**Abstract**

In order to improve the quality of a construction foam on a protein basis for nonautoclaved foam concrete, a proposal has been made to increase its stability by introducing nanosize additives—SiO2 and Fe(OH)3 sols. It is shown that the effect obtained is connected with various stabilization mechanisms. It is stated that these mechanisms are connected with different energies of chemical bonds formed between the molecules of the foaming agent and the injected sols. By means of electron microscopy, it is stated that the growth of foam stability is connected with an increase in the foam film thickness by one order. An increase in the coefficient of the foam resistance in the cement paste is shown. The stabilization of the construction foam leads to the possibility of using foam concrete hardening accelerators without destroying its structure. The resulting foam concrete is proved to get the increased compressive and bending tensile strength and reduced thermal conductivity and shrinkage in drying. The porosity of the foam concrete obtained is tested by means of mercury porometry. Its phase composition is investigated by X-ray phase and derivatographic analysis.

**Keywords:** construction foam, foam stability, protein foaming agent, nanosize additives, sol SiO2 and Fe(OH)3, non-autoclaved foam concrete
