Effect of Sand Particle Size on Soil-Side Corrosion Behavior of Aboveground Storage Tanks

Abstract Soil-side corrosion poses a significant challenge for operators of Aboveground Storage Tanks (ASTs), particularly affecting the bottom plates. The objective of this research is to investigate the effect of sand particle size and water saturation level on the corrosion behavior of AST bottom plates. Sand particle sizes ranging from 1.18 mm to 0.150 mm were investigated under 50% and 75% water saturation. Sands with 30 ppm chloride and 15 ppm sulfate content were selected for the study. ASTM A36 carbon steel coupons were exposed for 2 and 7 months. Weight loss measurements and pit depth analysis were conducted to evaluate corrosion damage. Additionally, carbon steel coupons were exposed in a salt solution containing 30 ppm chloride and 15 ppm sulfate to establish baseline corrosion rate. Profilometry was used to scan coupon surfaces, identifying the deepest pits, and determining the maximum pitting rate for various sand particle sizes and water saturation levels. The results from this study will help to identify optimal sand particles sizes that could be potentially less corrosive compared to the current practices and reduce the corrosion severity of future storage tanks.