An Approach for Grading of Soil Corrosiveness: A Case Study in Vicinity of Ring Road-Kathmandu

Abstract

Corrosion of the outer surface of underlying Zn-coated or carbon steel pipes in the soil becomes complex and intricate due the insufficient information about the electrochemical interactions between discrete pairs of all corrosive soil factors. To overcome such corrosive problems of the underlying metal pipes in the soil, an ongoing study has suggested a stochastic approach for a close analysis of the corrosive grading of each soil specimen, sampled from the vicinity of Ring Road (RR) of Kathmandu, Nepal, towards the pipes with modifying the previously utilized AWWA (American Water Works Association), ASTM and NACE methods. Four corrosive grades (CGs) of all the soil specimens were categorized based on their quantitatively calculated soil factors in the stochastic approach of the novel probabilistic modeling (NPM) method. Then, they grouped supplementary ten corrosive sub-grades (CSGs) taking the sum of the cumulative point (CuP) of every soil factor. An indeterminate examination of 10 soil specimens was accomplished to categorize their CSGs, which would be a more precise method to draw a corrosive soil mapping of the study areas. The outcomes of such analysis under the NPM method imparted that about 90% of the sampled soil specimens of the RR areas allied only to five specific CSGs belonging to two CGs, i.e., G-RAR and G-MID.