Evaluation of steel durability in a construction system of reinforced mortar-polystyrene-mortar panels

Abstract

This paper sumarises the research into steel durability in reinforced sandwich panels made of mortar-polystyrene mortar, which is a new construction system for buildings. In this type of system the main risk of steel corrosion is that of the steel connectors, which cross the polystyrene, and the corrosion of the reinforced mesh, owing to the carbonatation of the mortar coating. The evaluation of different suplementary protection methods which increase expected service life in aggressive environments is also presented.

The different tests carried out are described. The specimens were of small, medium and full size. The corrosion was monitored with electrochemical techniques (polarization resistance). The specimens were submitted to wet and dry cycles and some of them were carbonated. Galvanized, stainless and bare steel were tested. Also addition in the mix of calcium nitrite as an inhibitor was used. Results show that the steel connectors are not the weakest point of the system as previously thought.

Finally, practical recomendations are given which allow a reasonable increase in the service life of the reinforced mortar-polystyrene-mortar system. The specifications are presented considerinng three levels of environmental aggressivity.