This paper analyzes influence of additives for crystallization on mechanical and durability properties of concrete. The paper is divided into theoretical and experimental part. Theoretical part covers state of the art about additives for crystallization in concrete, some examples of work so far and comments on their results. Theoretical part also covers some practical applications of these supplements. With experimental part it is included all tests for mechanical and durability properties od concrete with additive for crystallization. Percentage dosage of the additive is 1 % by weight of cement. Four concrete mixtures were designed, two as control and two with additive for crystallization, with difference in compressive strength of the concrete. The main objectives for this study is to test effect of additives for crystallization with a view to make waterproof concrete. Tests that were performed are water pressure test, compressive strength, modulus of elasticity, capillary absorption and diffusion od chloride in concrete. Based on the work there are some recommendations for practical application in concrete constructions.