Correct answer is (a) True
Easiest explanation: Subgrades are commonly compacted before the construction of a road, pavement or railway track, and are sometimes stabilized by the addition of asphalt, lime, portland cement or other modifiers. The subgrade is the foundation of the pavement structure, on which the subbase is laid.
The load-bearing strength of subgrade is measured by California Bearing Ratio (CBR) test, falling weight deflectometer back calculations and other methods.
