ABSTRACT
The degradation of roads due to erosion and poor drainage systems in various parts of the country has resulted in increased expenses for road rehabilitation. A particular example is 19th Street, BDPA, where the road is frequently exposed to high levels of surface runoff, which may have caused a decline in soil quality over time. To address this issue, geotextiles, which are permeable materials that prevent soil erosion while allowing water to drain off, can be utilized to improve soil characteristics. The study presented in this research paper focuses on the use of a typical geotextile called HungKung Net, which acts as a means of filtration/drainage and separation of sub-grade from sub-base course. The objective is to investigate the behavior of soil samples collected and to determine their respective moisture contents.
The study location for this project was 19th Street, BDPA, Ugbowo, where soil samples were collected from three different depths: 1.0 m, 0.5 m, and 1.0 m for sample A, B, and C, respectively. To characterize and classify the soil, a series of laboratory tests were performed in accordance with British standards, including tests for natural moisture content, specific gravity, sieve analysis, atterberg limit, compaction, and California Bearing Ratio. To determine the moisture content of the soil samples after exposure to normal weather conditions, such as rainfall and sunshine, separation and filtration/drainage tests were conducted on four pavement models, each with dimensions of length = height 40 cm and width 20 cm. The three soil samples were then fitted with HungKung net, which has an opening size of 1.18 μm, while one sample (sample D) was left without geotextile. Each layer, marked at 12 cm intervals, was compacted with 55 blows from a hand rammer.
The separation and filtration/drainage tests carried out on the soil samples from three different locations at 19th Street, BDPA yielded moisture content results of 12%, 10.71%, 13.36%, and 15.53% for sample A, B, C, and D, respectively. The sample D, which did not contain geotextile, had a higher moisture content than the other samples after exposure to normal weather conditions. The use of HungKung net was found to effectively separate the sub-grade samples by providing a U-stabilizer feature that provides extended resistance to direct sunlight. The specific gravity tests resulted in 2.46 g, 2.59 g, and 2.59 g for samples A, B, and C, respectively. Sample A had a maximum dry density (MDD) of 1.67 g/m3 and an optimum moisture content (OMC) of 11.02%. Sample B had an MDD of 1.77 g/m3 and OMC of 11.12%, while sample C had an MDD of 1.59 g/m3 and an OMC of 16.09%. According to the sieve analysis test, sample A was classified as an A-2-4 soil consisting of silty/clayed gravel sand, sample B was classified as an A-2-6 soil with the same constituent material as sample A, and sample C was classified as an A-6 soil (i.e., clayey soil).
