No abstract

This study explored the possibility of employing burnt bricks produced locally by completely traditional methods as pavers on unpaved agrarian and rural earth roads in indigent communities. The pavers would eliminate the problems on such roads of being waterlogged and impassible during the rainy season months and those of environmental and health hazards from raised dust during the dry season months. Three clay soils were investigated in the Ado region of Western Nigeria. Burnt brick pavers were produced using entirely traditional methods readily available in the indigent and rural environments. The engineering properties of the brick pavers were determined and it was found that they satisfied the requirements stipulated by ASTM C 902 Specification for Pedestrian and Light Traffic Paving Brick, thus making them suitable for usage on the earth roads

This study on stabilization of tropical lateritic soils using self-cementing coal fly ash evaluated the effects of the addition of self-cementing coal fly ash on the engineering properties of three lateritic soils from southwestern Nigeria. The engineering properties investigated were those normally involved in highway design and construction. Increasing percentages (by weight of dry soil) of coal fly ash, ranging from 0% through 15% in 2.5% increments, were added and the geotechnical properties assessed. It was observed, for all the soils, that increasing coal fly ash contents brought about increasing improvements in the plasticity and mechanical properties of the soils. When comparing the average value of the properties at 0% coal ash content to their average values at 12.5% coal ash content, there was a reduction in the liquid limits (from 39.0% to 33.3%), a reduction in the plasticity indices (from 15.3% to 9.3%), a reduction in the optimum moisture contents (from 15.8% to 9.7%) accompanied by an increase in the maximum dry densities (from 1920 to 2180 kg/m 3 ), and an increase in the unsoaked CBR values (from 20.0% to 53.0%). For the stabilization of lateritic soils with coal fly ash, a coal fly ash of 12.5% by weight of dry soil was recommended because the improvements in the soil's properties tapered off at about that percentage of coal ash content.

A web-based geotechnical database management system (GDBMS) is developed for Nigerian soils. The point database (GeoDataNigeria) comprises the results of soil tests and observations from past soil investigations by different researchers and from diverse sources, with a view to maximizing the economic and scientific benefits of such test results by ensuring their unlimited accessibility. Adequate web interface is provided without limitations to all members of the public to query, report and visualize the data contained within the database. The system is designed to be infinitely extensible as managed by authorized administrators. Appropriate data templates are therefore provided for data submission while ensuring data integrity and accuracy before inclusion in the database. The data are stored raw without any pre-analysis, giving the potential users the freedom to make their own independent deductions from them. Recommendations are made for the establishment of a Geotechnical Data Centre to enhance the sustainable management and continual expansion of the database.

This study assessed groundwater quality around an open dump municipal solid waste (MSW) disposal site at Ilokun, a village on the outskirts of Ado-Ekiti, Ekiti State, Nigeria. Three geotechnical boreholes and three water boreholes (tube wells) were drilled at intervals of 15m, 30m and 45m away from the disposal site. Soil samples were obtained near the top and at the bottom of the geotechnical boreholes. Tests carried out on these samples included the sieve analysis, specific gravity, bulk density, natural moisture contents, Atterberg limits, linear shrinkage, and hydraulic conductivity tests, and these were used to index and classify the soils at the landfill dumpsite. It was discovered that the soils belonged to the clay and clayey-sand USCS groups (CL and SC mainly). Groundwater samples were taken from the three water boreholes (tube wells), and physical, chemical and microbiological investigations carried out on the water samples and on water obtained from an existing hand-dug well in the neighbourhood of the dumpsite. The parameters obtained from the tests on the samples were compared with the Guidelines for Drinking Water Quality of the World Health Organisation (WHO) and the Nigerian Standard for Drinking Water Quality of the Standards Organisation of Nigeria. The water quality parameters determined included: the acidity (pH), temperature, electrical conductivity (EC), colour and odour, turbidity, dissolved oxygen (DO), biochemical oxygen demand (BOD), total dissolved solids (TDS), total hardness (TH), and contents of the constituents such as total iron, chloride, sulphate, nitrate, etc. The microbiological characteristics determined are the Total Bacterial Count (Total coliform count), and the presence of Faecal streptococci, Staphylococcus aeurus and Escherichia coli. It was discovered that the groundwater at the dumpsite has been heavily contaminated and unfit for human consumption or usage without appropriate treatment to render them potable and fit for domestic use.