## 1 Introduction
The lower degree of adsorption of PCE in AAC is a result of a competitive adsorption action of the functional groups of polymer and hydroxides [38; 39]. Thus, a certain molecular structure of PCE is to be synthesized to provide the required degree of adsorption. The adsorption of polymer increases with the increase in charge of its main chain and _molecular weight_, as well as the decrease of the surface area of the cement mineral particles and surface covered by polymer [40; 41]. In AAC, the required adsorption of the polymer can be reached through an increase in charge, as well as the adjustment of its _molecular weight_ and length of side chains [39]. A variety of high- and low-_molecular-weight_ compounds or their combination can be used with high effectiveness as plasticizing surfactants in AAC [36]. High molecular surfactants form, first of all, structured adsorption layers on the surface of the interphase, whereas low molecular surfactants decrease surface tension, thus promoting the processes of dispergation and plasticization. The use of ionic surfactants in combination with nonionic surfactants is effective in the plasticization of AAC [42; 43; 44]. Ionic surfactants are adsorbed due to hydrophilic groups; nonionic surfactants increase surface activity due to the covalent bonds of hydrophobic (lipophilic) groups. The stability of a molecular structure is another important factor that determines the action effect of plasticizing admixtures. The results of infrared spectroscopy confirmed the degradation of the molecular structure of admixtures in the hydration medium of AAC. Naphthalene-based admixtures are characterized by a relatively stable molecular structure in NaOH, but they undergo alterations in the SO\({}_{3}\) groups when waterglass is used as an alkaline component [29; 45; 46]. Melamine-based admixtures undergo the same alterations in their formulation both NaOH and waterglass. PCE undergoes alkaline hydrolysis of the ester groups in the mentioned high alkaline mediums [46]. Furthermore, it can be concluded that a decrease in the action effect of plasticizers in the AAC water suspensions is caused not only by high pH values but also by another independent factor--_the nature of the alkaline component (its anion)_. The highest degree of degradation, accompanied by cleaving of side chains due to alkaline hydrolysis, was found in sodium and potassium silicate solutions compared with sodium and potassium hydroxides [47]. Soluble sodium silicates also lead to structural changes in melamine- and naphthalene-based admixtures [48; 49]. A molecular structure degradation of traditionally used plasticizing admixtures, when used in the AAC concretes, results in a higher water content. With the increase in water requirement, the strength decreases [50]. When the alkaline component is represented by sodium hydroxide (NaOH) of a low concentration (0.3%), the plasticizing effect is achieved through the use of sodium salts as admixtures: sodium phosphate (Na\({}_{5}\)P\({}_{3}\)O\({}_{10}\)), sodium gluconate (NaC\({}_{6}\)H\({}_{11}\)O\({}_{7}\)), sodium citrate (Na\({}_{3}\)C\({}_{6}\)H\({}_{5}\)O\({}_{7}\)), and sodium tartrate (Na\({}_{2}\)C\({}_{4}\)H\({}_{4}\)O\({}_{6}\)) [51]. Polyols (ethylene glycol C\({}_{2}\)H\({}_{4}\)(OH)\({}_{2}\), glycerol C\({}_{3}\)H\({}_{5}\)(OH)\({}_{3}\), sorbitol C\({}_{6}\)H\({}_{8}\)(OH)\({}_{6}\)) are effective admixtures for plasticizing the NaOH-activated AAC [52]. The influence of polyols on the consistency of the AAC concrete mix and its retention time, as well as on the concrete strength, depends upon the quantity of hydroxyl groups in a molecule and its _molecular weight_[36]. Sodium lignocellulosic (NaLST) exhibits an independent plasticizing effect on AAC with different activators (NaOH, Na\({}_{2}\)CO\({}_{3}\), Na\({}_{2}\)SiO\({}_{3}\)) [53; 54; 55]. However, the action effect of NaLST as a plasticizing admixture is restricted by its high dosage [56].