Why should compaction testing be performed?

Compaction testing is a critical process in highway construction that focuses on assessing whether the subgrade, which serves as the foundation for pavement, meets specified density standards. Proper compaction is essential to ensure that the soil has adequate strength and stability to support the loads placed on it by traffic and other environmental factors.

When compaction testing is conducted, it typically involves measuring the density of the compacted soil compared to the optimum density determined through laboratory tests. This process helps identify areas that may not have been compacted sufficiently, which could lead to issues such as settlement or pavement distress over time. Meeting the required density standards is vital for the durability and longevity of the roadway infrastructure.

While other options may have their own relevance in construction, they do not directly align with the primary purpose of compaction testing. For instance, soil color is not a determining factor for structural integrity, measuring water content is important for understanding moisture but not the immediate compaction requirement, and enhancing visual inspection quality, though helpful, does not replace the need for quantitative measures of compaction. Hence, ensuring the subgrade meets density standards is the fundamental reason for performing compaction testing.