Title: Reducing Crack Risk in Industrial Concrete Floors

Author(s): Johan L. Silfwerbrand and Ali A. Farhang

Publication: Materials Journal

Volume: 111

Issue: 6

Appears on pages(s): 681-690

Keywords: crack risk; creep; industrial concrete floors; material tests; restrained shrinkage; shrinkage

DOI: 10.14359/51686833

Date: 11/1/2014

Abstract:
Cracking and curling are two important problems in industrial concrete floors. In many practical cases, it is easier to design the concrete floor slab for mechanical loads than for shrinkage stresses. This paper proposes a simple equation that mirrors the major factors influencing the crack risk in concrete floor slabs. By using this equation, the industrial floor designer or contractor can make a proper material selection that leads to a substantially reduced crack risk. Tests on strength, free shrinkage, restrained shrinkage, and flexural creep support this hypothesis. Furthermore, the use of shrinkage-reducing admixtures (SRAs) seems to not only reduce the free shrinkage, but also maintains the beneficial condition of substantial creep that leads to shrinkage stress reduction.