Standard Specification for Rapid Hardening Hydraulic Cement

Abstract

This specification covers performance requirements for rapid hardening hydraulic cements. There are no restrictions on the compositions of the cement or its constituents. The specification classifies cements by type based on specific requirements for very early compressive strength development. The following are the four types of rapid hardening cement: (1) Type URH, ultra rapid hardening for use where high early strength is desired; (2) Type VRH, very rapid hardening for use where very high early strength is desired; (3) Type MRH, medium rapid hardening for use where mid-range hardening high early strength is desired; and (4) Type GRH, general rapid hardening for use when the higher strength properties of a Type VRH or a Type MRH cement is not required. Cement of the type specified shall conform to all of the applicable standard physical requirements for compressive strength and drying shrinkage. Cement shall be tested using the following methods: autoclave expansion; time of setting; compressive strength; drying shrinkage of mortar; heat of hydration; surface resistance; alkali silica resistivity; and expansion in water.