Throughout history, bridges have always been important, valuable structures in their own right. By their very nature, bridges are built in a variety of areas where the topography, ground conditions, or other existing structures and developments are unsuitable for conventional pathways, roads or railway construction. Therefore, bridges are found in the most challenging, exposed environments.
Modern bridges built using reinforced concrete or steel often require a service lifespan of more than 100 years. Recent surveys in Europe and North America have shown that the majority of existing bridges already exhibit significant degrees of degradation. Many of them are therefore in need of substantial and often urgent repair and refurbishment.
Systems Plus Knowhow
Sika provides full support to bridge owners, architects, engineers, and contractors with necessary technical advice and assistance to ensure a successful project. In particular for refurbishment projects, this includes assistance throughout the process, from the initial survey and assessment, root cause diagnosis, specification writing, detailing, method statements, on-site quality control, and practical application assistance. For new construction, Sika can offer support to design structures for long service life. Sika’s expertise can make a significant contribution to minimizing the total project cost over the full defined service life-cycle.
Sika today provides a complete range of innovative products and systems specially designed to solve all challenging requirements in differing bridge projects anywhere in the world.
Concrete admixtures
Watertight joint systems
Liquid applied waterproofing membranes
Concrete repair systems
Corrosion inhibitors
Post-tensioning systems
Bridge Exposures
Water can penetrate naturally through the capillary pore structures of reinforced concrete. In areas of carbonated concrete, or where there is a high chloride content on the surface of the steel reinforcing bars, reinforcement corrosion, cracks or spalling can occur on the surface.
Overloading due to increasing traffic loads, inadequate design, damage to the structure, stress/fatigue failure, earthquake effects, or any other mechanical impact such as vehicle impact, can all exceed or reduce the load capacity of the structure.
By their nature and locations, bridges are subjected to a wide variation of temperatures between day and night/winter and summer conditions, or between different sides or surfaces of the structure. These frequent cycles result in thermal stresses and movement in the concrete structure that can also result in cracks.
Carbon Dioxide (CO²) reacts with the Calcium Hydroxide (Ca(OH)²) in the pore liquid of the cement matrix of concrete structures and deposits as calcium carbonate (CaCO³). This process known as carbonation reduces the protection of embedded steel reinforcement, when the process reaches the reinforcement bars.
Chlorides come from de-icing salts used in winter, or from saltwater in marine environments. They can penetrate the concrete structure and once they reach the reinforcement bars, they can locally destroy the passivation film causing fast pitting corrosion.
The freeze-thaw process creates stresses in the concrete matrix due to the expansion of free water in the capillary pores during freezing conditions; this can result in the scaling of the surface of poor quality concrete. This action is also greatly accelerated by the presence of chlorides in the water.
Concrete elements submerged in water such as the bridge piers or columns are continuously exposed to erosion and abrasion of their surfaces. Damage occurs from the action of fast-flowing water, and the particles of sand or other solid materials in the water.
Fire due to traffic accidents, for example, can result in a reduction of the structural integrity of any of the concrete elements including the columns, decks or precast segments, etc.
What Causes Damage and Deterioration to Bridges?
| Type of Deterioration | Root Cause |
|---|---|
| Steel Reinforcement Corrosion |
|
| Structural Steel Corrosion |
|
| Deck Corrosion (Reinforced concrete or steel deck) |
|
| Leaching / Efflorescence |
|
| Concrete Spalling |
|
| Structural Cracks |
|
| Non-Structural Cracks |
|
| Scaling of Concrete Surface |
|
1. Concrete Repair
Repairing damaged concrete is one of the primary requirements in the maintenance of concrete bridges. Localized spalling or full surface scaling of concrete surfaces has to be repaired with durable concrete repair materials. A sound and correctly repaired concrete substrate is also the basic requirement for any additional waterproofing, protection or strengthening systems to be applied.
Sika provides an extensive range of thoroughly tested and proven repair materials and systems based on different technologies for each specific requirement and situation. These include bonding and corrosion protection primers, hand and machine applied repair mortars, suitable for the vertical and overhead application, semi-fluid mortars for efficient bridge deck repairs, plus combined surface leveling and protection mortars, not requiring additional protective treatments (EpoCem®-technology).
Thin-layer repair system for bridge decks:
Bonding bridge primer for large area repairs (where relevant): SikaTop® Armatec®-110 EpoCem®, Sikadur®-32
Hand applied repair mortars: Sika MonoTop®-622 F, Sika Top®-122 Plus, SikaQuick®-1000, SikaQuick®-2500, King RS-S2
Self-levelling, epoxy modified, cement-based levelling mortars: Sikafloor®-81, Sika Top®-121 Plus
Concrete: Sikacrete®-211 Flow plus, King MS-S10/S6, King FA S6/S10, King LM S6/S10, King RS S6/S10
Structural concrete repair system for columns and beams:
Bonding primer (where relevant): SikaTop® Armatec®-110 EpoCem®
Hand applied repair mortars: Sika MonoTop®- 623 F, Sika Top®-123 Plus/-123 FL
Ready to use-cement-based concrete: Sikacrete®-08 SCC, King MS-S10/S6 SCC, King RS S6/S10 SCC
Wet spray machine applied repair mortars: SikaRepair®-225
Structural concrete repair systems for soffits and other surfaces under live dynamic loading:
Bonding bridge primer: SikaTop® Armatec®-110 EpoCem®
Hand or machine applied repair mortar: Sika MonoTop®- 623 F, Sika Top®-123 Plus/-123 FL
2. Structural Strengthening
If the existing steel reinforcement is reduced in capacity due to corrosion, if the traffic loads are increased (i.e. permissible axle weights), or if the structural design or seismic resistance needs improvement, then reinforced concrete bridges have to be strengthened.
Sika has been involved in structural strengthening since the development of the technology in the 1960’s using bonded steel plates. Since 1991, Sika has also been a pioneer with the development of carbon fiber reinforced polymer (CFRP) based structural strengthening systems. As a leader in strengthening all types of reinforced concrete structures, Sika provides a full range of fully tested and approved strengthening systems.
Strengthening systems for shear strengthening of beams and columns, consisting of Sikadur® structural epoxy adhesives and:
Prefabricated L-shaped plates – Sika CarboShear L for application on rectangular T-beams
SikaWrap® fabric strengthening system based on unidirectional carbon and glass fibers, for application on beams and beam-column joints
Structural strengthening systems for the flexural strengthening of bridge decks, beams, and girders, consisting of Sikadur® structural epoxy adhesives and:
The carbon fiber reinforced polymer-based, pultruded plate system Sika CarboDur®, available with different E-moduli and in various dimensions, for external application
The carbon fiber reinforced polymer-based Sika CarboDur® S/-M system for application in near-surface slits
Structural strengthening system for the post-tensioned strengthening of bridge decks and beams, consisting of:
Tendon based on CarboDur® plates and special CarboStress® anchorage heads
End-anchorage solutions based on project needs
Strengthening system for axial strengthening of columns (column confinement), consisting of Sikadur® epoxy adhesives and:
Unidirectional SikaWrap® fabrics, based on carbon and glass fibers, available in a range of area weights
3. Waterproofing
Bridges are an essential part of modern infrastructure and are often subject to the harshest weather that climates have to offer. In order to maintain the durability over its design life, special attention should be given to the waterproofing and protection of exposed elements and critical areas such as the bridge deck itself, to prevent serious damage to the concrete and structural reinforcement.
Waterproof for bridge decks: Sikadur 22 Low mod
Structural bonding and flexible watertight injection systems for crack sealing in concrete structures:
For the surface sealing of bridge decks: Flexible polyurethane and acrylic resin-based injection systems – Sika® Injection systems
For structural cracks and void repair: Sikadur®-52, Sikadur®-35, Sikadur®-673, Sikadur®-55 SLV
4. Joint Sealing
Bridges are complex and demanding structures. There are many joints that need waterproofing, from simple saw cut contraction joints to exposed movement and connection joints. These joints are exposed to thermal movement, constant vibrations, extreme weathering, mechanical impact from the traffic and chemical impact from spillage or de-icing.
The sealants must reliably prevent water from entering the structure and causing decay of concrete and steel components through corrosion. Durable waterproofing has a significant impact on the life expectancy of the bridge.
High performance watertight joint sealing systems for use on bridge decks, parapets, and other elements:
For facade and parapet joint waterproofing: Sikadur® Combiflex® SG system
For facade joint waterproofing: Sikaflex® joint sealants
The rapid completion of construction and refurbishment works has been a driver of innovation since many years. Examples are reduced curing times of concrete and application over a wider temperature range, application on humid substrates or fast curing of sealants, adhesives and coatings.
Sikasil®-728 SL is designed to seal saw cut and expansion joints in pavement on highways, airports, bridges, garages, and car park top decks as well as driveways. Application can be executed in cold and hot temperature conditions. Sikasil®-728 SL withstands an exposure from -40°C to +150°C, high UV radiation and severe weather conditions.
Advantages:
- Very high movement capability
- Very good adhesion, especially to concrete
- Very long service life due to outstanding UV resistance
- Very good flexibility for use in extremely high and low temperatures
The EMSEAL BEJS is a traffic-durable bridge and roadway expansion joint which provides a primary watertight seal preventing and decreasing maintenance costs to bridge bearing pads and support structures. It is designed for new construction and refurbishment of old or failed bridge expansion joint systems to handle harsh environmental conditions and features great movement capability, very good low temperature flexibility and high temperature stability.
Non-invasive anchoring provides for quick turnaround and repairs. The system is composed of a pre-compressed, silicone-foam hybrid installed into field-applied adhesive on the joint faces, with the silicone bellows locked to the joint faces with a silicone sealant band.
The EMSEAL BEJS is designed for:
- Concrete-to-concrete substrates
- Rebuilt joint faces, where demolition and removal of existing embedded metal angles is not feasible or affordable
- As a lasting replacement for all failed liquid-sealant joints in parapets, sidewalks or jersey-barriers.
Advantages:
- EMSEAL systems enable watertight expansion joints in all kind s of substrates delivering continuity of seal for bridge and highway conservation
- Ability to adjust to varying joint gap widths
- Easy installation, because system is delivered in pre-compressed form smaller than the gap
- Staged installation preserves traffic flow
5. Concrete Protection
To improve the performance and durability of reinforced concrete surfaces on bridge structures, additional protection systems are frequently required, particularly in refurbishment situations. Typical concrete protection systems for bridges can be classified as hydrophobic impregnations, sealing impregnations, surface coatings, or corrosion inhibitors. These are designed for use in different situations or collectively in alternative combinations, to greatly reduce damage to the concrete surfaces, to stop or reduce the rate of steel reinforcement corrosion and prevent significant structural damage.
Sika provides a wide range of tested and well proven concrete protection systems based on different technologies including hydrophobic or sealing impregnations, rigid and elastic surface coatings, galvanic anodes, and surface applied corrosion inhibitors. All of these Sika products and systems fully comply with various standards and regulations.
Liquid, surface applied corrosion inhibitor: Sika® FerroGard®-903 Plus/-908
Galvanic protection systems: Sika® Galvashield XP Product Line
Deep penetrating hydrophobic impregnations Sikagard® SN-40 Lo VOC/SN-100
For invisible protection of fair-faced concrete, count on Sika's solutions with cost effective products which cause no change in the structure's appearance. For facades, beams, columns and all areas of the bridge superstructure, Sika provides durable, deep penetrating, protective hydrophobic impregnations with a unique and complete concrete protection system, including:
Sika® FerroGard®-903 Plus/-908 corrosion inhibitor
Hydrophobic impregnations: Sikagard® SN-40 Lo VOC/SN-100
Rigid, continuous film-forming, protective concrete surface coatings:
High performance, solvent dispersed, acrylic resin coating Sikagard® Color A-50 VOC
Water dispersed, protective acrylic resin coating Sikagard®-552 W Aquaprimer, Sikagard® 670 W
High build, film-forming protective concrete coating system with crack-bridging abilities:
Water-based, high build, elastic crack-bridging, colored, protective top-coating: Sikagard®-550 W Elastic
Water-based, protective coating Sikagard®-550 W Elastic - high dynamic and static crack-bridging ability, even at subzero temperatures, not requiring intermediate coat. Applicable from 300 to 600 g/m2 per coat according to the desired level of crack bridging.
6. Grouting and Fixing
Remedial works on concrete bridge structures often include the requirement for void filling, fixing and sealing or bedding and grouting with free-flowing materials. Typical examples are concrete repairs using formwork, high precision grouting under bridge bearing plates, or for cable duct grouting. Additionally flowable resin and cement grouts are used to fix manholes or other steel frames and equipment, where rapid hardening materials are usually required to reduce closure times.
Sika provides a wide range of tested and well proven grouts and fixing materials based on all of the different technologies available including cement, epoxy, polyurethane and PMMA. For many decades, Sika has also provided special products for high precision applications such as bearing plates, rail tracks and duct sealing.
Materials for grouting under bridge bearing plates and to fill voids, holes, and cavities or for embedding drainage pipes and other elements:
Cement-based, high precision grouting products: SikaGrout®-300 PT
Epoxy resin-based, rapid hardening, high strength grouting products for use under dynamic loading: Sikadur® VPC, Sikadur® LT Grout
PMMA resin-based, grouting products for application at low temperatures down to -10 °C: Sika® Pronto-11
Rail fixing, damping and bedding solutions for all types of rail track systems to be installed on bridge decks:
Discrete fixing solutions: Icosit® KC range
Direct rail track fixing and bedding solutions: Icosit® KC range
7. Structural Bonding
Structural adhesives are used for many bonding applications in new construction and refurbishment. The bond must allow the transfer of high loads without deformation and creep. The main function of structural adhesives is in the bonding of similar or dissimilar materials together (i.e. concrete to steel, steel to composites etc). Dependent on their design, structural adhesives can not only bond the elements together, but they can also fulfil additional functions such as waterproofing, sealing, concrete protection or even vibration dampening.
Sika has been a pioneer in the use of resin adhesives for structural bonding of precast concrete elements since the 1960’s. Sika’s epoxy adhesives have now been used to bond segmental bridge structures all around the world. This extensive experience has allowed the development of a wide range of additional structural bonding products and systems for unique applications. In the 1990’s Sika also introduced a complete range of cartridge applied resin anchoring adhesives for many different applications.
Segmental bridges are built in short sections (called segments) one piece at a time, whereby traditional methods build a bridge in very large sections. Segmental bridges are made of precast concrete, which is manufactured at another location and then transported to the final location for placement within the complete structure. They are very economical for long spans (over 100 meters), especially when access to the construction site is restricted, and also allow for special design features to enhance the beauty of the structure.
Sika offers Sikadur-31 SBA: Range of thixotropic, structural two-part adhesive specially formulated for segmental bridge construction; available in different grades to suit different applications and environmental conditions. All grades present advantages including: meets and/or exceeds internal and national standards (FIP, BS, AASHTO, ASTM, etc.), high strength, high modulus of elasticity, no primer required and more.
Epoxy adhesives for bonding different elements or components to concrete, steel or bituminous substrate:
Sikadur®-30 for high-performance bonding of steel plates on to concrete
Special structural adhesives tested according to European or US-standards for anchoring all types of fittings and equipment to bridge structures, such as for the installation of cable trays or other services, crash barriers, drainage pipes, inspection access equipment, catch nets, reinforcing steel, and more.
ETA and AC approved, structural resin anchoring adhesive Sika® AnchorFix®-2 Artic, for installation of threaded rods and rebar at temperatures as low as -5 °C.
ETA approved, structural resin anchoring adhesive Sika® AnchorFix®-2 Artic, for installation of threaded rods and rebar, including cracked concrete and seismic testing. With different hardener grades (arctic and tropical), suitable at temperatures from -10°C/-25°C up to 40°C.
AC approved, structural resin anchoring adhesive Sika® AnchorFix®-2020, for installation of threaded rods and rebar including cracked concrete and seismic testing.
ETA and AC approved, high performance, epoxy resin based, structural anchoring adhesive Sika® AnchorFix®-3001/-3030, for installation of threaded rods and rebar even into damp substrates, including cracked concrete and seismic testing.
Special epoxy mortars for the bedding, bonding, and dry-packing of many different types of fixtures and fittings, including steel frames and parapet railings, etc.:
Three-component, non-shrink, epoxy resin-based mortars Sikadur®-42, Sikadur®-43 Patch Pack, and Sika® Pronto-11
