A Review of Plant-Based Biopolymers for Application in Road Pavement

In some parts of Indonesia, the unavailability of natural materials that meet the required specifications makes road construction very limited. Efforts towards using natural alternative materials combined with local materials are expected to produce materials that meet the required specifications. One material that has attracted attention is plant-based biopolymers. This study aims to determine the potential use of plant-based biopolymers for road pavements. Six types of biopolymers were discussed: agar, starch, cellulose, lignin, sodium alginate, and xanthan gum. The test methods were physical characteristics, marshall stability, tensile strength, flexural strength, rutting, crack, fatigue, moisture, temperature resistance, resilient modulus, shrinkage growth, Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR). As a result, cellulose, lignin, and starch can modify asphalt to improve marshall stability, tensile strength, flexural strength, rutting, cracks, fatigue, moisture, temperature resistance, and resilient modulus. In subgrade applications, agar increased the UCS of clay from 155 kPa-320 kPa. Starch increased the UCS of clay soil by 54.63%. Lignin increased the UCS of clay soil by 44%. Cellulose increased the UCS of silt soil from 172.4 kPa–304.7 kPa, and CBR increased by 33.19%. Cellulose increased the UCS of expansive clays from 109 kPa-226 kPa. In lateritic soil, cellulose increased the CBR by 110.41% (soaked) and 34.95% (unsoaked). Sodium alginate increased the UCS of clayey sand from 132.17 kPa–393.41 kPa, silt soil from 340 kPa–381 kPa, and CBR 7.73%-15.47%. Xanthan gum increased the UCS of silty sand, from 2000 kPa-4900 kPa. These results indicate that plant-based biopolymers can be used in pavements for both asphalt mixture modification and subgrade stabilization.