Determination of Soil Stabilizer Content Using X-Ray Fluorescence

Currently, there are no simple methods routinely used to quantify the amount of chemical additive mixed into the soil during subgrade stabilization. Such a method was developed and validated for commonly used chemical additives including lime, cement kiln dust, and Class C fly ash mixed with different fine-grained soil types. The method employs the well-established x-ray fluorescence (XRF) technique. X-ray fluorescence was used to detect the amount of stabilizer, in the form of calcium oxide (CaO), in several stabilized subgrade soils. This technique was validated using four soils of different mineralogy and classification stabilized with three chemical stabilizers, and successfully implemented on several roadway stabilization projects. The results show that XRF accurately measures the amount of CaO in various soils, using different stabilizers, and can be a valuable tool for not only quality control, but forensic geotechnical investigations as well.