To not exclude materials in C595 that are already successful in C150 and to have harmonization between C150 and C595 on limestone characteristics. C150 and C595 use different methods to calculate the percentage of mineral forms in limestone. Some dolomitic limestones that are permitted for use in C150 cements are not permitted in C595 cements. Currently producers may need to source limestone from a different quarry to make blended cements, i.e. Type IL.