Diagnosis and rehabilitation possibilities of real reinforced concrete structure

Abstract

A diagnosis and rehabilitation study of a reinforced concrete structure is presented in this paper. The Public building was corstructed in 1939, located in marine environment, distant less than I km of the coastal border, in a seismic zone, that for more than one decade has presented pathologies like: cracks, steel corrosion, loosening of concrete coverings and slab deformations. Quantitative analyses of profile chloride and sulphate ions to the concrete in different zones of the building, scanner of the reinforcements with Ferroscan, measurements of corrosion potential, compressive strength and capillary absorption were made. The quantity of chloride and sulphate ions in the concrete exceeded in 1.000% the amount acceptable by Chilean standards: 1,20 kg Cl- /m(3) concrete and 0,600 kg of SO42- /m(3) concrete.

The structural steel was oxidized even not existing in some zones, in according with the Ferroscan images and confirmed with appropriated tools.

In addition, the compressive strength in the last 10 years has diminished from 25 MPa to 20 MPa in some zones. Corrosion potential of reinforcements presented values of high probability of corrosion (- 550 mV in front of Cu/CuSO4 electrode).

A structural rehabilitation project have two principal objectives, to provide a compressive strength to the structure during its service life, and to guarantee restitution of the structural capacity, in agree with the use of the building, the rehabilitation project resources, and others.

In the present study, it was possible to conclude that it is not possible to formulate a structural rehabilitation project that assures any service life to the building, even more, the present use of the building is dangerous for the people who work in it.