In order to prevent segregation of the constitutents of a light concrete, with a base composed of cement, sand and expanded polystyrene beads, without recourse to adhesives, but be able to place (the concrete) by vibration as in a classic hydraulic concrete, several auxiliary substances were used. Among the products used, a one percent mixture (in relation to the weight of the cement) of polyethylene oxide and one percent of a carboxylate and metal sulfonate composition gave the best results, obtaining a concrete very easily put into place, of a good homogeneity and with smooth surfaces thanks to a light coating of a thin mixture of concrete.