scholarly journals Application of Base Force Element Method to Mesomechanics Analysis for Recycled Aggregate Concrete

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yijiang Peng ◽  
Yinghua Liu ◽  
Jiwei Pu ◽  
Lijuan Zhang
Keyword(s):  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Triangular Element ◽  
Aggregate Model ◽  
Energy Principle ◽  
Aggregate Concrete ◽  
Tension Tests ◽  
Random Aggregate ◽  
Force Element ◽  
Element Method

The base force element method (BFEM) on potential energy principle is used to analyze recycled aggregate concrete (RAC) on mesolevel. The model of BFEM with triangular element is derived. The recycled aggregate concrete is taken as five-phase composites consisting of natural coarse aggregate, new mortar, new interfacial transition zone (ITZ), old mortar, and old ITZ on meso-level. The random aggregate model is used to simulate the mesostructure of recycled aggregate concrete. The mechanics properties of uniaxial compression and tension tests for RAC are simulated using the BFEM, respectively. The simulation results agree with the test results. This research method is a new way for investigating fracture mechanism and numerical simulation of mechanics properties for recycled aggregate concrete.

scholarly journals Numerical Simulation of Recycled Concrete Using Convex Aggregate Model and Base Force Element Method

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yijiang Peng ◽  
Hao Chu ◽  
Jiwei Pu
Keyword(s):  
Damage Model ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Model ◽  
Energy Principle ◽  
Force Element ◽  
Damage Processes ◽  
Random Convex ◽  
Element Method

By using the Base Force Element Method (BFEM) on potential energy principle, a new numerical concrete model, random convex aggregate model, is presented in this paper to simulate the experiment under uniaxial compression for recycled aggregate concrete (RAC) which can also be referred to as recycled concrete. This model is considered as a heterogeneous composite which is composed of five mediums, including natural coarse aggregate, old mortar, new mortar, new interfacial transition zone (ITZ), and old ITZ. In order to simulate the damage processes of RAC, a curve damage model was adopted as the damage constitutive model and the strength theory of maximum tensile strain was used as the failure criterion in the BFEM on mesomechanics. The numerical results obtained in this paper which contained the uniaxial compressive strengths, size effects on strength, and damage processes of RAC are in agreement with experimental observations. The research works show that the random convex aggregate model and the BFEM with the curve damage model can be used for simulating the relationship between microstructure and mechanical properties of RAC.

Numerical Simulation on Damage and Failure of Recycled Aggregate Concrete with a Lattice Model

2009 ◽  
Vol 417-418 ◽  
pp. 689-692 ◽  
Author(s):  
Jian Zhuang Xiao ◽  
Qiong Liu ◽  
Vivian W.Y. Tam
Keyword(s):  
Lattice Model ◽  
Structural Damage ◽  
Fortran Program ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Model ◽  
Mixture Ratio ◽  
Aggregate Concrete ◽  
Damage And Failure ◽  
Random Aggregate

A random aggregate model of recycled aggregate concrete is developed in this paper on the base of a mixture ratio. Combining a lattice model with random aggregate of recycled aggregate concrete, lattice elements in the lattice model of recycled aggregate concrete can be classified into five types: (1) nature aggregate, (2) old hardened mortar, (3) new hardened mortar, (4) old interface transition zone (ITZ), and (5) new ITZ. The fundamental mechanical parameters of the lattice elements are chosen from the authors’ test as well as other references. A FORTRAN program of the lattice model is then written with basic theories of finite element method (FEM) for simulating the meso-structural damage of recycled aggregate concrete under uniaxial compression.

scholarly journals Numerical Studies on Damage Behavior of Recycled Aggregate Concrete Based on a 3D Model

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 355
Author(s):  
Yao Wang ◽  
Huawei Zhao ◽  
Minyao Xu ◽  
Chunyang Wu ◽  
Jiajia Fu ◽  
...  
Keyword(s):  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Energy Principle ◽  
Aggregate Concrete ◽  
Numerical Studies ◽  
Weak Points ◽  
Force Element ◽  
Gaussian Integral ◽  
Major Factors ◽  
Weak Zones

This paper develops a 3D base force element method (BFEM) based on the potential energy principle. According to the BFEM, the stiffness matrix and node displacement of any eight-node hexahedral element are derived as a uniform expression. Moreover, this expression is explicitly expressed without a Gaussian integral. A 3D random numerical model of recycled aggregate concrete (RAC) is established. The randomness of aggregate was obtained by using the Monte Carlo random method. The effects of the recycled aggregate substitution and adhered mortar percentage on the elastic modulus and compressive strength are explored under uniaxial compression loading. In addition, the failure pattern is also studied. The obtained data show that the 3D BFEM is an efficient method to explore the failure mechanism of heterogeneous materials. The 3D random RAC model is feasible for characterizing the mesostructure of RAC. Both the substitution of recycled aggregate and the percentage of adhering mortar have a non-negligible influence on the mechanical properties of RAC. As the weak points in the specimen, the old interfacial transition zone (ITZ) and adhered mortar are the major factors that lead to the weakened properties of RAC. The first crack always appears in these weak zones, and then, due to the increase and transfer of stress, approximately two-to-three continuous cracks are formed in the 45°direction of the specimen.

Mesoscopic numerical analysis of dynamic tensile fracture of recycled concrete

2020 ◽  
Vol 37 (6) ◽  
pp. 1899-1922 ◽  
Author(s):  
Liping Ying ◽  
Yijiang Peng ◽  
Mahmoud M.A. Kamel
Keyword(s):  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Failure Pattern ◽  
Recycled Aggregate ◽  
Tensile Fracture ◽  
Aggregate Model ◽  
Element Mesh ◽  
Content Type ◽  
Random Aggregate ◽  
Force Element

Purpose Based on the random aggregate model of recycled aggregate concrete (RAC), this paper aims to focus on the effect of loading rate on the failure pattern and the macroscopic mechanical properties. Design/methodology/approach RAC is regarded as a five-phase inhomogeneous composite material at the mesoscopic level. The number and position of the aggregates are modeled by the Walraven formula and Monte–Carlo stochastic method, respectively. The RAC specimen is divided by the finite-element mesh to establish the dynamic base force element model. In this model, the element mechanical parameters of each material phase satisfy Weibull distribution. To simulate and analyze the dynamic mechanical behavior of RAC under axial tension, flexural tension and shear tension, the dynamic tensile modes of the double-notched specimens, the simply supported beam and the L specimens are modeled, respectively. In addition, the different concrete samples are numerically investigated under different loading rates. Findings The failure strength and failure pattern of RAC have strong rate-dependent characteristics because of the inhomogeneity and the inertial effect of the material. Originality/value The dynamic base force element method has been successfully applied to the study of recycled concrete.

scholarly journals Micromechanical Numerical Modelling on Compressive Failure of Recycled Concrete using Discrete Element Method (DEM)

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4329
Author(s):  
Xin Tan ◽  
Zhengbo Hu ◽  
Wengui Li ◽  
Suhua Zhou ◽  
Tenglong Li
Keyword(s):  
Discrete Element Method ◽  
Numerical Simulations ◽  
Discrete Element ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Image Correlation ◽  
Recycled Aggregate ◽  
Nanoindentation Test ◽  
Aggregate Concrete ◽  
Element Method

This paper investigates the failure processes of recycled aggregate concrete by a model test and numerical simulations. A micromechanical numerical modeling approach to simulate the progressive cracking behavior of the modeled recycled aggregate concrete, considering its actual meso-structures, is established based on the discrete element method (DEM). The determination procedure of contact microparameters is analyzed, and a series of microscopic contact parameters for different components of modeled recycled aggregate concrete (MRAC) is calibrated using nanoindentation test results. The complete stress–strain curves, cracking process, and failure pattern of the numerical model are verified by the experimental results, proving their accuracy and validation. The initiation, growth, interaction, coalescence of microcracks, and subsequent macroscopic failure of the MRAC specimen are captured through DEM numerical simulations and compared with digital image correlation (DIC) results. The typical cracking modes controlled by meso-structures of MRAC are concluded according to numerical observations. A parameter study indicates the dominant influence of the macroscopic mechanical behaviors from the shear strength of the interfacial transition zones (ITZs).

scholarly journals Application of Base Force Element Method to Mesomechanics Analysis for Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yijiang Peng ◽  
Yao Wang ◽  
Qing Guo ◽  
Junhua Ni
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fracture Process ◽  
Damage Mechanics ◽  
Hardened Cement ◽  
Aggregate Model ◽  
Random Aggregate ◽  
Random Aggregate Model ◽  
Force Element ◽  
Element Method

The base force element method (BFEM) on damage mechanics is used to analyze the compressive strength, the size effects of compressive strength, and fracture process of concrete at mesolevel. The concrete is taken as three-phase composites consisting of coarse aggregate, hardened cement mortar, and interfacial transition zone (ITZ) on mesolevel. The random aggregate model is used to simulate the mesostructure of concrete. The mechanical properties and fracture process of concrete under uniaxial compression loading are simulated using the BFEM on damage mechanics. The simulation results agree with the test results. This analysis method is the new way for investigating fracture mechanism and numerical simulation of mechanical properties for concrete.

Effects of Recycled Aggregate Replacement Rate on Compression Mechanical Behavior of Concrete Based on Base Force Element Method

2021 ◽  
Vol 894 ◽  
pp. 121-126
Author(s):  
Li Ping Ying ◽  
Yi Jiang Peng
Keyword(s):  
Failure Process ◽  
Strain Curve ◽  
Simple Algorithm ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Test Results ◽  
Force Element ◽  
Element Method

A meso-analysis method which is derived from the base force element method (BFEM) was proposed for recycled aggregate concrete (RAC). A simple algorithm was used to generate the convex recycled concrete aggregate (RCA) model. Uniaxial compression numerical simulations were carried out on the numerical specimens with different replacement rates of RCA. The model predictions were in a good agreement with the test results. The proposed method is very promising. It can totally predict the full stress-strain curve of RAC, as well as the failure process and failure mode, including strain softening and strain localization.

scholarly journals Modeling the Failure Pattern of Prenotched Recycled Aggregate Concrete Using FEM on Complementary Energy Principle

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yao Wang ◽  
Gang Zong ◽  
Juan Liu ◽  
Chunyang Wu ◽  
Minyao Xu ◽  
...  
Keyword(s):  
Crack Path ◽  
Numerical Models ◽  
Recycled Aggregate Concrete ◽  
Failure Pattern ◽  
Recycled Aggregate ◽  
Complementary Energy ◽  
Energy Principle ◽  
Compliance Matrix ◽  
Aggregate Concrete ◽  
Complementary Energy Principle

The reuse of recycled aggregate concrete (RAC) is being researched all over the world and lots of works are focused on the notched specimen to study the crack path of RAC. A mathematical algorithm of RAC meshing was presented to explore the failure pattern in RAC. According to this algorithm, the interfacial transition zone can be defined to be an actual thickness at the micron level. Further, a new finite element method (FEM) on the complementary energy principle was introduced to simulate the mechanical behavior of RAC’s mesostructure. The compliance matrix of the element with any shape can be calculated and expressed to be a uniform and explicit expression. Several numerical models of RAC were established, in which the effecting factors of the prenotch size, thickness of ITZ, and the distance from the prenotch to the aggregate were taken into account. Hereafter, these RAC models were subjected to uniaxial tension. The effect of the aforementioned factors on the crack path was simulated. The simulated data manifest that both the mesh mode of RAC and the FEM on complementary energy principle are effective approaches to explore the failure pattern of RAC. The size of the prenotch, thickness of ITZ, and distance from the prenotch to the recycled aggregate have a powerful influence on the path and distribution of the isolated crack, width and length of the crack path, and the shape and path of continuous cracks, respectively.

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