Metals And Concrete Degradation By Hydrogen Sulfide

The H2S as well as representing a risk to human health, also represents a source of economic risk, it can cause corrosion in metals of interest in civil and industrial and alteration of cement manufactures with considerable economic losses. The metals most prone to processes of sulfurization are copper, silver and iron, particularly in metal armatures of reinforced concrete, the chemical process leads to swelling and disaggregation of the concrete itself. Among the aggressive concrete sulfates are undoubtedly the most dangerous, the sulphate attack is manifested through the excessive swelling of the conglomerate of entities that may occur cracking or detachment of material. The swelling is expressed mainly on cortical areas of the concrete in contact with sulphates from the external environment. Destructive reactions of the concrete due to the presence of sulfates in the environment are basically the formation of bi-hydrated gypsum, Ettringite and Thaumasite.An expeditious and easily applicable method is now allowed through the application of the VOP®© Test, patented by Palmisano and Voltaggio (CNR). This test helps detect and determine on a quantitative basis and on different matrices, but especially in situ, traces of soluble sulfates at different concentrations (from a few hundred ppm to several percentage units) coupled Rodizonato of the use of sodium in aqueous solution with a solution of salts of barium. The proposed method can be calibrated for a specific threshold in sulfate content, simply changing the title of the barium nitrate solution. In this paper the authors introduce a casuistry on bridge-pylons and pipelines in r.c., steel lampposts and stone face-works and explain rehabilitation techniques.