An efficient transportation system requires a good network of roads provided with pavements that can withstand both the heavy and frequent traffic demands and environment variations while requiring minimal maintenance. However, roads are sometimes built where the sub-grade soil does not comply with the specifications and needs to be replaced with an acceptable soil that satisfies these requirements. To minimize the construction cost and the impact on the environment that the road construction would have, stabilizing agents (lime, cement or fly ash), are commonly used to improve the characteristics of in-situ soils. However, this process adds to the cost of road construction and maintenance. Therefore, alternative, environmental-friendly solutions have been investigated to reduce these costs. In recent years, enzymes have been used successfully to stabilize mostly fine-grained soils. This paper reports on an on-going research program on the use of various stabilizing agents to improve the properties of in-situ sub-grades for rural roads. Two locally-sourced soils were used in this investigation. The effects of cement, cement-fly ash mix and Perma-zyme binders on the properties of the selected soils were investigated. A series of tests was performed to establish the strength, stress-strain and deformation characteristics of the supplied soils. The results were compared to establish if Perma-zyme is suitable as stabilizing agent for the supplied soils.
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