Use of Water Reducers, Retarders, and Superplasticizer
Retarding admixtures. The use of this admixture is defined in ASTM C494. There are two kinds of retarders, defined as Type B (Retarding Admixtures) and Type D (Water Reducing and Retarding Admixtures). The main difference between these two is the waterreducing characteristic in Type D that gives higher compressive strengths by lowering w/cm ratio.