Concrete for ambitious engineering projects, including bridges, must meet certain requirements related to strength, water resistance, frost resistance and plasticity. The objective of the article is to improve the efficiency of concrete for bridge structures. The compositions of high-strength building composites have been optimized with a reduction in the proportion of the clinker component. The densest packing of filler particles has been achieved, providing a self-compacting effect during hardening. The compositions of building composites have been optimized at the macro-, micro- and nanolevels to obtain a high-density matrix packing and increase the strength of the composite (including taking into account the granulometric analysis of fillers and the choice of superplasticizer). New properties of high-strength building composites (rheology of highly concentrated dispersed systems, shrinkage deformations, workability, setting time, etc.) have been studied. The results of fresh properties of the developed mixtures showed their compliance with the P5 grade, which indicates that they have good transportability to the place of manufacture of bridge structures. The study of the physical and mechanical characteristics of cement composites (average density, porosity, compressive and bending strength, elastic modulus, frost resistance, shrinkage, Poisson's ratio) showed that the obtained materials can be effectively used for the construction of critical structures, including bridges.