Salt Effects on Atterberg Limits of Bentonite Clay
摘要
Bentonite clay (BC) is a highly expansive soil, that shows very complex behavior in contact with water or liquid solution. During the last few dec-ades, extensive research studies have been carried out on swelling or shrinkage characteristics of BC by incorporating different mineral or chemical additives. However, the impact of salt on Atterberg limits of BC has hardly been studied. The main objective of the present study is to investigate the salt effects on the Atterberg limits of bentonite clay. The study analyzed the results of Atterberg limits i.e. liquid limit (LL), plastic limit (PL), shrinkage limit (SL) for five different mixes prepared with 100 g of BC by adding 1, 2, 3, 4, and 5% of either black salt or white salt. The study indicates that the incremental addition of salt content leads to a consistent fall in the LL and PL of BC. It may be attributed to alterations in the physicochemical properties of BC, specifically the water-adsorbing capacity of tiny BC particles. The study also reveals the interesting trends in shrinkage limit (SL) variation of BC owing to salt addition. No considerable rise in SL is initially noticed up to 3% of white salt. However, beyond this limit, the rise in SL became significant. Conversely, a considerable rise in the SL of BC is continuously noted due to incorporation of black salt. The effects of 5% of both white and black salt on the SL are found to be comparable. Thus, the study intends to showcase an understanding of complex clay-salt interactions to help in developing tailored solutions for soil improvement and relevant construction practices.