Autogenous self-healing of ultra-high-performance fiber-reinforced concrete with varying silica fume dosages: Secondary hydration and structural regeneration. (March 2023)

• Record Type: Journal Article
• Authors: Zheng, Qiaomu; Li, Chen; Song, Facheng; He, Bei; Li, Wenting; Jiang, Zhengwu
• Is Part Of: Cement & concrete composites. Volume 137(2023)
• Publication Date: 2023-03
• Subjects: Silica fume -- Ultra-high-performance fiber-reinforced concrete -- Autogenous self-healing -- Secondary hydration -- Amorphous silica dissolution; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2022.104905
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Secondary hydration is the main driving force of autogenous self-healing and directly impacts the closure of cracks in damaged cementitious materials. In fiber-reinforced cement composites, secondary hydration also dominates the regeneration of the fiber-matrix interface during the self-healing processes. As an important factor influencing the cement hydration, silica fume (SF) addition can be crucial to the self-healing performance of cementitious materials and composites. In this paper, the effect of SF on the autogenous self-healing of ultra-high-performance fiber-reinforced concrete was investigated. With a ≥20% SF addition, the secondary hydration the cement matrix adjacent to the cracks was accelerated. The dissolution of amorphous silica and the formation of Si-containing healing phases was observed. These effects predominated the closure of the mouth and the inner part of the cracks. SF addition also enhanced the regeneration of fiber-matrix interface by promoting the growth of self-healing products in these areas. The closure of cracks and the regeneration of fiber-matrix interface are both responsible for the restoration of flexural properties. Highlights: The secondary hydration acceleration of the cement matrix after cracking was found with a ≥20% SF addition, which promoted the self-healing of the cracks in UHPFRC. The effect of SF on the structural regeneration of the cracks in UHPFRC was elucidated with a self-healing mechanism of the amorphous Si dissolution. The self-healing of the deep matrix crack and fiber-matrix interface together induced the flexural property restoration of the SF-containing UHPFRC.