Durability Characteristics of Lime-Wood Ash Stabilized Lateritic Soils for Pavement Construction

This study was to assess the durability characteristics of limewood ash stabilized lateritic soils. This was carried out to establish it as a more environmentally friendly and cheaper alternative to cement addition under moisture condition as is practice in standard stabilization techniques for pavement construction. Field sampling and testing were carried out in accordance to British Standard ۱۳۳۷ of ۱۹۹۲. The soil samples were subsequently stabilized at constant lime contents of ۲% and ۴%, with variations of wood ash at ۲%, ۴% ۶% and ۸% and all percentages used were by the weight of dry soil to determine the influence of the stabilizing agents on the engineering properties of the soils. Durability tests were carried out according to BS ۱۹۲۴: Part ۲: ۱۹۹۰. Specific gravity was gotten to be ۲.۶۶, while grain size analysis value of ۲.۵۶%, ۸۶.۰۶% and ۱۱.۳۸% respectively was obtained for Gravel, Sand and Fine portions. The soils were classified as Fair to Poor, Clayey Soil (A-۷-۶) using the AASTHO classification system and Clay of High Plasticity (CH) in the Unified Classification System. The lateritic soils were of relatively high plasticity. Stabilization of the lateritic soil using lime in addition with wood ash was quite effective. Significant increase from ۲۰۰.۵kN/m۳ to ۵۳۲.۸kN/m۳ and ۵۷۱.۵kN/m۳ for ۲% and ۴% Lime addition at ۶% Saw Dust Ash Content were obtained upon stabilization. Durability tests carried out on the samples showed that a resistance to loss in strength within the range of ۶۷.۳۳% to ۷۵.۳۳% with maximum value obtained for samples with ۴% Lime and ۶% Wood Ash addition. Although, the values fell short of the ۸۰% used as evaluation criterion, the improvement of the soil shows effectiveness under poor moisture conditions, without losing much of their strength.

Keywords:

Stabilization , Lateritic Soil , Lime , Wood Ash , Strength , Durability