Corrosion of metallic reinforcements, ageing materials, structural cracks. Faced with the gradual deterioration of buildings (car parks, listed buildings, monuments) and infrastructure (bridges, motorway junctions), civil engineers are faced with a dilemma: rebuild or rehabilitate.
Demolition and/or reconstruction is expensive, time-consuming and has a high carbon footprint. Rehabilitation using carbon fiber composite materials offers a more economical and efficient approach.
For over 10 years, Toray Carbon Fibers Europe has been providing civil engineering companies with high-performance composite solutions (carbon fiber, pultruded rods and laminates) to extend the service life of infrastructures, while meeting new seismic, mechanical and environmental requirements.
Applying carbon fiber composite laminates to reinforce a multi-storey car park
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What are the Key Issues in Civil Engineering?
Reinforced concrete infrastructures, whether bridges, car parks or buildings, are subject to the following issues:
- Steel corrosion due to moisture and salts,
- Material fatigue due to repetitive loading,
- Public safety requiring urgent interventions.
At the same time, some structures must evolve to meet new requirements, such as reinforcing supports to support heavier loads.
In many cases, reconstruction is neither technically justified nor economically viable. Targeted rehabilitation then becomes the preferred solution, particularly in the context of programmes such as France’s National Bridges Scheme (2023–2026), which finances repairs or reconstruction of damaged infrastructure.
Composite Materials: A Reliable, High-Performance and Long-Term Solution
What is a Composite Material and Why Is it Used in Civil Engineering?
A composite material is an assembly of two components with different properties:
- A reinforcement (here, carbon fiber), which ensures the mechanical performance, especially in traction,
- A polymer matrix, usually an epoxy resin or vinylester, which provides cohesion, protects the fibers and transmits the fiber’s performance.
In civil engineering, carbon fiber reinforced plastics (CFRP) are used to increase load-bearing capacity, stiffness, and upgrade flexural or shear strength, without adding significant weight to the existing structure.
Technical Properties of Carbon Fiber
The carbon fibers manufactured by Toray Carbon Fibers Europe are made from polyacrylonitrile (PAN) fibers which undergo a carbonization process. This provides mechanical properties that are particularly suited to the requirements of civil engineers:
| Property | Nominal Value | Advantages |
| Tensile Modulus | 230–600 GPa | Comparable to or even superior rigidity to steel, offering effective reinforcement |
| Tensile Strength | >3,000 MPa | Ideal for compensating traction weaknesses in concrete structures |
| Density | ~1.8 g/cm³ | Up to 5 times lighter than steel |
| Resistance to Corrosion | Excellent | No risk of rust or deterioration over time |
| Durability | Excellent | Resistance to freeze/thaw cycles, chemical agents, humidity |
Unlike conventional metal reinforcements, carbon fiber is not affected by corrosion, even in aggressive environments (marine environments, polluted urban areas, etc.).
Therefore, the use of carbon fiber ensures that mechanical performance is retained over time, without any particular maintenance.
Toray Carbon Fibers Europe’s Composite Solutions
Toray Carbon Fibers Europe offers ready-to-use products, suitable for all types of structural reinforcements:
All our products are made in France and available to purchase allowing for fast on-site interventions to manage sensitive sites or urgent situations.
| Product Type | Usage | Advantages |
| Pultruded rods | Anchoring, reinforcement | High precision, easy installation, corrosion resistance |
| Carbon laminates | Load transfer on slabs and beams | Fast installation, high resistance |
Rehabilitation Case Studies: Strengthen, Adapt, Prolong Use
Carbon fiber-based composite materials have now proven their effectiveness on a wide range of infrastructures, buildings and monuments.
Toray Carbon Fibers Europe regularly provides its targeted solutions to customers working on sites requiring rehabilitation. These composite solutions enable structures to be repaired and adapted to new regulations and/or technical requirements and avoid the need for expensive, invasive and time-consuming building works.
1. Car Park Reinforcement
With the rise of electric vehicles, whose weight is significantly higher than that of internal combustion vehicles (between 20 and 30% more), many existing car parks are now no longer able to bear safely the weight of current rolling loads.
- Issue: Concrete slabs designed 20 to 30 years ago have structural weaknesses and are at risk of cracking prematurely due to the additional weight of vehicles.
- Solution: Toray Carbon Fibers Europe’s solution is to install carbon laminates on the underside of the slabs to increase their load-bearing capacity, without the need to demolish or close the site. This operation can be carried out in a few days, making it possible to secure these structures for the long-term.
Electric vehicle charging in a reinforced concrete multistorey car park that has been rehabilitated with carbon fiber laminates.
2. Earthquake Resistance: Adapting Public Buildings
Many buildings built before the adoption of the European Standard Eurocode 8: Design of Structures for Earthquake Resistance (EC8), do not have the necessary reinforcements to withstand a low- or medium-intensity earthquake.
- Issue: schools, hospitals, town halls or residential buildings located in moderate to high seismic zones require compliance with the EC8 standard. To avoid widespread disruption, the rehabilitation process must avoid having to relocate the occupants.
- Solution: Toray Carbon Fibers Europe’s solution is to apply carbon fiber laminates or rods on load-bearing walls, floors or structural nodes. This solution helps to improve the stability of the structure and limit the risk of collapse during seismic activity.
3. Rehabilitating Infrastructure
Through the National Bridge Scheme 2023–2026, the French government is providing finance to support local councils in the repair or reconstruction of critical infrastructure. Priority is given to infrastructure that is in poor condition, risking the safety of users or compromising the continuity of local services. A significant number of these structures require beams, slabs or decks to be repaired and/or reinforced, without disrupting or halting the flow of traffic.
- Issue: repair works must be carried out quickly, often in a constrained environment, and on a limited budget.
- Solution: Toray Carbon Fibers Europe’s solution is to use carbon laminates that can be applied with an adhesive to the underside of a bridge’s decking or substructure. Composite products allow quick interventions without the need to use cranes or a large workforce.
In addition to providing high-performance technical solutions, Toray Carbon Fibers Europe’s composite products offer a more sustainable approach to civil engineering projects: avoiding the need for demolitions, reducing construction waste and extending the lifespan of infrastructure.
Rehabilitation emerges as a strategically sound approach, delivering measurable benefits in cost efficiency, operational performance, and environmental impact.
