What is the drop height for the rammer used in the standard Proctor test?

In the standard Proctor test, the rammer used for compacting soil has a specified drop height of 305 mm (12 inches). This height is crucial because it ensures consistent energy application across test samples, which directly affects the density and moisture content measurements. The rammer impacts the soil in a controlled manner, and when utilizing a standardized height, you can reliably replicate testing conditions. This consistency is vital for comparing results across different tests and material types, making it an essential aspect of laboratory procedures in soil mechanics and civil engineering.