Repairing concrete structures is a constant task due to the action of time and weather – increasing the useful life of not only buildings but also repairs is what the structural reinforcement method developed by researchers at the Korean Institute of Civil Engineering and Technology does Construction (KICT), using a non-flammable carbon mesh and a 50% cement mortar reinforced with blast furnace slag (a by-product of pig iron production, which is dried and ground).
The product was designed for the situation in South Korea (more than 90% of the country’s infrastructure was built in concrete, from buildings to bridges, poles and tunnels), but it can have applications anywhere.
Today, to repair structures, carbon fiber sheets normally used on deteriorated concrete are used using organic adhesives, which have the disadvantage of being flammable and still contraindicated for damp surfaces (they peel off and may fall from where they are fixed).
How TRM plates are manufactured (in figure a, you can see the carbon mesh).Source: Materials / Young-Jun You et al / disclosure
The method developed by materials engineer Hyeong-Yeol Kim and his team uses carbon sheets, but in the form of a textile grid, inserted in precast mortar panels (textile reinforced mortar, or TRM) of two square meters and 20 mm thick.
They are fixed to the surface that needs repair with cement mortar, instead of organic adhesives. Its use still extends to precast buildings, reducing costs by 40% and improving fire resistance.
TRM plates are fixed to a structure with degraded concrete.Source: Materials / Young-Jun You et al / disclosure
The panels, applied to wet surfaces, do not suffer corrosion or by sea salt. In the tests carried out at KICT, even exposed to the sea, the material withstand twice the load of similar ones without the carbon mesh; its calculated useful life is over a century.