Title: Frost Action on Immature Cement Paste -Microstructural Features

Author(s): Obada A. Kayyali, Christopher L. Page, and Alistair G. B. Ritchie

Publication: Journal Proceedings

Volume: 77

Issue: 4

Appears on pages(s): 264-268

Keywords: air entrainment; cement pastes; compressive strength; cracking (fracturing); freeze-thaw durability; freezing; hydration; mechanical properties; microstructure.

DOI: 10.14359/7004

Date: 7/1/1980

Abstract:
Microstructural features, associated with the irreversible loss in strength experienced‘ by immature plain cement paste when exposed briefly to freezing and thawing conditions, have been examined. An important factor is believed to be the formation of large, easily-cleaved portlandite crystals surrounded by stress-intensifying pores. Air-entrained paste, however, contained air voids into which segregation of portlandite occurred during early freezing and thawing. This is thought to have led to reduction in the quantity of portlandite deposited in the body of the paste when normal curing was resumed, and may account for the enhanced strength and toughness values recorded for such specimens.