EP22 Campaccio

These are works to preserve and modernize the existing route and widen the two Campaccio viaducts for a total section of 1.8 km, along the N02 highway north of the Mendrisio interchange, from km 8.200 to km 10.000.

The work, carried out by an average of 20 CSC Costruzioni employees with peaks of 40, consists of upgrading the structures, roadway and safety barriers, correcting the cross slopes of the route in accordance with current regulations, in particular with the creation of rigid banks on the Campaccio viaducts, upgrading the rainwater collection network and building two new roadway water treatment plants (SABA), as well as upgrading the operating and safety equipment (BSA).

The casting of fiber-reinforced ultra-high-performance concrete (CFAP) on the deck of the phase 3E viaduct at the EP22 site in Campaccio, Ticino, involves a series of complex stages in order to enable the optimal fabrication of a 4cm-thick CFAP reinforced cap for reinforcing the existing platform and associated widening.

The preparatory stages of the surface involve mechanical roughening of the platform and subsequent cleaning with high-pressure water. Finally, the reinforcement of the stage to be cast overnight is laid.

The CFAP production plant is installed downstream in the area adjacent to the paving to limit transshipment time as much as possible; the mobile plant uses premixed Big-Bags whose recipe has been previously certified.

Traffic is interrupted on the entire north-south roadway to prevent vibrations created by adjacent circulating traffic from disrupting the newly placed material.

CFAP is transported by dump truck from the plant mouth to the casting stage. The 11 CS Consortium employees can then spread the 4cm of CFAP evenly by vibrating screed.

Post-treatment involves applying a layer of Sika Antisol E-20, wetting the surface and covering it with plastic sheeting to prevent over-drying of the surface.

Ultra-high performance fiber-reinforced concrete (CFAP) has very interesting characteristics, such as strengths, both compressive and tensile, that are much higher than conventional concrete. In compression, the minimum strength at 28 days is 120 MPa, but in practice much higher values are reached. Moreover, after only 24 hours, the strength is already above 70MPa. In tensile strength, UA-type CFAP achieves a minimum strength of 7 MPa and is mainly characterized by work hardening behavior, which, if desired, easily allows the fabrication of structural elements without slow reinforcement.

The high strengths just mentioned and the very small diameter aggregates allow the construction of very thin elements, even with special shapes, with important material and weight savings, as well as very interesting architectural potential.

Last but not least, CFAP has a very dense and compact structure that makes it waterproof and significantly increases its durability over time.