Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics

Reliable models for structural materials are a vital issue. Hierarchical multiscale models for concrete, incorporating microstructural properties of the material, have been developed to predict the mechanical behavior. The present paper aims to study the major sources of uncertainty in the framework of multiscale modeling based on continuum micromechanics. The effect of uncertainy in input parameters on the Young's modulus of cement-based materials is studied systematically by means of a probabilistic multiscale modeling approach covering three length scales. Sensitivity and uncertainty analyses are adapted to assess the stochastic predictions of the multiscale model. The total order sensitivity indices are computed using the variance-based sensitivity analysis. The total uncertainty according to the adjustment factor approach, comprising the parameter uncertainty and the model uncertainty, is quantified, aiming at the comparison of two commonly utilized hydration models. Application of the probabilistic methodology reveals that the uncertainties of the model responses increase significantly during the upscaling process. Hence, considering the stochastic variability of the predicted mechanical properties is of utmost importance for the assessment and evaluation of the model responses.