The identification and treatment of poor durability Karoo dolerite base course aggregate - evidence from case studies (comment and response)

Table 1 (referencing COLTO 1998) of the above-mentioned technical paper incorrectly states that the PI shall be < 12 when the PI is determined on the -0.075 mm fraction because -0.425 mm fraction is non-plastic. COLTO requires that the PI of the -0.075 mm fraction shall not exceed 12 without any qualification. If the PI exceeds 12, the material shall be chemically modified. After chemical modification the PI of the -0.075 mm fraction shall not exceed 8. The Technical Committee involved in the COLTO 1998 edition based these criteria.