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Mesoscale investigation on concrete creep behaviors based on discrete element method
Highlights A multi-phase concrete creep model considering the real surface topography and geometric shapes of aggregate were developed. The sensitivity of Burgers model parameters was conducted. A contact-force-based method was proposed to quantitatively assess the effect of ITZ on creep. Contact network, force-chain probability distribution, and meso-fabric anisotropy were assessed to explain the creep mechanism of concrete.
Abstract Studying creep behaviors of concrete materials at a mesoscale level is crucial to understanding their mechanism. Discrete element method (DEM) could provide an effective numerical tool to explain the mesoscale mechanism of concrete materials. In this study, the creep characteristics of concrete are analyzed by combining DEM and Burgers model. Firstly, a multi-phase concrete numerical model consisting of matrix, aggregate, and interfacial transition zone (ITZ) was developed. Then, the sensitivity of the Burgers model parameters was conducted. Finally, to investigate concrete creep behaviors at a mesoscale level, a series of numerical simulations were carried out. Simulation results show that Burgers model can reflect the creep behavior of concrete well. The porosity gradually decreased as the loading duration increase, and deceleration became stable at the later stage. The creep contribution of ITZ decreases with the increase of the ratio of ITZ strength to matrix strength. Force-chain strength in ITZ was greater than that in matrix, and viscoelastic sliding or squeezing occurs at Burger contact. Meanwhile, the direction distribution of force-chain strength in the matrix is regular and the main direction of the contact distribution is about 90° or 270°. In addition, the probability function of contact force is exponential, and the strength probability distribution of matrix and ITZ contact reached the peak at 0.7 and then decreased, and the proportion of strong contact and weak contact in matrix and ITZ was about 70% and 30%, respectively. The current study can bridge the gap between simulation and experimental research.
Mesoscale investigation on concrete creep behaviors based on discrete element method
Highlights A multi-phase concrete creep model considering the real surface topography and geometric shapes of aggregate were developed. The sensitivity of Burgers model parameters was conducted. A contact-force-based method was proposed to quantitatively assess the effect of ITZ on creep. Contact network, force-chain probability distribution, and meso-fabric anisotropy were assessed to explain the creep mechanism of concrete.
Abstract Studying creep behaviors of concrete materials at a mesoscale level is crucial to understanding their mechanism. Discrete element method (DEM) could provide an effective numerical tool to explain the mesoscale mechanism of concrete materials. In this study, the creep characteristics of concrete are analyzed by combining DEM and Burgers model. Firstly, a multi-phase concrete numerical model consisting of matrix, aggregate, and interfacial transition zone (ITZ) was developed. Then, the sensitivity of the Burgers model parameters was conducted. Finally, to investigate concrete creep behaviors at a mesoscale level, a series of numerical simulations were carried out. Simulation results show that Burgers model can reflect the creep behavior of concrete well. The porosity gradually decreased as the loading duration increase, and deceleration became stable at the later stage. The creep contribution of ITZ decreases with the increase of the ratio of ITZ strength to matrix strength. Force-chain strength in ITZ was greater than that in matrix, and viscoelastic sliding or squeezing occurs at Burger contact. Meanwhile, the direction distribution of force-chain strength in the matrix is regular and the main direction of the contact distribution is about 90° or 270°. In addition, the probability function of contact force is exponential, and the strength probability distribution of matrix and ITZ contact reached the peak at 0.7 and then decreased, and the proportion of strong contact and weak contact in matrix and ITZ was about 70% and 30%, respectively. The current study can bridge the gap between simulation and experimental research.
Mesoscale investigation on concrete creep behaviors based on discrete element method
Ma, Gang (author) / Xie, Youjun (author) / Long, Guangcheng (author) / Tang, Zhuo (author) / Zhou, Xiang (author) / Zeng, Xiaohui (author) / Li, Jiangteng (author)
2022-05-24
Article (Journal)
Electronic Resource
English
Thermoviscoelastic Analysis of Concrete Creep at Mesoscale
| British Library Conference Proceedings | 2016