16, SMA-16 exhibits reductions of 63.4 %, 22.4 %, 42.89 %, 45.29 %, 46.85 % and 27.19 % in positive and negative vertical deformations, making SMA-16 more suitable for enhancing the rutting resistance of asphalt pavement.
{"title":"Investigation on the high-temperature rutting failure of asphalt pavement structures under the combined effect of measured temperature and applied load","authors":"Tengfei Nian , Baosen Wu , Jiaqi Song , Mingjuan Zhang","doi":"10.1016/j.cscm.2025.e05711","DOIUrl":"10.1016/j.cscm.2025.e05711","url":null,"abstract":"<div><div>The semi-rigid base pavement in the Jiayuguan area experiences significant challenges, particularly rutting deformation resulting from the combined effects of high-temperature weather and vehicle loads. By collecting meteorological data from the Jiayuguan area and inputting 24-hour temperature and solar radiation values during summer high-temperature periods, a solid heat transfer physical field and a surface radiation physical field were established to analyze the temperature distribution within the pavement structure. Two typical pavement materials, AC-16 and SMA-16, were selected as asphalt surface materials, with numerical simulations performed using the finite element software COMSOL Multiphysics to study asphalt pavement under combined environmental and vehicle loading conditions. Considering the temperature-dependent properties of asphalt mixtures (e.g., elastic modulus, creep coefficient), solid mechanical physical fields and vehicle load models were developed to estimate the mechanical response and rutting deformation of asphalt pavement under continuous temperature and load coupling conditions. The results indicate that the daily road surface temperature variation reaches 33.89°C, significantly impacting the material properties of asphalt mixtures. Under the combined effects of temperature and load, the mechanical response trends for pavements with AC-16 and SMA-16 surface materials are similar. Maximum vertical deformation, shear creep, and compressive creep all occur within the top 0–4 cm pavement depth, alternating between positive and negative across the transverse direction of the pavement. Compared to AC-16, SMA-16 exhibits reductions of 63.4 %, 22.4 %, 42.89 %, 45.29 %, 46.85 % and 27.19 % in positive and negative vertical deformations, making SMA-16 more suitable for enhancing the rutting resistance of asphalt pavement.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05711"},"PeriodicalIF":6.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788424","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}
Pub Date : 2025-12-17DOI: 10.1016/j.cscm.2025.e05716
Fatheali A. Shilar , Dhafer Ali Alqahtani , Mubarakali Shilar , T.M. Yunus Khan
This study examines the growing need for sustainable and thermally efficient lightweight concretes, specifically through the advancement of geopolymer foam concrete (GFC). This novel material integrates industrial red mud (RM) and agricultural corncob ash (CCA) as partial replacements in a fly ash–based binder. This study aims to investigate the issues associated with foam instability, increased water absorption, and reduced mechanical strength that are commonly observed in waste-derived GFC materials. Six mix formulations (GC1–GC6) were developed by adjusting the CCA content from 0 to 250 kg/m³, and their rheological, thermal, mechanical, electrical, and microstructural properties were assessed. The measurement of compressive strength was conducted at both 3 and 28 days, whereas all additional tests were executed on samples that had been cured for 28 days.The findings indicated that the incorporation of moderate amounts of CCA (100–150 kg/m³) led to improvements in foam stability, enhanced thermal insulation properties, and preserved sufficient structural integrity, with GC3 demonstrating the highest 28-day compressive strength of 2.86 MPa. Excessive CCA (GC6) resulted in unstable pore structures, diminished gel formation, increased water absorption (62.7 %), and the lowest strength recorded (1.45 MPa). The thermal conductivity exhibited a reduction from 0.91 to 0.52 W/m·K, while the electrical resistivity demonstrated an increase from 6.1 to 35.2 Ω·m across the various mixes, suggesting enhanced insulating characteristics as the content of CCA increased. SEM–EDS analysis validated the presence of well-structured geopolymer gels in low-to-moderate CCA mixtures, while revealing disrupted matrices at elevated CCA concentrations.The findings of the study indicate that optimized RM–CCA–FA ternary binders are capable of generating lightweight, low-carbon GFC that exhibits enhanced thermal and electrical properties, thereby supporting the development of sustainable construction materials in accordance with the Sustainable Development Goals 9, 11, 12, and 13.
{"title":"Valorization of agricultural and industrial wastes in geopolymer foam concrete, a ternary binder approach using corncob ash, red mud, and fly ash","authors":"Fatheali A. Shilar , Dhafer Ali Alqahtani , Mubarakali Shilar , T.M. Yunus Khan","doi":"10.1016/j.cscm.2025.e05716","DOIUrl":"10.1016/j.cscm.2025.e05716","url":null,"abstract":"<div><div>This study examines the growing need for sustainable and thermally efficient lightweight concretes, specifically through the advancement of geopolymer foam concrete (GFC). This novel material integrates industrial red mud (RM) and agricultural corncob ash (CCA) as partial replacements in a fly ash–based binder. This study aims to investigate the issues associated with foam instability, increased water absorption, and reduced mechanical strength that are commonly observed in waste-derived GFC materials. Six mix formulations (GC1–GC6) were developed by adjusting the CCA content from 0 to 250 kg/m³, and their rheological, thermal, mechanical, electrical, and microstructural properties were assessed. The measurement of compressive strength was conducted at both 3 and 28 days, whereas all additional tests were executed on samples that had been cured for 28 days.The findings indicated that the incorporation of moderate amounts of CCA (100–150 kg/m³) led to improvements in foam stability, enhanced thermal insulation properties, and preserved sufficient structural integrity, with GC3 demonstrating the highest 28-day compressive strength of 2.86 MPa. Excessive CCA (GC6) resulted in unstable pore structures, diminished gel formation, increased water absorption (62.7 %), and the lowest strength recorded (1.45 MPa). The thermal conductivity exhibited a reduction from 0.91 to 0.52 W/m·K, while the electrical resistivity demonstrated an increase from 6.1 to 35.2 Ω·m across the various mixes, suggesting enhanced insulating characteristics as the content of CCA increased. SEM–EDS analysis validated the presence of well-structured geopolymer gels in low-to-moderate CCA mixtures, while revealing disrupted matrices at elevated CCA concentrations.The findings of the study indicate that optimized RM–CCA–FA ternary binders are capable of generating lightweight, low-carbon GFC that exhibits enhanced thermal and electrical properties, thereby supporting the development of sustainable construction materials in accordance with the Sustainable Development Goals 9, 11, 12, and 13.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05716"},"PeriodicalIF":6.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921491","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}
Pub Date : 2025-12-17DOI: 10.1016/j.cscm.2025.e05712
Ruiyan Yu , Jinming Jiang , Shaochun Li , Renyu Geng , Koji Takasu , Weijun Gao
Concrete structures in marine environments are highly vulnerable to sulfate attack, which leads to microstructural degradation and severe durability loss. Modified fly ash (MFA), obtained by flotation to reduce unburned carbon, has shown promise as a supplementary cementitious material due to its pozzolanic reactivity and ability to refine pore structures. However, its performance remains limited under aggressive sulfate exposure. To address this challenge, this study evaluates the combined use of MFA and a graphene oxide-isobutyltriethoxysilane (GO/IBTS) composite emulsion as an internal modifier for improving hydration behavior and long-term durability. Comprehensive experimental analyses, including calorimetry, compressive strength testing, thermogravimetric analysis (TG), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM), were conducted to assess hydration kinetics, microstructural evolution, and resistance to sulfate attack. The results reveal that low dosages of GO/IBTS emulsion (≤ 2 %) promote secondary hydration of MFA and refine the pore network, thereby enhancing structural stability during prolonged erosion. In contrast, higher dosages (> 2 %) significantly suppress cement hydration, increase total porosity, and lead to marked strength loss. Under sulfate exposure, the incorporation of GO/IBTS reduces the formation of expansive phases such as gypsum and calcium aluminate hydrates, effectively limiting internal cracking and ensuring long-term stability. This study demonstrates a novel and reliable strategy for enhancing the durability of MFA-based cementitious systems in marine environments. The findings provide both theoretical insights and practical guidance for the design of eco-friendly, sulfate-resistant construction materials.
{"title":"Enhancing the sulfate resistance of modified fly ash-based cementitious materials in marine environments using a graphene oxide–silane emulsion","authors":"Ruiyan Yu , Jinming Jiang , Shaochun Li , Renyu Geng , Koji Takasu , Weijun Gao","doi":"10.1016/j.cscm.2025.e05712","DOIUrl":"10.1016/j.cscm.2025.e05712","url":null,"abstract":"<div><div>Concrete structures in marine environments are highly vulnerable to sulfate attack, which leads to microstructural degradation and severe durability loss. Modified fly ash (MFA), obtained by flotation to reduce unburned carbon, has shown promise as a supplementary cementitious material due to its pozzolanic reactivity and ability to refine pore structures. However, its performance remains limited under aggressive sulfate exposure. To address this challenge, this study evaluates the combined use of MFA and a graphene oxide-isobutyltriethoxysilane (GO/IBTS) composite emulsion as an internal modifier for improving hydration behavior and long-term durability. Comprehensive experimental analyses, including calorimetry, compressive strength testing, thermogravimetric analysis (TG), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM), were conducted to assess hydration kinetics, microstructural evolution, and resistance to sulfate attack. The results reveal that low dosages of GO/IBTS emulsion (≤ 2 %) promote secondary hydration of MFA and refine the pore network, thereby enhancing structural stability during prolonged erosion. In contrast, higher dosages (> 2 %) significantly suppress cement hydration, increase total porosity, and lead to marked strength loss. Under sulfate exposure, the incorporation of GO/IBTS reduces the formation of expansive phases such as gypsum and calcium aluminate hydrates, effectively limiting internal cracking and ensuring long-term stability. This study demonstrates a novel and reliable strategy for enhancing the durability of MFA-based cementitious systems in marine environments. The findings provide both theoretical insights and practical guidance for the design of eco-friendly, sulfate-resistant construction materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05712"},"PeriodicalIF":6.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788423","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}
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