What is the primary function of the Liquid Limit in soil testing?

The primary function of the Liquid Limit in soil testing is to measure the consistency change of fine-grained soils. This test determines the water content at which the soil changes from a plastic state to a liquid state, which is crucial for understanding the soil's behavior under varying moisture conditions.

By establishing the Liquid Limit, engineers can assess the soil's workability and stability in engineering applications. This metric helps in classifying soils and reveals important characteristics relevant to construction and excavation projects. Understanding the consistency changes indicates how the soil will perform under different loading and environmental conditions, aiding in the design of foundations and other structures.

The other choices, while they reference aspects relevant to soil properties, do not specifically relate to the direct function of the Liquid Limit test. Determining soil density pertains more to bulk density assessments, assessing moisture retention involves different testing methods like Atterberg limits or moisture content tests, and evaluating particle size is specifically related to grain size analysis techniques like sieve analysis or hydrometer tests.