Effect of the Combination of Superabsorbent Polymers for Autogenous Shrinkage Control with Steel Fibers of High-Performance Concrete under Uniaxial Tension Using DIC

• Published in: Materials Vol. 13; no. 20; p. 4638
• Main Authors: Santos, Karyne Ferreira dos, Ribeiro, António Carlos Bettencourt Simões, Silva, Eugênia Fonseca da, Manzano, Manuel Alejandro Rojas, Motta, Leila Aparecida de Castro, Toledo Filho, Romildo Dias
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 17-10-2020; MDPI
• Subjects: autogenous shrinkage; Cement; Compressive strength; Concrete mixing; Crack bridging; digital image correlation; Digital imaging; Ductility tests; High speed; high-performance fiber reinforced concrete; Investigations; Particle size; Polymers; Reinforced concrete; Reinforcing steels; Shrinkage; Side effects; Steel fiber reinforced concretes; Steel fibers; Strain gauges; superabsorbent polymer; Superabsorbent polymers; tensile behavior; Brazil
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma13204638

This paper presents a study of the effect of a superabsorbent polymer (SAP) for autogenous shrinkage control on the uniaxial tensile behavior of steel fiber reinforced concrete (SFRC). The use of fibers and SAP potentially increases the durability of the concrete, preventing cracking by autogenous shrinkage and enhancing post-cracking behavior. Furthermore, SAP can provide further hydration for self-healing purposes and improve the ductility of the SFRC. In order to evaluate the effect of the addition of SAP in SFRC, dog-bone SFRC specimens with different dosages of superabsorbent polymers were cast and tested under uniaxial tension. The digital image correlation (DIC) technique was used to understand the effect of SAP on the steel fibers’ crack-bridging mechanisms. Surface strains and crack openings were inferred using the DIC technique. The effect of SAP and fibers on fresh and hardened concrete was individually investigated by flow tests and compressive strength tests. Autogenous shrinkage was measured in plain concrete to investigate the minimum SAP content required to mitigate autogenous shrinkage of 0.3%. The use of 0.3% SAP was also sufficient to reach multiple cracking behavior. This content of SAP completely suppressed the autogenous shrinkage with minimal side effects on compressive strength. An analytical formulation for the tensile behavior of SFRC was developed using the variable engagement model, presenting a mean correlation of R2 of 0.97 with the experimental results.