Meso-scale modelling of the thermo-mechanical response for concrete with complex-shaped aggregates in early age

Qiu, Wenjing and Fu, Shaojun and Zhu, Jihua and Ye, Jianqiao (2022) Meso-scale modelling of the thermo-mechanical response for concrete with complex-shaped aggregates in early age. Construction and Building Materials, 323: 126485. ISSN 0950-0618

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Abstract

Self-restraint stress produced in early age is a matter of interest associated with cracking of concrete. Mesoscopic modelling nowadays is one of the effective approaches to investigate internal stresses, deformation, damage of concrete at much smaller scale. However, grid discretization and mesoscopic properties calibration are still challenging issues that prevent fast pre-processing and require extremely dense meshes for accurate solutions. In this paper, a thermo-mechanical model required only regular-element discretization is proposed by developing a diffuse meshing technique to analyze the evolution of self-restraint stress. Cross-scale numerical validations are carried out to calibrate the mesoscopic parameters, along with verifying the feasibility of the proposed model. Furthermore, the effect of simplified aggregate mesostructure on the thermo-mechanical behavior of concrete is evaluated through comparisons with the results obtained by considering complex-shaped aggregate using the proposed diffuse element model. The results show the thermo-mechanical mismatch between different components is the main reason for producing the self-restraint stress, and aggregate meso-structure have nonnegligible influence on the global response or local behavior.