EFFICACY OF SODIUM CARBONATE AND CALCIUM CARBONATE IN STABILIZING A BLACK COTTON SOIL
The problem of damage to structures in expansive soils is world wide. These soils are very often referred as black cotton soils. The properties of black cotton soil may be improved to make the soil suitable for construction purposes. There are several techniques to improve the soil properties like sand cushions, CNS layer techniques, sand columns, stone columns, vibration techniques and by adding chemicals etc. Among these, chemical stabilizing is more expensive than other types of stabilization methods. But the main advantage of it is that setting time and curing time can be controlled. The efficacy of sodium carbonate and calcium carbonate is stabilizing a black cotton soil is presented in this paper. The efficacy of calcium carbonate is much better than sodium carbonate from strength and stability point of view.
Effect of Calcium Exchange Capacity on the Properties of Black Cotton Soil
This research work presents the efficacy of Calcium chloride and fly ash as an additive in improving the engineering properties of Black cotton soil which is expansive soil. Calcium chloride of 1%, 2% and 3% were mixed with black cotton soil used in the laboratory experiments. The fly ash percentages of 20% and 30% were used for compare the results obtained with calcium chloride percentages. The effectiveness of the calcium chloride and fly ash tested by conducting unconfined compressive strength and swelling pressure test. The unconfined compressive test has done for curing period of 7, 14, and 28 days to compare the results with 0 days unconfined compressive strength. The soil samples were subjected to wet and dry cycles and observed that increase of unconfined compressive strength and reduction of swelling pressure. The results were obtained from calcium chloride mixes soil sample after wet and dry cycles has better strength, less swelling pressure and less swelling index
Chemical aspects of quick-clay formation
Abstract In connection with the systematical examination of the slope stability in the Go¨ta River Valley in Sweden it was impossible to get a satisfactory explanation of the cause of the high sensitivity of quick clays which could be used in the continued examination as a basis for geotechnical investigations. It was concluded that the quick-clay problem must be regarded as a problem of colloid chemical nature. Many of the results obtained pointed out the fact that the surface properties of the grains will play an important role, and in this connection the problem with the possible existence of surface-active agents (dispersing agents) in natural quick clays has been studied. Systematic isolations of dispersing agents have been made by different methods, and the subsequent extracts have been analysed chromatographically. It is found to be easy to isolate dispersing substances by most of the methods tested, but it is very difficult to find any substances with a known composition. Instead, this part of the examination will approach the humic problem. In one case it has been possible to break up the complexes into individual components of known composition, i.e., in the case of fatty acids and soaps. Quick clay contains homologuous series of normal saturated fatty acids and for this reason soaps seem to be components which contribute to the quick-clay formation.