## 4 Discussion  
The principles for choosing plasticizing surfactants for use in the AAC materials based on the systematization of plasticizing surfactants that are known in the art were developed and proposed. The AAC materials were studied in terms of the basicity of AAC based on GBFS (M\({}_{\rm b}\) = 1.6-2.4), the content of alkaline components, and three degrees of dispersing of the AAC suspensions (low--heavyweight concretes, medium--building mortars,  
Figure 11: Effect of polyols (sorbitol, glycerol, ethylene glycol) on the plastic viscosity (**a**) and dynamic shear stress (**b**) of lightened grouts based on AAC with M\({}_{\rm b}\) = 1.1 (Mix 11) at t = 22 \({}^{\circ}\)C (blue) and t = 75 \({}^{\circ}\)C (red).  
Figure 12: Effect of polyols (sorbitol, glycerol, ethylene glycol) on the static shear stress of lightened grouts based on AAC with M\({}_{\rm b}\) = 1.1 (Mix 11) at t = 22 \({}^{\circ}\)C (**a**) and t = 75 \({}^{\circ}\)C (**b**).  
high--lightened grouts). Plasticizing surfactants were divided into high- (Figure 13) and low-molecular-weight surfactants (Figure 14). Depending on the type of hydrophilic (functional) groups, the above-mentioned surfactants were divided into anionic, cationic, and nonionic, and depending upon the structure of the carbon chain, they were divided into cyclic and acyclic (aliphatic) surfactants.  
Figure 14: Systematization of low-molecular-weight plasticizing surfactants in the action effect for the AAC materials. _Designation:_ R—recommended (green), P—permissible (yellow), N—not recommended (red).  
Figure 13: Systematization of high-molecular-weight plasticizing surfactants classified in the action effect for the AAC materials. _Designation:_ R—recommended (green), P—permissible (yellow), N—not recommended (red).  
A combined action of NaLST and polyhydrosiloxane in the AAC materials was studied, and a conclusion was made about the importance of a surfactant molecular weight as a factor determining its surface activity.  
The main criteria to be considered for choosing an appropriate surfactant were the following: the type of hydrophilic (functional) groups, structure of the carbon chain, and molecular weight.  
Polyesters were discovered to be the most effective for the materials based on AAC with high basicity (M\({}_{\rm b}\) = 2.4) like heavyweight concretes, building mortars, and lightened grouts, regardless of the degree of dispersing. These surfactants are still good for use in the suspensions based on AAC with M\({}_{\rm b}\) = 1.3-1.6. However, they are not recommended for the materials based on AAC with M\({}_{\rm b}\) = 1.1-1.2 due to a loss of plasticizing effect and uncontrolled changes of the consistency.  
High-molecular-weight surfactants like polyethers and ethoxylated fatty alcohols are -required for AAC with M\({}_{\rm b}\) = 1.1-1.2 to stabilize consistency, whereas low-molecular-weight surfactants like carboxylic acids and their alkaline salts are required for plasticizing the materials with low degrees of dispersing.  
Polyols are recommended for the materials based on AAC with M\({}_{\rm b}\) = 1.1-1.6 for a wider range of applications. These surfactants are effective independent of the degree of dispersing and are especially recommended for lightened grouts based on AAC with M\({}_{\rm b}\) = 1.1-1.2.  
Quaternary ammonium compounds are recommended to preserve the consistency retention of the suspensions based on AAC with M\({}_{\rm b}\) = 1.3.