Statistical analyses of SEM-EDS results to predict the quantity of added quicklime in a treated clayey soil

Abstract

In the road construction sector, soil treatment is a method for increasing the strength and durability of fine soils that would otherwise be waste: the treatment with lime allows building embankments with clayey soils. However, in-situ and laboratory tests should be carried out to verify the correct addiction of lime during earthworks. This study deals with SEM-EDS analyses in order to identify the most reliable method to prepare specimens and obtain relationship between added quicklime and Calcium content after treatment. A natural clayey soil has been tested: more than one thousand values of Calcium content have been analyzed with statistical approach. The results from one-way and two-way ANalysis Of VAriance (ANOVA) and Tukey’s test confirmed the usefulness of SEM-EDS analyses to verify quickly the quantity of added quicklime in treated soils. The most reliable method for specimen preparation consists of a sequence of procedures similar to those that occur in worksite. The high variability of Ca content in the natural soil did not allow definition of a linear reliable relationship between the added quicklime and the after-treatment Ca content. Therefore, further experimentation is on-going to define a method based on SEM-EDS analyses and valid for clays with non-uniform chemical composition.