Effects of polyvinyl acetate content on contact erosion parameters of pavement embankment constructed by dispersive soils

This study deals with the contact erosion investigation and mechanical properties of both the un-stabilized and polyvinyl acetate (PVAc)-stabilized dispersive embankment layer. To this end, in addition to performing the specific dispersivity identification tests, i.e. pinhole and double hydrometer tests and contact erosion test for measuring the contact erosion parameters, a series of basic geotechnical tests was carried out. The microstructural changes with the aid of scanning electron microscopy (SEM) test and financial analysis were studied respectively to understand underlying mechanisms of stabilization and to estimate the economic benefits owing to PVAc addition. The results indicated that 2% PVAc content was the most effective proportion such that it decreased the dispersion potential, mass loss, and settlement of the dispersive soil by 69.6%, 70.5%, and 68.5% respectively, and at the same time, the strength of the samples increased by 107.4% only after 7 days of curing. The reaction between the polarity carboxyl hydrophilic group of PVAc and the hydroxyl group of the soil led to form the strong hydrogen bonds, and therefore, the structure stability and strength of the soil were enhanced. The formation of reticulated membrane structures and stronger bonds between soil particles, as documented by SEM images, testified to the excellent efficiency of PVAc in dispersive soil stabilization. Finally, the accuracy of available correlations between soil dispersivity and contact erosion parameters was examined, and then, the correlations were developed to cover a broad range of soils by using the results of this study.