Abstract

To study the energy evolution law and damage constitutive behavior of high-strength concrete based on the conventional triaxial compression tests of C60 and C70 high-strength concrete subjected to five different confining pressures, the failure characteristics of high-strength concrete are analyzed at different confining pressures, and the evolution of the input energy density, elastic strain energy density, and dissipation energy density with axial strain and confining pressure are quantified. Combined with a continuous damage theory and non-equilibrium statistical method, the ratio of dissipation energy density of concrete to dissipation energy density corresponding to peak stress is used as the mechanical parameter. Assuming that the mechanical parameter obeys the Weibull distribution laws, the statistical damage variable describing the damage characteristics of concrete were derived. According to the Lemaitre strain equivalent principle, the damage variable is introduced to the generalized Hooke law to establish the statistical damage constitutive model for high-strength concrete. The results show that: (1) the input energy density and dissipation energy density increases with the increase of axial strain, while the elastic strain energy density increases first and then decreases as a function of the axial strain and reaches the maximum value at the peak stress; (2) the input, elastic strain, and dissipated energy densities corresponding to the peak stress of the two high-strength concretes all increase as a function of confining pressure, and the elastic strain energy density corresponding to the peak stress increases linearly as a function of the confining pressure; (3) the statistical damage constitutive model results of C60 and C70 high-strength concrete are in good agreement with the test results, and the average relative standard deviations are only 3.64% and 3.99%. These outcomes verify the rationality and accuracy of the model.

Highlights

  • With the application of high-strength concrete in civil engineering, transportation, water conservancy, municipal engineering, and other engineering fields, it is of great significance to study the deformation law and failure characteristics of high-strength concrete subject to complex stress states aiming to improved scientific designs of concrete buildings and to the guarantee of their safety [1,2]

  • To study the energy evolution law and damage constitutive behavior of high-strength concrete subjected to complex stress states, conventional triaxial compression tests at different confining pressures were conducted with ZTCR-2000 rock triaxial testing system

  • Based on the continuum damage theory and non-equilibrium statistical method, a statistical damage constitutive model was established for high-strength concrete based on the use of the ratio of dissipation energy density of concrete to the dissipation energy density that corresponded to peak stress

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Summary

Introduction

With the application of high-strength concrete in civil engineering, transportation, water conservancy, municipal engineering, and other engineering fields, it is of great significance to study the deformation law and failure characteristics of high-strength concrete subject to complex stress states aiming to improved scientific designs of concrete buildings (structures) and to the guarantee of their safety [1,2]. The energy method based on thermodynamic theory is an effective way to study the constitutive relationships and failure behaviors of concrete materials. The aforementioned studies showed that the constitutive behavior of concrete materials can be studied from the perspective of statistics, but at present, most studies use the mechanical or deformation parameters of concrete materials as the basis for establishing statistical damage constitutive equations, and few studies have introduced the energy dissipation density parameter into the constitutive relationship. To study the energy evolution law and damage constitutive behavior of high-strength concrete subjected to complex stress states, conventional triaxial compression tests at different confining pressures were conducted with ZTCR-2000 rock triaxial testing system. Based on the continuum damage theory and non-equilibrium statistical method, a statistical damage constitutive model was established for high-strength concrete based on the use of the ratio of dissipation energy density of concrete to the dissipation energy density that corresponded to peak stress

Test Materials and Equipment
Results
Conventional
Mechanical
When the confining pressure
Energy
Relationship between Energy Density and Axial Strain
Relationship between
Relationship
Establishment of Constitutive Model
Verification of Constitutive Model
Comparison
Damage Analysis of High-Strength Concrete
Full Text
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