What weight hammer is used in the Modified Proctor Test?

In the Modified Proctor Test, a hammer weighing 10 pounds is employed for the compaction of soil samples. This test is specifically designed to determine the optimal moisture content at which a specified soil achieves maximum density. The use of the 10-pound hammer is a critical aspect of the test, as it impacts the compaction energy applied to the soil, which is set at 56,000 foot-pounds per cubic foot.

In contrast, the Standard Proctor Test utilizes a lighter hammer, weighing 5.5 pounds, and applies a different energy level, resulting in different compaction characteristics. The Modified Proctor Test is typically used for materials that will undergo heavier loading, requiring a higher degree of compaction than what would be achieved using the lighter hammer in the standard version. Therefore, the 10-pound hammer is integral to ensuring that the test effectively estimates the maximum dry density and optimal moisture content for engineering applications.