Durable, functional, and aesthetically beautiful 

The Hangzhou Bay Bridge, opened in 2008, was once the world’s longest sea bridge at 36 kilometers. Though no longer holding that title, its dimensions remain impressive with 660 bridge arches and 7,000 piers anchored deep in the seabed supporting the structure that spans Hangzhou Bay on China’s east coast. Constructed with 800,000 tons of steel and 2.5 million tons of concrete, the bridge is designed to withstand wind speeds up to 230 kilometers per hour. 

To maintain the long-term load-bearing capacity of a bridge, it is crucial to prevent water and dissolved contaminants from penetrating the building material. Sea water and de-icing salts containing chloride-ions cause corrosion of reinforced steel by destroying their passivation layer. This leads to cracks in the concrete or in the worst case crumbling and loss of stability. 

Protectosil® corrosion protection from Evonik penetrates deep into the substrate, bonds at the molecular level, and thus protects concrete and steel. The passivation layer is strengthened and can regenerate , creating a lasting protective effect. "In the case of the Hangzhou Bay Bridge, our Protectosil® ensures that the reinforced concrete structure is protected from damage - even decades later," says Nico Freudl, Junior Marketing Manager at Evonik Silanes .  

Structures worldwide, including the Sydney Opera House, Paris’ Louvre, New York’s World Trade Center subway station, and Hawaii’s Ala Moana Shopping Center, have been treated with building protection products from the Protectosil® portfolio. 

The silane-based products offer comprehensive protection for a wide range of mineral substrates, like concrete, granite, natural stone, clinker, sandstone or brick. In addition to corrosion protection, they have a number of other effects that preserve valuable building fabric. 

An important effect of Protectosil® building protection products is hydrophobization. The molecules of the hydrophobing agents are very small and penetrate quickly and deeply into the substrate where they bond inseparably with the building material. This creates a water-repellent protective layer that permanently prevents moisture penetration. The advantage: the material remains breathable, so moisture can continue to escape from the inside to the outside. "Water absorption is reduced by more than 90 percent - even after 10 years of intensive use," Freudl explains.

Building facades and monuments require protection not only from moisture but also from unsightly traces left by mold, algae, moss, or soot. Our invisible Protectosil®‘easy-to-clean’ surface protection ensures easy removal of microorganisms and dirt. It even prevents their adherence altogether, preserving the clean and well-maintained appearance of buildings. 

Graffiti attacks on facades can pose an aesthetic and expensive challenge. Our specialized Protectosil® products offer reliable protection against spray attacks by preventing paint from penetrating the substrate and causing it to run off upon application, facilitating easier removal. 

Stone consolidation also serves an aesthetic purpose, as monuments are built to commemorate famous individuals or historical events for eternity. However, especially porous building materials are in danger of deterioration and unsightly efflorescence or discoloration. Protectosil® stone consolidation products protect natural stones from weathering and enhance their strength and stability, slowing the deterioration of historic buildings and preserving their structure. 

Therefore, it is clear that investing in Protectosil® building protection products pays off. The long-term protection prevents or minimizes damage to the building fabric. This extends the service life of the structures and thus helps to save resources, while maintenance costs are also significantly reduced. "Evonik's customized building protection solutions provide a win-win solution as they protect the environment and safeguard public and private investments," says Freudl.