The Challenge
A 22 km section of the Kaduna–Abuja corridor had failed repeatedly because of a weak lateritic subgrade that pumped fines into the sub-base during the rainy season, causing rutting and pothole formation within months of resurfacing.
Our Solution
A woven geotextile separation layer was laid across the full carriageway width to stop fines migrating into the imported sub-base, with a biaxial geogrid placed directly above to reinforce the sub-base and distribute axle loads across the weak subgrade.
The Outcome
Sub-base thickness was reduced by 150 mm against the original design, cutting aggregate haulage by an estimated 9,000 m³ across the section, and the rehabilitated section has carried two full rainy seasons without rutting.