Corrosion of the material in a state of stress, so-called. stress corrosion, is a very complex phenomenon, occurring under the action of long-term continuously operating loads. For steel stretch elements, like. anchors, downloads, accepting struts of arches or vaults, sometimes ceiling beams, the effect of corrosion occurs in the form of a sudden rupture, the characteristic features of scrap metal are: lack of constriction and destruction of metal occurring over the entire cross-sectional area.

The phenomenological approach to the phenomenon of stress corrosion is explained by a sudden decrease in strength due to a change in the crystal structure of a metal subjected to long-term stresses.

Stress corrosion is accelerated by structural defects of the material, as well as conditions conducive to the action of aggressive substances contained in the environment surrounding the structure. Chlorine connections are particularly harmful for steel, Sulphur, Cyanogen, Fluoride.

In mineral materials, the phenomenon of stress corrosion is not yet sufficiently studied, therefore, it is very difficult to detect, because this phenomenon is not accompanied by any visible symptoms. Masonry materials in working cross-section, so stone, brick and mortar, do not deform in a homogeneous way (I07>. The heterogeneous structure of masonry systems is also the reason for this., that with prolonged loads, the destruction of the walls, especially brick, .occurs before the compressive strength of the brick is exhausted.. Usually, an increase in stresses in the masonry leads to the fission of the structure, and this is visible in the form of scratches, vertical cracks of welds and local deformations.

For masonry structures, operating under concentrated conditions of long-term loads are included: Columns, pillars and columns, inter-window pillars, load-bearing walls. In these elements, as a result of plasticization of weaker materials, deformations may occur. A visible symptom of deformation will be local deflections or displacements due to intense pressure; this is usually accompanied by deflection or subsidence of the ceiling beams, or changes in the curvature of the vaults.

Plastic deformations in masonry structures are n.ie dangerous, if they do not lead to fatigue of materials, changes in their internal structure and physical properties. In the case, however,, when masonry elements are exposed to long-term concentration of structural stresses, as well as as a result of internal forces, local intermolecular displacements may occur in the materials, which can accumulate and suddenly lead to the destruction of a given structural element or a major construction disaster.

The phenomenon of stress corrosion in masonry materials can be particularly dangerous, when it is accompanied by other factors supporting it, especially moisture and atmospheric corrosion.