What do laboratory compaction tests provide in practice?

Laboratory compaction tests, such as the Proctor test, are critical in geotechnical engineering for assessing the optimal moisture content and density of soil. These tests provide insights into how much compaction can be achieved in the field by establishing the relationship between the moisture content of the soil and its dry density.

The correct response highlights that these tests determine the percent compaction and the required molding water. The results allow engineers to understand the maximum dry density that can be achieved at a certain moisture level and establish guidelines for field compaction efforts to ensure that soil meets necessary strength and stability criteria for construction projects.

In contrast, other options do not encompass the primary objectives of laboratory compaction tests. For instance, solely measuring moisture content does not provide the complete picture needed for construction applications. Similarly, assessing soil color and texture or expansion and shrinkage characteristics lies outside the scope of what compaction tests aim to ascertain, as these factors relate more to soil classification and plasticity rather than compaction performance.