This document explains and demonstrates the influence of plasticizing additives on concrete – wet cured concrete with aggregate based on silicon carbide specifically. These special products have been designed for the foundry industry and have specific requirements for treatment in their early curing stage. The paper deals with the optimization of the currently used formula in order to increase their mechanical and surface properties by adding several different types of plasticizing additives and/or combinations thereof. Indicators of the measured characteristics have been mechanical tests, surface properties, and bulk density, which represented the SiC indicator of the mixture. With regard to the measured data, it can be stated that the effect of the plasticizing additive on special concrete with SiC aggregate have been considerable and depended very much on the type of additive used and its dosage, as the resulting mechanical properties differed by up to 40%.