Throwing power of the zinc-hydrogel anode for sacrifical protection of steel in concrete

Abstract

The throwing power of the Zinc-Hydrogel Anode for sacrificial protection of steel in concrete was studied in the laboratory under controlled environments. The anode to steel ratio in the specimens was 1. The corrosion state of the rebar is moderate. The results indicate that for a concrete resistivity of 600 Qm and higher the ohmic drop in the concrete is an important factor in the lateral protection of steel with diameter of 8 mm and a cover of 15 mm. For 600 Qm a lateral throwing power of 220 mm or more was obtained, while for 1900 SZm this decreases to less than 120 mm. Our results on the throwing power in the depth direction indicate that for a concrete resistivity between 600 and 1000 Qm protection of two corroding rebar layers of 8 mm diameter at two different depths between 0 and 150 mm can be obtained. The measurements show that for a higher concrete resistivity proper protection is questionabl