Field assessment of enzyme-based stabilization for Sustainable Forest Roads in Sweden

Sweden's climate goals require innovative strategies for maintaining forest road infrastructure. Increasing the gross weight of timber transport trucks can significantly cut CO₂ emissions but also places added stress on gravel roads, demanding improved stabilization techniques. This study assesses the effectiveness of enzyme-based stabilization methods in enhancing the load-bearing capacity and durability of forest roads. Two test sections were constructed on a pilot road in Trosa, Sweden: one treated with Road Stabilizr (RS) and Dust Blokr-Sugar Blend (DB-SB), and another with TerraZyme (TZ). Field assessments, including lightweight deflectometer (LWD) testing, surface profiling, and visual inspections, were conducted before and after exposure to weather conditions and simulated traffic. Laboratory analysis confirmed that Trosa’s fine-grained material was suitable for enzyme-based stabilization. The results indicated that both stabilization methods improved the road’s structural strength, with LWD tests showing a 17 % increase in the dynamic deformation modulus (Evd) for the RS/DB-SB section and an 11.4 % increase for the TZ section after stabilization. Additionally, dust suppression benefits were observed in the RS/DB-SB section, contributing to reduced environmental impact and enhanced road longevity. This study highlights the potential of enzyme-based stabilization as a sustainable solution to improve forest road performance and minimize maintenance needs.