Type of post-tensioning
High-strength steel tendons are used as pre-tensioned reinforcement in post-tensioning technology. Tensioning is carried out by means of special hydraulic jacks and fastening both ends of the tendon by anchors. The resulting load creates a compression effect in the concrete. Thus, it becomes resistant to the effects resulting from tensioning of reinforced concrete construction.
Formation of pre-tensioned concrete using post-tensioning technology provides two methods: a tendon with or without a coupling to concrete.
The essence of the first method being applied in formation of pre-stressed slabs in civil construction is as follows. For reinforcement are used steel tendons being protected in a specific way against corrosion. Firstly, such tendon is coated with a corrosion-inhibiting grease at a plant. Secondly, it is encased in a plastic pipe providing initial protection against corrosion. After tensioning both ends of the tendon are fastened by anchors. In this way, the construction of reinforced concrete serves the entire period being declared by the manufacturer.
The second method is as follows: a tendon is placed in a steel mould (perforated pipe) and both ends of the tendon are anchored. After pouring concrete and reaching the required concrete hardness, a tensioning of tendons is carried out. This is followed by injecting mortar into the moulds ensuring that tensioning force is being transferred from anchors in full length of the tendon. A force of the tensioned tendon of fully hardened construction is being transferred to the concrete. Moreover, the steel tendon is sufficiently protected against corrosion. This particular method is frequently applied in formation of bridge spans as well as other structures being subjected to high loads.
Our company supplies both types of post-tensioning equipment: with or without a coupling. For each particular case economically most advantageous solution of application is selected and compliance with the requirements relating to the secure application of post-tensioned reinforced concrete constructions is provided.