Title: Concrete Cover Cracking with Localized Corrosion of Reinforcing Steel

Author(s): A. A. Torres-Acosta, and A. A. Sagues

Publication: Symposium Paper

Volume: 192

Issue:

Appears on pages(s): 591-612

Keywords: corrosion; cracking; energy; fracture properties; strain

DOI: 10.14359/5773

Date: 4/1/2000

Abstract:
This work estimated experimentally the critical amount of steel corrosion (Xcrit) needed for concrete cover cracking of a reinforced concrete element where only a fraction of the steel bar length is corroding. The amount of corrosion needed to crack the concrete cover (Xcrit) was ~49 um to ~137 um in specimens with localized corrosion, in comparison to ~15 um to 75 um for uniform corrosion reported for other investigations in comparable systems. An empirical equation is proposed for Xcrit as a function of specimen dimensions (concrete clear cover, C; rebar diameter, ; and anodic length, L). In this equation Xcrit is proportional to the first power of C/ and to the higher power of [C/L+1]. Quantitative determinations of the development and magnitude of stresses produced by corroding steel in concrete have been obtained. Estimated pressures at the steel/concrete interface for C/ > 3 reached values comparable to the concrete compressive strength. The potential use of a fracture-energy-based model to predict Xcrit was supported by indications of approximate agreement between estimates of the work of corrosion expansion and the energy required to crack the concrete.