Associate Contractors License Practice Exam

The Modified Proctor test is the correct choice for evaluating fill material designated for high design loads, such as airport runways. This test is essential because it determines the optimal moisture content and maximum dry density of the soil when compacted, particularly under conditions that simulate the stresses and conditions found in high-load scenarios.

The Modified Proctor test uses a heavier hammer and a higher drop height compared to the Standard Proctor test, which results in denser soil compaction. This characteristic makes the Modified Proctor test particularly suitable for applications where the material must support significant loads and resist deformation, such as in the construction of runways.

In contrast, while the Standard Proctor test is used for general compaction assessment, it is less effective for high design loads since it does not adequately simulate the high energy and compactive effort typically necessary for such applications. The California Bearing Ratio (CBR) is useful for assessing the strength of subgrade materials but focuses more on the bearing capacity than on the compaction process itself. The Unconfined Compression Test measures the compressive strength of soil samples but does not provide information on compaction density related to moisture content, which is crucial for high-load applications. Therefore, the Modified Proctor test stands out as the