Effects of wood saw dust ash admixed with treated sisal fibre on the geotechnical properties of lateritic soil

摘要

The preliminary investigation conducted on the lateritic soil collected at Shika, Zaria shows that it falls under A-7-6 (10) classification for AASHTO (1986) and CL according to unified soil classification system USCS (ASTM 1992). The soil was treated with both wood saw dust ash (WSDA) and treated sisal fiber, in stepped concentration of 0,2,4,6, and 8% for WSDA and 0, 0.25, 0.5, 0.75 and 1% treated sisal fibre by dry weight of soil using Standard proctor. The Sisal Fibre was treated with Sodium Borohydride (NaBH₄) (1% wt/vol) for 60 minutes at room temperature to remove the cellulose content present in the Fibre. Statistical analysis was carried out on the obtained results using XLSTART 2017 software and analysis of variance with the Microsoft Excel Analysis Tool Pak Software Package . The liquid limit (LL) of the soil was found to be 48% while the plastic limit(PL) is 21.27%. The maximum dry density(MDD)however, decreases generally from a value of 1.85 Mg/m³ to 1.68Mg/m³ at 0.25% sisal fiber content/0% WSDA. It has its least value of 1.57Mg/m³ at 1% sisal fiber and 8% WSDA. The OMC increased from 18 % of the natural soil to 23.7% at 0.75% sisal fiber / 6% WSDA content. There was a general increase in the value of UCS of the soil-sisal fibre mixture with WSDA content from 100 kN/m² of the natural soil to 696 kN/m² at 0.75 % sisal fibre content / 6% WSDA. The UCS value met the standard of 687-1373 kN/m² requirements of sub base for adequate lime and cement stabilization, respectively (Ingas and Metcalf 1972).