Modification of strength properties of lime-stabilized laterites with sawdust ash

Abstract

The potential of sawdust ash as a stabilizer for lateritic soils was investigated to determine the modifying effects on strength properties required for road construction. Three laterite samples, A, B and C were collected respect- ively from Akoda, Osogbo and Ile-Ife (Nigeria). Atterberg limits and strength tests were performed on the raw samples and stabilized samples A and B only. Sample C exhibited Plastic Index > 15 and required no stabilizat-ion. Stabilization was performed at lime optimum of 6 % for sample A and 8 % for sample B using 2, 4, 6, 8, and 10 % of sawdust ash by weight of the samples. The unsoaked California Bearing Ratio increased from 1.69 to 4.64 % for sample A, but decreased from 2.62 to 1.92 % for sample B. The compressive strength of sample A increased from 34.25 to 73.26 kN/m2, but decreased from 53.27 to 50.43 kN/m2 for sample B. The shear stre-ngth increased from 28.49 to 46.70 kN/m2 for sample A, but decreased from 84.19 to 34.08 kN/m2 for sample B. Therefore, sawdust ash could be used to modify the strength properties of lime-stabilized lateritic soils for road construction.