Oil palm empty fruit bunch ash as a sustainable stabilizer for laterite sub-base of highway pavements

• Published in: IOP conference series. Materials Science and Engineering Vol. 640; no. 1; pp. 12086 - 12096
• Main Authors: Oke, J A, Osinubi, K J
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 13.11.2019
• Subjects: Additives; Ashes; California bearing ratio; Compacted soils; Compressive strength; Curing; Environmental impact; Laterite; Laterites; Local government; Oil palm empty fruit bunch ash; Penetration tests; Soil compaction; Soil improvement; Soil lime; Stabilization; Subbases; Unconfined compressive strength
• ISSN: 1757-8981; 1757-899X; 1757-899X
• DOI: 10.1088/1757-899X/640/1/012086

Laterite characterized by its reddish-brown colour collected from Ikorodu North Local Government Area in Lagos state was treated with up to 14 % oil palm empty fruit bunch ash (EFBA) by the dry weight of the laterite soil then compacted using the West African Standard (WAS) compaction. Index, compactions and strength (unconfined compressive strength; UCS and California bearing ratio; CBR) assessments were carried out on the untreated and treated laterite soil samples. Tests results showed a general improvement on the engineering properties with the addition of oil palm EFBA. UCS results increased with days of curing to peak values of 310, 658 and 725 kN/m2 for 7, 14 and 28 days respectively at 8 % oil palm EFBA treatment. The 725 kN/m2 strength recorded at 28 days curing period is in line with the 687-1373 kN/m2 strength requirement for the stabilization of material used for sub-base construction with additives other than lime or cement. Similarly, peak un-soaked and soaked values of 80 % and 50 % were recorded at 8 % oil palm EFBA treatment during the CBR test. These values also met with the 20 - 30 % CBR sub-base requirement specified by Nigerian General Specifications. Hence, laterite optimally treated with 8 % oil palm EFBA compacted with the WAS energy can be utilized for sub-base construction for low-volume traffic road. Advantages of its use include savings in the cost of soil improvement as well as the adverse environmental impact of oil palm empty fruit bunch waste.