9e53c149__Cement___Pavement_Interactive__ASTM_Types_of_Portland_Cement_2
[0] V [1] High Sulfate Resistance [2] 
Used as a precaution against severe sulfate action – principally where soils or groundwaters have a high sulfate content. It gains strength at a slower rate than Type I cement. High sulfate resistance is attributable to low C3A content.
Portland Cement | Pavement Interactive
2