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European Journal of Applied Sciences – Vol. 9, No. 5

Publication Date: October 25, 2021

DOI:10.14738/aivp.95.10888. Shyshkina, A., & Shyshkin, A. (2021). Application of Colloid Surface-Active Substances as a Nanocatalyst of Reactions Cement

Hydration. European Journal of Applied Sciences, 9(5). 83-99.

Services for Science and Education – United Kingdom

Application of Colloid Surface-Active Substances as a

Nanocatalyst of Reactions Cement Hydration

Alexandra Shyshkina

Department of Technology of Building Products

Materials and Structures Kryvyi Rih National University, Ukraine

Alexandr Shyshkin

Department of Technology of Building Products

Materials and Structures Kryvyi Rih National University, Ukraine

ABSTRACT

The purpose of this work is to establish the fundamental possibility of using

complex complexes consisting of colloidal and molecular surfactants to catalyze the

hydration of cement compositions, the study of mechanical properties. As a result

of research, it was found that the introduction of colloidal surfactant into the

reaction powder concrete leads to a sharp increase in the strength of concrete at the

age of 7 days. It is noted the presence of the optimal content of colloidal surfactant

in the amount of 0.0007% by weight of water, which ensures the formation of the

maximum strength of the system. In the next step of the experiment, an additional

molecular surfactant was introduced into the system. As a result of experiments it

was found that the introduction of this substance increases the strength of concrete.

Thus, it was found that dimers of colloidal surfactant, which are nanocatalysts for

cement hydration reactions, lead to an increase in the strength of concrete and the

rate of its formation.

Keywords: surfactant; cement; concrete; strength.

INTRODUCTION

Every year in the world practice of concrete and reinforced concrete production the production

of high-quality, high and especially strong concretes is growing rapidly and this progress has

become an objective reality due to significant savings of material and energy resources.

Practically all countries actively develop new generations of concretes including with the

accelerated terms of hardening and a set of durability especially in monolithic construction.

To accelerate the hardening of concrete in the manufacture of structures using a variety of

methods:

- mechanical - increasing the specific surface of cement;

- thermal - the effect of elevated hardening temperature of concrete, both at normal

atmospheric and at elevated pressure;

- chemical - the introduction of additives that accelerate hardening [1].

Each of these methods has its drawbacks.

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European Journal of Applied Sciences (EJAS) Vol. 9, Issue 5, October-2021

Services for Science and Education – United Kingdom

Increasing the specific surface of cement has its limitations both in magnitude excess which

leads to reverse aggregation of cement particles [2] , and with the cost for manufacturing

concrete , which significantly increase Xia.

Heat treatment of concrete also has its limitations. So even according to regulatory documents,

to obtain high-quality (including frost-resistant) concrete, it is necessary to reduce the

temperature of isothermal heating to 333 K.

Traditionally, hardening accelerators are used to solve the problem of accelerating the

formation of concrete strength [3]. However, their disadvantage is the interference in the

chemical processes of hardening of binders, in particular, changes in their direction and the

formation of new "non-standard" minerals [3].

Recently, a new approach in the production of composites due to the targeted regulation of the

structure of materials at the nanoscale has become widely used. Nanomodification of the

structure of composites due to the introduction of very small (up to 100 nm) particles

in relatively small quantities (up to 0.1%) allows to obtain new in composition and qualitatively

different in structure and properties structural and special materials due to increased activity

of nanomaterials in the matrix structure. Researchers have shown the positive effect of

artificially synthesized carbon nanotubes on improving the structure of cement stone,

increasing its crack resistance and dynamic viscosity, water resistance, corrosion

resistance. This effect is manifested because the carbon nanotubes in the matrix act as

"embryos" of crystals of elongated shape, regulate the pore structure, contribute to its ordering

in the direction of increasing conditionally closed micropores. These positive changes in the

microstructure of cement stone, of course, affect the synthesis of artificial stone with the

predicted high properties, which is extremely important for the creation of waterproof and

corrosion-resistant mortars and concretes.

Analysis of the results of research in the field of surfactants showed that almost all modern

surfactants, which are used in concrete technology, refer to the molecular. At the same time,

from the point of view of physicochemical mechanics the most expedient application of colloidal

surfactants. These types of surfactants have features that distinguish them from other

surfactants. So with increasing concentrations of the molecules of

the surfactant's compounds form complexes, whose properties differ from the properties of

molecules. First of all, complexes of two molecules are formed - dimmers, a further increase in

concentration leads to the formation of complexes - micelles, which contain a significant

number of molecules (Fig. 1). Dimmers and micelles have the size and shape of

nanoparticles. These nanoparticles - dimmers and micelles, to a much lesser extent compared

to molecular surfactants shield the cement grains, which reduces their effect on the time of

hardening and hardening of concrete.

In addition, dimmers and micelles of colloidal surfactants practically do not lead to

hydrophobization of the surface of cement particles, absorbing hydrophobic particles that

could get into the concrete mixture or are specially introduced into it.

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Shyshkina, A., & Shyshkin, A. (2021). Application of Colloid Surface-Active Substances as a Nanocatalyst of Reactions Cement Hydration. European

Journal of Applied Sciences, 9(5). 83-99.

URL: http://dx.doi.org/10.14738/aivp.95.10888

Figure 1. Scheme of aggregation of molecules of colloidal surfactants

Cement-water systems are complex systems that are part of a network of subreactions that

relate to multicomponent reactions. One of the disadvantages of many multicomponent

reactions, as well as "cement-water" systems is their rather low speed. Thus, for the reaction of

hydration of cement minerals, the usual conversion time is several weeks or even months, so

the search for effective methods to accelerate these reactions is an urgent task.

At this time, a stable trend has been the application of different types of catalysis to almost all

reactions used in chemistry [4]. Even those transformations that were previously carried out

without the use of any catalysts are now involved in the range of catalytic processes, reflecting

the general direction.

It should be noted that the use of catalytic methods to increase the efficiency of multicomponent

reactions has a special specificity. Therefore, traditional methods of accelerating chemical

processes (the use of high temperatures, chemicals) often do not give the desired result. Of

course, they act non-selectively, accelerating the two-component side effects, leading to the

appearance of unwanted products in the system.

Thus, the use of the phase boundary in emulsions and suspensions to accelerate chemical

reactions, as well as the conduct of syntheses in thin films on the surface of inorganic materials

has allowed the development of new approaches to obtaining a variety of substances, including

heterocyclic compounds. Such methods that increase the efficiency of chemical synthesis

include the use of micellar solutions [5-7], which is becoming increasingly popular in recent

years.

Interest in micellar solutions arises because of their general ability to solubilize chemicals in

aqueous systems, and to act as a catalyst in chemical reactions. Micelle catalysis involves at least

three stages [7]. First, the substrates bind to the micelle, and then in this micelle or on its surface

there is a chemical reaction. In the third stage, the target product is isolated. The micellar

accelerating effect is caused by a combination of non-covalent interactions between micelles on

the one hand and reagents and the activated complex on the other hand. T ak a micellar solution

can be regarded as microheterogeneous system, the reaction catalyzed micelles effect also

affects local environment.