Experimental tests for the evaluation of the durability of a tunnel under construction

A wide experimental campaign has been planned to evaluate the durability of prefabricated segments of reinforced concrete used for a flat railway tunnel, under construction. The prefabricated segments were made with six different concrete mixes, that slightly differ for the composition in terms of wa-ter/cement ratio and type of aggregate. The campaign includes inspections to measure the concrete cover thickness and to evaluate the corrosion conditions of the bars, and the coring of specimens to evaluate the concrete properties, as the resistance to the carbonation penetration. These results will be used to evaluate, in a probabilistic manner, the service life that can be guaranteed in the segments having the same composition. This paper reports the results of the accelerated carbonation test and the preliminary evaluation of the service life.