What type of rod must the tamping tool be made of?

The tamping tool must be made of steel or abrasion-resistant plastic because these materials provide the necessary durability and strength required during the compaction process. Steel offers excellent strength and resistance to wear, making it suitable for tasks that involve significant force and impact. On the other hand, abrasion-resistant plastic can withstand repeated use without degrading quickly, ensuring that the tool lasts over time without yielding to wear and tear, which is crucial in achieving consistent and reliable test results.

Other materials, such as aluminum and wood, may not provide the same level of robustness and may be prone to damage or deformation when subjected to heavy use. Rubber, while flexible and resilient, does not have the hardness needed for effective tamping, which requires a denser and more rigid material to properly compact the sample being tested. Thus, the combination of steel and abrasion-resistant plastic ensures the tool is both effective and long-lasting in its application.