Interchangeability of dry mixes: putties, plasters and block adhesives

Recommendation points

• Properties of building binders
• Adhesives
• Dry plaster mixes
• Screeds and mortars for masonry

Usually we point out the very categorically the fact that each material has its own scope, but there are exceptions to this rule. We will tell you if you can mix different plaster, adhesive and finishing mixtures or use them for other purposes..

Properties of building binders

The vast majority of building mixtures include three components: filler, binder and various modifiers of an organic nature. In some cases, the functions of two of the components can be performed by the same substance, for example, gypsum in the composition of the finishing plaster simultaneously serves as both a filler and a binder.

There is practically nothing innovative in modern building mixtures: the addition of PVA glue to the solution for laying tiles was practiced by Soviet builders in the middle of the last century, as well as increasing the frost resistance of the screed by adding sodium sulfite to the cement-sand mixture. The main advantage of dry mixes is a very long shelf life and a simple preparation procedure immediately before use without the need to personally control the proportions of the components, regardless of the serving size.

If we consider building mixtures from the point of view of compatibility and interchangeability, it is necessary, first of all, to take into account the type of binder. It can be cement, gypsum or polymer, respectively, compositions in which the type of binder is the same is not prohibited to mix. As for the compatibility of modifiers, this is a much more complex issue, the roots of which lie in the depths of organic chemistry, but practice shows that various additives rarely conflict with each other. The filler is completely chemically inert, and therefore the presence of different types of sand in the mixture does not have a significant role on its properties..

It is also necessary to remember one more important nuance: modifiers are added to improve certain characteristics: setting time, frost resistance, mixture mobility. Therefore, if you use glue for stone, which is diluted with sand, cement with an expired shelf life and the remains of unknown mixtures, when finishing the basement, there can be no guarantees of the durability of such a facing. In other words, it is better to use mixed compositions for low-responsibility work: sealing cracks, rough leveling, installing beacons and others..

Adhesives

Dry adhesive mixtures are presented in the greatest variety: for tiles, stones, insulation and aerated concrete blocks, while in each category there are very specific products. All types of construction adhesives have characteristic compositional differences, which determine their purpose..

Tile adhesive has a high filler content, which is necessary to ensure sufficient layer thickness – to protect the tile cladding from movement of the base and to ensure the possibility of final leveling. The main binder in such glue is cement, from polymer additives, set normalizers and plasticizers are mainly used, which provide an appropriate consistency to hold the tile in a given position.

Adhesive for natural stone, on the contrary, has polymeric substances as the main binder, which is due to the structure of the surface of the material to be glued. Also, the abundance of modifiers contributes to an increase in the density and plasticity of the glue joint material, providing it with frost resistance and low water absorption. Stone glue with the addition of up to a third of sifted sand with cement can be used when laying tiles, especially in outdoor conditions.

As for the adhesive for aerated concrete blocks, this material cannot be found an adequate replacement, as well as it is not possible to determine another method of application. Aerated concrete masonry has a basic requirement for observing the minimum joint thickness, therefore, there is very little mineral filler in such mixtures. A set of plasticizers is also characteristic, which should not only improve the adhesion of the adhesive to the material with high porosity, but also clog the pores, the structure of which was broken during the cutting of blocks..

Dry plaster mixes

There are two types of plaster: cement-based and gypsum-based. In terms of performance, they are not very different, but there is some difference in technology and permissible application thickness.

Cement plaster mix, in addition to the cement of a certain brand itself, includes sifted sand, while strict proportions of the components apply. In fact, after mixing with water, an ordinary cement mortar is formed, which is suitable for rough floor preparation, brickwork or for the purpose of diluting stone glue when laying tiles, as well as a repair compound.

Gypsum plaster mixes can only be used for their intended purpose and should not be mixed with cement-based compounds. The problem is that gypsum and cement have different degrees of shrinkage during hardening, which is why the mixed formulations quickly become loose after drying. However, it is not forbidden to mix gypsum-based compositions with each other. In particular, if the requirements for surface cleanliness are not high, a mixture of “starting” gypsum plaster and “finishing” putty can be used to level it. Also, to seal large cracks and seams, you can use a mixture of plaster and gypsum glue for drywall.

There is also a separate category of plastering compounds intended for the formation of decorative surfaces. Such products differ from ordinary plaster either by the inclusion of a coarse filler of a fixed fraction, or by the presence of polymer components based on acrylic or silicone. In principle, the remnants of such compositions in small quantities can be added both to ordinary plaster and to tile adhesive for interior work, but we repeat: only if the gypsum and cement base are compatible.

Screeds and mortars for masonry

A separate group of building mixtures is represented by compositions for the preparation of various types of concrete. The main difference from cement plaster is either in the presence of a large filler in the form of crushed stone of various fractions, or in the addition of special modifiers, for example, to ensure increased curing times and reduce shrinkage of a self-leveling screed.

All types of mixtures for the preparation of concrete are based on a cement binder, and therefore have a very high compatibility with each other. The only exception is the self-leveling screed: it cannot be diluted with cement and sand, the opposite simply does not make sense due to the high cost of the self-leveling mixture. At the same time, due to its low viscosity, such a screed is well suited for grouting floor tiles..