Assessment of fire-damaged concrete: combining metamorphic petrology and concrete petrography
conference paper
Metamorphic petrology is a branch of geology that deals with the study of changes in rocks due changing physio-chemical conditions. As conditions shift in or out of the thermodynamic stability field of phases, new phases may appear whereas others disappear. A basic approach is mapping of so-called isograds, which are lines separating the occurrence of (combinations of) phases in the field. Concrete is a poor conductor of heat, but can suffer considerable damage at elevated temperatures or when exposed to fire. Unravelling the heating history of concrete is important to forensic research or to determine whether a fire-attacked concrete structure and its components are still structurally sound. Analogous to metamorphic petrology, thermally triggered reactions in concrete resulting in changes in specific phases may be used to trace isograds. As these occur in response to temperature alone, they may be used to trace temperature variations in concrete with depth. Concrete petrography is a quick and a well-suited method for unravelling the heating history of concrete. The method involves a combination of visual inspection and the use of microscopic methods in a systematic way to study the thermally affected concrete. It is a powerful diagnostic tool that has successfully been applied in routine research and testing of concrete lining in tunnels, assessment of fire-damage to structures and evaluation of fireproofing in waste incinerators.
TNO Identifier
329963
Source title
Proceedings of the 8th Euroseminar on Microscopy Applied to Buildings Materials, Athens, Greece, 4-7 September 2001
Collation
9 p.
Pages
191-199
Files
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