Garry Mcarnold2024-04-192024-04-192024-04-16https://hdl.handle.net/20.500.12311/1371Weak subgrade soils are usually expansive in nature characterized by swelling and shrinkage tendencies at different moisture contents, making then unsuitable for engineering projects like road construction without proper stabilization or reinforcement. Over the years, cement and lime have played a role as common stabilizers for improvement of such soils. However, in Uganda, the cost of these additives have been escalating creating a need to come up with alternative solutions. Henceforth, this research aims to assess the viability of river sand and saw dust ash as efficient stabilizers for the weak subgrade soils. Through analytical experimentation, the percentages of river sand were varied with increasing percentages of 15%, and saw dust ash was varied in reducing percentages of 3%. The objectives of the research were accomplished through a number of laboratory tests, such as gradation analysis, atterberg limits, proctor compaction test, and California Bearing Ratio (CBR) test. The discoveries after carrying out the tests disclosed the soil is clayey with high plasticity, calling for the need for stabilization. More so, the incorporation of river sand and sawdust ash resulted in a considerable decrease in the plasticity index, from 30.5% to 5.3%. Furthermore, the of addition of river sand sawdust ash led to a significant increase in the maximum dry density and a decrease in the optimum moisture content as its proportion was augmented. The optimum percentages of river sand and saw dust ash were 45% and 3% respectively. These end results disclose the prospects of river sand and sawdust ash as an economical alternative to traditional stabilizers like as cement and lime.enProject report