Numerical simulation of mechanical properties of recycled concrete based on characterization of interfacial transition zone characteristics

Purpose This paper aims to propose the five-phase sphere equivalent model of recycled concrete, which can be used to deduce the theoretical formulas for the Poisson’s ratio and effective elastic modulus. Design/methodology/approach At a mesoscopic level, the equivalent model converts the interfacial layer, which consists of the new interfacial transition zone (ITZ), the old mortar and the old (ITZ), into a uniform equivalent medium. This paper deduces a strength expression for the interfacial transition zone at the microscopic level using the equivalent model and elastic theory. In addition, a new finite element method called the base force element method was used in this research. Findings Through numerical simulation, it was found that the mechanical property results from the five-phase sphere equivalent model were in good agreement with those of the random aggregate model. Furthermore, the proposed model agree on quite well with the available experimental data. Originality/value The equivalent model can eliminate the influence of the interfacial layer on the macroscopic mechanical properties, thereby improving the calculation accuracy and computational efficiency. The proposed model can also provide a suitable model for multi-scale calculations.

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Properties characterization of interfacial transition zone of recycled concrete for reducing the resource waste and environmental pollution

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/804/2/022097 ◽

2021 ◽

Vol 804 (2) ◽

pp. 022097

Author(s):

Yichao Zhang ◽

Xingyi Chen ◽

Aixia Liu ◽

Jinghai Zhou

Keyword(s):

Environmental Pollution ◽

Transition Zone ◽

Interfacial Transition Zone ◽

Recycled Concrete ◽

Properties Characterization

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Numerical Simulation of Uniaxial Compression Performance for Recycled Concrete Using Micromechanics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.253-255.550 ◽

2012 ◽

Vol 253-255 ◽

pp. 550-554 ◽

Cited By ~ 1

Author(s):

Hua Ping Zhou ◽

Yi Jiang Peng ◽

Na Na Dang ◽

Ji Wei Pu

Keyword(s):

Numerical Simulation ◽

Transition Zone ◽

Uniaxial Compression ◽

Cement Paste ◽

Interfacial Transition Zone ◽

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Hardened Cement ◽

Hardened Cement Paste ◽

Compression Performance

Recycled Aggregate Concrete (RAC) is referred to as Recycled Concrete (RC). In this paper, the compression performance of recycled concrete was researched using the micromechanics. The recycled concrete was taken as a five-phase composite material consisting of recycled coarse aggregate, old hardened cement paste, new hardened cement paste, the old interfacial transition zone (Old ITZ) and the new interfacial transition zone (New ITZ) on meso-level. A random aggregate model was used to simulate the meso-structure of recycled concrete. The propagation process of cracks and the mechanical properties of uniaxial compression specimens of recycled concrete were simulated using finite element method (FEM) with damage model. The numerical simulation results agree well with the corresponding experimental results. The results show that the specimen usually damaged along the old interfacial transition zone and the new interfacial transition zone.

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Strengthening Effect of Graphene Oxide on Mechanical Properties of Interface Transition Zone of Recycled Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.852.49 ◽

2020 ◽

Vol 852 ◽

pp. 49-58

Author(s):

Kai Guo ◽

Jing Hai Zhou ◽

Ming Liu ◽

Lin Liu

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Elastic Modulus ◽

Transition Zone ◽

Structural Characteristics ◽

Interfacial Transition Zone ◽

Recycled Concrete ◽

Strengthening Effect ◽

Transition Zones ◽

The Mean

The micro-mechanical properties and micro-structural characteristics of the interfacial transition zones of recycled concrete with graphene oxide were studied by using nanoindentor. The results showed that the average elastic modulus and width of the interfacial transition zone of recycled concrete with graphene oxide between new paste matrix and natural aggregate were about 20GPa and 30-35μm, respectively; The mean elastic modulus and transition zone width of the interfacial transition zone between new paste matrix and old paste matrix was about 35GPa and 25-30μm, respectively. By analyzing and calculating the probability distribution of hydration products, it was found that the graphene oxide template increased the proportion of calcium silicate hydrate in the hydrate and enhanced the content of calcium hydroxide crystal group. Compared with ordinary recycled concrete, the elastic modulus distribution in the interfacial transition zone was more uniform and the microstructure was more stable. It can be concluded that graphene oxide can enhance the mechanical properties and microstructure of the interfacial transition zone of recycled concrete so as to improve the macroscopic mechanical properties of recycled concrete.

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