Comprehensive study of subgrade stabilization with polyacrylamide (PAM) in Ciwaruga, Indonesia: Increased bearing capacity

This study aims to analyse the effect of 0.4% Polyacrylamide (PAM) stabilization on the California Bearing Ratio (CBR) values of subgrade soils in field conditions, as well as to formulate a practical method for implementing PAM-based soil stabilization. The research was conducted through both laboratory testing and direct field application, using a PAM concentration of 0.4% by the dry weight of the soil. The local soil sample, obtained from Ciwaruga Road, exhibited an Optimum Moisture Content (OMC) of 30.6% and a Maximum Dry Density (MDD) of 1.39 g/cm³. Initial CBR test results indicated un-soaked and soaked values of 3.72% and 2.81%, respectively. Following stabilization with 0.4% PAM, the laboratory CBR values increased to 8.15% (un-soaked) and 7.19% (soaked). Field implementation demonstrated a further increase in subgrade CBR, reaching 8.52% on the fifth day of curing. The findings of this study indicate that 0.4% PAM effectively enhances the load-bearing capacity of subgrade soils and has the potential to reduce the required pavement thickness in road construction.