Investigation on the Engineering Properties of Peat Soil Stabilised Using Lime Stabilisation and Alkaline Activation

Abstract

Peat soil is typically classified as a problematic soil due to its expansive behaviour that possesses geotechnical drawbacks. Thus, the condition of peat soil must be improved prior to any construction works. Stabilisation of peat soil can be done via chemical stabilisation and alkaline activation while incorporating industrial by-products or wastes as addictive. This study aims to investigate the effect of press mud as an additive in lime-stabilized and alkaline activator-stabilized peat soils. Press mud is a by-product of sugarcane juice filtering. The lime adopted is at 3 % and 5.5 % while the alkaline activator is used in cold and warm condition. A total of 5 percentages of press mud have been employed, namely 0%, 0.25%, 0.5%, 1% and 2%. The investigations revealed that regardless of the percentage of lime adopted, the optimum moisture content increases while the maximum dry density decreases when the percentage of press mud incorporated is increased. However, when the lime content is increased, the optimum moisture content increases significantly. The UCS of lime-stabilised peat soil sample achieved the greatest strength improvement when the lime and press mud is used at 5.5% and 0.25%, respectively. In contrast, the unconfined compressive strength (UCS) of 3% lime-stabilised peat soil samples with or without press mud shows comparable 28-day strength. On the other hand, the UCS of peat soil stabilised with alkaline activator shows significant improvement, while addition of press mud further improves the strength. Nonetheless, using warm alkaline activator improves the early strength development but cold alkaline activator results in higher 28-day UCS.