Pub Date : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145326
Shiru Long, Yue Li, Nan Wang, Hui Lin
The replacement of dead-burned MgO with uncalcined magnesium source for magnesium phosphate cement (MPC) has attracted considerable attention. This study assessed the life-cycle environmental impacts of dead-burned MgO and natural brucite (NB) and evaluated the feasibility of substituting NB for MgO. Through matrix regulation and modifier enhancement, sustainable NB-based MPC (NBMPC) was developed. Results revealed that the global warming potential of NB was 88.86 % lower than that of MgO. Under synergistic modification with dual-setting regulators (10 % borax and 5 % sodium tripolyphosphate), 10 % silica fume, and 7 % waterborne epoxy, NBMPC exhibited a setting time of 25 min, a 28 d compressive strength of 56.3 MPa, a softening coefficient of 0.97, and strength retentions of 90.2 % and 51.1 % after 14 days of immersion in 5 % Na2SO4 and NaOH solutions, respectively. Microstructural analysis revealed that the composite retarders suppressed the formation of MgNH4PO4·6 H2O but enhanced chemical bonding through bridging effect. The incorporation of silica fume promoted the generation of MgNH4PO4·6 H2O and induced the formation of M-S-H gel on microsphere surfaces, thereby strengthening interfacial structure. The waterborne epoxy facilitated the reaction of NB through adsorption and dispersion effects. This study provides theoretical support for low-carbon MPC and promotes its sustainable application under aggressive environments.
{"title":"Sustainable and durable synergistic construction of brucite-based magnesium phosphate composites: From matrix regulation to epoxy resin modification","authors":"Shiru Long, Yue Li, Nan Wang, Hui Lin","doi":"10.1016/j.conbuildmat.2026.145326","DOIUrl":"10.1016/j.conbuildmat.2026.145326","url":null,"abstract":"<div><div>The replacement of dead-burned MgO with uncalcined magnesium source for magnesium phosphate cement (MPC) has attracted considerable attention. This study assessed the life-cycle environmental impacts of dead-burned MgO and natural brucite (NB) and evaluated the feasibility of substituting NB for MgO. Through matrix regulation and modifier enhancement, sustainable NB-based MPC (NBMPC) was developed. Results revealed that the global warming potential of NB was 88.86 % lower than that of MgO. Under synergistic modification with dual-setting regulators (10 % borax and 5 % sodium tripolyphosphate), 10 % silica fume, and 7 % waterborne epoxy, NBMPC exhibited a setting time of 25 min, a 28 d compressive strength of 56.3 MPa, a softening coefficient of 0.97, and strength retentions of 90.2 % and 51.1 % after 14 days of immersion in 5 % Na<sub>2</sub>SO<sub>4</sub> and NaOH solutions, respectively. Microstructural analysis revealed that the composite retarders suppressed the formation of MgNH<sub>4</sub>PO<sub>4</sub>·6 H<sub>2</sub>O but enhanced chemical bonding through bridging effect. The incorporation of silica fume promoted the generation of MgNH<sub>4</sub>PO<sub>4</sub>·6 H<sub>2</sub>O and induced the formation of M-S-H gel on microsphere surfaces, thereby strengthening interfacial structure. The waterborne epoxy facilitated the reaction of NB through adsorption and dispersion effects. This study provides theoretical support for low-carbon MPC and promotes its sustainable application under aggressive environments.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145326"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036603","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145154
C. De Nardi, D. Gardner
Built heritage is increasingly exposed to diverse and intense environmental stressors as a consequence of climate change. Consequently, historic masonry repair strategies must evolve to support a more resilient and long-lasting preservation approach. Drawing on biomimetic principles, recent innovations have introduced vascularisation techniques to enable autonomous crack repair in lime-based mortars, including targeted patching applications where localized material loss needs to be effectively restored. However, the effectiveness of these self-healing systems depends largely on the performance of the healing agents, particularly their long-term reactivity and compatibility with traditional materials. This study evaluated lithium silicate solutions, LS15 and LS20 (15 % and 20 % lithium wt. respectively) as healing agents in natural hydraulic lime mortars using simplified vascular networks. Samples were pre-cracked to a crack width of 0.1 mm and were allowed to heal over 14 days. Three-point bending tests were conducted to assess mechanical recovery at 14, 28, and 365 days, including up to three damage–healing cycles for long-term evaluation. No significant autogenous healing was observed in the control specimens. LS20 achieved maximum single-cycle strength and stiffness recovery of 187 % and 124 %, respectively, at early age. Over multiple cycles, in samples aged 1 year, LS15 showed greater consistency, reaching up to 68 % strength and 51 % stiffness recovery by the third cycle. These results demonstrate lithium silicate’s potential for repeatable, cyclic self-healing in heritage-compatible mortars.
{"title":"Lithium silicate as a healing agent in vascular networks for natural hydraulic lime mortars: a step towards cyclic self-healing systems for heritage materials","authors":"C. De Nardi, D. Gardner","doi":"10.1016/j.conbuildmat.2026.145154","DOIUrl":"10.1016/j.conbuildmat.2026.145154","url":null,"abstract":"<div><div>Built heritage is increasingly exposed to diverse and intense environmental stressors as a consequence of climate change. Consequently, historic masonry repair strategies must evolve to support a more resilient and long-lasting preservation approach. Drawing on biomimetic principles, recent innovations have introduced vascularisation techniques to enable autonomous crack repair in lime-based mortars, including targeted patching applications where localized material loss needs to be effectively restored. However, the effectiveness of these self-healing systems depends largely on the performance of the healing agents, particularly their long-term reactivity and compatibility with traditional materials. This study evaluated lithium silicate solutions, LS15 and LS20 (15 % and 20 % lithium wt. respectively) as healing agents in natural hydraulic lime mortars using simplified vascular networks. Samples were pre-cracked to a crack width of 0.1 mm and were allowed to heal over 14 days. Three-point bending tests were conducted to assess mechanical recovery at 14, 28, and 365 days, including up to three damage–healing cycles for long-term evaluation. No significant autogenous healing was observed in the control specimens. LS20 achieved maximum single-cycle strength and stiffness recovery of 187 % and 124 %, respectively, at early age. Over multiple cycles, in samples aged 1 year, LS15 showed greater consistency, reaching up to 68 % strength and 51 % stiffness recovery by the third cycle. These results demonstrate lithium silicate’s potential for repeatable, cyclic self-healing in heritage-compatible mortars.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145154"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036604","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145370
Alessandra Ranesi, Paulina Faria
Air lime-earth mortars remain relatively underexplored despite their promising potential for use in conservation and restoration practices. Traditionally, both air lime and earth were key binders in construction, making them valuable references for heritage preservation. This study explores the combination of hydrated air lime and earth inspired by traditional techniques that mixed clayish earth, extracted from the local soil, with quicklime or lime putty. In the experimental design, earth replaced air lime (up to 50 % by wt.) and fine sand (up to 25 % by wt.) in mortars with a binder-to-sand volumetric ratio of 1:2 and 1:3, respectively. These earth substitutions required more mixing water in production to obtain similar flow, resulting in mortars with lower bulk densities once hardened. The modified mortars showed higher open porosity and lower mechanical strength and thermal conductivity. However, the clay induced-rise in small pore volume improved sorption capacity. Although capillary water absorption increased with clay; the drying was faster mitigating the drawback. Notably, this was the only property observed to exceed the recommended range for conservation mortars, supporting the viability of air lime-earth mortars for conservation applications. When exposed to salts, the mortars showed sodium sulphate resistance, with no collapse by the end of the test confirming the absence of hydrated compounds. Moreover, the higher moisture buffering activity suggests that the partial replacement of raw materials by earth – a potential byproduct of local excavation – not only supports sustainable conservation but can also be applied to enhance indoor air quality and comfort in modern buildings.
{"title":"Traditional air lime-earth mortars: The effect of earth replacing the binder and the aggregate on performance and durability","authors":"Alessandra Ranesi, Paulina Faria","doi":"10.1016/j.conbuildmat.2026.145370","DOIUrl":"10.1016/j.conbuildmat.2026.145370","url":null,"abstract":"<div><div>Air lime-earth mortars remain relatively underexplored despite their promising potential for use in conservation and restoration practices. Traditionally, both air lime and earth were key binders in construction, making them valuable references for heritage preservation. This study explores the combination of hydrated air lime and earth inspired by traditional techniques that mixed clayish earth, extracted from the local soil, with quicklime or lime putty. In the experimental design, earth replaced air lime (up to 50 % by wt.) and fine sand (up to 25 % by wt.) in mortars with a binder-to-sand volumetric ratio of 1:2 and 1:3, respectively. These earth substitutions required more mixing water in production to obtain similar flow, resulting in mortars with lower bulk densities once hardened. The modified mortars showed higher open porosity and lower mechanical strength and thermal conductivity. However, the clay induced-rise in small pore volume improved sorption capacity. Although capillary water absorption increased with clay; the drying was faster mitigating the drawback. Notably, this was the only property observed to exceed the recommended range for conservation mortars, supporting the viability of air lime-earth mortars for conservation applications. When exposed to salts, the mortars showed sodium sulphate resistance, with no collapse by the end of the test confirming the absence of hydrated compounds. Moreover, the higher moisture buffering activity suggests that the partial replacement of raw materials by earth – a potential byproduct of local excavation – not only supports sustainable conservation but can also be applied to enhance indoor air quality and comfort in modern buildings.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145370"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036606","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145344
Yong Ke , Tingting Xiao , Xiaoxin Shi , Wanlan Wu , Hui Xu , Qin Zhang , Cong Peng , Yun Li , Yunyan Wang , Xiaobo Min
Non-ferrous smelting slag (NSS), a by-product of pyrometallurgical processes of non-ferrous metals, is commonly stockpiled or used in cement production, causing environmental pollution and resource waste. Given its high content of glass-forming oxides such as SiO2 and CaO, this study adopts analytically pure reagents to simulate the NSS and prepare glass-ceramics using the melt method. According to the composition characteristics of NSS, a basic formula was selected, and the effects of Fe2O3 (0–10 %), FeO (0–10 %), CuO (0–2 %), and ZnO (0–2 %) on the crystallization and properties of the glass-ceramics were studied. Based on DSC, XRD, and SEM analyses, the results showed that the incorporation of Fe2O3, FeO, CuO, and ZnO significantly enhanced the crystallization ability of the base glass. When Fe2O3, FeO, and ZnO were added, the main crystalline phases of the glass-ceramics were augite and nepheline. However, the addition of CuO resulted in the formation of not only augite and nepheline but also cuprite. The incorporation of Fe2O3, FeO, and CuO contributed to grain refinement, while ZnO addition led to grain coarsening. After incorporating each oxide individually, the glass-ceramics exhibited excellent acid and alkali resistance (>99 %). Moreover, when the Fe2O3 content was 5 %, the glass-ceramics exhibited optimal comprehensive performance, achieving a density of 3.08 g/cm3, Vickers hardness of 865.12 HV1. With 4 % FeO, the above properties were 3.03 g/cm3, 840.81 HV1. At 2 % CuO, the density of the samples was 3.03 g/cm3, and the hardness was 791.08 HV1. Meanwhile, at 2 % ZnO, the corresponding properties were 2.94 g/cm3, 753.72 HV1. This study confirms the critical role of these oxides within an appropriate range of addition amounts, providing a theoretical basis and experimental support for controlling Fe, Cu, and Zn contents during the preparation of glass-ceramics with NSS.
{"title":"Effects of iron and typical heavy metals in non-ferrous smelting slag on the crystallization and properties of glass-ceramics","authors":"Yong Ke , Tingting Xiao , Xiaoxin Shi , Wanlan Wu , Hui Xu , Qin Zhang , Cong Peng , Yun Li , Yunyan Wang , Xiaobo Min","doi":"10.1016/j.conbuildmat.2026.145344","DOIUrl":"10.1016/j.conbuildmat.2026.145344","url":null,"abstract":"<div><div>Non-ferrous smelting slag (NSS), a by-product of pyrometallurgical processes of non-ferrous metals, is commonly stockpiled or used in cement production, causing environmental pollution and resource waste. Given its high content of glass-forming oxides such as SiO<sub>2</sub> and CaO, this study adopts analytically pure reagents to simulate the NSS and prepare glass-ceramics using the melt method. According to the composition characteristics of NSS, a basic formula was selected, and the effects of Fe<sub>2</sub>O<sub>3</sub> (0–10 %), FeO (0–10 %), CuO (0–2 %), and ZnO (0–2 %) on the crystallization and properties of the glass-ceramics were studied. Based on DSC, XRD, and SEM analyses, the results showed that the incorporation of Fe<sub>2</sub>O<sub>3</sub>, FeO, CuO, and ZnO significantly enhanced the crystallization ability of the base glass. When Fe<sub>2</sub>O<sub>3</sub>, FeO, and ZnO were added, the main crystalline phases of the glass-ceramics were augite and nepheline. However, the addition of CuO resulted in the formation of not only augite and nepheline but also cuprite. The incorporation of Fe<sub>2</sub>O<sub>3</sub>, FeO, and CuO contributed to grain refinement, while ZnO addition led to grain coarsening. After incorporating each oxide individually, the glass-ceramics exhibited excellent acid and alkali resistance (>99 %). Moreover, when the Fe<sub>2</sub>O<sub>3</sub> content was 5 %, the glass-ceramics exhibited optimal comprehensive performance, achieving a density of 3.08 g/cm<sup>3</sup>, Vickers hardness of 865.12 HV1. With 4 % FeO, the above properties were 3.03 g/cm<sup>3</sup>, 840.81 HV1. At 2 % CuO, the density of the samples was 3.03 g/cm<sup>3</sup>, and the hardness was 791.08 HV1. Meanwhile, at 2 % ZnO, the corresponding properties were 2.94 g/cm<sup>3</sup>, 753.72 HV1. This study confirms the critical role of these oxides within an appropriate range of addition amounts, providing a theoretical basis and experimental support for controlling Fe, Cu, and Zn contents during the preparation of glass-ceramics with NSS.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145344"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036622","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145332
Lei Yang , Xin Zhao , Shaonan Cai , Pinghua Zhu , Hui Liu , Xinjie Wang , Lingchao Lu , Chunhong Chen , Mingxu Chen
Although recycled fine aggregate (RFA) derived from construction waste offer an eco-friendly alternative to natural aggregate resources in concrete, their high chloride ions (Cl⁻) permeability harms the durability of concrete structures, particularly in marine field. In this study, a layered double hydroxides@colloidal nanosilica (LDHs@CNS) composite was synthesized to enhance Cl⁻ adsorption in simulated marine concrete solutions (SMCSs), aiming to improve mechanical strength and durability of RFA marine concrete. The results showed that well-dispersed CNS effectively inhibited LDHs layer stacking via electrostatic repulsion and spatial steric hindrance, greatly improving Cl⁻ adsorption in SMCSs. Thus, the LDHs@CNS showed excellent Cl⁻ adsorption performance (up to 53.3 mg/g), demonstrating pH-dependent behavior with an inverse correlation. Optimal adsorption conditions of LDHs@CNS in SMCSs were identified at artificial seawater dilution ratios of 0, W/C ratios of 2.0, and hydration time of 1.5-h. Besides, compared to the control, adding 0.8 wt% LDHs@CNS enhanced RFA concrete performance, increasing flexural strength by 23.1 % (12.15 MPa), compressive strength by 15.2 % (94.5 MPa), and Cl⁻ penetration resistance by 28.8 % (2.74 ×10⁻12 m2/s). This study demonstrates an effective strategy to enhance Cl⁻ adsorption, strength, and penetration resistance in RFA marine concrete through LDHs@CNS incorporation, which operates via three mechanisms: CNS-induced LDHs morphological control, secondary hydration, and micro-nano filling. This multifunctional approach resolves the dual challenges of low strength and poor durability, enabling high corrosion resistance for marine use.
{"title":"Multifunctional synergy of LDHs@CNS in high-strength recycled fine aggregate marine concrete: Enhancement of chloride adsorption, strength and penetration resistance","authors":"Lei Yang , Xin Zhao , Shaonan Cai , Pinghua Zhu , Hui Liu , Xinjie Wang , Lingchao Lu , Chunhong Chen , Mingxu Chen","doi":"10.1016/j.conbuildmat.2026.145332","DOIUrl":"10.1016/j.conbuildmat.2026.145332","url":null,"abstract":"<div><div>Although recycled fine aggregate (RFA) derived from construction waste offer an eco-friendly alternative to natural aggregate resources in concrete, their high chloride ions (Cl⁻) permeability harms the durability of concrete structures, particularly in marine field. In this study, a layered double hydroxides@colloidal nanosilica (LDHs@CNS) composite was synthesized to enhance Cl⁻ adsorption in simulated marine concrete solutions (SMCSs), aiming to improve mechanical strength and durability of RFA marine concrete. The results showed that well-dispersed CNS effectively inhibited LDHs layer stacking via electrostatic repulsion and spatial steric hindrance, greatly improving Cl⁻ adsorption in SMCSs. Thus, the LDHs@CNS showed excellent Cl⁻ adsorption performance (up to 53.3 mg/g), demonstrating pH-dependent behavior with an inverse correlation. Optimal adsorption conditions of LDHs@CNS in SMCSs were identified at artificial seawater dilution ratios of 0, W/C ratios of 2.0, and hydration time of 1.5-h. Besides, compared to the control, adding 0.8 wt% LDHs@CNS enhanced RFA concrete performance, increasing flexural strength by 23.1 % (12.15 MPa), compressive strength by 15.2 % (94.5 MPa), and Cl⁻ penetration resistance by 28.8 % (2.74 ×10⁻<sup>12</sup> m<sup>2</sup>/s). This study demonstrates an effective strategy to enhance Cl⁻ adsorption, strength, and penetration resistance in RFA marine concrete through LDHs@CNS incorporation, which operates via three mechanisms: CNS-induced LDHs morphological control, secondary hydration, and micro-nano filling. This multifunctional approach resolves the dual challenges of low strength and poor durability, enabling high corrosion resistance for marine use.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145332"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037015","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145384
Xiangqian Zhao , Jianbiao Bai , Hao Pan , Xiangyu Wang , Yunbo Gou , Shuai Yan , Ying Xu , Rui Wang , Shuaigang Liu
To address the environmental issues caused by coal gangue piles and promote green and economical mining, an innovative coal gangue recycling strategy using a high-water material filling body containing coal gangue and fibers (GFH-CPB) was proposed, specifically designed for gob-side entry retaining applications.Uniaxial compression tests were conducted on 80 GFH-CPB specimens with varied coal gangue contents, particle size distributions, and fiber dosages to analyze the evolution of GFH-CPB bearing capacity under different parameter combinations. The results indicate that the compressive strength of GFH-CPB is predominantly influenced by the characteristics of the coal gangue, with the deformation capacity deteriorating significantly as coal gangue content increases and particle size decreases. Incorporating appropriate fiber content can enhance both ductile deformation characteristics and mechanical strength of GFH-CPB, enabling GFH-CPB to meet the dual requirements of high strength and deformation pressure relief for gob-side entry retaining. Furthermore, multiscale experimental methods, including SEM and acoustic emission (AE) analysis, were employed to reveal the failure mechanisms of GFH-CPB under coupled coal gangue-fiber interactions. These investigations elucidated the critical role of fibers in modifying the damage mode. AE characterization, in particular, demonstrated that fiber incorporation transformed the damage process from localized brittle fracture to a more uniform and stable mode, dominated by tensile cracking. Finally, we developed a machine learning model that integrates support vector regression (SVR) with genetic algorithm (GA) and NSGA-II optimization algorithms to achieve high-precision bidirectional prediction between GFH-CPB’s strength-strain and coal gangue-fiber parameter ratios. Verification experiment results indicate that the bidirectional predictive errors of the learning model are all less than 10 %, demonstrating reliable predictive performance. The findings can provide guidance for the efficient utilization of solid waste and economical filling in gob-side entry retaining.
{"title":"Study on the failure mechanism and performance prediction of high-water filling body with coal gangue and fiber","authors":"Xiangqian Zhao , Jianbiao Bai , Hao Pan , Xiangyu Wang , Yunbo Gou , Shuai Yan , Ying Xu , Rui Wang , Shuaigang Liu","doi":"10.1016/j.conbuildmat.2026.145384","DOIUrl":"10.1016/j.conbuildmat.2026.145384","url":null,"abstract":"<div><div>To address the environmental issues caused by coal gangue piles and promote green and economical mining, an innovative coal gangue recycling strategy using a high-water material filling body containing coal gangue and fibers (GFH-CPB) was proposed, specifically designed for gob-side entry retaining applications.Uniaxial compression tests were conducted on 80 GFH-CPB specimens with varied coal gangue contents, particle size distributions, and fiber dosages to analyze the evolution of GFH-CPB bearing capacity under different parameter combinations. The results indicate that the compressive strength of GFH-CPB is predominantly influenced by the characteristics of the coal gangue, with the deformation capacity deteriorating significantly as coal gangue content increases and particle size decreases. Incorporating appropriate fiber content can enhance both ductile deformation characteristics and mechanical strength of GFH-CPB, enabling GFH-CPB to meet the dual requirements of high strength and deformation pressure relief for gob-side entry retaining. Furthermore, multiscale experimental methods, including SEM and acoustic emission (AE) analysis, were employed to reveal the failure mechanisms of GFH-CPB under coupled coal gangue-fiber interactions. These investigations elucidated the critical role of fibers in modifying the damage mode. AE characterization, in particular, demonstrated that fiber incorporation transformed the damage process from localized brittle fracture to a more uniform and stable mode, dominated by tensile cracking. Finally, we developed a machine learning model that integrates support vector regression (SVR) with genetic algorithm (GA) and NSGA-II optimization algorithms to achieve high-precision bidirectional prediction between GFH-CPB’s strength-strain and coal gangue-fiber parameter ratios. Verification experiment results indicate that the bidirectional predictive errors of the learning model are all less than 10 %, demonstrating reliable predictive performance. The findings can provide guidance for the efficient utilization of solid waste and economical filling in gob-side entry retaining.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145384"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037484","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145380
Jingling Wang , Jiwang Jiang , Lusheng Qin , Xiaodi Niu , Chenhe Zhuang , Duo Xu , Fujian Ni , Xiang Ma
Thermal cracking occurs when thermal stress exceeds the fracture strength of asphalt pavements. As a typical climatic feature in cold regions, the impact of long-duration low temperatures on the cracking resistance of asphalt mixtures remains insufficiently understood. This research aims to investigate the degradation in cracking resistance induced by long-duration low-temperature conditioning. A modified Semi-Circular Bending (SCB) test protocol was developed by evaluating the effects of notching, loading rate, conditioning temperature, and duration. Digital Image Correlation (DIC) technique was employed to analyze strain evolution and crack propagation. The effects of binder type, mixture type, and aging level on cracking resistance were further examined. The finalized SCB protocol, featuring notched 150 mm specimens, a 5 mm/min loading rate, a conditioning temperature of −20 °C, and conditioning durations of 4 h and 7 days, proved effective in capturing the influence of long-duration conditioning. DIC results revealed that conditioning increased fracture brittleness by intensifying strain heterogeneity and shrinking the fracture process zone. Pre-peak fracture energy (Gpre) exhibited the highest sensitivity to both conditioning and material factors and is recommended as a reliable evaluation indicator. A new indicator, GpreLoss, was proposed to quantify degradation in cracking resistance caused by long-duration conditioning, with an average value of 29.4 % observed across eight test groups. These findings highlighted that short-duration conditioning may not adequately capture the degradation induced by long-duration conditioning. Incorporating long-duration conditioning protocols and responsive evaluation indicators is recommended for asphalt mixture design and durability assessment in cold-region applications.
{"title":"Mechanistic assessment of cracking resistance degradation in asphalt mixtures subjected to long-duration low-temperature conditioning","authors":"Jingling Wang , Jiwang Jiang , Lusheng Qin , Xiaodi Niu , Chenhe Zhuang , Duo Xu , Fujian Ni , Xiang Ma","doi":"10.1016/j.conbuildmat.2026.145380","DOIUrl":"10.1016/j.conbuildmat.2026.145380","url":null,"abstract":"<div><div>Thermal cracking occurs when thermal stress exceeds the fracture strength of asphalt pavements. As a typical climatic feature in cold regions, the impact of long-duration low temperatures on the cracking resistance of asphalt mixtures remains insufficiently understood. This research aims to investigate the degradation in cracking resistance induced by long-duration low-temperature conditioning. A modified Semi-Circular Bending (SCB) test protocol was developed by evaluating the effects of notching, loading rate, conditioning temperature, and duration. Digital Image Correlation (DIC) technique was employed to analyze strain evolution and crack propagation. The effects of binder type, mixture type, and aging level on cracking resistance were further examined. The finalized SCB protocol, featuring notched 150 mm specimens, a 5 mm/min loading rate, a conditioning temperature of −20 °C, and conditioning durations of 4 h and 7 days, proved effective in capturing the influence of long-duration conditioning. DIC results revealed that conditioning increased fracture brittleness by intensifying strain heterogeneity and shrinking the fracture process zone. Pre-peak fracture energy (<em>G</em><sub><em>pre</em></sub>) exhibited the highest sensitivity to both conditioning and material factors and is recommended as a reliable evaluation indicator. A new indicator, <em>G</em><sub><em>pre</em></sub> <em>Loss</em>, was proposed to quantify degradation in cracking resistance caused by long-duration conditioning, with an average value of 29.4 % observed across eight test groups. These findings highlighted that short-duration conditioning may not adequately capture the degradation induced by long-duration conditioning. Incorporating long-duration conditioning protocols and responsive evaluation indicators is recommended for asphalt mixture design and durability assessment in cold-region applications.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145380"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036602","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145349
Fábio Pereira , Petrucia Duarte da S. Meireles , Natasha Pergher Silva , Gilson Campos , Glauco Soares Braga , Eduardo Jorge da C. Lins , Bruno Costa , Edgar Perin Moraes , Júlio Cezar de O. Freitas , Rodrigo Cesar Santiago
High-temperature well cementing presents critical challenges due to the thermal degradation of traditional Portland cement systems, often resulting in mechanical strength loss and compromised well integrity. Despite advances, there remains a lack of sustainable, thermally stable cement blends designed for demanding conditions such as steam injection and geothermal wells. This study aimed to develop and validate a low-carbon, high-performance cementitious system incorporating industrial wastes to replace silica flour, enhancing thermal stability while reducing environmental impact. A systematic experimental workflow was implemented, including raw material characterization, fluid and hardened-state testing of 24 binary and ternary formulations, and high-temperature curing simulations representative of bottomhole conditions (280 °C, 1500 psi). A support vector regression (SVR) model guided the blend optimization, followed by experimental validation, microstructural analysis (XRD and SEM), and thermal behavior. The optimized ternary blend (B31.3RHA45), composed of Portland cement, rice husk ash (RHA), and mortar sand residue (MSR), achieved compressive strength of 40.6 ± 0.6 MPa after thermal cycling and exhibited low permeability (0.12 mD). Experimental values closely matched SVR predictions (deviation <1 %). These findings demonstrate the technical and environmental viability of using alternative pozzolanic materials and machine learning to design cement systems for high-temperature wells. The proposed blend advances well integrity, aligns with circular economy principles, and supports the transition toward low-carbon oilfield technologies.
{"title":"Design of low-carbon cement blends for thermal well conditions using machine learning and industrial wastes","authors":"Fábio Pereira , Petrucia Duarte da S. Meireles , Natasha Pergher Silva , Gilson Campos , Glauco Soares Braga , Eduardo Jorge da C. Lins , Bruno Costa , Edgar Perin Moraes , Júlio Cezar de O. Freitas , Rodrigo Cesar Santiago","doi":"10.1016/j.conbuildmat.2026.145349","DOIUrl":"10.1016/j.conbuildmat.2026.145349","url":null,"abstract":"<div><div>High-temperature well cementing presents critical challenges due to the thermal degradation of traditional Portland cement systems, often resulting in mechanical strength loss and compromised well integrity. Despite advances, there remains a lack of sustainable, thermally stable cement blends designed for demanding conditions such as steam injection and geothermal wells. This study aimed to develop and validate a low-carbon, high-performance cementitious system incorporating industrial wastes to replace silica flour, enhancing thermal stability while reducing environmental impact. A systematic experimental workflow was implemented, including raw material characterization, fluid and hardened-state testing of 24 binary and ternary formulations, and high-temperature curing simulations representative of bottomhole conditions (280 °C, 1500 psi). A support vector regression (SVR) model guided the blend optimization, followed by experimental validation, microstructural analysis (XRD and SEM), and thermal behavior. The optimized ternary blend (B31.3RHA45), composed of Portland cement, rice husk ash (RHA), and mortar sand residue (MSR), achieved compressive strength of 40.6 ± 0.6 MPa after thermal cycling and exhibited low permeability (0.12 mD). Experimental values closely matched SVR predictions (deviation <1 %). These findings demonstrate the technical and environmental viability of using alternative pozzolanic materials and machine learning to design cement systems for high-temperature wells. The proposed blend advances well integrity, aligns with circular economy principles, and supports the transition toward low-carbon oilfield technologies.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145349"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037020","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 investigates the role of aggregate minerology in influencing the recycling efficiency of waste concrete. To gain a fundamental understanding, different concrete systems (lean, medium, and high-strength) were formulated, varying water-cement ratios and aggregate mineralogies — two siliceous rocks (extrusive basalt and intrusive granite) and a calcareous rock (dolomite) were studied. Initially, the influence of minerology on the behaviour of parent concrete was understood, and later, the parameters governing the recyclability of these concrete systems (under identical crushing procedure) were investigated by conducting an extensive series of experiments, ranging from morphological evaluation of recycled concrete aggregates (RCA) using image analysis to aggregate-mortar interface characterization, quantifying the physical, chemical, and mechanical interactions. Nano-indentation technique was also employed to validate the findings. The results indicated that the bulk characteristics of the parent concrete are dominated by the rock strength as well as the morphological parameters. However, the adhered mortar (AM) retention capacity of RCA was found to depend on the acid-base interaction as well as the mechanical interlocking between the parent rock and the surrounding paste during the crushing stage. Under the studied conditions, linear relationships were observed between work of adhesion at the parent rock-mortar interface and AM content in RCA, as well as between the surface texture and AM content. Based on the results of this study and for the considered scenarios, it can be concluded that rock mineralogy may govern the recycling potential of waste concrete, wherein concrete made with acidic and rough-textured rocks may exhibit less recycling efficiency (∼20 %), and vice versa, regardless of the parent strength.
{"title":"Elucidating the role of parent rock mineralogy on the recycling efficiency of waste concrete","authors":"Abhinav Kumar Thakur , Surender Singh , Piyush Chaunsali","doi":"10.1016/j.conbuildmat.2026.145372","DOIUrl":"10.1016/j.conbuildmat.2026.145372","url":null,"abstract":"<div><div>This study investigates the role of aggregate minerology in influencing the recycling efficiency of waste concrete. To gain a fundamental understanding, different concrete systems (lean, medium, and high-strength) were formulated, varying water-cement ratios and aggregate mineralogies — two siliceous rocks (extrusive basalt and intrusive granite) and a calcareous rock (dolomite) were studied. Initially, the influence of minerology on the behaviour of parent concrete was understood, and later, the parameters governing the recyclability of these concrete systems (under identical crushing procedure) were investigated by conducting an extensive series of experiments, ranging from morphological evaluation of recycled concrete aggregates (RCA) using image analysis to aggregate-mortar interface characterization, quantifying the physical, chemical, and mechanical interactions. Nano-indentation technique was also employed to validate the findings. The results indicated that the bulk characteristics of the parent concrete are dominated by the rock strength as well as the morphological parameters. However, the adhered mortar (AM) retention capacity of RCA was found to depend on the acid-base interaction as well as the mechanical interlocking between the parent rock and the surrounding paste during the crushing stage. Under the studied conditions, linear relationships were observed between work of adhesion at the parent rock-mortar interface and AM content in RCA, as well as between the surface texture and AM content. Based on the results of this study and for the considered scenarios, it can be concluded that rock mineralogy may govern the recycling potential of waste concrete, wherein concrete made with acidic and rough-textured rocks may exhibit less recycling efficiency (∼20 %), and vice versa, regardless of the parent strength.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145372"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037017","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 : 2026-01-23DOI: 10.1016/j.conbuildmat.2026.145347
Yujiang Shi , Suhe Zhang , Panyue Gao , Wenjian Xie , Chaofan Wang , Bing Chen
High-phosphogypsum supersulfated cement still suffers from strength deficiency, loose gel skeletons, and poorly understood mechanisms of hydration and P/F immobilization. This paper develops an innovative NMK-modified high-phosphogypsum supersulfated cement, revealing the synergistic mechanisms among its components and significantly enhancing mechanical properties. Research indicates that nano-metakaolin (NMK) not only improves physical structure through enrichment effects and fine-scale filling but also plays a vital chemical function. NMK modifies the chemical and activates slag through pozzolanic reactions, promoting phosphorus solidification and generation of brushite. Simultaneously, NMK regulates the Ca/Si ratio, structural compactness, and the Al content within C-(A)-S-H gel. At NMK contents of 0.5–1.0 %, the system exhibits significant synergistic promotion during cement clinker activation and sulfate attack, driving the formation of a dense three-dimensional framework dominated by AFt and cross-linked C-(A)-S-H gel. At this optimum dosage, NMK enrichment at PG–slag interfaces supplies nucleation sites, accelerates AFt and C-(A)-S-H co-precipitation, transforms loose needle bundles into a continuous load-bearing skeleton, and co-adsorbs P/F species, sharply reducing their leaching. The binder attains a 28 days compressive strength of 65.8 MPa, providing a basis for high-performance, eco-efficient cementitious binders derived from multiple solid waste streams.
高磷石膏过硫酸盐水泥仍然存在强度不足、凝胶骨架松散、水化和P/F固定机制尚不清楚的问题。本文研制了一种新型的nmk改性高磷石膏过硫酸盐水泥，揭示了其组分之间的协同作用机制，显著提高了其力学性能。研究表明，纳米偏高岭土（NMK）不仅通过富集作用和细尺度填充改善物理结构，而且具有重要的化学功能。NMK通过火山灰反应对矿渣进行化学改性和活化，促进磷的凝固和电刷石的生成。同时，NMK调节C-(A)- s - h凝胶中的Ca/Si比、结构致密性和Al含量。当NMK含量为0.5 ~ 1.0 %时，体系在水泥熟料活化和硫酸盐侵蚀过程中表现出明显的协同促进作用，形成以AFt和交联C-(a)- s- h凝胶为主的致密三维框架。在此最佳投加量下，在pg -渣界面富集的NMK提供了成核位点，加速了AFt和C-(A)- s - h共沉淀，将松散的针束转变为连续的承重骨架，并共同吸附P/F物质，大幅减少了它们的浸出。该粘合剂的28天抗压强度达到65.8 MPa，为从多种固体废物流中提取的高性能、生态高效胶凝粘合剂提供了基础。
{"title":"Reaction mechanism regulation in high-phosphogypsum supersulfated cement: Nano-metakaolin–induced formation of a compact AFt/C-(A)-S-H network and immobilization of phosphorus and fluorine","authors":"Yujiang Shi , Suhe Zhang , Panyue Gao , Wenjian Xie , Chaofan Wang , Bing Chen","doi":"10.1016/j.conbuildmat.2026.145347","DOIUrl":"10.1016/j.conbuildmat.2026.145347","url":null,"abstract":"<div><div>High-phosphogypsum supersulfated cement still suffers from strength deficiency, loose gel skeletons, and poorly understood mechanisms of hydration and P/F immobilization. This paper develops an innovative NMK-modified high-phosphogypsum supersulfated cement, revealing the synergistic mechanisms among its components and significantly enhancing mechanical properties. Research indicates that nano-metakaolin (NMK) not only improves physical structure through enrichment effects and fine-scale filling but also plays a vital chemical function. NMK modifies the chemical and activates slag through pozzolanic reactions, promoting phosphorus solidification and generation of brushite. Simultaneously, NMK regulates the Ca/Si ratio, structural compactness, and the Al content within C-(A)-S-H gel. At NMK contents of 0.5–1.0 %, the system exhibits significant synergistic promotion during cement clinker activation and sulfate attack, driving the formation of a dense three-dimensional framework dominated by AFt and cross-linked C-(A)-S-H gel. At this optimum dosage, NMK enrichment at PG–slag interfaces supplies nucleation sites, accelerates AFt and C-(A)-S-H co-precipitation, transforms loose needle bundles into a continuous load-bearing skeleton, and co-adsorbs P/F species, sharply reducing their leaching. The binder attains a 28 days compressive strength of 65.8 MPa, providing a basis for high-performance, eco-efficient cementitious binders derived from multiple solid waste streams.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"512 ","pages":"Article 145347"},"PeriodicalIF":8.0,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037019","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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