CTI™ is the nomenclature given to a family of ultra-high-performance concretes developed at the US Army Engineer Research and Development Center. It is an advanced fibre-reinforced cementitious material with greater strength, tensile ductility, and durability properties when compared to conventional or even high-performance concrete. CTI 150™ exhibits elastic-plastic or strain-hardening characteristics under uniaxial tension and has a very low permeability due to its dense and discontinuous pore structure.
CTI 150™ is a tailored UHPC and was designed to work with local raw materials. The CTI 150™ premixed compounds, the core ingredient of the UHPC, is only 25 percent of the final product’s volume. And sourcing all other constituents locally eliminates the need to ship large volumes around the world.
Together with Portland cement, the active components of a CTI 150™ Compound create a reactive binder that, when combined with fine aggregates and high-range water reducers, hydrates into a densely-packed matrix.
The main characteristics of CTI 150™ are achieved through homogeneity encasement by eliminating coarse aggregates in the matrix, density encasement by optimising the packing density, and ductility enhancement by the introduction of fibres. The result of combining these concepts is an extremely compact material, in which pores are not communicated, so the lifespan of a structure made of CTI 150™ is significantly extended. The corrosion resistance even in the cracked state increases significantly even when exposed to an aggressive environment due to the low permeability and discontinues fibre reinforcement.
Fibre reinforcement solves the problem of brittleness in CTI 150™ and drastically improves tensile strength in impact resistance. Alongside the low water-binder ration optimised particle packing, fibres are an essential part of ultra-high-performance concrete. There are up to 60 million fibres in just 1 cubic metre of CTI 150™. And for special requirements, this number can go even further. Other types of fibres such as synthetic, mineral or even recycled steel can also be used to reinforce CTI 150™. They can be combined with conventional reinforcement and prestressing when needed.