Дворкін, Л. Й. та Ніхаєва, Л. І. та Мироненко, Т. В. та Dvorkin, L. Y. та Nikhaeva, L. I. та Myronenko, T. V. (2021) АДГЕЗІЙНА МІЦНІСТЬ МОДИФІКОВАНИХ ЦЕМЕНТНО-ЗОЛЬНИХ РОЗЧИНІВ. Вісник Національного університету водного господарства та природокористування (1(93)). с. 394-404.

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Анотація

В результаті досліджень встановлено позитивний вплив на адгезійну міцність цементно-зольних розчинів комплексних доба- вок-модифікаторів, що включають суперпластифікатор нафталін- фор-мальдегідного типу, повітровтягувальну та водоутримуючу добавки.

Title in English

ADHESIVE STRENGTH OF MODIFIED CEMENT AND ASH SOLUTIONS

English abstract

One of the main tasks of modifying mortars is to increase their adhesive ability. It is especially important to ensure the adhesiveness of adhesive masonry solutions. Due to the specificity and variety of phenomena that occur at different stages of the bonding process, the creation of a general theory of bonding is much more difficult. There are a number of ways to improve the adhesiveness of cement stone by limiting its content in concrete. One of them is based on the concept that considers cement stone as microconcrete. In accordance with this concept, it is advisable to increase the dispersion of the cement adhesive, ensuring its complete hydration. Cement grains larger than 40 microns, which are practically not hydrated, should be rationally replaced with fillers. This concept is based on the technology of dry and wet cement domel in combination with sand and other fillers, obtaining colloidal cement adhesive. Domel cement, however, has not become widespread due to high energy consumption, imperfect design of grinding units, rapid loss of activity of the ground mate rial. The use of colloidal cement adhesive, which is obtained using vibrating mills and mixers, is limited to a very narrow range of adhesive mixtures. Studies on the activation of cement binders, as well as mixtures of cement and fillers, have been significantly developed. The fillers include powdered or fibrous materials, which are used to save the binder and regulate the physical and technical properties of composite materials. One of the most common fillers of mortar mixtures is coal ash. Fly ash – removal actively influences at all stages of hydration and structure formation of cement systems, formation of structure of composite building materials, ie consecutive transition from coagulation structure to formation of a spatial crystalline framework. The introduction of fly ash in mortar mixtures as an active filler is an effective technological technique, which aims to reduce the consumption of cement, lime and improve a number of construction and technical properties of solutions. The criterion of physicochemical activity of fillers can be their surface energy. In accordance with the thermodynamic concept of adhesion, the main role in the formation of adhesive strength is assigned to the ratio of the values of the surface energy of the adhesive. There are currently a number of recommendations for activating binders and fillers by modifying the surface with various chemicals, including surfactants. As a result of research, a positive effect on the adhesive strength of cement-ash solutions of complex additives-modifiers, including superplasticizer of naphthalene-formaldehyde type, air-repellent and water-retaining additive is shown.

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