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This scientific paper delves into 1the physical and chemical aspects of the interaction of the microfibers of mineral and polymer origins in cement solutions. The research done showed that the polyester microfiber with the silicon appret impart the properties to the fiber that allow it to be used as the substrate for cement hydration products just as the vitreous substrate and on the one hand it prevents the surface hydrolysis in the alkaline environment and on the other hand it facilitates an optimum binding of the fiber in the cement stone structure. It was established that during the hardening of the cement composition containing the polyester microfiber the cement hydration products, in particular hexagonal Portlantide crystalline hydrates, cubic hydrated calcium aluminate and gel-like hydrated calcium silicate can form the shell on the surface of its fibers that corresponds to the condensation and crystallization structure of the microfiber material. It was established that the addition of the polyester fiber to the cement waterproof composition in the amount of 4.0 to 4.2 % of the cement mass provides a maximum increase in the bending strength, however an increase in its content above 4.5 % results in an abrupt decrease of the strength. An increase in the cement stone strength requires the condensation and crystallization structure of its new hydrate formations consisting of the particles of a minimum size in order to increase the number of contacts and to decrease the probability of the formation of dangerous flaws inside the particles. [ABSTRACT FROM AUTHOR]

A two-dimensional finite element model of a cement stone with the addition of fly ash particles from thermal power plants has been developed. Fly ash was modeled by solid and hollow circular particles, regularly located on a plate of unit thickness, simulating cement stone. The model is verified by comparing the results obtained using the SCAD and Abaqus computing systems. Based on the results of a computational experiment on the model, graphical dependences of the change in the Young's modulus and Poisson's ratio of cement stone were established depending on the flow of fly ash and the content of solid and hollow particles in it. [ABSTRACT FROM AUTHOR]

The present work is devoted to the synthesis and experimental study of zinc hydrosilicates. The possibility of low-temperature synthesis of such hydrosilicates from zinc acetate and silicic acid is demonstrated. The silicic acid was synthesized in presence of acidic Fe(OH)3 sol. It is found that the size of the nanoparticles is in the range 10-30 nm. High values of particle size correspond to the high values of silicic acid and Fe(OH)3 sol concentrations. High α values also lead to the formation of enlarged particles. The lowest pH value of the colloidal solution is observed for C(Fe(OH)3) = 0.7 % and α = 0.5. Such colloidal solution of zinc hydrosilicate is characterized by high aggregate and sedimentation stability. The latter allows to prolong the shelf life of nanomidifier. [ABSTRACT FROM AUTHOR]