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

Abstract

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.

Chloride Diffusion in Concrete Modified with Polyacrylic Superabsorbent Polymer (SAP) Hydrogel—The Influence of the Water-to-Cement Ratio and SAP-Entrained Water

“…Internal curing in concrete technology was introduced to positively influence the durability of high-performance concretes [37][38][39]. With an increase in the amount of the binder within the composite, a reduction in the water amount, and an increase in the mass of fine aggregate, the influence of autogenous shrinkage on composite's properties and durability had to be, among the influence of others, mitigated [20].…”

Recent progress in superabsorbent polymers for concrete

“…For example, Wehbe et al observed that cement paste that contained both SAP and SRA displayed greater autogenous shrinkage than cement paste containing only SAP, most likely due to altered SAP sorption behavior in the presence of SRA as described in Section 2.2 [90]. SAPs are also used in concert with composite-based physical strategies to reduce autogenous shrinkage, including SAP in steel fiber reinforced concrete [191] and with other fibers, including polypropylene (PP) [192], steel and polyvinyl alcohol (PVA) microfibers [193], basalt and PP fibers [194], and barchip (PPbased) fibers [195].…”