Early-age cracking of cementitious materials jeopardizes their service life. A thorough understanding of the involved mechanisms is needed to mitigate cracking with effective and appropriate methods. One of the most common types of cracking is caused by plastic shrinkage, which can occur from time of casting and before the time of final set. This PhD dissertation is dedicated to poromechanics modeling of plastic shrinkage and cracking in fresh cementitious materials. The model is based on a generalized consolidation equation derived in this project, which includes the chemical shrinkage together with moisture flow according to Darcy’s law. This allows to predict deformations of concrete in the plastic phase due to self-weight consolidation and early-age drying using genuine experimental data as an input. Furthermore, plastic shrinkage cracking was studied by establishing a failure envelope, which requires the estimated pseudo-elastic limit as an input. Both models for moisture transfer and solid mechanics were implemented in COMSOL Multiphysics® software. The study was started by characterization of material properties, i.e. coefficient of permeability and bulk modulus in the bleeding state derived from the simple bleeding test, and was expanded to the material properties for the drying state, which included the determination of the water retention characteristic curve (WRCC) for fresh cementitious materials. Novel experimental methods were utilized for the model validation, including digital image correlation (DIC) system for measurements of three dimensional plastic shrinkage and Tempe cell and tensiometers for WRCC, together with the ASTM C1579-13 standard and X-ray radiography for crack quantification. According to the developed models, the plastic shrinkage cracking mechanisms were explained extensively and different mitigation strategies were analyzed according to the thorough understanding gained in the project.