Application of nickel-coated carbon fibre material in cathodic protection of underground-buried steel structures

Abstract

The present paper reports the results of a preliminary study on potential suitability of a chopped nickel-coated carbon fibre (NiCCF) material to an impressed current, cathodic protection (CP) system, for an underground-buried steel structure. A primary role of a conductive NiCCF filler (Toho-Tenax ®-J MC HTA-12K A302 fibre) was to enhance distribution of a protective current, by significantly lowering the corrosion environment’s resistivity. Initially, the resistivity of sand-based soil (with humidity of ca. 20%) was optimized through addition of small amounts of chopped (15 ± 3 mm long) pieces of Toho-Tenax fibre. An operational efficiency for two laboratory CP setups (in the presence and absence of NiCCF soil modifier) was then monitored, over a period of 30 days. Each cathodic protection setup consisted of a protected structure (simulated by a steel rebar: ϕ = 10 mm and length 0.5 m) and a DSA (Ti/MMO: ϕ a = 95 mm) anode. Obtained results demonstrated a continuous increase of the soil resistivity parameter during a preliminary, 30-day cathodic polarization cycle, for the NiCCF-modified CP setup.