Silane-nanoSiO2 composite surface modification of steel fibres: A multiscale experimental study of fibre-UHPC interfaces

IF 14.2 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering Pub Date : 2025-09-04 DOI:10.1016/j.compositesb.2025.112999

Jiefu Tian , Yaqi Li , Guojun Yang , Meini Su , Zhenjun Yang

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引用次数: 0

Abstract

An innovative silane-nanoSiO₂-based surface modification technique for steel fibres was developed recently and proved promising to significantly enhance the strength of ultra-high performance fibre reinforced concrete (UHPFRC). This study aims to further elucidate the fibre-UHPC interfacial modification mechanisms through extensive fibre pullout tests and advanced nano/micro characterization techniques. The FTIR and EDS tests revealed higher Fe–O–Si and Si–O–Si covalent bonds in the composite coating, supporting a proposed chemical modification mechanism. The SEM and WLI tests showed uniform dispersion of nanoSiO₂ particles and a 16.3 % increase in surface roughness compared with brass coating. The double-sided pullout tests on 27 specimens with nine parallel embedded fibres demonstrated that bond strength and pullout energy of composite-coated fibres increased with curing age, reaching 14.7 MPa and 0.12J at 28 days, which were 345 % and 222 % higher than brass-coated fibres, respectively. The μXCT scans revealed that the composite coating reduced the thickness, porosity, and weighted average pore diameter of interfacial transition zone (ITZ) by 37.5 %, 43.3 %, and 47.6 %, respectively, compared with brass coating. Fibres with composite coating were fully covered by the UHPC matrix, with bumpy tunnels surrounded by dispersed cracks, unlike smooth tunnels in silane or brass-coated fibres. The XRD and TGA tests indicated that the composite coating accelerated the hydration process and led to more C–S–H hydrates and thus much denser ITZ and much stronger interfacial bond than the silane or brass coating alone.

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硅烷-纳米二氧化硅复合钢纤维表面改性：纤维-超高性能混凝土界面的多尺度实验研究

近年来，一种新型的硅烷-纳米二氧化硅基钢纤维表面改性技术被开发出来，有望显著提高超高性能纤维增强混凝土（UHPFRC）的强度。本研究旨在通过广泛的纤维拉拔试验和先进的纳米/微表征技术，进一步阐明纤维- uhpc界面改性机理。FTIR和EDS测试显示复合涂层中Fe-O-Si和Si-O-Si共价键较高，支持了化学改性机制。SEM和WLI测试表明，纳米sio2颗粒分散均匀，表面粗糙度比黄铜涂层提高了16.3%。对27个试件进行了9根平行嵌入纤维的双面拉拔试验，结果表明，复合涂层纤维的粘结强度和拉拔能随着龄期的增加而增加，28 d时达到14.7 MPa和0.12J，分别比黄铜涂层纤维高345%和222%。μXCT扫描结果表明，与黄铜涂层相比，复合涂层使界面过渡区（ITZ）厚度、孔隙率和加权平均孔径分别降低了37.5%、43.3%和47.6%。与硅烷或黄铜涂层纤维的光滑隧道不同，具有复合涂层的纤维被UHPC基质完全覆盖，凹凸不平的隧道被分散的裂缝包围。XRD和TGA测试表明，复合涂层加速了水化过程，产生了更多的C-S-H水化产物，因此比单独的硅烷或黄铜涂层更致密，界面结合更强。

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来源期刊

Composites Part B: Engineering 工程技术-材料科学：复合

CiteScore

24.40

自引率

11.50%

发文量

784

审稿时长

21 days

期刊介绍： Composites Part B: Engineering is a journal that publishes impactful research of high quality on composite materials. This research is supported by fundamental mechanics and materials science and engineering approaches. The targeted research can cover a wide range of length scales, ranging from nano to micro and meso, and even to the full product and structure level. The journal specifically focuses on engineering applications that involve high performance composites. These applications can range from low volume and high cost to high volume and low cost composite development. The main goal of the journal is to provide a platform for the prompt publication of original and high quality research. The emphasis is on design, development, modeling, validation, and manufacturing of engineering details and concepts. The journal welcomes both basic research papers and proposals for review articles. Authors are encouraged to address challenges across various application areas. These areas include, but are not limited to, aerospace, automotive, and other surface transportation. The journal also covers energy-related applications, with a focus on renewable energy. Other application areas include infrastructure, off-shore and maritime projects, health care technology, and recreational products.