Cracking caused by drying or autegenous shrinkage is a real risk for cementitious material and compromise its durability as crack may serve as intgression paths for gases and salts or might permit leaching. Due to special requirements as application thickness, spray application, etc. on the one hand and durability as well as strength on the other hand repair mortars show an increased shrinkage and crack probability, which is highly undesired. In this study it will be investigated wich are the consequences of shrinkage and cracking from the structural and construction point of view, as well as whether a combination of expansive and/or shrinkage reducing concrete admixture can improve deformation stability and increase crack resistance of mortars exposed to drying conditions.