Flexstren introduces a new way to give flexural behavior to concrete products, overcoming steel reinforcing limitations (cover requirements, and steel corrosion). Concrete products manufacturers can produce new cost effective products, and increase competitiveness versus non-concrete competitors. Some examples of application/benefits:
Concrete pipes become cost competitive versus plastic, GRP pipes, and traditional RCP pipes; they no longer need to be reinforced with steel reinforcing cages, so they are corrosion free. The external post tensioned composite wrapping ensures impermeability even for pressure applications, and the pipe can also be buried on aggressive soil environments. The elimination of a minimum depth of covers makes it possible to do pipes with a thickness 1/20 of the diameter. So thin concrete pipes have semi-rigid behavior, with easier soil compaction vs fiber / plastic pipes. It becomes possible and cost effective to do concrete pipes with diameter from 200 mm.
This technology will open up new markets such as irrigation, and the pressure part of the sewage applications (concrete pipe producers can now supply also the sections with pressure), along with thermal / hydroelectric plants.
Flexstren technology makes paver producers able to produce cost effective “flexible” pavers, by applying a post tensioned continuous composite material around the slab periphery. By adding flexibility, this eliminates broken or cracked pavers, weight is reduced and durability is increased.
Flooring with flexible pavers can be applied even on medium-high speed roads. Larger paving slabs with reduced thickness are now possible, enhancing the product applications vs. competitive materials. It is now possible to do pavers with a form factor that has one side much longer than the other.
Thanks to Flexstren technology, any immediate stripping product manufacturer could provide railway line operators much more effective corrosion free railway sleepers. Corrosion is now greately affecting sleepers durability. Solution is to produce dry cast concrete sleepers, then wrap them with post tensioned composite material. Both producers and railway line operators have many benefits: high productivity due to immediate demoulding process, resistance to freeze-thaw cycles by the use of dry cast concrete, insensitive to cracking, electrical conductivity free, thanks to the missing steel reinforcing. In addition, Flexstren technology ensures reduced relaxation losses compared to steel reinforcement, it is easy to make low volumes custom shapes, low cost sleepers, and reliable production lots identification.
Flexstren technology consists of applying a post-compression on dry cast concrete products – after normal curing – with a stressed and oriented high tensile continuous composite. This reinforcing is not dispersed in the concrete mix but applied only where it is needed. Regulations already exist in many countries such as the USA and Europe.
In addition to the technological benefits, Flexstren technology usually bring cost savings:
Cost for concrete pipes: post tensioned continuous composite material cost is generally less than the steel reinforcing cage, and the elimination of a minimum cover depth allows concrete thickness to be reduced to as much as 1/20 of the diameter.
Cost for pavers: post tensioned continuous composite material cost is about the same as the cost of the thickness reduction in concrete.
Cost for sleepers: dry cast concrete production combined with post tensioned high tensile continuous composite material costs less than traditional sleeper production.
Flexstren reduces enormously the CO2 footprint since impacts various aspects:
Corrosion free brings a lower CO2 emission because the longer product life cycle;
The flexural strength enhancement reduce the product thickness resulting in lower cement usage;
Composites have lower CO2 footprint versus steel reinforcement.