Modifications in the Chemical and Mineralogical Composition of Compacted Mature Residual Soil Submitted to the Percolation of Acidic Leachates
E.P. Korf, P.D.M. Prietto, A.A. Silveira, C. Ulsen, N.C. Consoli, L. Bragagnolo
Soils and Rocks, São Paulo, 43(1): 159-167, January-March, 2020 | PDF
The main goal of this paper is to evaluate the chemical and mineralogical composition of a compacted residual clay soil with the addition of Portland cement and under different compaction conditions to observe and to understand the chemical and mineralogical changes that these structures undergo. Results of chemical and mineralogical composition of compacted specimens in different unit weights (14.5, 15.0 and 15.5 kN/m3) and percolated by different concentrations of aqueous solution of sulfuric acid (0, 1 and 2 %), under the application of a vertical load of 280 kPa. The modifications in the chemical and mineralogical composition of the specimens were evaluated by the combination of X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetry with differential thermal analysis and exploratory differential calorimetry (TG/DTG/DSC). The results have shown that the percolation of H2SO4 resulted in changes in the Fe2O3, CaO and SO3 contents for different cement contents and for specific weights; it was also evidenced dissolution of Fe2O3 in the upper layers and the formation of Ca and S compounds in the lower layers. No changes in mineralogy and soil morphology were found out.
Submitted on April 17, 2019; Final Acceptance on January 29, 2020; Discussion open until August 31, 2020.