GSB (Granular Sub Base) is a vital component in road and highway construction, forming the foundational layer beneath pavements. It is composed of a well-graded mix of granular materials such as crushed stone, gravel, and sand, which together ensure effective load distribution, structural stability, and proper water drainage. 

GSB plays a key role in preventing pavement failure by reducing stress on upper layers and improving the overall durability and lifespanof the road. Its strength and reliability make it essential for a wide range of applications — from national highways to rural roads and infrastructure development.