Bamboo fiber-enhanced UHPC: Early hydration and microstructural/mesoscale analysis

• Published in: Construction & building materials 2024-11, Vol.450, p.138548, Article 138548
• Main Authors: Zhao, Hua, Li, Ziwei, Tang, Jie, Zhou, Tao, Xiong, Tianwang
• Format: Article
• Language: English
• Subjects: Bamboo fiber; Hydration; Internal curing; Micro-and meso-structure; UHPC
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2024.138548

This study investigates the impact of incorporating bamboo fibers, a natural and renewable material, into ultra-high performance concrete (UHPC) on its early hydration, mechanical properties, internal relative humidity, autogenous shrinkage, and microstructure. The results show that adding bamboo fibers significantly improves various UHPC properties. Bamboo fibers regulate hydration and prolong the hydration process through their water absorption and retention abilities. With a fiber content of 1.0 vol percent (vol%), the compressive strength increases by 10.2 %, reaching 97.1 MPa, and at 2.0 vol%, flexural strength and toughness increase by 37.9 % and 739.5 %, respectively. Additionally, bamboo fibers help maintain internal relative humidity above 98 % during the first 7 days of curing and reduce autogenous shrinkage by up to 55.9 %. The fibers also optimize the microstructure by minimizing voids, with a 1.0 % fiber content reducing the void ratio to 1.64 %. This reduces large voids and improves the material's density. Overall, bamboo fibers show great promise in enhancing UHPC's structural performance and environmental adaptability while being a sustainable and cost-effective material. •The compressive strength of UHPC improves with the addition of bamboo fibers (BF).•BF significantly increase the flexural strength and toughness of UHPC.•BF can maintain internal humidity in UHPC and reduce autogenous shrinkage.•BF regulate and extend the hydration of UHPC by controlling internal moisture.•BF improve the microstructure of UHPC by optimizing pore and void distribution.