Enhancement of Sub-grade Soil Strength with Additives: Cement and Molasses

Abstract

Increased vehicular traffic has tremendously increased the stresses on roads especially sub-grade. In order to make the roads more sustainable to the higher stresses, the stabilization of sub-grade is required. Therefore, the present study aims to enhance the subgrade soil strength by stabilization using cement and molasses (in combination with the lime). The results of the study propose using either 9% cement or 9% molasses (with 4.5% lime) for stabilizing the poorly graded sand. With the addition of cement, the liquid limit has decreased from 24 to 20%, however, with molasses it decreases to 19%. The maximum dry density of the soil has increased from 1.86 to 1.98 g/cm³ with the cement and increased to 2 g/cm³ by the addition of molasses. Moreover, the addition of cement increases the un-soaked CBR value from 1.75 to 3.5% whereas molasses increases the value to 2.83%. Likewise, soaked CBR value has augmented from 1.17 to 2.92% with cement and 2.54% with molasses. Therefore, the authors suggest using molasses for stabilization in case of low volume roads whereas for heavy traffic, cement should be preferred as it yield better results in enhancing the bearing strength of sub-grade as compared to molasses.