When a professional plans and builds a structure, he should not only worry about defining the resistance of the concrete, but also the characteristics that the concrete should have so that the structure fulfills the conditions of use required for its intented life span. For this matter, it is fundamental to know the aggressiveness of the conditions to which the different structural elements will be exposed. We will now discuss special concretes that can be fabricated in order to achieve adequate durability of the structures. In recent years the study of the durability of these special concretes against chemical attack has been developed in most investigative centers in the country and abroad. Saline soils, as well as water with sulphates, represent a problem when in contact with concrete, due to the progressive deterioration caused by sulphate attack. When structural elements that will be subjected to high concentrations of sulphates are built, it is fundamental that a sufficiently waterproof concrete is built. As an additional requirement, and depending on the severity of the conditions, the appropriate Portland cement should be used.