This specification pertains to admixtures for masonry mortars. Admixtures are substances other than the prescribed materials of water, aggregate, and cementitious materials that are used to improve one or more of the recognized desirable properties of conventional masonry mortar. Admixtures are classified by their effect on the performance characteristics of conventional masonry mortars. Admixed mortars are classified by their modified properties, as compared to a reference mortar. The following classifications are recognized: bond enhancer, workability enhancer, set accelerator, set retarder, and water repellent. The materials to be used include Portland cement, hydraulic cement, blended hydraulic cement, masonry cement, mortar cement, lime, and sand. Different test methods shall be implemented in order to determine the following properties: soluble chloride content, compressive strength, water retention, air content of plastic mortar, board life, time of setting, flexural bond strength, and rate of water absorption.