WATERPROOFING OF BRIDGES, TUNNELS, OVERPASSES AND OTHER TRANSPORT NETWORK FACILITIES WITH POLYUREA

A huge number of road infrastructure facilities and structures, such as bridges, tunnels, and interchanges, are constantly subjected to enormous loads, significantly reducing their ultimate strength and service life. Among other destructive factors, water ranks high in negative impact. It is everywhere, undermining foundations, penetrating the porous structure of bridge and tunnel structures, corroding metal parts, and reducing the stability of the road surface. The only way to avoid this problem is to thoroughly waterproof all parts of road and bridge structures.

Waterproofing Requirements for Road Elements, Bridges, and Tunnels

It seems like the task couldn't be simpler, but even here there are pitfalls. The fact is that waterproofing of transport hubs must meet specific requirements. Not all materials used in modern construction can withstand these conditions. Thus, the main requirements for waterproofing materials are:

• watertightness
• high frost resistance,
• high adhesion,
• tensile and fracture strength,
• resistance to aggressive environments,
• abrasion resistance,
• resistance to elevated temperatures.

Moreover, the high adhesive capacity of the waterproofing must be directed in both directions: both toward the base on which the material is laid and outward, toward the top, covering layer. This is a crucial factor in ensuring the strength of the entire structure.

Polyurea – The best waterproofing in bridge construction and tunnel construction. Complex systems capable of providing both waterproofing and corrosion protection for metal parts are considered the best materials for waterproofing transport hubs, bridges, and tunnels. This is especially important for reinforced concrete structures containing a significant percentage of metal parts. Polyurea is currently considered the most suitable waterproofing material for all these conditions. In addition to its other beneficial properties required for road construction, polyurea possesses another unique property. This is its so-called multivariability, which allows for the creation of a customized composition for each type of structure, containing the maximum range of necessary characteristics. Polyurea also serves as a universal composition for road surface repairs.

Polyurea Properties

• Polyurea's high mechanical strength significantly increases the service life of structures.
• Its resistance to abrasive wear makes it virtually indestructible.
• Its elasticity and high tensile strength prevent damage to the waterproofing coating when cracks form in the substrate.
• The spray application method creates a seamless, sealed waterproofing layer around the object.
• Its high resistance to attack by aggressive chemical environments. This quality is especially useful on roads where the coating is constantly attacked by gasoline, oil, and other substances.
• Polyurea provides reliable corrosion protection for metal parts of structures.
• Polyurea is not susceptible to UV radiation and does not lose its properties even with prolonged exposure.
• Polyurea can withstand quite extreme temperatures. It remains stable in temperatures ranging from -40 to +220°C.
• The polyurea spray method allows for the treatment of large surfaces in a short time. Two to three people can treat up to 1,500 m² of surface in a single workday.
• High adhesive strength allows polyurea to be used on structures made of any material. Importantly, polyurea adhesion is bidirectional. It ensures not only a tight fit to the substrate but also excellent adhesion to the topcoat material.
• The rapid curing of polyurea allows the next stage of work to begin just 12 hours after completion of treatment.
• Polyurea has a high durability. The service life of waterproofing without any repair work can reach 50 years.

When waterproofing road elements and structures, a certain sequence of actions must be followed:

• Assess the condition of the base
• Preliminary preparation of the base
• Coating the base with a primer
• Quality control of the applied primer layer
• Directly spraying a layer of polyurea
• Checking the quality of the waterproofing coating
• Correcting defects, if any,
• Applying an adhesion coating (if necessary, apply another layer over the waterproofing)
• Laying the road surface (if it is a roadbed)

Preliminary preparation of the base includes work on calking large cracks, wide joints, and possible holes, cavities, and other elements that could, over time, cause insulation damage. Furthermore, the base must be cleaned of any contaminants, including degreasing.