Cement & concrete composites最新文献

{"title":"Integrating Fe2O3-rich soda residue into alkali-activated materials: Evaluation of mechanical and structural properties","authors":"Xianhui Zhao ,&nbsp;Gaoqing Zhang ,&nbsp;Haoyu Wang ,&nbsp;Hongqi Yang ,&nbsp;Xian-en Zhao ,&nbsp;Renlong Zhao","doi":"10.1016/j.cemconcomp.2025.106151","DOIUrl":"10.1016/j.cemconcomp.2025.106151","url":null,"abstract":"<div><div>Soda residue, a by-product of the Na₂CO₃ industry, is recognized for its high alkalinity, which can lead to corrosion and the deposition of iron oxide (Fe₂O₃) from industrial procedures and lab infrastructure. This study delves into the effects of incorporating Fe₂O₃-rich soda residue (FSR) into alkali-activated materials (AAMs), specifically alkali-activated fly ash (FA) and/or slag powder (SP), on the fresh and hardened properties of the resulting materials. The methodology encompassed an evaluation of the materials' workability through electrical conductivity (EC) and fluidity measurements. The recordings of drying shrinkage, flexural, and compressive strengths over time were conducted to assess the long-term hardened performance of the AAMs. To dissect the underlying mechanisms, a suite of analytical techniques was employed. X-ray diffraction (XRD) was utilized to delineate the mineral phases present, while Fourier-transform infrared spectroscopy (FTIR) elucidated the chemical bonding within the materials. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) provided detailed insights into the morphological and elemental composition. Thermogravimetric-differential scanning calorimetry (TG-DSC) further characterized the thermal decomposition behavior of the constituents. Results indicate that the incorporation of 20 % FSR into the alkali-activated FA-SP matrix resulted in a significant enhancement in flexural and compressive strengths (higher than those of alkali-activated FA-only or SP-only matrix), reaching 3.3 MPa and 24.3 MPa, respectively, after a 360-day curing period. Additionally, a modest reduction in drying shrinkage and a pronounced decrease in EC and fluidity were observed. The release of Mg²⁺ (from SP) and Ca²⁺ (from SP and FSR) cations was identified as a key factor in the polymerization of Si–O–Al chains, leading to the formation of amorphous aluminosilicate structures. The physical presence of Fe₂O₃ and Cr₂O₃, due to its low solubility, functioned as a filler, improving the mechanical properties of the AAMs. Therefore, the strategic integration (active vs. inert) of FSR into FA-SP systems can significantly influence the formation of aluminosilicate structures, offering a promising avenue for the valorization of industrial by-products in the realm of sustainable AAMs.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106151"},"PeriodicalIF":10.8,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189027","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}

{"title":"New insights into hydration of MgO in the presence of polycarboxylate ether superplasticizers","authors":"Morteza Tayebi ,&nbsp;Nirrupama Kamala Ilango ,&nbsp;Hoang Nguyen ,&nbsp;Ali Rezaei Lori ,&nbsp;Navid Ranjbar ,&nbsp;Valter Carvelli ,&nbsp;Paivo Kinnunen","doi":"10.1016/j.cemconcomp.2025.106153","DOIUrl":"10.1016/j.cemconcomp.2025.106153","url":null,"abstract":"<div><div>MgO-based cement offers a promising solution to lower the carbon footprint compared to that of Portland cement, where MgO is sourced from fossil-free minerals. The hydration of MgO plays a key role in these cements. However, MgO required higher water demand to achieve a workable mix, which poses drawbacks in microstructure and strength development. In this work, we investigated the effects of 7 polycarboxylate-based superplasticizers at different dosages on the fresh and hardened properties of MgO hydration. We found that some superplasticizers not only enhanced mix workability but also significantly increased compressive strength. The hydration, phase assemblage and evolution of MgO pastes using these superplasticizers were identical to those of the neat system, in which brucite formed as the primary hydration product. However, rheological evaluations demonstrated a marked reduction in yield stress and viscosity owing to the effects of superplasticizers. Furthermore, the addition of superplasticizer was found to improve the viscoelastic properties of the composites, as evidenced by an increase in critical shear strain and storage modulus. The insights gained from this research highlight the benefits of water-reducing additives in enhancing MgO reactivity and tailoring the formation of various MgO-bearing phases, such as magnesium carbonates or magnesium silicate hydrate, thereby facilitating more sustainable cement production.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106153"},"PeriodicalIF":10.8,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189045","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}

{"title":"Studying water permeation behavior of cracked ECC based on lattice Boltzmann method and X-ray computed tomography","authors":"Zhiming Pang ,&nbsp;Biqin Dong ,&nbsp;Cong Lu ,&nbsp;Yiming Yao ,&nbsp;Victor C. Li","doi":"10.1016/j.cemconcomp.2025.106155","DOIUrl":"10.1016/j.cemconcomp.2025.106155","url":null,"abstract":"<div><div>Engineered Cementitious Composites (ECC) are high-performance cementitious materials that exhibit multiple cracking and self-controlled width under uniaxial loading, which can lead to a low permeability. Quantifying the water flow behavior of an ECC crack is a precondition for its practical application. However, the lack of characterization for internal crack profiles and advanced modeling for water flow behavior leads to unsatisfactory permeation predictions. Focusing on these two shortages, this study characterized and reconstructed the inner 3D crack profiles based on X-CT technology and, in combination with lattice Boltzmann method (LBM), simulated the water flow behavior in an ECC crack. According to permeation test on an ECC crack, a width reduction factor of 0.67 should be adopted for permeation prediction of this particular ECC sample in the present experiments. By considering rough surfaces, numerous bridging fibers and fragmented matrix blocks in the simulation, good agreement between simulation and test results was achieved. Based on the proposed modeling approach, the impact of crack width on permeability was then discussed. Moreover, a quantitative investigation on the effect of these three geometric elements revealed that rough surfaces, fiber diameter and volume fraction are critical factors that cannot be ignored when determining the width reduction factor.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"163 ","pages":"Article 106155"},"PeriodicalIF":10.8,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189043","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}

{"title":"Understanding the role of C-S-H seeds and sulfate in the lightweight cementitious composites containing fly ash cenospheres","authors":"Wenxiang Cao ,&nbsp;Xuesen Lv ,&nbsp;Xingang Wang ,&nbsp;Jian-Xin Lu ,&nbsp;Juhyuk Moon ,&nbsp;Fubing Zou ,&nbsp;Weichen Tian ,&nbsp;Chi Sun Poon","doi":"10.1016/j.cemconcomp.2025.106150","DOIUrl":"10.1016/j.cemconcomp.2025.106150","url":null,"abstract":"<div><div>Matrix strength and interfacial bonding between aggregate and matrix are critical factors influencing the performance of lightweight cementitious composites (LCC). This study proposes an environmentally friendly and efficient strategy for developing high-performance fly ash cenospheres (FAC)-containing LCC by combining sodium sulfate (SS) and calcium-silicate-hydrate (C-S-H) seeds. Moreover, the roles of SS and C-S-H seeds on achieving superior strength of LCC were elaborated by characterizing the hydration, microstructure, pore structure, and interfacial zone. Results show that the combined use of C-S-H seeds and SS accelerated silicate and aluminate hydration, shortened the setting time of LCC, and refined the pore size. FAC particles provided a nucleation site for the precipitation of ettringite due to the increased aluminum concentration and formation of gypsum on interface. Furthermore, C-S-H seeds and SS significantly improved the interfacial zone between FAC and matrix due to the enhanced pozzolanic reactivity of FAC. C-S-H seeds and SS primarily functioned through a physical nucleation and chemical activation to improve the matrix strength and interfacial zone, respectively, resulting in a high-performance LCC. Consequently, remarkable increases of 131.4 ± 19.8 % and 29.0 ± 5.1 % in early and late compressive strength of LCC were achieved. These findings present a novel approach for developing high-strength lightweight concrete with enhanced early strength under ambient curing.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106150"},"PeriodicalIF":10.8,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144153951","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}

{"title":"Highly activated pozzolanic materials to develop sustainable concrete: a new perspective from photoexcited nano-TiO2","authors":"Jihong Jiang ,&nbsp;Yanchun Miao ,&nbsp;Qianping Ran ,&nbsp;Yali Li ,&nbsp;Yunjian Li ,&nbsp;Zongshuo Tao ,&nbsp;Zeyu Lu","doi":"10.1016/j.cemconcomp.2025.106149","DOIUrl":"10.1016/j.cemconcomp.2025.106149","url":null,"abstract":"<div><div>Fly ash, a by-product of coal combustion, is a pozzolanic solid waste with annual production of 1.63 billion tonnes, which has been widely used to replace cement clinker to develop sustainable concrete. However, the incorporation of high volumes of inert fly ash significantly reduces the early mechanical strength of concrete due to its low pozzolanic activity. This study presents an innovative strategy to effectively enhance the reactivity of fly ash by utilizing hydroxyl free radicals (•OH), highly reactive oxidative species generated by nano-TiO₂ under UV light excitation. Experimental results demonstrated that photoexcited nano-TiO₂ significantly promoted the depolymerization of inert glassy phases in fly ash, resulting in a 28 % increase in Ca(OH)₂ consumption within 72 h. Consequently, the compressive and flexural strengths of mortar at 28 days increased by 37 % and 16 %, respectively, with a strength activity index reaching 95.4 %. In addition, the water absorption and chloride ion diffusion coefficient were reduced by 15 % and 18 %, respectively, due to a more refined pore structure driven by enhanced pozzolanic reactivity. Density Functional Theory (DFT) calculations further revealed that •OH substantially lowered the energy barrier for Si-O-Al bonds cleavage (from 22.93 kcal/mol for OH⁻ to 8.54 kcal/mol for •OH), confirming its superior catalytic efficiency and thermodynamic advantage. In conclusion, the findings confirm that photoexcited nano-TiO₂ can serve as an effective activator for enhancing the utilization efficiency of fly ash in sustainable concrete.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106149"},"PeriodicalIF":10.8,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144153950","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}

{"title":"Insight into the mechanism of sulfate and magnesium ions on chloride diffusion and phase assemblage in limestone calcined clay cement (LC3)","authors":"Shukai Cheng ,&nbsp;Kang Chen ,&nbsp;Xuyong Chen ,&nbsp;Yibing Zuo ,&nbsp;Jian-Xin Lu","doi":"10.1016/j.cemconcomp.2025.106147","DOIUrl":"10.1016/j.cemconcomp.2025.106147","url":null,"abstract":"<div><div>Limestone calcined clay cement <strong>(</strong>LC³), a low-carbon cementitious material, has demonstrated outstanding resistance to chloride ion penetration. However, the real environment is rich in many harmful ions beyond chloride ions, including sulfate and magnesium ions, making the interactions among these ions highly complex. This study systematically explores the impact of sulfate ions and the synergistic effects of sulfate and magnesium ions on the chloride ion transport properties and chloride ions binding capacity of LC³. The characteristics of phase assemblage, pore structure, and microstructure vary differently under different environments. Furthermore, a thermodynamic model was employed to determine the impact of ion concentration and type on the phase assemblage. The findings suggest that within LC³, sulfate ions significantly affect Friedel's salt stability, converting it into ettringite (Ett). In addition, sulfate ions can combine with monosulfate (Ms) or undergo ion exchange with hemicarboaluminate (Hc)/monocarboaluminate (Mc) to form Ett, refining the pore structure and reducing the diffusion coefficient of chloride ions. However, prolonged exposure leads to sample expansion, accelerating the diffusion rate of chloride ions. Furthermore, the duration of sulfate ion inhibition on chloride diffusion is associated with the content of calcium aluminate phases. The combined attack of sulfate and magnesium ions lead to C-(A)-S-H decalcification, generation of gypsum and brucite, and decomposition of Friedel's salt and Ett, which further degrades matrix and promotes chloride ion diffusion. However, reducing the clinker amount in LC³ effectively enhances chloride binding capacity and reduces gypsum and brucite formation.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106147"},"PeriodicalIF":10.8,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144145648","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}

{"title":"Synergistic reinforcement of recycled carbon fibers and biochar in high-performance, low-carbon cement composites: a sustainable pathway for construction materials","authors":"Huanyu Li ,&nbsp;Ning Zhang ,&nbsp;Jian Yang ,&nbsp;Lei Wang ,&nbsp;Thomas Köberle ,&nbsp;Viktor Mechtcherine","doi":"10.1016/j.cemconcomp.2025.106148","DOIUrl":"10.1016/j.cemconcomp.2025.106148","url":null,"abstract":"<div><div>The integration of biochar as a sustainable reinforcement in cementitious composites has emerged as a dual-benefit strategy for carbon sequestration and biomass waste management in the construction industry. However, excessive biochar incorporation often compromises the mechanical properties of cement matrices. This study introduces an innovative, eco-friendly approach by synergistically combining biochar (2 %–10 % cement replacement) with recycled carbon fibers (1 %–3 %) to develop high-performance, low-carbon cement mortars. Experimental findings reveal that while the biochar addition reduces fluidity and prolongs setting times, it enhances the cement hydration degree through nucleation effects, internal curing, and accelerated CO₂ diffusion, promoting the formation of ettringite, calcium silicate hydrate gels, and the carbonation process. Despite improvements in flexural strength, biochar-induced porosity negatively impacts compressive strength. The incorporation of recycled carbon fibers counteracts this limitation, significantly enhancing the compressive and flexural strengths of biochar-augmented mortars by up to 14 % and 62 %, respectively, compared to plain cement matrices, through fiber bridging mechanisms. Although a strong interfacial bond is observed between the fibers and the biochar-modified matrices, the reinforcing efficiency is diminished with higher biochar dosages. Furthermore, the fiber and biochar contents should be limited to specific amounts to avoid excessive porosity and the resulting strength loss. Additionally, incorporating 10 % biochar alone into cementitious composites (10BC) provides the most favorable balance of environmental and economic performance under compressive strength criteria, achieving an emission reduction of 3.7 kg CO₂ eq./m³/MPa and a net cost of 2.4 CNY/m³/MPa. Further enhancement is possible by adding 2 % recycled carbon fiber to the 10BC mortar, increasing the total emission reduction to 41.1 kg CO₂ eq./m³/MPa when both compressive and flexural strengths are considered—albeit with an increase in economic costs. This study not only advances the development of low-carbon, high-strength building materials but also paves the way for the scalable application of biochar in the construction sector.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106148"},"PeriodicalIF":10.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144136939","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}

{"title":"Calcined clays for climate neutral (“net zero”) cements: shear-dependent rheological behavior and application performance","authors":"Jiaxin Chen,&nbsp;Johann Plank","doi":"10.1016/j.cemconcomp.2025.106145","DOIUrl":"10.1016/j.cemconcomp.2025.106145","url":null,"abstract":"<div><div>The performance of low-carbon cements prepared from different neat calcined clays (CCs) can be very inconsistent due to substantial variations in the composition of the CC samples. To gain a better understanding and further promote the practical application of such low-carbon cements incorporating CCs, the influence of calcined clays possessing different mineralogical compositions on the rheological behavior of the blended cements was investigated. First, the shear-dependent rheology of pastes preparing from four types of CCs (1:1 and 1:2 type) blended with OPC at 70:30 and 30:70 wt./wt. ratios was elucidated. As it is well established that mortar tests are more representative for the behavior of actual concrete than cement paste, the rheological properties of OPC/CC mortars were evaluated via spread flow, flow line and V-funnel empty time tests. An industrial precast type HPEG (methallyl ether) PCE and a non-ionic co-dispersant were employed as dispersants. It was found that incorporation of CC greatly influences packing density and water film thickness of the composite cements. Moreover, performance of the blended cements significantly depends on the physio-chemical properties of the individual CCs, e.g. their particle size distribution, morphology and surface chemistry. To elucidate the underlying mechanism, PCE adsorption and surface charge (zeta potential) of the CC composite cements were determined, and a correlation between effectiveness of the PCE and its adsorbed amount per BET specific surface area of the binder was revealed.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106145"},"PeriodicalIF":10.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144137185","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}

{"title":"A novel insight into the physical implication of percolation threshold of cement suspensions from microscopic and macroscopic perspectives","authors":"Xiaohan Yu ,&nbsp;Jiaping Liu ,&nbsp;Le Teng ,&nbsp;Xin Shu ,&nbsp;Chen Chen ,&nbsp;Xin Liu","doi":"10.1016/j.cemconcomp.2025.106146","DOIUrl":"10.1016/j.cemconcomp.2025.106146","url":null,"abstract":"<div><div>The percolation threshold plays a significant role in influencing the yield stress of cement-based materials. However, this crucial parameter has not been well understood given the absence of robust and reliable experimental methods and computing models. This study estimates the percolation threshold through regression analysis of yield stress and reveals its physical implications from the microscopic and macroscopic perspectives. The results indicate that the regression approach does not capture the theoretical percolation threshold, but rather a rigidity percolation threshold. The rigidity percolation threshold, reflecting the formation of a mechanically stable interaction network, is governed by the balance between colloidal forces and dominant separating force, either gravity or Brownian force. In cement pastes where gravity dominates over Brownian motion, the rigidity percolation threshold is significantly higher than the theoretical percolation threshold. A power-law relationship has been established between rigidity and theoretical percolation thresholds where the exponent is dependent on the gravitational Péclet number. In pastes containing large amounts of finer particles, where Brownian motion exceeds gravity, the rigidity percolation threshold aligns with the theoretical percolation threshold. From a macroscopic perspective, the rigidity percolation threshold is directly linked to the bleeding of cement pastes. A reduction in the solid volume fraction below the rigidity percolation threshold can result in bleeding, since the insufficient cement grains cannot form an internal particle network to resist gravity.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106146"},"PeriodicalIF":10.8,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130270","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}

{"title":"Evaluation of photocatalytic ZnO-geopolymer composites: degradation of methylene blue and α-pinene","authors":"Jamie Wilson ,&nbsp;Xinyuan Ke ,&nbsp;Daniel Maskell ,&nbsp;Richard J. Ball","doi":"10.1016/j.cemconcomp.2025.106125","DOIUrl":"10.1016/j.cemconcomp.2025.106125","url":null,"abstract":"<div><div>Alkali-activated ZnO–geopolymer composites were synthesised using metakaolin to investigate their photocatalytic degradation efficiency toward methylene blue and α-pinene under 253.7 nm irradiation. Composites prepared with bulk Si/Al molar ratios (1 and 2), ZnO/Al loadings (0.10, 0.15, and 0.20), were characterised using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), N₂-sorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectroscopy. A custom-built flow cell was used for gas-phase α-pinene degradation, while aqueous methylene blue degradation was evaluated under batch conditions. A key finding of the study was that increasing ZnO content led to matrix densification, reduced surface area, and blue shifting of the adsorption band. Structural studies revealed that ZnO was integrated into the geopolymer framework through bonding with aluminium within the composite. The highest 160 mg/L methylene blue removal (91.05 %) was achieved by a geopolymer with Si/Al ratio of 2 and attributed to naturally occurring TiO₂ phases in the metakaolin coupled with a high surface area. These samples exhibited superior continuous α-pinene degradation, with a maximum removal of 26.93 %, which was attributed to reduced Al–OH surface groups and lower hydrophilicity, favouring VOC adsorption. Significantly, this research identifies the critical parameters of incorporating ZnO into a geopolymer framework, suggesting that both the concentration of ZnO added, and the microstructural modification induced by ZnO play important roles in determining photocatalytic activity. This study revealed how ZnO influences the physicochemical characteristics of geopolymers, and the remediation mechanism of pollutants from aqueous and gaseous environments.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106125"},"PeriodicalIF":10.8,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144104280","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}