Title:
Deicer Salt Scaling Resistance of Dry- and
Wet-Process Shotcrete
Author(s):
Denis Beaupre, Caroline Talbot, Martin Gendreau, Michel Pigeon, and Dudley R. Morgan
Publication:
Materials Journal
Volume:
91
Issue:
5
Appears on pages(s):
487-494
Keywords:
absorption; air entrainment; compression tests; curing; deic-ers;
dry process; freeze-thaw durability; scaling; shotcrete; wet process.
DOI:
10.14359/9759
Date:
9/1/1994
Abstract:
ASTM C 672 deicer salt scaling tests were carried out on both dry- and wet-mix shotcretes. Twenty-jive dry-mix shotcretes and eleven wet-mix shotcretes were used to fabricate different test panels. The mix variables included cement type (Types 10 and 30), silica fume, latex (dry-mix process only), polypropylene and steel fibers, set-accelerating and air-entraining admixtures. All test panels were wet-cured for 7 days except two additional panels, one of which was not cured and the other of which was cured with a curing compound. Water containing 2.5 or 3 percent NaCl solutions was used for the scaling tests. The scaling residues were collected and weighed to evaluate deterioration. The mass of scaling residues was found to vary between 0. 1 and 24.0 kgm2. These tests indicate that the scaling resistance of both dry- and wet-mix shotcrete improves with an increase in the air content, and that the use of silica fume generally reduces the mass of scal-ing residues. These tests also indicate that the use of a set-accelerating admixture can significantly reduce the scaling resistance of shotcrete. The use of Type 30 cement and of an air-entraining admixture was found to markedly improve the scaling resistance of dry-mix shotcretes.