ABSTRACT
The Methylene Blue Test provides a method to give a measurement of the adsorption of methylene blue dye by clay. The test procedure gives the methylene blue index (MBI) of the soil. The test is a simple indicator test that has been shown to be very useful in estimating other surface properties of fine-grained soils, such as Specific Surface Area (SSA) and Cation Exchange Capacity (CEC) when these laboratory tests are not readily available. The test method was developed in France in the 1970s (Lan 1977) for evaluating qualities of clay used for manufacturing ceramics, but it has grown in popularity in geotechnical engineering around the world as a means of evaluating the presence of smectite (montmorillonitic) clays in concrete aggregates. The test has now been used extensively in geotechnical studies, especially for fine-grained soils. The testing time takes between 15 and 60 minutes to complete, depending on the type and amount of clay.
