EFFECTS OF THERMO-MECHANICAL STRESSES ON THE STRENGTH BEHAVIOR OF CONCRETE IN MACRO SPECIMENS IN FIRE CASE
Abstract
Rheological research works investigate for fire
case the material behavior of small specimens and derive from the test results
material laws to determine the behavior of structural elements due to fire
exposure. However, as it is known, the heat and mass transport processes can
significantly happen in different phases in macro concrete elements. Besides,
in case of a fire, different heating rates occur in the cross section of
structural elements. The validity of the transferred test results from small
test specimens to the material behavior of structural elements indicates a
phenomenon, which has not been investigated up to now. Such a research work has
been done for the first time through close cooperation of subprojects A and B3
of SFB (Sonder-ForschungsBereich: A special fire research activity for structural
elements in Braunschweig Technical University, 1971-1986). The results of the
rheological investigations presented in this paper can lead to a new research
conception about the determination of realistic fire behavior of concrete
structures. By means of further purposive research work, it will be possible to
reproduce the structural behavior in case of fire with simple but realistic mathematic-rheological
relationships.
Keywords
Fire case,reinforced concrete,macro specimens,fire resistance,relaxation,material behavior
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