ABSTRACT
The addition of lime to fine-grained soils to improve their engineering properties and behavior has been a common method of ground Improvement since the 1930s. The reaction of soil + lime is complex and depends on the mineralogy, Cation Exchange Capacity, Specific Surface Area, clay content and other soil constituents, such as Carbonate Content. The addition of lime to soil also results in an increase in pH of the mixture to a maximum value of 12.4 (lime–water mixture). At this pH the solubility of silica and alumina are significantly increased.
The Initial Consumption of Lime (ICL) test measures the pH of a soil + lime suspension using different percentages of lime added to the soil. Either hydrated lime (CaOH2) or quicklime (CaO) may be used for the test. A saturated solution of lime in distilled water completely free of carbon dioxide has a pH value of 12.4 at 25° C. This pH is required to maintain reaction between lime and any reactive components in the soil. Lime in different percentages by air dry mass of the soil are mixed with water and the minimum amount of lime needed to give a pH of 12.4 is defined as the ICL of the soil. This value is used as an initial guide to the amount of lime needed in the field to be mixed with the soil.
