ABSTRACT
Carbonate minerals (calcium carbonate (CaCO3) and calcium-magnesium carbonate (MgCaCO3)) may be present in many geologic deposits and can act as cementing agents to hold individual particles or clusters of particles together, influencing soil behavior. The presence of carbonates in varying degrees can influence both the classification characteristics as well as the behavioral characteristics of soils and may help explain unusual behavior in a geologic deposit or differences in behavior within the same geologic deposit. The amount and type of carbonates present in soils depends largely on carbonates present in the original deposit or parent material and also depends on any addition or removal by precipitation or leaching that may have occurred after deposition.
Carbonate composition may be useful to geotechnical engineers in several ways, including: 1) evaluating effect on geotechnical behavior; 2) identifying individual geologic strata; 3) identifying leached/severely modified zones; 4) identifying cemented strata; and 5) identifying a source of bonding in soils. The amount and type of carbonates present may exert substantial influence on the engineering properties and behavior.
