Mix-Designs of Concretes in Durable Reinforced and Prestressed Structures of a Viaduct for a Railway Train Connecting Venice with Cortina, in Italy
Mario Collepardi, Silvia Collepardi, Roberto Troli
Appears on pages(s):
Carbonation; Durability; Freezing-Thawing Cycles; Mix-Design; Sea-Water
In this paper, the mixture designs of the concrete in durable reinforced and prestressed structures of a viaduct for a railway train connecting Venice directly with Cortina are illustrated. Three mixture designs, based on the European Norms for the 100-year durable concrete reinforced or prestressed structures of the above construction, are developed as a function of the environmental region crossed by the viaduct of this railway train. The first region of the travel connects the Santa Lucia railway station in Venice with the mainland where the reinforced and prestressed concrete structures are exposed to tidal, splash, and spray zones of the close seawater. The second region crossed by the viaduct of the railway train is the oriental Po Valley exposed to air and rain and then to the penetration of CO2 with the risk of corrosion of the metallic reinforcements. The last region crossed by the viaduct of the railway train is a large area of up to 1,500 m (4,920 ft)-high mountains and is exposed in winter seasons to freeze-thaw cycles. A pozzolanic cement type CEM II-B/V 42.5 N, with about 20% Portland cement replaced by siliceous fly ash, is recommended to ensure that the alkali-reactive aggregates, if any, are neutralized by the presence of fly ash. For structural reasons, a cube characteristic strength (fcu/ck) of 50 MPa (7,250 psi) is prescribed for all the viaducts crossing the three regions.