Title:
Canadian Experience With Air-Entrained High-Performance Concrete
Author(s):
Pierre-Claude Aitcin and Michel Lessard
Publication:
Concrete International
Volume:
16
Issue:
10
Appears on pages(s):
35-38
Keywords:
air-entrainment; bridges (structures); cold weather construction; concrete durability; high-performance concrete; Construction
DOI:
Date:
10/1/1994
Abstract:
It has been shown that high-performance concretes (HPC) must contain entrained air if they have to pass ASTM C 666 (Procedure A) resistance to rapid freezing and thawing when their w/(c+m) ratio is higher than 0.25. Entraining air and maintaining a suitable air-void system under various field conditions requires careful attention when selecting and proportioning the constituent materials. Two bridges incorporating air-entrained high-performance concrete have been built in Quebec under two completely different temperature conditions. Portneuf Bridge was built in late October, 1992 with an average daily air temperature of +3 C during the day, but -4.5 C during the night. Highway 50 viaduct was built in June, 1993 with a maximum air temperature of 27.8 C and delivery temperature of the concrete at 15 C < T < 25 C. The mixing water had to be heated for Portneuf Bridge while for the Highway 50 viaduct ice was substituted for an average of 40 kg of water.