Study of the Air-Entraining Behavior Based on the Interactions between Cement Particles and Selected Cationic, Anionic and Nonionic Surfactants

Abstract

The essential role of the air void size distribution in air-entrained cementitious materials is widely accepted. However, how the air-entraining behavior is affected by features such as the molecular structure of air-entraining agents (AEAs), the type of solid particles, or the chemical environment of the pore solution in fresh mortars is still not well understood. Besides, methods to assess the interaction between AEAs and cement particles are limited. Thus, in this study, the air-entraining behaviors of three kinds of surfactant (cationic, anionic, and nonionic) were examined. The general working mechanisms of these surfactants were studied by zeta potential and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Results indicate that the cationic surfactant entrains improper coarse air voids due to the strong electrical interaction between air bubbles formed by the cationic surfactant and negatively charged cement particles. The anionic surfactant interacts with the positively charged part of cement particles, and thus entrains finer air voids. The interaction between the nonionic surfactant and cement particles is very weak; as a result, the nonionic surfactant entrains the finest and homogeneous air voids.

Water–Sulfuric Acid Foam as a Possible Habitat for Hypothetical Microbial Community in the Cloud Layer of Venus

“…The main parameters providing foam stability are surface tension and the Gibbs' effect of the surface elasticity of thin liquid films which are reflected in the stability of separate bubbles [40,41]. Surface active substances (surfactants), while being added to the water phase, reduce surface tension at the gas-liquid boundary and decrease energy loss which results in the stabilization of the foam structure.…”

“…The heterophase system (water droplets in air phase) of Earth's atmosphere has been well studied, supramolecular forces acting at the boundaries of phases, conditions affecting the size and stability of droplets etc. have been extensively analyzed [39,40,45]. It is reasonable to assume that the laws behind intermolecular relations, the forces of intermolecular attraction and equilibrium distances between the surface layer molecules in liquid-gas systems on Venus are analogous to those on Earth.…”

“…The stability of ecological niches is based on the most important principle of the recovery of reaction components involved in energy release reactions driven by microorganisms. We should note that the stability of microbial communities does not contradict their ability to contribute to the stabilization of foam structure, in particular, owing to their ability to produce gaseous metabolites and to the synthesis of organic compounds acting as surfactants [40,51]. Such a hypothetical microbial community inhabiting the Venusian cloud layer can consist of thermo-acidophilic chemolithotrophic anaerobic microorganisms (Figure 1).…”

Impact of Surfactant and Calcium Sulfate Type on Air-Entraining Effectiveness in Concrete

“… Petit et al showed that, to maintain high foam stability, it is necessary to obtain monolayer adsorption of the surfactant on the solid’s surface [ 26 ]. Liu et al studied the air void parameters of mortars and the adsorption of different types of surfactants on cement grains [ 27 ]. The presented explanation was contrary to the aforementioned results obtained by Planck and Zingg [ 8 , 19 ].…”

“…Liu et al studied the air void parameters of mortars and the adsorption of different types of surfactants on cement grains [ 27 ]. The presented explanation was contrary to the aforementioned results obtained by Planck and Zingg [ 8 , 19 ].…”