A proposed modification to barium chloride method for CEC measurement of calcareous clayey soils

Cation exchange capacity (CEC) is one of the major characteristics of clayey soils which its correct determination is directly related to their industrial, engineering, and geo environmental engineering applications. It is reported by several researches that the CEC measurement of calcareous clayey soils cannot be precisely determined due to the solubility of calcite fraction. In addition, the appropriate soil weight for CEC determination is a common challenge among researches. This paper is aimed to propose a modification to the barium chloride method for CEC measurement of calcareous clayey soils. In this paper the common barium chloride method for CEC measurement is developed by saturating the exchangeable solution with carbonate calcium prior to addition of exchangeable solution to soil sample. A smectite soil was used in this study. The achieved results indicate that the proposed modification to the barium chloride method solves the common problem associated with the traditional barium chloride method in calcareous soils. Furthermore, the modification is simple in application and its performance takes in an acceptable period of time.