Table 400-1 of MORTH

Granular Sub Base (GSB) is a fundamental component used in road construction, serving as a sub-base layer. Whether sourced naturally or created through artificial means, GSB consists of crushed aggregates that are utilized in granular form. Positioned above the subgrade layer and below the base layer, this essential layer is commonly referred to as the granular subbase.

Key Benefits Of GSB

  • Load Distribution and Prevention of Deformation

    GSB evenly distributes surface wheel loads, reducing deformations and minimizing stress on the subgrade, enhancing durability.

  • Enhanced Pavement Strength and Stability

    The Granular Sub Base helps in strengthening the pavement structure, improving stability and resistance to deformation like rutting.

  • Effective Drainage

    It acts as a reliable drainage layer, preventing moisture accumulation and preserving pavement integrity.

  • Stress Dispersion

    GSB disperses wheel load stresses, minimizing localized damage and improving overall pavement performance.

GSB Applications

  • Granular Sub Base (GSB) serves as a sub-base course whose primary function revolves around ensuring effective drainage within the pavement system, with secondary involvement in load transfer support
  • In flexible pavements, the sub-base layer, including GSB, plays a pivotal role in boosting the load-carrying capacity. By distributing the load across layers with a finite thickness, GSB reduces the risk of frost susceptibility and enhances overall stability