Journal of the Korean Geo-Environmental Society ISSN:1598-0820(Print) 2714-1233(Online) 한국지반환경공학회 논문집

To determine relative density, it is essential to establish the minimum and maximum dry unit weights. The methods proposed by Bowles and those using an automatic compaction device yield higher maximum dry unit weights compared to the ASTM method. In this study, the Bowles method was considered. Since the Bowles method uses a rubber mallet, the maximum dry unit weight is significantly influenced by the experimenter’s individual differences and proficiency. To mitigate this variability, indoor experiments were conducted to verify the feasibility of using an air hammer as a mechanical alternative to the rubber mallet. The results showed that the maximum dry unit weight increased with the number of blows, air pressure, and compaction layers when using the air hammer. Consequently, it was confirmed that the Bowles method using an air hammer is a valid experimental method for determining the maximum dry unit weight, achieving higher values compared to using a rubber mallet.