Goal. Consider the use of hybrid slag binders with alkaline and sulfate activation, as well as increased dispersion in the presence of a fine fraction of expanded clay in order to obtain a concrete composite with guaranteed quality indicators. Methods and materials. wo types of coarse aggregate were used in light-weight concrete mixtures: expanded clay gravel. For fine aggregate, expanded clay sand was used, which was sieved through a 1.25-mm sieve to eliminate large carbonate particles and clay. A hybrid binder based on slag, phosphogypsum, and cement dust was used as an activator. The properties of binder components were assessed in accordance with relevant regulatory standards and Russian standards. Results. Improvement of the structure of expanded clay concrete on sulfate-slag binders is caused by a change in the conditions of its formation. Reducing the viscosity of the suspension due to an increase in the Sud of the binder at the stage of preparation of the expanded clay mixture reduces the viscosity of the binder solution and contributes to better colmatation of open pores of coarse aggregate. Under such conditions, the contact surface раствора of the binder solution with the aggregate increases, which contributes to the intensification of contact interaction processes. The material composition of such binders causes a lime-gypsum environment during the hardening of expanded clay concrete, which intensifies the reactivity of expanded clay aggregate during pretreatment of the binder. Practical significance. The results obtained will contribute to the development of production of hybrid cements in places where large-tonnage cements are formed. by-products of industry, in the manufacture of concretes, including light ones such as expanded clay.