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Bridge decks endure constant exposure to harsh environmental conditions and mechanical stresses, making them highly susceptible to deterioration over time. Effective waterproofing is essential to safeguard their structural integrity, ensuring durability, safety, and cost-efficiency in maintenance.
Content index
Why Bridge Decks Need to be Waterproofed
Exposure to deicing salts, water, snow, and temperature fluctuations
which can penetrate the deck and reach the reinforcement, accelerating corrosion and deterioration.
Aging of structure and reinforcement
can be significantly accelerated by environmental exposures, making waterproofing a critical maintenance measure to extend the lifespan of the bridge.
Failure to adequately waterproof a bridge deck can lead to severe consequences, including accelerated corrosion of reinforcement, reduced structural integrity, increased maintenance costs, and potentially hazardous conditions for bridge users.
Inadequate waterproofing can also compromise the durability and safety of the bridge, leading to a shortened service life and increased risk of failure.
Sika Bridge Deck Waterproofing System Types
Sika supplies mainly three different groups of bridge deck waterproofing systems using three different technologies.
As the regulations and project requirements differ from country to country, please consult your local Sika technical expert to find the best systems for your region.
1. Bitumen Waterproofing Systems
Strengths
Bitumen waterproofing systems, either torch-applied or self-adhesive, offer a proven and widely used solution for bridge decks. They are cost-effective, provide good waterproofing and protection performance with good elasticity and flexibility to handle minor structural movements and, aside from a few exceptions, it can be applied during the full year. Bitumen membranes also have good adhesion to the substrate and are compatible with different types of asphalt overlays.
Considerations
Bitumen systems can be sensitive to temperature fluctuations, becoming less flexible in cold conditions and potentially softening in extremely high temperatures. Therefore, it is important to select the most suitable bitumen waterproofing system as per country or region conditions. Over time, UV exposure can degrade the material, though this is less of an issue when applied beneath asphalt. Installation can be labor-intensive and may require torching, which poses safety risks if not handled properly.
Best for
- Projects with standard requirements where cost-efficiency is a priority and temperature extremes are not a major concern.
Typical system examples
SikaShield® bridge deck one-layer (EN 14695 & ZTV-ING 6-1)
Waterproofing system buildup composed of a “more sustainable and more performance” epoxy primer and one layer of APP-modified bitumen membrane
Key characteristics and advantages
- Epoxy primer / scratch coat as per ZTV-ING 6-1
- Improved adhesion between membrane and substrate
- Easy to apply
- Cost-effective
SikaShield® bridge deck two-layers (EN 14695 & RVS 15.03.11)
Waterproofing system buildup composed of an epoxy primer, one layer of SBS-modified bitumen membrane and one layer of APP-modified bitumen membrane
Key characteristics and advantages
- Epoxy primer offering extra layer of waterproofing and concrete protection
- Improved adhesion between membrane and substrate
- Easy to apply
- Cost-effective
SikaShield® bridge deck one-layer (EN 14695)
Waterproofing system buildup composed of a bitumen primer and one layer of SBS- or APP-modified bitumen membrane
Key characteristics and advantages
- Applicable with simple equipment / tools
- Very easy to apply
- Cost-effective
2. Hot-Spray Waterproofing Systems
Strengths
Hot-spray waterproofing systems are highly flexible and ideal for complex geometries or irregular surfaces. The liquid-applied membrane forms a seamless and fully bonded layer, which ensures excellent crack-bridging properties. This method is fast-curing, allowing for rapid installation, reducing downtime, and enabling quick overlaying with asphalt. The strong adhesion to the substrate provides durability, even under dynamic loads and vibrations typical on bridge decks.
Considerations
The application of hot-spray systems requires specialized equipment and trained personnel, making the installation process more dependent on skilled labor. Additionally, weather conditions can affect the application, requiring a dry and clean surface, which may not always be available in all climates.
Best for
- Projects that require quick turnarounds, seamless waterproofing, and flexibility for complex structures.
Typical system examples
Sikalastic® Bridge 5000
Polyurethane-based waterproofing multi-layered systems composed of a primer with broadcast sand, a fast cure waterproofing membrane, and adhesion promoter with broadcast sand and a tack coat
Key characteristics and advantages
- Long track record of system being used since over 20 years
- Excellent adhesion and shear resistance with asphalt pavement
- Fast-setting deck system suitable for horizontal and vertical areas
Sikalastic® 851 System
Polyurethane (PU) based bridge deck multi-layered coating system composed of a primer, a fast cure waterproofing membrane and a wear coat plus pellets for a high-performing adhesion to hot-rolled or mastic asphalt
Key characteristics and advantages
- Use of Sikalastic® M 851 offers the ability to apply over 1,000 m² area in one shift (depending on applicator's equipment and experience), which reduces labor costs during installation
Sikalastic® Traffic 2304
Polyurethane (PU) based bridge deck multi-layered coating system composed of a primer and broadcast sand, a fast cure waterproofing membrane and a tack coat, overlaid with mastic asphalt
Key characteristics and advantages
- TL/TP – ING Part 6 (formerly ZTV-BEL B 3)
- Hot spray applied membrane Sikalastic® M 811 offers rapid curing, typically 10 – 20 seconds gel time for minimal downtime and a quick installation process
3. Cementitious Waterproofing Systems
Strengths
Cementitious waterproofing systems are durable and resistant to chemical attacks, making them ideal for bridge decks exposed to harsh environments like de-icing salts. They can also offer high compressive strength, making them an excellent option for projects that need enhanced structural integrity. These systems are easy to spray apply and don’t require specialized equipment, making them more accessible for a wider range of projects.
Considerations
In general, cementitious systems are rigid, offering limited flexibility and crack-bridging capacity, which can be a disadvantage in structures that experience movement or vibrations. They are more prone to cracking over time due to their brittle nature. However, the newly developed Sikalastic® -6100 FX perfectly overcome this weakness, showing exceptional elastic features.
Best for
- Projects with standard requirements where movement or flexibility is not a primary concern
Innovative solution
Sikalastic®-6100 FX
One-component, cement based, elastic and flexible, lightweight and fast curing membrane for waterproofing and concrete protection
Key characteristics and advantages
- High performance: high durability, concrete protection, and crack-bridging thanks to its excellent elasticity
- Sustainable: low consumption, less material, less transport, and less waste; recycled
- Easy to apply: one-component, 2 mm thickness, no VOC, can be hand and spray applied
- Cost-effective: direct application of ashpalt - no additional adhesion promoter needed
Why Sika Waterproofing Systems are the Best Choice
More sustainable due to use of bio-polymers
In combination with G-Type epoxy resins will lead to over 20% CO2 reduction
Low CO2 using G-type epoxy resins
Improved performance through Sika patented technology
Significantly increased
blush-resistance extends application window and reduces risk of claims
Long track-record of over 20 years
Proven performance per external test certificates and approvals by BAST, NEXCO, EOTA, and BBA HAPAS
How to Specify the Right Waterproofing for Your Bridge Project
Specifying the correct waterproofing system for a bridge deck requires a thorough understanding of various factors that influence the performance and longevity of the system.
By carefully considering these factors, you can specify the right waterproofing system that will ensure the longevity, safety, and performance of your bridge deck.
Here are the key considerations:
Consider the type of bridge structure (e.g., concrete, steel, composite) and its specific needs. Different structures may require different waterproofing approaches and materials.
Ensure that the selected waterproofing system is resistant to any chemicals or UV radiation it may be exposed to. This is particularly important in industrial areas or regions with high UV exposure.
Compliance with local standards and regulations is crucial. Ensure that the chosen waterproofing system meets all relevant standards and guidelines for bridge construction and maintenance.
Evaluate the overall cost of the waterproofing system, including material, labor, and maintenance expenses. While it is important to stay within budget, prioritize long-term performance and durability over short-term savings.
Evaluate the typical weather conditions in the area, including temperature ranges, precipitation levels, and freeze-thaw cycles. These factors will influence the choice of waterproofing materials and their application.
Determine the desired service life of the waterproofing system. This will guide the selection of materials and application methods that can meet the longevity requirements of the bridge.
Consider the expected traffic load on the bridge. Heavy traffic can accelerate wear and tear on the waterproofing system, necessitating the use of more robust and durable materials.
Consider the timing of the project. Some waterproofing materials may require specific weather conditions for application, while others may need longer curing times. Plan accordingly to avoid delays.
The geographic location of the bridge impacts the choice of waterproofing system due to varying environmental conditions such as humidity, temperature, and exposure to deicing salts.
Assess the environmental conditions, including potential exposure to chemicals, pollutants, or UV radiation, which can affect the performance and durability of the waterproofing system.
Identify any constraints related to the application process, such as limited access, traffic management requirements, or specific project timelines. These constraints can impact the choice of waterproofing materials and methods.
