Soil Resistivity Measurement for Corrosivity Assessment using Barnes Method
Authors: Adeoti L, Adegbola RB, Ademilola JA, Oyeniran TA
Corrosion attacks are frequently responsible for most material’s failures and its effect on underground metallic materials is a very widespread problem. In order to avoid unpleasant corrosion of pipes and steel structures, the electrical resistivity technique using Barnes method was utilised at PZ Cussons Ikorodu, Lagos State, Nigeria. Electrical resistivity survey (Wenner array method) was carried out with a resistivity meter in which four electrodes were deployed at each of the fifteen electrical resistivity test (ERT) locations. The pattern of distribution of resistivity based on geophysical analysis reflects four groups. Group 1 has resistivity values less than 50 ohm-m. Group 2 accommodates resistivity values between 50 and 100 ohm-m. Group 3 has resistivity values between 100 and 200 ohm-m. Group 4 houses resistivity values above 200 ohm-m. The general trend of the geophysical analysis in Group 4 revealed that resistivity values are high and therefore do not pose a corrosive risk to proposed metal pipes and steel structures at the aforementioned depths. In contrast, groups 1-3 which are predominant, have resistivity values that are less than 200 ohm-m which correspond to low to very high corrosive probability. The analysis revealed that mitigation measure should be considered via good cathodic protection for these groups where resistivity values are considered low at various depths within the study area. Therefore, proposed metal pipes and steel structures should be buried between depth intervals 1.50–4.50 m in the area under investigation.
Affiliations: Department of Geosciences, University of Lagos, Nigeria.
Keywords: Electrical Resistivity Test, Barnes Method, Metal Pipes, Mitigation Measures, Cathodic Protection
Published date: 2018/12/30