ASTM C 50 Type I/II Cement is a dual designation indicating that the cement will meet either Type I or Type 2 Cement. ASTM stands for the American Society for Testing and Materials. ASTM C 50 is for physical tests, a standard practice for sampling, sample preparation, packaging, and marking of lime and limestone products. Type I is to be used when the special properties specified for any other type are not required. Such applications for Type I are for general construction like most buildings, bridges, pavements, precast units and more. Type II is for general use, more especially when moderate sulfate resistance or moderate heat of hydration is desired. Applications for Type II are for structures that are exposed to soil or water containing sulfate ions. Type II is important because when sulfate attacks concrete is can cause severe damage to concrete structures, when this happens it creates stresses that force the concrete to expand and crack.