For the tamping end of the rod, what is the recommended shape?

The recommended shape for the tamping end of the rod being rounded to a hemispherical tip is important for several reasons related to the principles of effective sample compaction in testing. A hemispherical tip allows for an even distribution of force when tamping, which contributes to more uniform compaction of the material being tested. This shape helps to minimize the likelihood of damaging the aggregate particles, leading to a more accurate representation of the sample's density and material properties.

In addition, a rounded end reduces the risk of creating fractures in the sample during tamping, which can skew the results. This design promotes a smoother interaction with the material, allowing for better penetration and compaction without excessive disturbance to the sample's structure. Thus, the hemispherical tip is favored in achieving a consistent and reliable density measurement in various testing scenarios. The use of this shape contributes to more standardized practices across different testing environments, thus enhancing the reliability and comparison of test results.