Subgrade modulus is a measure of the resiliency or compressibility of the soil.

• A. A measure of resiliency or compressibility of the soil
• B. A measure of moisture content
• C. A measure of soil color
• D. A measure of soil texture

Answer: (A)

Subgrade modulus measures how stiff the soil is under load, which is a direct indicator of its deformation response. It reflects the soil’s ability to resist crushing and long-term settlement: a higher modulus means the soil is stiffer and less compressible, showing greater resiliency, while a lower modulus means it’s more compressible and prone to larger deformations. This property is used to predict how a slab will settle under the subgrade.

Moisture content isn’t what this value represents, since it’s about the amount of water in the soil rather than how the soil resists or recovers from loading. Soil color and texture describe appearance and grain size distribution, not the mechanical response under load.