Prediction of Compaction Parameters of Soil Based on Liquid Limit

Determination of laboratory compaction parameters, i.e., maximum dry unit weight (MDU) and optimum moisture content (OMC) are prerequisite for ensuring proper field compaction in all earthwork projects. However, evaluation of MDU and OMC by employing laboratory Proctor compaction tests is laborious, time-consuming, and requires a substantial quantity of material. In this study, an attempt has been made to predict the MDU and OMC from the liquid limit (LL) of soil. To achieve this, standard and modified Proctor compaction tests were conducted on six distinct soil types, apart from the data available in existing literature. The six soil types were prepared in the laboratory by blending a fine-grained cohesive soil with varying proportions of sand (10%–50%), resulting in mixtures that span a wide range of plasticity indices. Regression analysis was performed on the experimental data, and correlations have been developed to predict the compaction parameters based on the liquid limit. Findings indicate that LL of the soil bears a good correlation ( \(R^2 > 0.90\) ) with both OMC and MDU. The liquid limit determination is relatively simple and cost-effective, requiring no specialized equipment, making it a practical alternative for preliminary field compaction assessments. The proposed correlations offer a valuable tool to designers and practicing engineers, enabling rapid assessment of soil suitability for compaction-related applications.