[期刊论文][Full-length article]

出版年：2023

This study aimed to improve the durability of concrete in the marine environment through the utilization of waste glass-ceramics as aggregates. The investigation focused on their effects on the mechanical strength, chloride attack resistance, and abrasion resistance of high-ferrite Portland cement mortar (HFCM). Inductively coupled plasma, X-ray diffraction, scanning electron microscopy-backscattered electronic, and microhardness techniques analyzed the impacts of glass-ceramics on the interfacial transition zone’s (ITZ) composition, structure, and strength. Results demonstrated that glass–ceramic fine aggregates possessed low alkali activity, posing no potential risk of alkali silicate reaction. The partial substitution of natural sand with glass-ceramics improved HFCM’s mechanical strength and resistance to chloride attack and abrasion. The dissolution of trace amounts of Si⁴⁺ and Al³⁺ from the glass-ceramics contributed to the hydration reaction and facilitated the development of a compact and robust ITZ. Overall, HFCM with glass-ceramics effectively resisted the harsh marine environment, specifically against chloride ion erosion and wave erosion. Introduction The durability of concrete in marine engineering is a crucial research topic [1], [2], [3], given its susceptibility to two prominent factors: chloride attack and seawater scouring [4], [5]. The intrusion of chloride ions can trigger corrosion and volume expansion of reinforcing steel, ultimately compromising the integrity of the concrete structure [6]. Simultaneously, seawater scouring not only damages the concrete surface but also accelerates salt intrusion by deepening existing cracks [7]. Therefore, improving resistance against chloride erosion and seawater scouring is a pivotal factor in ensuring the successful application of concrete in marine environments. The composition and properties of cement play a vital role in determining concrete durability and, consequently, its resistance to chloride attack and abrasion. Notably, a high C₄AF content offers various advantages, including improved abrasion resistance, chemical attack resistance, and sustained strength improvement [8], [9], [10]. Deng et al. [11] conducted a study revealing that high-ferrite Portland cement (HFC) exhibits superior abrasion resistance owing to increased C₄AF content. Moreover, Huang et al. [12] demonstrated that HFC exhibits moderate resistance to chloride attack. Therefore, HFC stands as a specialized cement suitable for marine engineering applications. The interface transition zone (ITZ) represents the cement-aggregate adherence area and is recognized as the weakest point in concrete structures [13]. It is characterized by high porosity [14], [15], [16]. This high porosity makes the ITZ susceptible to chloride ion intrusion [17]. Therefore, current research emphasizes enhancing the ITZ structure to improve its resistance against ion attacks. An effective method involves incorporating supplementary cementitious materials, such as silica fume, fly ash, and ground granulated blast furnace slag, which undergo continuous volcanic ash reactions and enhance the ITZ of concrete [18], [19], [20]. Additionally, the properties of aggregates significantly influence the ITZ. Prior studies have concentrated on the physical attributes of aggregates, suggesting that those with regular shapes and smooth surfaces contributed to a thinner ITZ. Furthermore, aggregates with suitable water absorption capabilities can mitigate ITZ porosity through internal maintenance [21], [22], [23]. Aggregates’ hardness and abrasion resistance significantly determine concrete’s ability to withstand seawater scouring. Glass-ceramics, characterized by microcrystalline and residual glass phases, exhibit exceptional hardness and abrasion resistance [24]. Consequently, they possess the potential to serve as high-strength aggregates in concrete. Notably, the annual production of architectural glass-ceramics in China surpasses 300 million square meters [25], resulting in a substantial increase in waste glass-ceramics due to production process remnants and glass replacements. Thus, investigating the impact of HFC and waste glass-ceramics on concrete performance becomes imperative. This study aimed to develop concrete suitable for marine engineering, achieved by utilizing waste glass-ceramics as aggregates and incorporating HFC to impart favorable properties. The alkali aggregate activity of glass-ceramics was assessed through inductively coupled plasma atomic emission spectroscopy (ICP-AES) and rapid mortar bar tests. This study examined the influence of glass-ceramics on the mechanical properties, chloride attack resistance, and abrasion resistance of high-ferrite Portland cement mortar (HFCM). Furthermore, microhardness, X-ray diffraction (XRD), and scanning electron microscopy-backscattered electronic (SEM-BSE) techniques were employed to analyze the ITZ of HFCM. The results demonstrate that HFCM formulated with glass-ceramics not only proves advantageous for marine engineering applications but also facilitates the efficient utilization of waste glass-ceramics resources. Section snippets Materials The chemical composition of the raw materials is shown in Table 1, including HFC 42.5 cement (HFC), P·Ⅰ 42.5 cement (PI), ISO-sand and glass-ceramics. The mineral phase of cement is shown in Table 2. The particle size distribution of PI and HFC is shown in Fig. 1. The apparent densities of ISO-sand and glass-ceramics are 2630 kg/m³ and 2530 kg/m³, respectively. The glass–ceramic was a low-expansion glass–ceramic with a lithium-aluminum–silicon system. HFC was produced by Guangxi Yufeng Cement ICP-AES and rapid mortar bar test The concentrations of Al³⁺ and Si⁴⁺ in the 3-d leaching solution of glass-ceramics aggregates were measured as 7.00 mg/L and 16.07 mg/L, respectively. Following 28 d of soaking, these concentrations increased to 241.78 mg/L for Al³⁺ and 619.04 mg/L for Si⁴⁺. The glass-ceramics demonstrated a certain level of alkali activity, necessitating the use of the rapid mortar bar method to determine the glass–ceramic mortar expansion rate. As depicted in Fig. 3, the expansion rates of the glass–ceramic Conclusions This study examined the alkaline aggregate activity of glass-ceramics and their impact on the mechanical properties, resistance to chloride attack, and abrasion of HFCM. Additionally, the effect of ion dissolution in glass-ceramics on the ITZ was also investigated. Based on the analysis of the experimental data, the following conclusions can be drawn: (1) In the alkaline environment, only a small amount of ion dissolution occurred from the glass-ceramics, and the dissolved ions did not cause CRediT authorship contribution statement Yu Gao: Investigation, Formal analysis, Data curation, Conceptualization, Writing - original draft, Writing - review & editing. Jinrui Gao: Investigation. Meijuan Rao: Conceptualization, Supervision, Writing - review & editing. Fazhou Wang: Funding acquisition, Supervision. Lu Yang: Funding acquisition. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments Financial support from the National Natural Science Foundation of China (No. 52172025) is gratefully acknowledged. References (30) D. Wang et al. Chloride ion penetration resistance of concrete containing fly ash and silica fume against combined freezing-thawing and chloride attack Constr. Build. Mater. (2018) B. Dong et al. Investigation of the Cl^- migration behavior of cement materials blended with fly ash or/and slag via the electrochemical impedance spectroscopy method Constr. Build. Mater. (2019) E.G. Moffatt et al. Performance of 25-year-old silica fume and fly ash lightweight concrete blocks in a harsh marine environment Cem. Concr. Res. (2018) X. Shi et al. Durability of steel reinforced concrete in chloride environments: an overview Constr. Build. Mater. 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