Reiners, Jochen
[Author]
;
Zehfuß, Jochen
[Contributor];
Dehn, Frank
[Contributor]
The Influence of the Physical and Chemical Properties of Hardened Cement Paste on the Fire-Induced Spalling of Concrete ; Der Einfluss der physikalischen und chemischen Eigenschaften von Zementstein auf das Abplatzen von Beton im Brandfall
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Title:
The Influence of the Physical and Chemical Properties of Hardened Cement Paste on the Fire-Induced Spalling of Concrete ; Der Einfluss der physikalischen und chemischen Eigenschaften von Zementstein auf das Abplatzen von Beton im Brandfall
Contributor:
Reiners, Jochen
[Author]
Published:
TU Braunschweig: LeoPARD - Publications And Research Data, 2023-05-05
Footnote:
Diese Datenquelle enthält auch Bestandsnachweise, die nicht zu einem Volltext führen.
Description:
A number of major fire incidents in recent decades, particularly in tunnels and indoor car parks, have increased the awareness among construction designers towards the potential susceptibility of concrete to fire-induced explosive spalling. In some fields of application, this violent breaking-off of concrete layers may reduce the fire resistance time of fire-exposed construction elements. The mechanisms causing explosive spalling are not yet fully understood and discussed controversially among scientists. In cement production, a steadily increasing proportion of the market volume is constituted by cement types with several main constituents. In these types of cement, Portland cement clinker is replaced by granulated blast furnace slag, lime stone, fly ash or other inorganic materials. Fire tests of concrete specimens presented in a previous publication and the present paper have shown that the type of cement may have a marked influence on the susceptibility of concrete to explosive spalling. The main objectives of this thesis were therefore to: - determine the way in which the physical and chemical properties of the hardened cement paste influence the spalling propensity of heated concrete; and in this manner - contribute to a better understanding of the mechanisms causing explosive spalling. A particular focus was placed on the way in which the moisture present in the concrete pores promotes spalling. Three common characteristics of those concretes that were found to have an increased susceptibility of spalling were identified. For each of the three common characteristics, a corresponding hypothesis describing its possible contribution to the fire-induced concrete spalling was proposed. Each of the three hypotheses in turn was verified through a dedicated experimental programme. The evaluation of the experiments showed that explosive spalling was caused by the following principal mechanisms: • In the concretes that showed explosive spalling in the corresponding tests, the interfacial transition zone (ITZ) ...