## 1 Introduction  
Current trends in construction prescribe the wider use of concretes with enhanced performance and durability, prioritizing cements alternative to ordinary Portland cement (OPC) [1]. The production of 1 ton of OPC requires an energy consumption of 3000-6000 kJ/kg and 1.5 tons of natural resources [2]. The requirement to reduce energy consumption and limit CO\({}_{2}\) emissions through the substitution of OPC clinker for wastes and industrial by-products [3, 4, 5, 6, 7] has been prescribed by the UN recommendations (Sustainable Development Goals) and the EU Green Deal [8, 9]. Thus, the use of alkali-activated cements (further, AAC), including the compositions without clinker constituent, is becoming more important in light of the above [10]. AAC are presented mainly by the system R\({}_{2}\)O-CaO-Al\({}_{2}\)O\({}_{3}\)-SiO\({}_{2}\)-H\({}_{2}\)O [11, 12], where R--Li, Na, and K. The system R\({}_{2}\)O-Al\({}_{2}\)O\({}_{3}\)-SiO\({}_{2}\)-H\({}_{2}\)O (geopolymers) is a particular case of AAC and is used in materials for special uses, such as coatings (sulphate-resistant, fire-resistant, decorative), adhesives, bonds, low-temperature ceramics, etc. [13, 14, 15]. The requirement for the concrete mix design with high consistency is determined by practical application [16, 17]. Concretes with controlled rheological properties are in great demand today [18, 19]. Expanding the AAC scope needs a one-part technology, using an alkaline component (i.e., precursor, alkaline activator) in a solid form [20, 21] and further mixing with water as it occurs in the case of OPC. The AAC production requires the use of plasticizing admixtures [22; 23]. This is necessary to achieve the required content of the alkaline component in the process of AAC hydration and control technology-related and physico-mechanical properties [24; 25; 26]. The action mechanism of traditional plasticizing admixtures in AAC differs from that in OPC [27; 28; 29; 30]. The effectiveness of plasticizing surfactant is connected with such characteristic features related to a chemical nature as the _degree of adsorption_ on the surface of cement mineral particles and the _stability of their molecular structure_. Adsorption of plasticizing surfactants (polymers) on the surface of particles in AAC systems is lower than in OPC systems. This can be attributed to the following: an electrokinetic (zeta) potential on the surface of the AAC mineral particles differs greatly from that of OPC--that is, less positive or negative values. The value of the zeta potential depends upon a cement compositional build-up and characteristics of the hydration medium or aqueous pore solution [31; 32; 33]. Charges of the functional groups of the polymer and zeta potential on the surface of the AAC mineral particles are in contradiction, negatively affecting the adsorption of plasticizing surfactants and, respectively, their effectiveness. Another reason is that in the systems with a high ionic force, the worsening of the adsorption of ionic surfactants is connected with \"competition\" in the adsorption action that takes place between the cement itself and functional groups of admixtures, for example, hydroxyl [33], sulphate ions [34], and anion of citric acid [35]. There is also competition between superplasticizers and alkaline activators in their interaction with the precursors (whether blast furnace slags or fly ashes). An assumption was put forward that in aqueous solutions of sodium silicates, a possibility of adsorption of the functional groups of anionic surfactants by the cement mineral particles is restricted by the competition not only with hydroxyls (OH\({}^{-}\)) but anions of silicic acid (SiO\({}_{3}\)\({}^{2-}\)) as well [36]. The adsorption ability of anionic surfactants, like melamine- or naphthalene-based surfactants, as well as vinyl copolymer in AAC, almost does not depend upon pH values; however, it is considerably lower compared to that of OPC [31; 37].