Digital imaging monitoring of fracture processes in hybrid steel fiber reinforced concrete. (15th October 2022)

• Record Type: Journal Article
• Authors: He, Fengzhen; Biolzi, Luigi; Carvelli, Valter; Monteiro, Paulo J.M.
• Is Part Of: Composite structures. Volume 298(2022)
• Publication Date: 2022-10-15
• Subjects: Concrete -- Hybrid steel fibers -- Digital image correlation (DIC) -- Fracture process -- FPZ length -- Damage evolution; Composite construction -- Periodicals; Composites -- Périodiques; 624.18
• DOI: 10.1016/j.compstruct.2022.116005
• Languages: English
• ISSNs: 0263-8223

Abstract

Abstract: Ten hybrid fiber reinforced concrete mixtures are designed to investigate the effect of three different steel fibers and their combination on the Mode I fracture of concrete. The fracture process and damage characteristics are studied by measuring the full-field displacement and strain on the surface of the specimen by the digital image correlation technique. A horizontal strain standard deviation method is proposed for determining the tip of the fracture process zone (FPZ). The FPZ length before the peak load and the damage degree factor ( Ddf ) are measured. The results indicate four stages during the fracture process development: microcrack propagation, fracture formation, rapid fracture expansion, and post-peak propagation. The critical FPZ length increases from 21.6 mm to 79.1 mm when the fiber volume fraction increases from 0 % to 2 %. The hybridization of the reinforcement has a negligible effect on the growth trend of the FPZ length and the critical FPZ length. Within the reinforcement content of 0 %–1.5 %, the inhibiting effect on the Ddf produced by the hybrid fibers is enhanced with increasing volume fraction.