Title: Performance of Permeability-Reducing Admixtures in Marine Concrete Structures

Author(s): Vinh T. N. Dao, Peter F. Dux, Peter H. Morris, and Alan H. Carse

Publication: Materials Journal

Volume: 107

Issue: 3

Appears on pages(s): 291-296

Keywords: chloride-induced corrosion; coastal environment; durability; permeability-reducing admixture

DOI: 10.14359/51663758

Date: 5/1/2010

Abstract:
The use of permeability-reducing admixtures is a potential preventative of the chloride-induced corrosion of steel reinforcement, which is the main cause of the deterioration of concrete structures exposed to coastal environments. This paper presents an experimental investigation into the effectiveness of two typical commercially available permeability-reducing admixtures: one characterized by crystallization activity and the other by hydrophobic and poreblocking effects. Concrete specimens were exposed to simulated coastal environments, and chloride concentration profiles at 28-, 365-, and 730-day exposures were determined by X-ray fluorescence spectrometry. The results suggested that the incorporation of the admixture, characterized by hydrophobic and pore-blocking effects, appeared to considerably enhance the concrete durability with respect to chloride-induced corrosion. The inclusion of the admixture characterized by crystallization activity, however, seemed to have almost no detectable effect. This implies the necessity of exercising a degree of caution during specification.