Semi-rapid drying and hardening hydraulic binder based on high-strength special cements and synthetic additives for making laying substrates. Enables the creation of adherent and floating screeds (also heating screeds) from 2 to 10 cm thick. To be mixed with gravel in a grain size curve from 0 to 8 mm. Shrinkage-free. The screed thus obtained is suitable for the subsequent laying of ceramic flooring already after 24 hours and the laying of wood after 4-7 days.