Estimating Stress Relaxation and Cracking Potential of High-Strength Concrete Reinforced with Polyvinyl Alcohol Fiber at Early Age

Abstract

High-strength concrete (HSC) with a low water-to-cement (w/c) ratio always exhibits high shrinkage at an early age. Concrete with shrinkage that is subjected to restraint is prone to trigger harmful cracking, which facilitates the application of fibers. Although mechanical properties of cementitious materials with various fibers have been extensively investigated, little research has characterized the stress relaxation and cracking potential of HSC with polyvinyl alcohol (PVA) fibers. This paper aimed to expand the limitation by means of the experiment campaign, including free shrinkage measurements and restrained ring tests on HSC with PVA fibers. The proportion of PVA fibers was 0.0%, 0.2%, 0.4%, and 0.6% by volume of HSC. Experimental study and the corresponding analysis indicated the following: free shrinkage of HSC diminished as the PVA fiber proportion increased; residual stress induced from the restrained shrinkage of the concrete ring diminished with an increase of the PVA fiber proportion; the reduction in the stress rate correlated with an increase in the PVA fiber proportion. Relaxed stress increased as PVA fiber proportion increased; the age of cracking of the HSC was postponed due to the incorporation of PVA fibers; and a low cracking potential of HSC was revealed as the PVA fiber proportion increased.