Cement & concrete composites最新文献

{"title":"Chloride-induced corrosion of galvanized steel in ordinary Portland cement and alkali-activated fly ash mortars with benzotriazole","authors":"Jinjie Shi ,&nbsp;Xiangdong Guan","doi":"10.1016/j.cemconcomp.2025.106117","DOIUrl":"10.1016/j.cemconcomp.2025.106117","url":null,"abstract":"<div><div>Galvanized steel can be passivated in ordinary Portland cement (OPC) due to the formation of a protective calcium hydroxyzincate (CHZ) layer. However, it is rarely concerned about the corrosion resistance of galvanized steel in alkali-activated fly ash (AAFA). Accordingly, this study evaluated the passivation performance and chloride-induced corrosion behavior of galvanized steel in OPC and AAFA mortars, and the impact of benzotriazole (BTA) on the corrosion resistance of galvanized steel was also investigated. The results demonstrated that, unlike OPC mortar, AAFA mortar failed to provide effective protection for galvanized steel due to the inability to form a stable CHZ protective layer. This phenomenon primarily results from the rapid dissolution of the galvanized coating by the alkali activator during the early hydration stage, combined with the lack of adequate calcium ions in the highly alkaline pore solutions. Moreover, BTA enhanced the corrosion resistance of galvanized steel in OPC mortar, whereas it exhibited no inhibition effect in AAFA mortar. These findings could enhance our understanding towards the design of novel low-carbon and high-durable concrete structures.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106117"},"PeriodicalIF":10.8,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932652","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":"Self-healing assessment of fibre reinforced cementitious mortars developed for 3D concrete printing: recovery of mechanical performance and self-sealing capability","authors":"Behzad Zahabizadeh ,&nbsp;João Pereira ,&nbsp;Eduardo N.B. Pereira ,&nbsp;Vítor M.C. F. Cunha","doi":"10.1016/j.cemconcomp.2025.106113","DOIUrl":"10.1016/j.cemconcomp.2025.106113","url":null,"abstract":"<div><div>This study investigated the self-healing capability of two fibre reinforced cementitious mortars, with and without crystalline admixture, which were specifically developed for 3D concrete printing. Four-point bending tests were carried out to assess the recovery of mechanical properties, focusing on resistance and stiffness recovery indexes. Two residual crack opening displacements of 50 μm and 500 μm were imposed on the different series of the specimens to compare their influence on the self-healing capability. Crack self-sealing efficiency was investigated by capturing crack images using a digital microscope. In addition to the assessment of the self-healing efficiency over time, the relationship between mechanical recovery indexes and average crack widths, as well as the relationship between different recovery indexes were also studied. The results showed a higher recovery performance for mixtures with crystalline admixture in the case of stiffness recovery and self-sealing capabilities. Moreover, the results showed a decreased on the healing efficiency with the increase of the crack widths.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106113"},"PeriodicalIF":10.8,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143926963","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":"Reaction kinetics and thermodynamic modeling of alkali-activated calcined marine clay with mechanical activation","authors":"Ziyang Li ,&nbsp;Jianhang Feng ,&nbsp;Subhasis Pradhan ,&nbsp;Shaohua Chu ,&nbsp;Shunzhi Qian","doi":"10.1016/j.cemconcomp.2025.106115","DOIUrl":"10.1016/j.cemconcomp.2025.106115","url":null,"abstract":"<div><div>A clinker-free, one-part alkali-activated materials (AAM) using calcined marine clay (CMC) and Ca(OH)₂ (CH) was developed in this study. The influence of mechanical activation on the mechanical properties, morphology, and the microstructure of one-part AAM was explored. Chemical dissolution test elucidates the relationship between reacted SiO₂/Al₂O₃ content, CH content, and pH values throughout the reaction process. Leveraging these experimental and statistical analysis results, a novel quantitative study on the kinetics of alkali activation process and the impact of milling on one-part AAM was conducted through thermodynamic modeling. CH dissolution-controlled reaction kinetics was revealed through experimental and modeling equilibrium comparisons. It demonstrates that the co-milling of CMC and CH can facilitate the alkali activation by synergistically improving the reacted CaO, SiO₂, and Al₂O₃ content via accelerated dissolution of CH and CMC. This research advances understanding for one-part AAM design by optimization of precursor/activator content and mechanical activation time via experimental and modeling approaches.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106115"},"PeriodicalIF":10.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143926964","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":"Chemically foamed geopolymers for 3D printing applications","authors":"Ali Rezaei Lori ,&nbsp;Rui M. Novais ,&nbsp;Guilherme Ascensão ,&nbsp;Fábio Fernandes ,&nbsp;Navid Ranjbar ,&nbsp;Jon Spangenberg","doi":"10.1016/j.cemconcomp.2025.106116","DOIUrl":"10.1016/j.cemconcomp.2025.106116","url":null,"abstract":"<div><div>Using chemically foamed geopolymers in 3D-printed building applications offers multifunctionality to the construction sector and enhances environmental sustainability; however, this topic remains virtually unexplored. To this end, the first part of this paper focuses on the fundamental stabilisation mechanism of chemically foamed geopolymers. In the second part, the most promising compositions were selected for applications in two potential areas: i) integration as an infilling material in 3D-printed sandwich envelopes, and ii) direct 3D printing of foam geopolymers. The findings indicated that to prevent instability mechanisms, various mix-design practices are necessary, including the use of an appropriate surfactant to inhibit coalescence, and the regulation of rheological properties to control drainage and coarsening. Implementing stabilised foam as infill in 3D-printed walls significantly enhances thermal performance due to its low thermal conductivity. Additionally, by adjusting Al dosage (up to 0.3 %) and using SDS as a stabilising surfactant, the foams were successfully printed with densities and compressive strengths ranging from 0.58 to 1.1 g/cm³ and 1.2–13.5 MPa, respectively. Moreover, 3D-printed foams demonstrated a thermal conductivity of 0.097 W/m·K and an impressive sound absorption coefficient (0.84 at 630 Hz) for the mix containing 0.3 % Al. The results underscore the viability of 3D-printed chemically foamed geopolymers in future construction projects.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"161 ","pages":"Article 106116"},"PeriodicalIF":10.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920424","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":"Effect of curing methods on strength and microstructure development in rice husk ash-based magnesium silicate binders","authors":"G.V.P. Bhagath Singh ,&nbsp;Karri Mohan ,&nbsp;Yedida Sriram ,&nbsp;K.V.L. Subramaniam","doi":"10.1016/j.cemconcomp.2025.106112","DOIUrl":"10.1016/j.cemconcomp.2025.106112","url":null,"abstract":"<div><div>The environmental impact of Portland cement production has intensified the search for alternative low-carbon cement. Reactive magnesium oxide cement has emerged as a promising option. The current study investigates the hydration behavior, strength development, and phase evolution of MgO and MgO-RHA blends cured under sealed and carbonation conditions. Two RHA sources with differing amorphous content and particle size were used. A detailed investigation was conducted using various techniques, including calorimetry, TGA, FTIR, XRD, Raman spectroscopy, and SEM. Results showed that higher glassy content and finer particles in RHA enhanced cumulative heat release, hydration product formation, and compressive strength. Carbonation curing further improved strength consistently by promoting the formation of nesquehonite and magnesium silicate hydrate. Quantitative XRD revealed that M-S-H formation was influenced by the consumption of periclase and unreacted glassy phase. Raman and FTIR analyses confirmed significant chemical and structural transformations, including the formation of brucite, nesquehonite, and carbonate phases. The D and G-band features in MgO-RHA samples suggested variations in carbonated products, influenced by processing conditions. Finally, SEM analysis revealed various carbonated products, M-S-H, and a dense microstructure. Overall, the study emphasizes the critical role of RHA properties and curing strategies in optimizing the performance of MgO-RHA systems for sustainable binder applications.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"161 ","pages":"Article 106112"},"PeriodicalIF":10.8,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915313","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":"Quantitative analysis of pore structures and microcracks in self-healing concrete after freeze-thaw exposure: An X-ray computed tomography-based approach","authors":"Jialuo He ,&nbsp;Yong Deng ,&nbsp;Xianming Shi","doi":"10.1016/j.cemconcomp.2025.106105","DOIUrl":"10.1016/j.cemconcomp.2025.106105","url":null,"abstract":"<div><div>X-ray computed tomography (CT) is a valuable tool for investigating the microstructure of concrete. This study introduces a method for analyzing the pore structures and microcracks of self-healing concrete after 300 rapid freeze/thaw (F/T) cycles using CT images with a relatively low resolution of 18.08 μm. Urea-formaldehyde microcapsules alone and in combination with polyvinyl alcohol microfibers were able to reduce 39.1 % and 65.5 % of the microcracks, respectively. Our approach involves calculating the total porosity and identifying constituents within the damaged pore structure based on geometric characteristics, employing the concepts of both circularity and roundness to discriminate intact pores, microcracks, and small/large-size pores with microcracks. The method's reliability is validated by comparing the total porosity results with the mercury intrusion porosimetry data. Our approach provides an effective tool for quantitative evaluation of the microstructure of self-healing concrete after freeze-thaw exposure, paving the way for more efficient and cost-effective analyses of concrete durability.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"162 ","pages":"Article 106105"},"PeriodicalIF":10.8,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143909912","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":"Investigation of fracture property of the fiber-reinforced cementitious composites casted using a novel fiber orientation method","authors":"Honglei Chang ,&nbsp;Zihang Kong ,&nbsp;Shuyuan Fan ,&nbsp;Yuxi Cai ,&nbsp;Feng Guo ,&nbsp;Qianping Ran ,&nbsp;Hongzhi Zhang ,&nbsp;Pan Feng","doi":"10.1016/j.cemconcomp.2025.106111","DOIUrl":"10.1016/j.cemconcomp.2025.106111","url":null,"abstract":"<div><div>Fiber-reinforced cementitious composites (FRCC) exhibit enhanced mechanical properties when fibers are uniformly dispersed and aligned parallel to the principal stress direction. This study introduces a novel fiber-ball vibration method to improve fiber orientation in FRCC. The fracture performance of FRCC prepared with this method was evaluated, and the fiber distribution within the matrix was analyzed in relation to the fiber orientation factor and fracture performance. Additionally, the interfacial transition zone (ITZ) between the fiber-balls and the paste was characterized, revealing the mechanisms through which the fiber-ball vibration method influences FRCC fracture performance. Experimental results indicate that the fiber-ball vibration method causes fibers to align more effectively, resulting in a 62.5 % increase in the fiber orientation factor along the principal stress direction compared to conventional mixing techniques. FRCC produced by this method demonstrates enhanced fracture performance, with a 26.2 % increase in initial crack toughness over plain cement mortar and a 29.8 % increase over FRCC fabricated using the conventional mixing method. Furthermore, unstable fracture toughness and fracture energy increased by 40 % and 470 %, respectively, compared to plain cement mortar, although these enhancements remained lower than those achieved with conventional mixing. The disparity is primarily attributed to the wider ITZ and lower elastic modulus between fiber-balls and paste, stemming from the negative effects of clustering of fibers and the smooth surface of steel balls, which increase the internal vulnerability in internal regions of FRCC. Nevertheless, the fiber-ball vibration method offers a promising approach for orienting fibers in FRCC. With further refinement, this method could achieve even greater toughening effects by optimizing the distribution of fibers along the principal stress direction.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"161 ","pages":"Article 106111"},"PeriodicalIF":10.8,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143909838","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":"High early strength alkali-activated mortar from artificial slag blended with high-volume limestone powder: Reaction kinetics and thermodynamic modeling","authors":"Hamdy A. Abdel-Gawwad ,&nbsp;Tamino Hirsch ,&nbsp;Christian Lehmann ,&nbsp;Dietmar Stephan","doi":"10.1016/j.cemconcomp.2025.106108","DOIUrl":"10.1016/j.cemconcomp.2025.106108","url":null,"abstract":"<div><div>The European Unions goal of climate neutrality by 2050 and the associated switch in pig iron production from the CO₂-intensive blast furnace process to the direct reduction process means that blast furnace slag is becoming increasingly scarce and will no longer be available in some regions in the foreseeable future. This applies to its use in classic cements as well as in alkali-activated binders. This study explores a new type of artificial slag (AS), with adapted chemical and physical properties, as an alternative to traditional BFS. Thanks to the adapted chemical and physical performance of AS, it exhibits exceptional reactivity, achieving high mechanical performance even when a significant portion is replaced with a widely available and inexpensive filler. Replacing a high volume of AS (≥70 vol%) with limestone powder (LP) in the alkali-activated system results in the formation of a hardened material with high early strength. The mortar composed of a 30–70 AS-LP volume ratio and activated with sodium silicate at a Na₂O equivalent of 5 wt% by weight of all powder exhibited the highest 2-, 28- and 90-day strengths of 67.8 MPa, 81.7 MPa, and 82.4 MPa, respectively. However, decreasing Na₂O equivalent to 3 wt% results in a comparable 90-day strength value. GEMS modeling revealed that the LP-AS content, as well as the source and dosage of Na₂O, significantly influenced the type and quantity of activation products. Furthermore, the results demonstrated that LP promotes the formation of activation products, while quartz powder had no appreciable effect.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"161 ","pages":"Article 106108"},"PeriodicalIF":10.8,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143907679","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":"Exploring a feasible inhibitor-coating protective system for corrosion protection of steel in mortar","authors":"Yongqi Liu ,&nbsp;Jinjie Shi","doi":"10.1016/j.cemconcomp.2025.106109","DOIUrl":"10.1016/j.cemconcomp.2025.106109","url":null,"abstract":"<div><div>This study aims to reduce the adverse effects of corrosion inhibitors on mortar performance while improving the corrosion resistance of steel in mortar exposed to chloride-bearing aggressive environments. To achieve this target, a novel inhibitor-coating protective system was designed, consisting of an admixed phytate corrosion inhibitor in mortar and a phytate-based smart protective coating on steel. The protective system operates through a synergistic inhibition mechanism, where phytate ions adsorb on the damaged regions of coating and interact with molybdate ions released from the coating to form a multilayer protective film, thereby significantly enhancing the corrosion resistance of steel. Moreover, the addition of phytate had no obvious impact on the mechanical properties of mortar, while the formed phytate-based complexes positively contributed to the mortar compactness by filling the pores and defects, providing additional corrosion protection against chloride attack for the embedded steel.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"161 ","pages":"Article 106109"},"PeriodicalIF":10.8,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143898094","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 expansion-tolerant strategy to improve the sulfate resistance of cementitious materials: Guided formation of CaSO4 within superabsorbent polymers (SAPs) pores","authors":"Han Wang ,&nbsp;Tongning Cao ,&nbsp;Junlin Lin ,&nbsp;Yali Li ,&nbsp;Guoxing Sun ,&nbsp;Zeyu Lu ,&nbsp;Jinyang Jiang","doi":"10.1016/j.cemconcomp.2025.106107","DOIUrl":"10.1016/j.cemconcomp.2025.106107","url":null,"abstract":"<div><div>During the sulfate attack process, the expansion of CaSO₄ formation in dense cement matrix resulted in the mechanical deterioration of cementitious materials. In this research, a novel expansion-tolerant strategy was proposed to mitigate the expansion pressure by guiding the formation of CaSO₄ within the preset pores introduced by superabsorbent polymers (SAPs). The experimental results showed that the compressive strength of cement paste (C₃A content: 5.61 <em>wt</em>%) with 0.1 <em>wt</em>% addition of SAPs can be sustained after 240 d of sulfate attack, whereas the one without SAPs showed a 21 % reduction with obvious surface spalling and cracking. In addition, the numerical simulation results indicated that the expansion pressure of CaSO₄ formation was correspondingly reduced by 41 %, which beneficially increased the sulfate resistance of cement paste by 170 %. Such a remarkable enhancement was built on the enrichment of Ca(OH)₂ within SAPs pores, which were previously dispersed randomly throughout the cement matrix. During the sulfate attack, sufficient Ca²⁺ provided by Ca(OH)₂ facilitated the in-situ formation of CaSO₄ in micro-scaled SAPs pores, which offered space for accommodating the CaSO₄ crystallization therefore reducing the expansion pressure. In conclusion, the current study presents a novel strategy to guide the formation of CaSO₄ in SAPs pores, effectively mitigating expansion-related damage and opening new frontiers for improving the sulfate resistance of cementitious materials.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"161 ","pages":"Article 106107"},"PeriodicalIF":10.8,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143889995","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}