Unified failure criteria for freeze-thaw damaged concrete under multiaxial stress state: An innovative uniaxial strength-dependent prediction method

Abstract

When concrete is subjected to freeze-thaw (FT) cycles, its mechanical properties under multiaxial stress states will deteriorate. In order to establish corresponding failure criteria, it is common practice to conduct FT and multiaxial tests. However, due to the multiple FT factors, extensive multiaxial tests are required, resulting in low applicability of the existing failure criteria for FT damaged concrete. In this paper, according to the collected multiaxial test data, a rule has been revealed that the normalized failure surface of FT damaged concrete is related to the relative uniaxial compressive strength (fcD/fc), regardless of the types of FT factors. This correlation is related to the degree of confined state. On this basis, a uniaxial strength-dependent method has been proposed to predict the multiaxial ultimate stress state of FT damaged concrete. Through the proposed method, to facilitate various applications, three models including two types of failure criteria for concrete and a peak axial stress model for confined concrete after FT cycles have been established with broad applicability and good accuracy. The proposed method and models might be extended to other damaged concrete with the same mechanism of developing internal cracking.