Granular soil stabilization alternatives for unpaved roads: a laboratory experimental evaluation

Abstract

Unpaved roads commonly exhibit subgrade deterioration associated with meteorological effects, insufficient preventive maintenance, traffic exceeding design loads, drainage deficiencies, and variability in soil and terrain conditions. To address this problem, soil-stabilization alternatives were assessed through laboratory testing aimed at improving performance under the laboratory conditions assessed of unpaved road grades. The study considered a granular A-2-4 (AASHTO) soil with a plasticity index around 9.6% and selected four stabilizing agents based on the reviewed literature: Type I Portland cement (cementitious benchmark), sodium chloride (NaCl), calcium chloride (CaCl2), and cane molasses. The agents were compared in terms of compressive strength, plasticity index, and permeability response. Results indicate that molasses meaningfully reduce soil plasticity and that a 2% dosage increases compressive strength compared to untreated soil; conversely, the chloride treatments showed no significant strength improvement under the tested conditions. Accordingly, further research is recommended on the molasses–soil-cement interaction, focusing on mechanical and hydraulic performance for practical implementation in unpaved road networks.