Abstract: Calcareous sand is a marine sediment with main component of calcium carbonate. The calcium carbonate content in calcareous sand is a major index that of mechanical properties that is different from those in the quartz sand. In accordance with the general accepted classification standards, when the calcium carbonate content in the calcareous sand is more than 50%, the mechanical properties of the calcareous sand will have significantly different. Therefore, it is important to accurately determine calcium carbonate content in order to accurately evaluate the engineering properties of calcareous soils. The calcareous soil samples were collected from in Sanya, Hainan Province. Four different test methods, namely, comparative gasometric method, EDTA titration, atomic analysis method and atomic absorption spectrometry, were performed to determine the calcium carbonate content in soil samples. The results indicate that test results are very different among all four different methods. Further analysis indicates that the EDTA titration method had the highest correlation with the Xray diffraction method. Comparisons among the test difficulty, cost, analysis speed and test precision and other factors, indicate that the EDTA titration method is more suitable for the determination of calcium carbonate content in calcareous soils.

Key words: Calcareous Sand, Calcium Carbonate Content, Gasometric Method, EDTA Titration, Atomic Analysis Method, Atomic Absorption Spectrometry