Open Access

ARTICLE

A Stochastic Multi-Scale Model for Prediction of the Autogenous Shrinkage Deformations of Early-age Concrete

S. Liu¹, X. Liu^2,3, Y. Yuan², P. F. He¹, H. A. Mang^2,4

1 Institute of Applied Mechanics, Tongji University, Shanghai, China.
2 Department of Geotechnical Engineering, Tongji University, Shanghai, China.
3 Corresponding author. Email: Xian.liu@tongji.edu.cn
4 Institute of Mechanics of Materials and Structures, Vienna University of Technology, Vienna, Austria.

Computers, Materials & Continua 2014, 39(2), 85-112. https://doi.org/10.3970/cmc.2014.039.085

Abstract

Autogenous shrinkage is defined as the bulk deformation of a closed, isothermal, cement-based material system, which is not subjected to external forces. It is associated with the hydration process of the cement paste. From the viewpoint of engineering practice, autogenous shrinkage deformations result in an increase of tensile stresses, which may lead to cracking of early-age concrete. Since concrete is a multi-phase composite with different material compositions and microscopic configurations at different scales, autogenous shrinkage does not only depend on the hydration of the cement paste, but also on the mechanical properties of the constituents and of their distribution. In this paper, a stochastic multi-scale model for early-age concrete is presented, which focuses on the prediction of autogenous shrinkage deformations. In this model, concrete is divided into three different levels according to the requirement of separation of scales. These levels are the cement paste, the mortar, and the concrete. A specific representative volume element (RVE) for each scale is described by introducing stochastic parameters. Different scales are linked by means of the asymptotic expansion theory. A set of autogenous shrinkage experiments on the cement paste, the mortar, and the concrete is conducted and used for validation of the developed multi-scale model. Furthermore, the influence of the type and the volume fraction of the aggregate on autogenous shrinkage is studied. Besides, a combined optimum of fine and coarse aggregates is determined. The analysis results show that the proposed model can effectively estimate the autogenous shrinkage deformations of concrete at early-age by taking the influence of the material composition and configuration into consideration.

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Keywords

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