A Simplified Mesoscale Approach for the Prediction of Drying Shrinkage of Concrete

The drying shrinkage of concrete is predicted in this study from shrinkage tests conducted on cement paste specimens, combined with mesoscale analysis of mortar and concrete images that were obtained from X-ray micro computed tomography (CT) scanning. A series of shrinkage tests were carried out on cement paste, mortar, and concrete prisms for a period of 6 months to generate input data and validate the model. The effect of aggregate size on drying shrinkage of concrete was also experimentally and numerically investigated. The proposed model uses a quadtree decomposition algorithm to convert digital images of mesostructures into meshes, which are then solved using the scaled boundary finite-element method. In the analysis, mortar was considered as a composite of viscoelastic cement paste and fine aggregates, whereas concrete was considered as a composite of viscoelastic mortar and elastic aggregates. A parametric study was carried out on mesostructures with various aggregate volume ratios to examine the ratio’s influence on shrinkage of concrete and to compare the proposed model with other simplified composite shrinkage models in the literature.