Study of the Mineralogical Changes of Clay Due to Cement and Lime Addition Using X Ray Diffraction Technique

摘要

Light structures in semi arid regions suffer from damage due to expansive subsurface soils subjected to frequent wetting and drying. The use of cement and or lime as stabilizers is a common remedy known to geotechnical engineers. This research is aimed at investigating the mineralogical changes as viewed by x-ray diffraction when lime and cement are added to expansive clay. The x-ray diffraction showed that the mineralogy is not significantly changed due to lime addition while serious alteration and peak collapse of smectite minerals reported with the addition of cement. The percentage of added cement was found proportional to the change in expanding minerals in clay. Adding 6% of cement was found to reduce the expanding minerals of Al-Qatif clay by half compared to 3% cement is added. The stabilization and soil improvement using lime was due to flocculation of clay particles while the improvement obtained by adding cement was due to the cementatious bond and alteration of the mineral structure. Flocculation of clay particles and formation of cementatious bond were found associated with a significant drop in the maximum dry density and changes in the clay compaction characteristics. The outcome of similar studies will serve as a guide to select the appropriate additive and quantity to chemically stabilize clay soils.