Title: Durability of an Arctic Concrete

Author(s): Micheline RegourdI

Publication: Symposium Paper

Volume: 100

Issue:

Appears on pages(s): 919-935

Keywords: aggregates; chlorides; compressive strength; concrete durability; low temperature; sulfates; sulfides; General

DOI: 10.14359/3718

Date: 4/1/1987

Abstract:
The use of unconventional aggregates, which includes several sulfide minerals, in making concrete in the Canadian Arctic aroused the interest of the authors to investigate the durability of such a concrete subjected to a very cold environment. Compressive strength measurements on concrete samples three and nine years old, cored in a dock, show that the concrete is still very strong--at least 28 MPa (4000 psi). A close examination of the aggregates and concrete microstructure suggests the concrete is durable. The presence of these aggregates does not give rise to any deleterious effect. The concrete is found to be a dense one. Only a superficial layer of a few millimeters thick has been transformed by carbonation. This zone, enriched in potassium, does not contain any Ca(OH)2 crystal. Its C-S-H has a low CaO/SiO2 ratio and is sometimes replaced by a siliceous gel. Penetration of chloride and sulfate ions is also observed but is not related to any concrete damage. The presence of a large amount of Ca(OH)2 and calcium rich C-S-H (C/S ÷ 1.7) below the thin carbonated layer corresponds to a high chemical stability of the concrete.