Two highway tunnels in the Vitacura section of Santiago were recently added to the city’s highway network to provide much-needed additional capacity for heavily-traveled routes through the eastern part of the city. In part of the Costanera-Norte, a 30.4 km (19 mile) toll highway, the tunnels run in a north-south direction along the Mapocho River and are 12 m (40 feet) high and 5 m (16 feet) wide; each tunnel accommodates two lanes of traffic. The Costanera-Norte tunnel is 608 m (1,995 feet) long and the Costanera-Sur tunnel is 490 m (1,610 feet) long.
To ensure impermeability of the concrete to encroaching groundwater and environmental influences, PENETRON crystalline technology delivered the needed durability and waterproofing performance for the concrete used in the walls and drainage system of the new tunnels. A PENETRON ADMIX-Enhanced Shotcrete (PAES) mix was applied to the interior surface of the tunnel walls to quickly waterproof the interior and prevent any water penetration of the construction site. PENETRON ADMIX was mixed into the concrete for the subsequent concrete tunnel walls to ensure a permanently dry interior.