Development of Unpaved Road Maintenance Management Strategy for Earth Reinforcement Using Fibre Geotextile and Cohesive Soil for Sandy Subgrade Improvement: A Case Study of Lindi District

Unpaved rural roads in Lindi District suffer from poor performance due to weak sandy subgrades with low cohesion and high erosion risk, especially in coastal areas. Traditional stabilisation using cohesive soils has proven insufficient for long-term durability. This study aimed to develop a sustainable maintenance strategy by reinforcing sandy subgrades with cohesive soil and fibre geotextile. This study used an experimental research design to develop a cost-effective unpaved road maintenance strategy by stabilising overburden sandy subgrades with fibre geotextiles and cohesive soil in Lindi District, Tanzania. Through field sampling and laboratory testing, including CBR, UCS, Proctor compaction, and Atterberg limits, the study found that blending 30–45% cohesive soil with sand improved strength, moisture retention, and workability. Adding fibre geotextile further enhanced compressive strength, load distribution, and deformation resistance, with CBR values increasing from 3% to 14%. Based on these results, a maintenance strategy was proposed focusing on material selection, application methods, and performance monitoring. The study recommends that TARURA and TANROADS adopt this approach and implement a 250-meter trial section. Additional recommendations include training for engineers, preventive maintenance budgeting, and regular performance assessments. The findings offer a practical, cost-effective solution to improve the strength and durability of unpaved roads in sandy soil regions