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چکیده
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The behavior of concrete structures that are exposed to extreme thermo-mechanical loading is an issue of great importance in nuclear engineering. The structural re-safety capacity of concrete is very complicated because concrete materials have considerable variations. Constitutive models and relationships for preloaded Normal and High Strength Concrete (NSC and HSC) subjected to re are needed, which are intended to provide ecient modeling and to specify the re-performance criteria of the behavior of preloaded concrete structures exposed to re. In this paper, formulations for estimating the parameters a ecting the behavior of uncon ned preloaded concrete at high temperatures are proposed. These formulations include residual compression strength, initial modulus of elasticity, peak strain, thermal strain, transient creep strain and the compressive stress-strain relationship at elevated temperatures. The proposed constitutive models and relationships are veri ed with available experimental data and existing models. The proposed models and relationships are general and rational, and have good agreement with the experimental data. More tests are needed to further verify and improve the proposed constitutive models and relationships.
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