Strength Enhancement of Fibre Reinforced Peat with Fly Ash as Stabilized Subgrade Layer

Abstract

High content of organic matter and fibre within peat results in a high degree of porosity; causing peat to have low bearing capacity. This study focuses on the application of nylon fibre as reinforcing material with fly ash as the chemical stabilizer to enhance the strength of the peat. The standard proctor tests were conducted to obtain the optimum moisture content (OMC) for all samples in which these OMC is then used for sample preparation of both the Unconfined Compressive Strength (UCS) tests and the California Bearing Ratio (CBR) tests. Samples for this study were categorized into control samples and modified samples for comparison purposes. Additives that were being used in this study are 5% cement, 5% nylon fibre and 10%, 15%, and 20% fly ash. For UCS test, the samples were cured for 7, 14, 28 and 56 days, whereas only 7 days of curing for CBR test. Throughout the study, improvements of strength were observed where sample added with 5% cement, 5% nylon fibre and 10% fly ash recorded the highest compressive strength value, of 123.71 kN/m2. As for CBR test, all samples exceeded the minimum requirement of 12% CBR value for subgrade design recommended by JKR Malaysia with the highest CBR value obtained from samples added with 5% cement and 10% fly ash. The CBR values were 43.85% and 43.70% for unsoaked and soaked condition, respectively.