Title: CN Tower

Author(s): John A. Bickley, Shondeep Sarkar, and Marcel Langlois

Publication: Concrete International

Volume: 14

Issue: 8

Appears on pages(s): 51-55

Keywords: air entrainment; calcium hydroxide; calcium-silicate hydrate; carbonation; compressive strength; ettringite; high-performance concrete; microcracking; microstructure; modulus of elasticity; General

DOI:

Date: 8/1/1992

Abstract:
The CN Tower, Toronto, Ontario, Canada, is the world's tallest freestanding structure at 1805 ft, of which the lower 1500 ft is concrete. The concrete was placed by slipforming in 1973 and 1974. As part of an ongoing inspection program, core samples were obtained and a test program carried out to determine in-place compressive strength, depth of carbonation, modulus of elasticity, and the air-void system. The microstructure was also examined. The results are compared to tests made at the time of construction.