Unconfined compressive strength characteristics of stabilized peat

Abstract

Deep stabilized peat columns could be considered as attractive and economical foundation for construction of highway embankments on deep peat ground. However, peat itself is very problematic and failure in the formation of the columns with adequate strength was often attributed to unsuitable type and insufficient dosage of binder added to the organic soil. Organic matter in peat was known to impede the cementing process in the soil, thus, retarding the early strength gain of stabilized peat. To evaluate the strength characteristics of stabilized peat, laboratory investigation on early strength gain of the stabilized soil was conducted to formulate a suitable and economical mix design that can be effectively used for the soil stabilization. To achieve such purpose, the study examined the effect of binder, sodium chloride as cement accelerator and silica sand as filler on the unconfined compressive strength of stabilized peat after 7 days of curing in water. Binders used to stabilize the peat were Ordinary Portland cement, ground granulated blast furnace slag, sodium bentonite, kaolinite, lime and bentonite. All the stabilized peat specimens were tested using unconfined compression apparatus. The test results revealed that the stabilized peat specimen (80% OPC: 10% GGBS: 10% SB) with addition of 4% sodium chloride by weight of binder and 50% well graded silica sand by volume of wet peat at 300 kg m-3 binder dosage yielded the highest unconfined compressive strength of 196 kPa. This implied that, the higher the dosage of silica sand in stabilized peat, the more solid particles will be available for the binder to unite and form a load sustainable stabilized peat. It could be summarized that, as the rate of hydration process of stabilized peat was accelerated by inclusion of sodium chloride, the solid particles contributed to the hardening of stabilized peat by providing the cementation bonds to form between contact points of the particles. © 2011 Academic Journals.