Lightweight, high resistance synthetic fibres to save historic buildings and monuments

Many of Europe’s historic buildings, monuments and civil engineering structures are gradually decaying. Already weakened by age, they are damaged by earth tremors, pollution and traffic vibration. And this is more than just a cultural problem. Continual maintenance is extremely costly and obtrusive, not least because of its negative impact upon tourism and traffic.

Conventional rehabilitation methods using wooden or steel buttresses, tie rods and scaffolding supports dominate the landscape and usually do not offer a long term, durable solution.

But EUREKA project COMREHAB has developed new techniques to strengthen masonry, wood and concrete buildings using carbon-fibre strips instead of steel bars. These will reinforce structures with less damage to the existing building.

Partners from Spain, the UK, Portugal and Slovenia worked together to create and test new advanced composites made of epoxy or polyester resin matrix.
The new high resistance synthetic fibres are applied in thin layers to strengthen and stiffen stress-critical areas.

The materials are lighter and less intrusive than an alternative like steel plate reinforcement, and have exceptional resistance to corrosion. They offer easier handling, adapt readily to shape irregularity and can be delivered to the site in rolls of 100m or more. Unlike traditional methods, the new approach is reversible. It is a less disruptive process, and can be implemented without the need for foundation reinforcement because the materials are so lightweight.

The application of this new technology at low temperatures will cut the cost of conventional reinforcement technologies by 15%. It can be applied on site using existing low-cost heating devices. The project team hope that this will open up a market to rehabilitate historic buildings and monuments throughout Europe worth in the region of 100 MEuro per annum.

Ebby Shahidi, Design and R&D Director of UK resins experts Advanced Composites Group Ltd, explains “the ability to cure at low temperature allows the production of reinforcement patches with a wide range of fibres that can be easily used for in-situ repair work.”

But more research is needed. Despite a total of 24 structural tests, the partners have experienced problems introducing a universal use of composites in the construction industry. “This difficulty is an educational one where engineers, architects and public administrators in the construction industry need to be shown the benefits of using these materials,” explains Juan Mieres, R&D Director of Spanish lead partner NECSO.

Mieres is anxious that further projects on the use of composites in the construction industry should be encouraged, in order to overcome existing problems such as creep, the ageing of resins, fire, and the difficulty of applying composites on site.

This was NECSO’s first European R&D project. “Working within the EUREKA framework has been an enriching experience, both from the technological and commercial points of view,” Mieres said. “It was an efficient way of introducing ourselves to working in the area of European technological research, which will lead to our involvement in future international R&D projects.”