Which procedure describes the Standard Proctor Test?

The Standard Proctor Test is a widely recognized method used to determine the optimal moisture content and maximum dry density of soil. This test is essential for assessing soil compaction and ensuring that materials meet engineering standards for construction.

The correct answer describes the procedure accurately, as the Standard Proctor Test involves a 5-pound hammer that is dropped from a height of 12 inches. The test consists of compacting soil into a specified mold using this hammer, which simulates the conditions that soil might experience in the field. By repeatedly dropping the hammer onto the soil, the test provides insights into how well soil can be compacted when moisture is added.

Other options refer to different compaction methods or aspects not related to the Standard Proctor Test. For instance, the first option incorrectly states the specifications of the hammer and height, which pertain to the Modified Proctor Test, a variation of density tests that uses a heavier hammer and different drop height. The second option describes a method that is not part of the Proctor Test but instead refers to different soil testing techniques involving vibration. Lastly, the fourth option introduces a soaking process not required in the Standard Proctor Test, which focuses on dry density and moisture without the necessity of saturating the sample beforehand.