Replacing or inspecting bonded, prestressed concrete reinforcement - by softening or dissolving bonding resin using heat, solvent or microorganisms so reinforcing bar can be removed

摘要

Changing or inspecting prestressed reinforcing elements in jacket tubes in post-bonded prestressed concrete parts uses bonding material of soluble thermoplastic or thermoset (I) with properties which can be modified at any time by heating, dissolution with a solvent or the action of plastic-digesting micro-organisms, so that the reinforcement is easily removed or examined. Alternatively, the bonding material is a thixotropic silicate e.g. bentonite, in which case the bonding properties are modified, e.g. by removing the prestressing load, or an electroviscous oil, the properties are altered by changing the electric field between two electrodes in the jacket tube. An additional tube or channel is specifically built into the jacket tube to enable introduction of heater, solvent or microorganisms, so that the change in properties of (I) is externally controlled by changing the heater voltage or the flow properties of the solvent, and/or additional means of access are provided, e.g. by drilling into (I) from the edges, joints or ventilation pts. etc. of the concrete part; (I) is polyethylene, polypropylene, polystyrene, polyamide, polyethyleneimine, PVC, PVAC, acrylic resin, polyvinyl ether or linear polyurethane with softening pt. 150-400 deg.C, in which case heat is applied by inserting a heater or by applying a voltage across the ends of the reinforcing bar itself, or (in)organic solvent or micro-organisms are injected through a tube. USE/ADVANTAGE - Reinforcing bars are removed easily from concrete parts for replacement or inspection, without damaging the concrete itself combining easy replacement of prestressing elements (as in construction without an adhesive concrete/reinforcement bond) with the static and financial advantages of bonding after construct