Crack Width of High-Performance Concrete due to Restrained Shrinkage

Abstract

Ring-type tests were performed for studying restrained shrinkage cracking of high-performance concrete. The effects of silica fume, fly ash, ground granulated blast furnace slag, and calcium nitrite inhibitor to restrained shrinkage cracking were investigated. The study shows that the crack width increases with increasing silica fume, fly ash, and calcium nitrite inhibitor. Even though the replacement of 50% cement by ground granulated blast furnace does not significantly change the shrinkage strain, it does change the restrained shrinkage cracking manners of the concrete. A crack growth model has been proposed to analyze the problem. The quantitative explanation for the relation between crack width and shrinkage strain in the restrained ring-type concrete has been obtained by introducing the concept of damage of a restrained surface. The numerical analysis of the experimental results indicates that the damage of the restrained surface makes a significant contribution to the crack width due to the restrained shrinkage. The decrease of the degree of damage at the restrained surface suggests that friction resistance and/or pozzolanic reaction could exist near the surface of the concrete.