Title: Importance of Portland Cement Quality on the Durability of Concrete

Author(s): H. E. Vivian

Publication: Symposium Paper

Volume: 100

Issue:

Appears on pages(s): 1691-1702

Keywords: concrete durability; fineness; free lime in portland cement; hydration; portland cement clinker; portland cements; soundness; General

DOI: 10.14359/3814

Date: 4/1/1987

Abstract:
The soundness of portland cement has a major effect on concrete durability. Mandatory standard specifications have been widely applied to control the manufacture and quality performance of portland cements. Despite these specifications there is evidence in aging concrete to suggest that potential unsoundness, which is due to excessively large amounts of uncombined lime occurring at least intermittently in clinker, is not detected by currently specified tests. This paper indicates that significantly large amounts of uncombined lime are intermittently present in clinker, that its presence is induced by variations in material preparation and in burning conditions during manufacture, and that it remains undetected by current tests. Some possible means of minimizing the amount of uncombined lime in clinker and improving its detection and measurement are discussed.