In which test is a hammer adjusted to 10 and 18 lbs for measurement?

• A. Standard Proctor Test
• B. Dynamic Cone Penetrometer Test
• C. California Bearing Ratio Test
• D. Falling Head Permeability Test

Answer: (B)

The Dynamic Cone Penetrometer Test involves the use of a hammer that is adjusted to specific weights, including 10 and 18 lbs, to drive a cone into the ground or a material. This test is primarily used to evaluate the strength of the subgrade and is effective for site investigations in the context of pavement design and construction.

The weights of the hammer play a critical role in determining the energy delivered to the cone during penetration, with the differing weights allowing for various levels of penetration resistance assessment. This feature enables engineers to make informed decisions regarding soil bearing capacity and to assess whether the subgrade material meets the required specifications for construction.

In contrast, the other tests listed focus on different aspects of material properties. The Standard Proctor Test is used to determine the maximum dry density and optimum moisture content of soils, while the California Bearing Ratio Test measures the strength of subgrade soils, and the Falling Head Permeability Test is conducted to assess the permeability of soils. Each of these tests has its own specific methodologies and equipment, distinct from the use of an adjustable hammer as seen in the Dynamic Cone Penetrometer Test.