Accelerated Rebar corrosion When Connected to Lightning Conductors and Protection of Rebars with Needles Diodes Using Atmospheric Electricity

Abstract

The regulations for construction in many countries impose the connection of lightning conductors to concrete rebars. In the present work the effect of this connection on the corrosion of rebars was studied in order to avoid connections that accelerate corrosion. With this objective, steel specimens, steel pipes, and normalized reinforced concrete specimens in the air, water, saline water, and buried in the soil connected to lightning conductors or needles were used, and measurements of potential time, potentiostatic curves, and weight loss were taken. In some cases artificial lightning and radioactive lightning conductors were used. It was found that these connections influence the corrosion rate. It depends on the electrical characteristics of the atmosphere (conductivity and type of charge of the atmosphere and earth), that is, on the season and the weather. In most cases (winter, mostly during December in Greece) the corrosion is accelerated. In some cases (spring, mostly during May in Greece) the electron flow is inversed, and protection is found. The overall phenomenon for the whole year is an acceleration of the corrosion from 35 to 70%. The artificial lightning and the use of radioactive lightning conductions also accelerate the corrosion. It follows that the grounding of lightning conductors must be separately made with a network to divide the charge of lightning and should not be connected to the rebars.