Title: Influence of Direct Electrical Current on Specific Volume of Mortar in Seawater

Author(s): A. Le Floch and W. Hartt

Publication: Symposium Paper

Volume: 163

Issue:

Appears on pages(s): 481-500

Keywords: concretes; electrical resistance; expansion; mortars (material); seawater; Materials Research

DOI: 10.14359/1372

Date: 8/1/1996

Abstract:
A series of hollow, cylindrical mortar specimens of 0.44 water-cement ratio were prepared without reinforcement and exposed to flowing natural seawater for up to 256 days. A direct electrical current of 2, 10, or 50 mA was impressed between the specimen core and exterior, using a pair of titanium or mixed metal oxide electrodes and a power supply. Embedded strain gage output and measurement of cylinder length and outside diameter as a function of exposure duration indicated that specific volume of the mortar increased with time with net expansion and expansion rate being greater for specimens exposed to current compared to baseline (no current) specimens. The cause of the enhanced expansion of the mortar in the presence of a direct current is discussed in this paper; the results are evaluated within the context of practical situations involving seawater exposure of cementitious materials.