Abstract Silages are important juicy bulky feedstuff, that has irreplaceable role in nutrition of farm animals – cattle, pigs and horses. The silages are made of a fresh plant mass (e.g. corn, alfalfa, rape, clover or grass), that is in a chopped form in an exactly given way ensiled, i.e. in a tamped or pressed form without access of air subjected to a fermentation process. Within this process acid juices are created and enter into a construction of containers aimed for the ensilage process. These containers are mainly from a reinforced concrete. Influence of the silage on the concrete is a difficult process and it depends on several factors. From the point of view of durability/resistance to the silage effect, a concrete composition is a significant factor, the other factors are silage properties as well as time of a contact of the concrete with the silage. In this paper we describe findings on a state of 3 concrete compositions, which were repeatedly subjected to a corn silage for 3 years. In a 1-year interval, an effect of the silages on physico-mechanical properties of the concrete (e.g. strength, absorptivity, porosity) was observed. The highest resistance to effect of the silages in the course of time was proven for the concrete with a higher content of Portland cement.