Title: Mechanism of Secondary Ettringite Formation in Mortars and Concretes Subjected to Heat Treatment

Author(s): D. Heinz and U. Ludwig

Publication: Symposium Paper

Volume: 100

Issue:

Appears on pages(s): 2059-2072

Keywords: concrete durability; deterioration; ettringite; expansion; heating; humidity; portland cements; precast concrete; SO3 content; temperature; water-cement ratio; General

DOI: 10.14359/3827

Date: 4/1/1987

Abstract:
In recent years, precast units made of high-strength concrete that have been heat treated during production have shown partly damaged structure related to loss of strength. This damage always occurred in those building components that, for several years, had been subjected to open-air weathering, e.g., front panels and sleepers. The damage has often been characterized by crack formation emerging from the edges of the building components, as well as by a loss of bond between the cement paste and the coarse aggregate. To explain this damage, a series of parameters have been examined as to their influence on the durability of heat-treated concretes. Besides others, the investigation concentrated on the threshold temperature of damage, the SO3 content of the cement, the humidity of storage, and the water-cement ratio.