Slab pathology
Introduction
Aluminosis or concrete fever is the name given to the damage to the concrete that manifests itself especially in the joists of the slabs of buildings, whereby the concrete used loses its properties, becoming less resistant and more porous, thus endangering the stability of the building.
This injury is due to the aluminous cement (CAC-R) used in the manufacture of some joists, since it set more quickly than traditional cements, reducing factory storage time. This cement has a high concentration of alumina, which causes chemical changes in the face of certain agents, altering its properties. At high temperatures and high humidity, the structure of this cement goes from hexagonal to cubic), the latter being denser. This causes the cement particles to occupy less space and therefore the overall structure acquires greater porosity, thereby losing mechanical resistance.
The agents that act are atmospheric, with a higher incidence of cases in maritime climates with saline environments and industrial areas with polluting environments. It is also common to find aluminosis associated with leaks due to the constant presence of humidity through the cracks that appear in roofs, which is why the appearance of the pathology is frequent in roof slabs, which are more exposed than the interior ones. In any other situation the joist works normally.
Beams made of aluminous cement that are not exposed to moisture in many cases do not develop this condition, although it is advisable to do a visual inspection every several years.
Currently, the mechanized beam systems that are placed under the defective beams allow this pathology to be corrected in a simple way, their cost usually being lower than that of demolition and new construction.
Cases in Spain
In Spain, this cement was especially used between 1960 and 1970 at the height of the construction boom. The most famous case of aluminosis in Spain is that of the Vicente Calderón Stadium, a construction that is especially vulnerable due to its location close to the Manzanares River (increased humidity) and other chemical agents (traffic on the M-30). Initially, instead of being demolished, its structure was restored as a safety measure. On the other hand, some buildings located on the Mediterranean coast in the construction of which this type of cement was used, especially in the city of Barcelona, had to be demolished as a preventive measure.