Use of a Biopolymer for Road Pavement Subgrade

Cabalar A. F., Akbulut N., Demir S., Yildiz Ö.

Sustainability (Switzerland), vol.15, no.10, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 15 Issue: 10
  • Publication Date: 2023
  • Doi Number: 10.3390/su15108231
  • Journal Name: Sustainability (Switzerland)
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Social Sciences Citation Index (SSCI), Scopus, Aerospace Database, Agricultural & Environmental Science Database, CAB Abstracts, Communication Abstracts, Food Science & Technology Abstracts, Geobase, INSPEC, Metadex, Veterinary Science Database, Directory of Open Access Journals, Civil Engineering Abstracts
  • Keywords: aggregate, biopolymer, California bearing ratio, prediction model, unconfined compressive strength
  • Yıldız Technical University Affiliated: No


This paper presents an extensive series of laboratory works and a prediction model on the design of a road pavement subgrade with Xanthan Gum (XG) biopolymer. The experimental works were carried out using mixtures of conventional aggregate for road pavement construction and XG at the ratios of 0%, 1%, 2%, and 5%, by dry weight. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted during the experimental works at the end of the various curing periods (4, 8, 16, and 32 days). An example of an improvement in the UCS values for a specimen with 5% XG addition tested at the end of 4-daycuring yields about a 200% increment by the end of a 32-daycuring. The CBR values of clean aggregates were found to be increased by about 300% by 5% XG addition for all curing periods applied. Furthermore, the energy absorption capacity of the aggregates was observed to be increased significantly by both XG inclusion and curing period. Moreover, scaled conjugate gradient (SCG) training algorithm-based models developed for the prediction of CBR and UCS test results displayed a very high estimation performance with the regression coefficients of R2 = 0.967 and R2 = 0.987, respectively. Evidently, XG biopolymer is provably of use as an alternative inclusion in road pavement subgrades constructed with conventional aggregates.