Stress-Strain Relationship of Concrete after High Temperature in Initial Compaction Stage

Abstract

Abstract: Uniaxial compression tests were carried out on concrete after five temperatures (20 ℃, 200 ℃, 400 ℃, 600 ℃ and 800 ℃). The compaction coefficient φ and relative compactness Φ were defined to evaluate the compaction degree of concrete after high temperature. The variation law of initial compaction stage of concrete with temperature was discussed. A unified piecewise function was used to establish the full stress-strain curve equation of concrete after high temperature considering the initial compaction stage. The results show that when the temperature is 200 ℃ and 400 ℃, the peak stress and elastic modulus of concrete decrease slightly. The concrete has a high degree of compaction, and the initial compaction stage of the stress-strain curve is not obvious and can be ignored. The whole compression damage process is brittle. When the temperature is 600 ℃ and 800 ℃, the peak stress and elastic modulus decrease greatly, and the peak strain increases rapidly. The compaction degree of concrete decreases rapidly. The stress-strain curve has an obvious initial compaction stage. The whole compression damage process is ductile. The stress-strain full curve equation established in this paper has the advantages of high fitting degree and relatively few parameters.

Key words: concrete, high temperature, uniaxial compression, stress-strain relationship, initial compaction stage

CLC Number:

TU528.1

WANG Lei, ZHAO Yanru, HAO Song. Stress-Strain Relationship of Concrete after High Temperature in Initial Compaction Stage[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(11): 3627-3633.

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