Protecting Concrete Power Poles from Stray Alternating Current

"Protecting Concrete Power Poles from Stray Alternating Current"

Aghajani Koopaee, A. , Golozar M.A., Saatchi, A., Reisi, K., Urgen, M. , Shabani, S.

Materials Performance , Oct. 2013

Abbstract :

The article describes how the impedance of concrete subjected to alternating current (AC) is affected by adding silica fume, reducing water-to-cement ratio, and adding polypropylene fibers. After the samples were cured and water saturated, 220 and 380 V AC were applied through two of the steel bars for 40 min. To create a water-saturated condition, the concrete samples were soaked in distilled water at room temperature for five days. Decreasing the w/c ratio and adding silica fume to the concrete mix design were the reasons why the volume of concrete pores reduced, the water absorption of the concrete decreased, and the number of the capacitor paths decreased and their impedance increased. So if the AC voltage is high enough and the concrete is saturated with water, then serious nonuniform current distribution forms in concrete. This will lead to thermal and shrinkage stress in concrete and cause the formation of cracks and an increase in the concrete's permeability.