A Study on Stabilization of Pavement Subgrade Soil using Chemical Additive

Abstract

The subgrade is a critical component of flexible pavement systems, as its engineering properties significantly influence the strength, stability, serviceability, and durability of the pavement structure. This study investigates the stabilization of pavement subgrade soil using a chemical additive to improve its engineering performance. Soil samples collected from the selected location are treated with different proportions of the chemical additive, and their properties are evaluated through laboratory investigations. The chemical additive is incorporated into the soil at varying percentages of 0.1%, 0.2%, 0.3%, and 0.4% by weight of dry soil. The effectiveness of the additive is assessed by comparing the properties of untreated and treated soil samples. Laboratory tests including consistency limits, Modified Proctor compaction test, moisture–density relationship, Unconfined Compressive Strength (UCS), and California Bearing Ratio (CBR) are conducted to determine the changes in the engineering characteristics of the subgrade soil. The study focuses on evaluating the influence of the chemical additive on maximum dry density, optimum moisture content, shear strength, compressive strength, and bearing capacity of the soil. The experimental results are used to identify the optimum percentage of chemical additive that provides maximum improvement in the subgrade properties. The findings of this study are expected to demonstrate the suitability of chemical stabilization as an effective and economical technique for improving weak subgrade soils and enhancing the performance and service life of flexible pavement structures. Keywords: Pavement Subgrade Soil, Soil Stabilization, Chemical Additives, Soil Strength, California Bearing Ratio (CBR), Atterberg Limits, Compaction, Bearing Capacity, Flexible Pavement, Subgrade Improvement.