Performance of granular soils reinforced with obsidian (volcanic glass) additives in different proportions subjected to freeze-thaw

The use of natural materials to improve the engineering properties of poor soils has become more common today. The main reasons of this situation are the economy, sustainability and environmental impact. The aim of this study is to determine the usability of the obsidian, which is a volcanic rock that is spreading mostly in the Eastern Anatolia Region, on the soils and foundation strengthening in the areas where the freeze-thaw events are frequently experienced. %5, %10 and %15 pulverized obsidian were added to the granular soil and unconfined compressive strengths were determined before and after freezing. Experiments were carried out on granular soil samples prepared by compression under standard proctor energy. At the end of the 28-day curing period where the highest unconfined compressive strength was obtained, the granular soil + 5% Obsidian mixture increased 63.50% before the freeze-thawing and 52.62% after freezing-thawing compared to the granular soil which is the main material. As a result, it was concluded that the highest strength increase of granular soil+ %5 obsidian mixture can be used especially in cold climatic zones.