Pub Date : 2026-01-14DOI: 10.1016/j.conbuildmat.2026.145162
Jin Liu , Renda Guo , Mingyuan He , Xingyi Wang , Xiaoyuan Wang , Fei Wang , Pengju Han
This study aims to overcome the challenge of efficiently utilizing high-calcium, low-reactivity circulating fluidized bed fly ash (CFBFA) as a cementitious material in a sustainable way. Traditional alkali activation methods impose high environmental loads and lead to long-term performance issues. We propose an alkali-free organic–inorganic synergistic approach by introducing waterborne polyurethane (WPU) to form a flexible interpenetrating network (IPN) within the CFBFA matrix. WPU improves rheology and interfacial bonding, and its polar groups bind with inorganic hydrates to create an IPN that refines the pore structure. This synergy accelerates early hydration and pozzolanic reactions, transforming the microstructure from connected pores into hierarchical isolated micropores and thereby greatly enhancing strength and durability. Consequently, high mechanical performance and stability are achieved without any external alkali activator. This work demonstrates a flexible, green modification route and provides a new paradigm for high-value reuse of industrial waste in next-generation low-carbon cementitious materials.
{"title":"Performance evolution of waterborne polyurethane–Circulating fluidized bed fly ash material based on an organic–inorganic synergistic mechanism","authors":"Jin Liu , Renda Guo , Mingyuan He , Xingyi Wang , Xiaoyuan Wang , Fei Wang , Pengju Han","doi":"10.1016/j.conbuildmat.2026.145162","DOIUrl":"10.1016/j.conbuildmat.2026.145162","url":null,"abstract":"<div><div>This study aims to overcome the challenge of efficiently utilizing high-calcium, low-reactivity circulating fluidized bed fly ash (CFBFA) as a cementitious material in a sustainable way. Traditional alkali activation methods impose high environmental loads and lead to long-term performance issues. We propose an alkali-free organic–inorganic synergistic approach by introducing waterborne polyurethane (WPU) to form a flexible interpenetrating network (IPN) within the CFBFA matrix. WPU improves rheology and interfacial bonding, and its polar groups bind with inorganic hydrates to create an IPN that refines the pore structure. This synergy accelerates early hydration and pozzolanic reactions, transforming the microstructure from connected pores into hierarchical isolated micropores and thereby greatly enhancing strength and durability. Consequently, high mechanical performance and stability are achieved without any external alkali activator. This work demonstrates a flexible, green modification route and provides a new paradigm for high-value reuse of industrial waste in next-generation low-carbon cementitious materials.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145162"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-14DOI: 10.1016/j.conbuildmat.2026.145221
Xiujie Jiang , Wei Huang , Sang Luo , Weiyi Kong , Gang Xu , Kaijun Du
To improve the low-temperature flexibility of conventional epoxy asphalt, this study proposes a composite modification approach using the S-type curing agent (SCA) and rubber oil (RO). First, the optimal addition sequence of SCA and RO was determined, and the correponding preparation process parameters were optimized via orthogonal experiments with tensile properties as the evaluation index. Subsequently, the mechanical properties, low-temperature crack resistance, and microstructure of modified epoxy asphalt (MEA) with varying modifier contents were evaluated to optimize SCA and RO compounding parameters and reveal their modification mechanisms. Finally, the properties of MEA and the modified epoxy asphalt mixture (MEAM) were investigated. Results indicate that pre-mixing SCA with the original curing agent and RO with the 70# asphalt yields the best mechanical performance. Increasing SCA content enhanced the tensile strength and viscosity of MEA, but reduced its low-temperature flexural strain. In contrast, increasing RO content significantly enhanced the fracture elongation of MEA and the low-temperature flexural strain, with a concurrent reduction in viscosity. Microscopic analysis shows that the SCA enhances the strength of MEA by increasing the pore size of the asphalt phase in the epoxy resin cross-linked network, whereas RO refines the pore size distribution of the asphalt phase, thus improving the toughness and low-temperature performance of MEA. When the content of SCA and RO is controlled at 2 wt% and 15 wt%, respectively, the MEA exhibits tensile properties meeting specification requirements and appropriate viscosity, and the MEAM shows significantly improved pavement performance. The results of this study provide theoretical support for the development and application of high-performance and sustainable epoxy asphalt.
{"title":"Investigation on optimal preparation process and performance modification mechanism of epoxy asphalt modified by S-type curing agent and rubber oil","authors":"Xiujie Jiang , Wei Huang , Sang Luo , Weiyi Kong , Gang Xu , Kaijun Du","doi":"10.1016/j.conbuildmat.2026.145221","DOIUrl":"10.1016/j.conbuildmat.2026.145221","url":null,"abstract":"<div><div>To improve the low-temperature flexibility of conventional epoxy asphalt, this study proposes a composite modification approach using the S-type curing agent (SCA) and rubber oil (RO). First, the optimal addition sequence of SCA and RO was determined, and the correponding preparation process parameters were optimized via orthogonal experiments with tensile properties as the evaluation index. Subsequently, the mechanical properties, low-temperature crack resistance, and microstructure of modified epoxy asphalt (MEA) with varying modifier contents were evaluated to optimize SCA and RO compounding parameters and reveal their modification mechanisms. Finally, the properties of MEA and the modified epoxy asphalt mixture (MEAM) were investigated. Results indicate that pre-mixing SCA with the original curing agent and RO with the 70# asphalt yields the best mechanical performance. Increasing SCA content enhanced the tensile strength and viscosity of MEA, but reduced its low-temperature flexural strain. In contrast, increasing RO content significantly enhanced the fracture elongation of MEA and the low-temperature flexural strain, with a concurrent reduction in viscosity. Microscopic analysis shows that the SCA enhances the strength of MEA by increasing the pore size of the asphalt phase in the epoxy resin cross-linked network, whereas RO refines the pore size distribution of the asphalt phase, thus improving the toughness and low-temperature performance of MEA. When the content of SCA and RO is controlled at 2 wt% and 15 wt%, respectively, the MEA exhibits tensile properties meeting specification requirements and appropriate viscosity, and the MEAM shows significantly improved pavement performance. The results of this study provide theoretical support for the development and application of high-performance and sustainable epoxy asphalt.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145221"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The creep properties of cement paste are critical for predicting the long-term performance of concrete structures. However, accurate characterization of these properties remains challenging due to the complex microstructure and heterogeneity of cement paste. This study proposed an inverse analysis method that integrated micro-scale indentation, micro-CT imaging and computational inversion to address this challenge. The three-dimensional microstructure of a cement paste sample with the water-to-cement ratio of 0.4 was obtained using micro-CT scanning. A machine learning algorithm was then employed to identify three distinct phases, i.e. unhydrated cement particles, hydration products and pores. Three-dimensional geometric models of the indented areas were constructed before and after indentation. Based on this information, the micro-indentation was simulated with the spatial distribution of multiple phases being considered. Furthermore, an inversion framework utilizing the genetic algorithm was established to determine the creep constitutive parameters of the hydration products. It is found that the creep constitutive model obtained in this way can well predict experimental data at other indentation points, underscoring the effectiveness and reliability of the proposed method in characterizing the time-dependent properties of cement paste.
{"title":"Inverse identification of viscoelastic/plastic creep parameters of cement paste based on micro-CT and micro-indentation","authors":"Yong Zhou , Sheng Liu , Weiping Zhang , Shuangqi Zhao , Zhilin Chen","doi":"10.1016/j.conbuildmat.2026.145150","DOIUrl":"10.1016/j.conbuildmat.2026.145150","url":null,"abstract":"<div><div>The creep properties of cement paste are critical for predicting the long-term performance of concrete structures. However, accurate characterization of these properties remains challenging due to the complex microstructure and heterogeneity of cement paste. This study proposed an inverse analysis method that integrated micro-scale indentation, micro-CT imaging and computational inversion to address this challenge. The three-dimensional microstructure of a cement paste sample with the water-to-cement ratio of 0.4 was obtained using micro-CT scanning. A machine learning algorithm was then employed to identify three distinct phases, i.e. unhydrated cement particles, hydration products and pores. Three-dimensional geometric models of the indented areas were constructed before and after indentation. Based on this information, the micro-indentation was simulated with the spatial distribution of multiple phases being considered. Furthermore, an inversion framework utilizing the genetic algorithm was established to determine the creep constitutive parameters of the hydration products. It is found that the creep constitutive model obtained in this way can well predict experimental data at other indentation points, underscoring the effectiveness and reliability of the proposed method in characterizing the time-dependent properties of cement paste.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145150"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-14DOI: 10.1016/j.conbuildmat.2026.145168
Qiang Li , Zhejie Lai , Haiying Yu , Tao Meng
This study introduces Layered Double Hydroxides (LDHs) and their calcined oxides (LDOs) as novel additives to enhance the carbon fixation capacity and mechanical performance of carbon-mixed cement, addressing the common challenges of performance degradation and microstructural deterioration associated with CO₂ incorporation. The effects of different LDHs (Mg-Al-LDH, Ca-Al-LDH) and LDOs (Mg-Al-LDO, Ca-Al-LDO) on the mechanical properties, hydration process, and microstructure of cement paste under varying CO₂ concentrations (0–2 %) were systematically investigated. The results demonstrate that while the addition of LDHs/LDOs reduces the fluidity of the cement paste, it significantly improves compressive strength, with an optimal enhancement observed at a CO₂ concentration of 1 %. Specifically, Mg-Al-LDO exhibited superior carbon fixation capacity compared to other additives, attributed to its high specific surface area and structural reconstruction via the memory effect, which facilitated greater CO₂ absorption and promoted hydration. Furthermore, the incorporation of these additives optimized the pore structure by refining pore size distribution, although Mg-Al-LDO showed a tendency to increase the proportion of larger pores due to carbonation-induced pore transformation. These findings propose an effective method for improving the performance of carbon-mixed cement, providing a viable pathway for advancing carbon reduction technologies in the cement industry.
{"title":"An effective way to improve the performance of carbon-mixed cement by LDHs incorporation","authors":"Qiang Li , Zhejie Lai , Haiying Yu , Tao Meng","doi":"10.1016/j.conbuildmat.2026.145168","DOIUrl":"10.1016/j.conbuildmat.2026.145168","url":null,"abstract":"<div><div>This study introduces Layered Double Hydroxides (LDHs) and their calcined oxides (LDOs) as novel additives to enhance the carbon fixation capacity and mechanical performance of carbon-mixed cement, addressing the common challenges of performance degradation and microstructural deterioration associated with CO₂ incorporation. The effects of different LDHs (Mg-Al-LDH, Ca-Al-LDH) and LDOs (Mg-Al-LDO, Ca-Al-LDO) on the mechanical properties, hydration process, and microstructure of cement paste under varying CO₂ concentrations (0–2 %) were systematically investigated. The results demonstrate that while the addition of LDHs/LDOs reduces the fluidity of the cement paste, it significantly improves compressive strength, with an optimal enhancement observed at a CO₂ concentration of 1 %. Specifically, Mg-Al-LDO exhibited superior carbon fixation capacity compared to other additives, attributed to its high specific surface area and structural reconstruction via the memory effect, which facilitated greater CO₂ absorption and promoted hydration. Furthermore, the incorporation of these additives optimized the pore structure by refining pore size distribution, although Mg-Al-LDO showed a tendency to increase the proportion of larger pores due to carbonation-induced pore transformation. These findings propose an effective method for improving the performance of carbon-mixed cement, providing a viable pathway for advancing carbon reduction technologies in the cement industry.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145168"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents an experimental and numerical investigation of two-level one-way reinforced concrete (RC) slabs strengthened using steel-based externally bonded reinforcement (EBR) and near-surface mounted (NSM) techniques. The novelty of the work stems from evaluating this uncommon and understudied slab configuration under multiple EBR and NSM steel strengthening systems, providing the first unified comparison of their structural performance. Four groups of slabs were tested: an unstrengthened control specimen, slabs strengthened with stainless steel sheets (1.0 mm and 1.2 mm), galvanized steel sheets (1.0 mm and 1.2 mm), NSM high-strength steel wires (uniform and non-uniform distributions), and NSM deformed steel bars (10 mm and 12 mm). The results showed that strengthening significantly enhanced structural performance, with ultimate load capacity increasing by 35–78 %, stiffness improving by up to 86 %, and energy absorption increasing by 82–218 % compared to the control slab. Among all strengthening systems, the slab strengthened with NSM 12 mm diameter steel bars achieved the highest ultimate load (83.68 kN, 78 % increase over the control) and a substantially high absorbed energy (937 kN·mm, 2.98 times the control). In contrast, the slab strengthened with externally bonded (EB) 1.2 mm thick stainless-steel sheets exhibited the greatest overall ductility, reflected in its maximum absorbed energy (1000 kN·mm, 3.18 times the control) and its gradual post-peak softening behavior. NSM wires with proper anchorage shifted the failure mode from brittle joint cracking to ductile bar rupture, whereas distributed anchorage of stainless-steel plates prevented debonding and restored a desirable flexural failure mode. A validated nonlinear finite element (FE) model closely matched the experimental results, with an average experimental/finite element (EXP/FE) ratio of 0.95 for ultimate load and 0.97 for cracking deflection, confirming its reliability for parametric studies. These findings demonstrate that EBR and NSM strengthening systems can substantially improve the strength, ductility, and energy dissipation capacity of two-level RC slabs, offering a robust and efficient retrofit solution for deteriorated or under-designed slab systems.
{"title":"Structural performance of two-level one-way RC slabs strengthened with stainless and galvanized steel sheets, high-strength steel wires, and reinforcing bars","authors":"Mohamed Ghalla , Galal Elsamak , Ayman El-Zohairy , Osama Youssf , Samar Khairy , Ahmed Badr el-din","doi":"10.1016/j.conbuildmat.2026.145134","DOIUrl":"10.1016/j.conbuildmat.2026.145134","url":null,"abstract":"<div><div>This study presents an experimental and numerical investigation of two-level one-way reinforced concrete (RC) slabs strengthened using steel-based externally bonded reinforcement (EBR) and near-surface mounted (NSM) techniques. The novelty of the work stems from evaluating this uncommon and understudied slab configuration under multiple EBR and NSM steel strengthening systems, providing the first unified comparison of their structural performance. Four groups of slabs were tested: an unstrengthened control specimen, slabs strengthened with stainless steel sheets (1.0 mm and 1.2 mm), galvanized steel sheets (1.0 mm and 1.2 mm), NSM high-strength steel wires (uniform and non-uniform distributions), and NSM deformed steel bars (10 mm and 12 mm). The results showed that strengthening significantly enhanced structural performance, with ultimate load capacity increasing by 35–78 %, stiffness improving by up to 86 %, and energy absorption increasing by 82–218 % compared to the control slab. Among all strengthening systems, the slab strengthened with NSM 12 mm diameter steel bars achieved the highest ultimate load (83.68 kN, 78 % increase over the control) and a substantially high absorbed energy (937 kN·mm, 2.98 times the control). In contrast, the slab strengthened with externally bonded (EB) 1.2 mm thick stainless-steel sheets exhibited the greatest overall ductility, reflected in its maximum absorbed energy (1000 kN·mm, 3.18 times the control) and its gradual post-peak softening behavior. NSM wires with proper anchorage shifted the failure mode from brittle joint cracking to ductile bar rupture, whereas distributed anchorage of stainless-steel plates prevented debonding and restored a desirable flexural failure mode. A validated nonlinear finite element (FE) model closely matched the experimental results, with an average experimental/finite element (EXP/FE) ratio of 0.95 for ultimate load and 0.97 for cracking deflection, confirming its reliability for parametric studies. These findings demonstrate that EBR and NSM strengthening systems can substantially improve the strength, ductility, and energy dissipation capacity of two-level RC slabs, offering a robust and efficient retrofit solution for deteriorated or under-designed slab systems.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145134"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To address the challenges of phase segregation and uneven distribution caused by the direct incorporation of water-soluble polymers in alkali-activated materials (AAMs), this study proposed a novel approach in which acrylamide (AC) monomers were directly incorporated into AAMs to initiate in-situ polymerization, forming an integrated polymer network that enhanced the toughness of AAMs. Macro-mechanical and fracture tests were used to evaluate the mechanical strength and fracture toughness of in-situ polymerization-modified AAMs (IP-AAMs). Micro-characterization techniques, including FTIR, BSE-IA, MIP, and nanoindentation, were employed to analyze the chemical structure, microstructure, porosity, and micromechanical/fracture properties of their gel products, respectively. This established a multi‑scale structure-property relationships for IP-AAMs and elucidated the influence of in-situ polymerization on their multi-scale structure and properties. Results showed that in-situ polymerization increased flexural strength and fracture toughness by 214 % and 55 %, respectively. Polymer-gel interactions grafted flexible chains onto gel particles, forming organic-inorganic composite gel particles that improved microfracture toughness but reduced stiffness of gel clusters due to the consumption of nucleation sites. In C-A-S-H gels, abundant Ca²⁺ competitively inhibited grafting, whereas in N-A-S-H gels, extensive grafting occurred. Unreacted monomers filled gel pores, further enhancing microfracture resistance of gel clusters. The weakened micro-mechanical properties of modified gel clusters, along with the delayed slag dissolution and altered early gel formation pathway that favored N-A-S-H over C-A-S-H gel formation —resulting from polymer carboxyl-Ca²⁺ chelation— reduced the early mechanical strength of the paste, while the improved microfracture toughness and refined inter-cluster porosity enhanced its fracture toughness.
为了解决水溶性聚合物直接掺入碱活性材料（AAMs）所带来的相分离和分布不均匀的问题，本研究提出了一种新的方法，将丙烯酰胺（AC）单体直接掺入碱活性材料（AAMs）中，引发原位聚合，形成一个完整的聚合物网络，增强AAMs的韧性。采用宏观力学和断裂试验对原位聚合改性AAMs （IP-AAMs）的力学强度和断裂韧性进行了评价。利用FTIR、BSE-IA、MIP和纳米压痕等微观表征技术，分别分析了凝胶产物的化学结构、微观结构、孔隙度和微力学/断裂性能。建立了IP-AAMs的多尺度结构-性能关系，阐明了原位聚合对其多尺度结构和性能的影响。结果表明，原位聚合可使材料的抗弯强度和断裂韧性分别提高214 %和55 %。聚合物-凝胶相互作用将柔性链接枝到凝胶颗粒上，形成有机-无机复合凝胶颗粒，提高了微断裂韧性，但由于成核位点的消耗而降低了凝胶团的刚度。在C-A-S-H凝胶中，丰富的Ca 2⁺竞争性地抑制了接枝，而在N-A-S-H凝胶中，则发生了广泛的接枝。未反应单体填充凝胶孔隙，进一步增强凝胶团簇的抗微断裂能力。改性凝胶团的微力学性能减弱，以及聚合物羧基- ca 2 +螯合导致的渣溶延迟和早期凝胶形成途径的改变（有利于N-A-S-H而不是C-A-S-H凝胶形成）降低了膏体的早期机械强度，而微断裂韧性的改善和团间孔隙度的改善增强了其断裂韧性。
{"title":"Mechanical properties, fracture toughness and multiscale structure-property relationships of alkali-activated materials toughened via in-situ polymerization of monomers","authors":"Kongfa Zhu , Hongliang Zhang , Qihan Zhong , Haodong Pu","doi":"10.1016/j.conbuildmat.2026.145240","DOIUrl":"10.1016/j.conbuildmat.2026.145240","url":null,"abstract":"<div><div>To address the challenges of phase segregation and uneven distribution caused by the direct incorporation of water-soluble polymers in alkali-activated materials (AAMs), this study proposed a novel approach in which acrylamide (AC) monomers were directly incorporated into AAMs to initiate in-situ polymerization, forming an integrated polymer network that enhanced the toughness of AAMs. Macro-mechanical and fracture tests were used to evaluate the mechanical strength and fracture toughness of in-situ polymerization-modified AAMs (IP-AAMs). Micro-characterization techniques, including FTIR, BSE-IA, MIP, and nanoindentation, were employed to analyze the chemical structure, microstructure, porosity, and micromechanical/fracture properties of their gel products, respectively. This established a multi‑scale structure-property relationships for IP-AAMs and elucidated the influence of in-situ polymerization on their multi-scale structure and properties. Results showed that in-situ polymerization increased flexural strength and fracture toughness by 214 % and 55 %, respectively. Polymer-gel interactions grafted flexible chains onto gel particles, forming organic-inorganic composite gel particles that improved microfracture toughness but reduced stiffness of gel clusters due to the consumption of nucleation sites. In C-A-S-H gels, abundant Ca²⁺ competitively inhibited grafting, whereas in N-A-S-H gels, extensive grafting occurred. Unreacted monomers filled gel pores, further enhancing microfracture resistance of gel clusters. The weakened micro-mechanical properties of modified gel clusters, along with the delayed slag dissolution and altered early gel formation pathway that favored N-A-S-H over C-A-S-H gel formation —resulting from polymer carboxyl-Ca²⁺ chelation— reduced the early mechanical strength of the paste, while the improved microfracture toughness and refined inter-cluster porosity enhanced its fracture toughness.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145240"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-14DOI: 10.1016/j.conbuildmat.2026.145190
Salem Merabti , Amar Mezidi , Smain Benyamina , Salah Bezari , Kaci Meziane , Rachid Chadouli
This study investigates the combined influence of incorporating expanded cork and using either potable or seawater as mixing water on the physical, mechanical, thermal, and ultrasonic responses of cementitious composites produced with expanded cork waste, crushed sand, and fine sand. Cork was introduced as a partial replacement by weight for dune and crushed sands, at substitution levels ranging from 0 % to 3 %. The results show that with 3 % cork and freshwater mixing, the eco-composite exhibits an apparent density of 1434.9 kg/m³ , a compressive strength of 1.54 MPa, and a thermal conductivity of 0.669 W/m·K, indicating a lighter and therefore more porous material. When seawater was used at the same cork content, the ionic environment promoted an increase in apparent density, compressive strength, ultrasonic velocity, and thermal conductivity, reflecting a denser microstructure. Overall, freshwater tends to reduce density and increase porosity, whereas seawater leads to densification and improved mechanical performance starting from 3 % substitution of sands with expanded cork.
{"title":"Effects of seawater on the properties of eco-friendly lightweight composites with cork waste and crushed sand","authors":"Salem Merabti , Amar Mezidi , Smain Benyamina , Salah Bezari , Kaci Meziane , Rachid Chadouli","doi":"10.1016/j.conbuildmat.2026.145190","DOIUrl":"10.1016/j.conbuildmat.2026.145190","url":null,"abstract":"<div><div>This study investigates the combined influence of incorporating expanded cork and using either potable or seawater as mixing water on the physical, mechanical, thermal, and ultrasonic responses of cementitious composites produced with expanded cork waste, crushed sand, and fine sand. Cork was introduced as a partial replacement by weight for dune and crushed sands, at substitution levels ranging from 0 % to 3 %. The results show that with 3 % cork and freshwater mixing, the eco-composite exhibits an apparent density of 1434.9 kg/m³ , a compressive strength of 1.54 MPa, and a thermal conductivity of 0.669 W/m·K, indicating a lighter and therefore more porous material. When seawater was used at the same cork content, the ionic environment promoted an increase in apparent density, compressive strength, ultrasonic velocity, and thermal conductivity, reflecting a denser microstructure. Overall, freshwater tends to reduce density and increase porosity, whereas seawater leads to densification and improved mechanical performance starting from 3 % substitution of sands with expanded cork.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145190"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-14DOI: 10.1016/j.conbuildmat.2026.145204
Wanli Wang, Baomin Wang
Carbon nanotubes (CNTs) and their modified derivatives show considerable potential for enhancing the impact resistance of alkali-activated materials (AAMs) under extreme loading conditions. In this study, three SiO₂-coated CNTs with different coating thicknesses (5Si-C, 10Si-C and 20Si-C) were synthesised, and their effects on the dynamic mechanical behaviour of alkali-activated slag–fly ash (SFA) composites were investigated using split Hopkinson pressure bar (SHPB) tests. The results demonstrate that SiO₂-CNTs provide a more pronounced strengthening and toughening effect than pristine CNTs (p-CNTs) and functionalised CNTs (f-CNTs). In particular, 10Si-C/SFA exhibits increases of 29.65 % and 34.19 % in static compressive and flexural strength, respectively; within the investigated strain-rate range, its dynamic compressive strength is enhanced by 33.97–57.59 %, while the peak and total impact toughness reach up to 6.63 and 3.37 times those of the control, respectively. The post-impact fragment size distributions display typical fractal characteristics, with SiO₂-CNTs—especially 10Si-C—significantly reducing the fragmentation fractal dimension and thus enabling a favourable “high SEA–low fragmentation” response. X-CT analysis shows that 10Si-C/SFA develops the densest and least-connected pore network among all mixtures, while SEM observations further indicate that the reactive SiO₂ coating chemically interacts with the matrix, promoting the formation of C(N)-A-S-H gels and enhancing interfacial bonding. Overall, the SiO₂-CNT interface-engineering strategy achieves synergistic toughening and densification of AAMs under high strain-rate loading, providing important experimental evidence and mechanistic insight for the design and optimisation of impact-resistant, low-carbon cementitious materials.
碳纳米管（CNTs）及其改性衍生物在增强碱活化材料（AAMs）在极端载荷条件下的抗冲击性方面显示出相当大的潜力。本研究合成了三种不同涂层厚度的SiO₂包覆CNTs (5Si-C、10Si-C和20Si-C)，并通过分离式霍普金森压杆（SHPB）试验研究了它们对碱活性渣-粉煤灰（SFA）复合材料动态力学行为的影响。结果表明，与原始碳纳米管（p-CNTs）和功能化碳纳米管（f-CNTs）相比，SiO₂-CNTs具有更明显的强化和增韧效果。其中10Si-C/SFA的静态抗压强度和抗弯强度分别提高29.65 %和34.19 %；在试验应变率范围内，其动态抗压强度提高了33.97 ~ 57.59 %，峰值和总冲击韧性分别达到对照的6.63倍和3.37倍。撞击后碎片尺寸分布呈现出典型的分形特征，sio2 -碳纳米管（尤其是10si - c）显著降低了碎片分形维数，从而实现了有利的“高sea -低破碎”响应。X-CT分析表明，10Si-C/SFA在所有混合物中形成了最致密、连通最少的孔隙网络，而SEM观察进一步表明，活性sio2涂层与基体发生化学相互作用，促进了C(N) a - s - h凝胶的形成，增强了界面键合。总体而言，SiO₂-CNT界面工程策略实现了AAMs在高应变率载荷下的协同增韧和致密化，为抗冲击低碳胶凝材料的设计和优化提供了重要的实验证据和机理见解。
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Pub Date : 2026-01-14DOI: 10.1016/j.conbuildmat.2026.145215
Jiaqing Wang , Shuang Hu , Xin Zhou , Qiang Li , Yao Ye , Dongzhao Jin , Feng Shen
Retarders are widely employed as chemical admixtures in cementitious construction materials to enhance workability. However, the production of conventional retarders causes significant environmental pollution and carbon emissions, which contradicts the overarching framework of sustainable development. This study developed a biomass retarder through a stepwise fermentation process guided by metabolic regulation using waste whey biomass of dairy production. Sodium galactonate, the primary component of the biomass retarder, was evaluated for its impact on the fresh properties, hydration kinetics, and microstructure of ordinary portland cement across a range of dosages. The results showed that the biomass retarder effectively prolonged the setting time of cement and improved the fluidity. The incorporation of a biomass retarder at a dosage of 0.04 % resulted in an 86.8 % increase in initial setting time and a 46.7 % enhancement in the initial fluidity, respectively. The biomass retarder exerted a detrimental impact on 3-d strength; however, after prolonged curing, its strength matched or even exceeded the original cement specimen. In addition, the drying shrinkage of cement mortar specimens was significantly reduced. Based on a comprehensive consideration of overall properties, an optimal dosage of 0.03 % was determined. Furthermore, this study utilized small-angle X-ray scattering to reveal the size variations of C-S-H agglomerations based on the fractal disc-shaped particle model and the Guinier approximation, thereby revealing the optimization of the gel distribution. This paper highlights the potential of recycled waste whey biomass retarder as an eco-friendly alternative for conventional retarders, offering a sustainable approach to valorizing biomass resources in cementitious materials.
{"title":"Hydration control and performance enhancement of cementitious materials with a sustainable retarder derived from waste cheese whey","authors":"Jiaqing Wang , Shuang Hu , Xin Zhou , Qiang Li , Yao Ye , Dongzhao Jin , Feng Shen","doi":"10.1016/j.conbuildmat.2026.145215","DOIUrl":"10.1016/j.conbuildmat.2026.145215","url":null,"abstract":"<div><div>Retarders are widely employed as chemical admixtures in cementitious construction materials to enhance workability. However, the production of conventional retarders causes significant environmental pollution and carbon emissions, which contradicts the overarching framework of sustainable development. This study developed a biomass retarder through a stepwise fermentation process guided by metabolic regulation using waste whey biomass of dairy production. Sodium galactonate, the primary component of the biomass retarder, was evaluated for its impact on the fresh properties, hydration kinetics, and microstructure of ordinary portland cement across a range of dosages. The results showed that the biomass retarder effectively prolonged the setting time of cement and improved the fluidity. The incorporation of a biomass retarder at a dosage of 0.04 % resulted in an 86.8 % increase in initial setting time and a 46.7 % enhancement in the initial fluidity, respectively. The biomass retarder exerted a detrimental impact on 3-d strength; however, after prolonged curing, its strength matched or even exceeded the original cement specimen. In addition, the drying shrinkage of cement mortar specimens was significantly reduced. Based on a comprehensive consideration of overall properties, an optimal dosage of 0.03 % was determined. Furthermore, this study utilized small-angle X-ray scattering to reveal the size variations of C-S-H agglomerations based on the fractal disc-shaped particle model and the Guinier approximation, thereby revealing the optimization of the gel distribution. This paper highlights the potential of recycled waste whey biomass retarder as an eco-friendly alternative for conventional retarders, offering a sustainable approach to valorizing biomass resources in cementitious materials.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145215"},"PeriodicalIF":8.0,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-13DOI: 10.1016/j.conbuildmat.2026.145132
Xiang Ma , Jiachen Xu , Weiyi Diao , Jitong Ding
Field aging of asphalt pavement does not progress linearly with service time but results from the combined effects of climatic conditions on asphalt concrete at different spatial positions and service stages, resulting in pronounced aging gradient characteristics. Existing studies mainly focus on laboratory-simulated short- and long-term aging of asphalt binders, whereas the early-stage aging behavior of asphalt concrete under natural conditions remains unclear, particularly the temporal variation of aging intensity within a one-year cycle. To investigate early-stage field aging, laboratory-prepared dense-graded asphalt concrete (AC-13) and porous asphalt concrete (PAC-13) were exposed to a natural outdoor environment in Nanjing, China. Specimens were divided into the top (AC-T/PAC-T), middle (AC-M/PAC-M), and bottom (AC-B/PAC-B) layers and monitored over 24 months. Periodic bending tensile tests were conducted, followed by binder extraction and recovery. The aged binders were characterized using a dynamic shear rheometer (DSR) and Fourier transform infrared spectroscopy (FTIR). Aging gradients were evaluated through mechanical performance, shear modulus master curves, and chemical functional group evolution. Gray relational analysis was applied to quantify the influence of temperature, precipitation, ultraviolet radiation, and humidity. The results indicate that early-stage asphalt concrete aging exhibits clear temporal and spatial dimensions. The carbonyl index change rate is a reliable indicator for aging gradients, showing distinct interlayer differences while being less affected by material heterogeneity and testing variability. Aging is more pronounced in the first year than in the second year, and consistently greater in the second half of each year. The highest carbonyl index change rate occurs during the hot and rainy period from June to September in the first year. Aging decreases with depth, forming a distinct spatial gradient. Dense-graded asphalt concrete exhibits a stronger top-to-bottom aging gradient than porous asphalt concrete. However, the average carbonyl index change rate of porous asphalt concrete is approximately 1.6 times higher than that of dense-graded asphalt concrete, attributed to its interconnected pore structure that accelerates coupled aging driven by light, heat, oxygen, and moisture. Aging shows significant correlations with temperature, ultraviolet radiation, and humidity, with average temperature being the dominant factor.
{"title":"Aging gradient characteristics of asphalt concrete during early-stage exposure to natural environments","authors":"Xiang Ma , Jiachen Xu , Weiyi Diao , Jitong Ding","doi":"10.1016/j.conbuildmat.2026.145132","DOIUrl":"10.1016/j.conbuildmat.2026.145132","url":null,"abstract":"<div><div>Field aging of asphalt pavement does not progress linearly with service time but results from the combined effects of climatic conditions on asphalt concrete at different spatial positions and service stages, resulting in pronounced aging gradient characteristics. Existing studies mainly focus on laboratory-simulated short- and long-term aging of asphalt binders, whereas the early-stage aging behavior of asphalt concrete under natural conditions remains unclear, particularly the temporal variation of aging intensity within a one-year cycle. To investigate early-stage field aging, laboratory-prepared dense-graded asphalt concrete (AC-13) and porous asphalt concrete (PAC-13) were exposed to a natural outdoor environment in Nanjing, China. Specimens were divided into the top (AC-T/PAC-T), middle (AC-M/PAC-M), and bottom (AC-B/PAC-B) layers and monitored over 24 months. Periodic bending tensile tests were conducted, followed by binder extraction and recovery. The aged binders were characterized using a dynamic shear rheometer (DSR) and Fourier transform infrared spectroscopy (FTIR). Aging gradients were evaluated through mechanical performance, shear modulus master curves, and chemical functional group evolution. Gray relational analysis was applied to quantify the influence of temperature, precipitation, ultraviolet radiation, and humidity. The results indicate that early-stage asphalt concrete aging exhibits clear temporal and spatial dimensions. The carbonyl index change rate is a reliable indicator for aging gradients, showing distinct interlayer differences while being less affected by material heterogeneity and testing variability. Aging is more pronounced in the first year than in the second year, and consistently greater in the second half of each year. The highest carbonyl index change rate occurs during the hot and rainy period from June to September in the first year. Aging decreases with depth, forming a distinct spatial gradient. Dense-graded asphalt concrete exhibits a stronger top-to-bottom aging gradient than porous asphalt concrete. However, the average carbonyl index change rate of porous asphalt concrete is approximately 1.6 times higher than that of dense-graded asphalt concrete, attributed to its interconnected pore structure that accelerates coupled aging driven by light, heat, oxygen, and moisture. Aging shows significant correlations with temperature, ultraviolet radiation, and humidity, with average temperature being the dominant factor.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"509 ","pages":"Article 145132"},"PeriodicalIF":8.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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