Improvement of subgrade soil by blending tyre driven aggregate (TDA)

Pavements are largely affected by the inherent variability of soil nature which may be change in type and condition. Subgrade soils are characterized by their resistance to deformation under load, which can be measured in terms of strength and stiffness. The subgrade strength of soil is the key factor to ensure the sustainability of the pavement and is considered as of prime importance for design of pavement. If pavements are constructed on weak subgrade soils, then there are chances of possible settlement and subsequent pavement failure. The aim of study is to improve the bearing pressure of existing subgrade soil using tyre driven aggregates obtained from scrap tyre. The California Bearing Ratio (CBR) tests were performed on existing subgrade soil and the improved soil with 5%, 15%, and 30% replacement of tyre driven aggregates. The maximum dry density of soil was found to be 1636 kg/m3 at optimum moisture content of 21.26%. The CBR of the existing ground was measured as 3.90%. It was revealed that CBR value was improved by 5.1%, 10% and 28.7% of existing value when subgrade grade soil was replaced by 5%, 15% and at 30% demolished aggregates, respectively