Physical and geotechnical characteristics of stabilized and unstabilized tropical peat soil

Abstract

This paper presents physical and geotechnical characteristics of unstabilized (original) and stabilized peat soil samples from Sarawak, Malaysia. Peat soil is heterogeneous, with high compressibility, high water content, low specific gravity and has medium to low permeability. As a result, evaluation of physical and geotechnical properties are very important for any types of construction on it. Different physical and geotechnical properties e.g. organic content, loss on ignition, liquid limit, specific gravity, fiber content, compaction and Unconfined Compressive Strength (UCS) tests have been carried out on peat soil sample. Locally available fly ash (FA) from coal fired thermal power plant and commercially available quick lime (QL) were used as stabilizers. The amount of FA and QL added to the peat soil sample, is 5 to 25% and 2 to 8%; respectively, for curing periods of 7 to 120 days. The standard Proctor compaction test and UCS test were carried out on original and stabilized peat soil samples with the above mentioned percentages of stabilizer and results show that the UCS value increases significantly with the increase of FA and QL percentage and also with curing periods. But, with 15 to 20 % FA and 6 % QL added with peat soil, the UCS values slightly decreases up to 28 days and again increases after 120 days curing periods. Furthermore, liquid limit and specific gravity tests have been carried out with only for the FA stabilized peat soil samples, in order to comprehend their stabilized behavior.