What does a Group Index (GI) of 0 indicate about a soil?

A Group Index (GI) of 0 indicates that the soil is considered to have good subgrade properties. The Group Index is a numerical value used to classify soils, particularly within the context of highway and road engineering. It provides a means of assessing the suitability of soil for use as a subgrade material based on factors such as plasticity and moisture content.

A GI of 0 suggests that the soil meets the criteria for good quality, meaning it has low plasticity and good drainage characteristics. Such soils typically have adequate strength and stability when compacted, making them suitable for supporting loads and providing a solid foundation for pavement structures. This classification is essential for engineers to ensure that the materials used in construction are appropriate for the intended purpose, thus ensuring the longevity and durability of the infrastructure being developed.

In contrast, higher values of the Group Index indicate less favorable conditions, suggesting poorer quality soil that may require additional treatment or consideration in engineering design.