Abstract

Biaxial compression-compression, biaxial tension-compression and compression-shear tests were carried out on self-compacting concrete (SCC) using the rock true triaxial machine and compression-shear hydraulic servo machine to explore the biaxial mechanical properties of SCC. The failure modes and stress-strain curves of SCC under different loading conditions were obtained through experiment. Based on the comparison with the biaxial loading test data of ordinary concrete, the following conclusions are drawn: the failure modes and failure mechanisms under biaxial compression-compression and biaxial tension-compression are similar between SCC and ordinary concrete. Under compression-shear loading, the oblique cracks formed on the lateral surface of the specimen parallel to the shear direction gradually increased and the friction marks on the shear failure section were gradually deepened with the increase of axial compression ratio. The development trend of the stress-strain curve in the principal stress direction was not related to the lateral stress. Under the influence of lateral compressive stress, the principal compressive stress of SCC was increased by 55.78% on average; under biaxial tension-compression, the principal tensile stress of SCC had a maximum reduction of 62.79%; and under the compression-shear action, the shear stress of SCC had a maximum increase of 3.35 times. Compared with the biaxial stress test data of ordinary concrete, it can be seen that the lateral compressive stress had a more significant effect on the principal stress of SCC under biaxial loading. Subsequently, the strength criterion equations of SCC under biaxial loading were proposed based on the principal stress space and octahedral space stress respectively, which have shown good applicability in practice.

Highlights

  • Self-compacting concrete (SCC) is a type of high-fluid concrete which can be compacted in engineering applications without applying vibration

  • 3.3.1 Analysis of Stress Characteristic Values The principal stress peak values were extracted from the principal compressive stress-strain curve under biaxial compressioncompression, the principal tensile stress-strain curve under biaxial tension-compression and the stress-strain curve under compression-shear loading as shown in Figures 7–9, respectively, in order to analyze the influence of lateral compressive stress on the principal stress

  • By comparing with the corresponding test data of ordinary concrete under biaxial loading, the following conclusions are drawn: 1) The lateral compressive stress has a significant impact on the failure mode of self-compacting concrete (SCC) under biaxial compression-compression

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Summary

INTRODUCTION

Self-compacting concrete (SCC) is a type of high-fluid concrete which can be compacted in engineering applications without applying vibration. The true triaxial machine can satisfy multiaxial loading conditions with unequal confining pressures by eliminating the defects of the conventional triaxial machine, so that the results are more consistent with the actual engineering states (Chi et al, 2014; Shi et al, 2014; Yu et al, 2018b). Mohamed et al (2019) carried out an experimental study on the mechanical properties of selfcompacting steel fiber concrete under biaxial loading by applying the biaxial loading technique; based on the experiment results, they proposed the biaxial failure criterion of self-compacting steel fiber concrete at different steel fiber contents. By extracting the characteristic values from the stress-strain curves and comparing with the biaxial loading test data of ordinary concrete, the biaxial mechanical properties of SCC were analyzed in detail and the corresponding failure criterion equations were proposed. The findings of this study are of great significance to the calculation and applications of SCC in engineering practice

Specimen Design
Loading Program
Failure Mode
Stress-Strain Curve
Analysis of Characteristic Values
FAILURE CRITERION
Plane stress space
Octahedral Space Stress
CONCLUSION
Findings
DATA AVAILABILITY STATEMENT
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