Penetration Characteristics Optimization and Design of Hilly Rural Road.

The present article deals with the optimization of additives used to improve penetration resistance of Himalayan soil and designing the pavement thickness. Eggshell powder, polypropylene fiber and sodium chloride were used as additives in a fine-grained soil for improvement in soil properties as a subgrade material. Optimization of additives was done using Taguchi method and MINITAB 21 software was employed for the analytical analysis of the responses obtained from the laboratory tests. The test results showed that the additives have potential for improvement in penetration resistance of fine-grained soil by 2.26 and 2.0 times that of untreated soil under unsoaked and soaked conditions respectively leading to considerable reduction in pavement thickness. The correlations given by the US Army Corps of Engineers and Indian Road Congress were used for determining the pavement thickness. Pavement thickness offered by US Army Corps of Engineers method is less and misleading to consider for pavement construction, whereas Indian Road Congress method has proved far better by offering rational lateral dimension for designing Indian rural hilly roads. [ABSTRACT FROM AUTHOR]