Experimental and theoretical investigation on the stress transfer across cracks due to combined action of steel fibers and aggregate interlock. (November 2021)

• Record Type: Journal Article
• Authors: Resende, Thomás L.; Cardoso, Daniel C.T.; Shehata, Lidia C.D.
• Is Part Of: Cement & concrete composites. Volume 124(2021)
• Publication Date: 2021-11
• Subjects: Aggregate interlock -- Steel fibers -- Shear transfer mechanisms; 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.2021.104239
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: One of the steps to achieve a rational approach to the shear strength of reinforced concrete members is to understand the force transfer mechanisms throughout the critical crack. This subject has been investigated for decades, but its full comprehension has not been achieved, especially in steel fiber reinforced concrete (SFRC). In the present work, an experimental/theoretical investigation on the combined action of fiber bridging and aggregate interlock was carried out. The experimental program included 12 push-off specimens in which the variables were the fiber volume content ( V f ) and aspect ratio ( l f /d f ). The results showed an increase in shear strength and an improvement in the post-cracking stage as residual flexural tensile strength ( f R ) and V f l f /d f increased. To gather information about the failure surface topography, 3D digital image correlation analysis was adopted for specimens without fibers. A contact density-based mechanical model is applied to plain concrete results to derive aggregate interlock parameters and, then, an extended model including fibers is proposed to evaluate the results for SFRC specimens. A reasonable agreement was achieved and the contribution of each mechanism could be estimated. Highlights: Stress transfer across cracks due to combined action of steel fibers and aggregate interlock is investigated. Results of tests on 12 push-off specimens without and with steel fibers are reported. Digital image correlation is used to monitor crack and strain evolution and to gather information about the failure surface topography. Fibers enhance stress transfer across cracks capacity and improve the post-cracking shear strength. Theoretical model proposed was essential for a better rational understanding of experimental results.