Plasticizing additives for concrete make it possible to obtain a more plastic mortar, allowing you to perform critical construction work. Using a plasticizer, it is possible to reduce the amount of water in the mixture, since the required consistency of the solution is achieved while maintaining the strength characteristics of concrete. These additives not only increase the convenience of laying the mortar, but also beneficially affect the strength properties of concrete.
The cost of the original materials is quite high and many private developers often look for options for how to replace the plasticizer for concrete with small amounts of work at home. Indeed, such an opportunity exists, although if we compare specially prepared material with a substitute, the latter will lose in many ways.
Specially designed polymer-based fluids have the best characteristics that improve the quality of concrete, and replacing this material with, for example, the usual liquid soap or washing powder, although it will improve the composition of the cement-sand mixture, but will not significantly change its properties.
Achieving the following positive results allows you to determine what you need a plasticizer in concrete:
- preparation of the mixture is much faster than in the case of preparation without the addition of a plasticizer;
- excessive penetration of moisture into the mixture is eliminated;
- due to increased adhesion to the reinforcing mesh, the structural strength is increased;
- less water is required to prepare the solution;
- the use of a plasticizer allows you to evenly mix the mixture during the preparation of the solution, while water does not create a separate layer;
- plasticization of concrete gives it additional characteristics (frost resistance, moisture resistance, strength);
- design service life increases.
The listed positive properties acquired by concrete with the use of additives give an understanding of why plasticizers are needed.
Scope of plasticizers
The use of plasticizers for cement, due to the increased plasticity of the solution, can significantly reduce the laying time of the material. These additives give the antifreeze properties of the mixture, allow the material to be used in aggressive environments and in places with high humidity. All these unique characteristics are in demand in the organization of the following works:
- pouring complex-shaped structures with a high frequency of reinforcement cells;
- pouring monolithic foundations of various types;
- as an additive for plaster and masonry mortars;
- for pouring screeds in civil and industrial buildings;
- for the production of paving slabs;
- for the production of concrete blocks, slabs and other supporting products.
Types of plasticizers and their characteristics
Additives that improve the properties of DSPs are classified by the nature of the main substance present in the composition of the material. There are three types of plasticizers in total:
- Additives with organic components.
- Additives with organic mineral components.
- Additives with inorganic components.
For organic Additives are characterized by the presence of a large number of derivatives of refining of petroleum products, by-products of woodworking and agriculture. For inorganic additives usually use formaldehyde-based chemicals; naphthasulfite acids may be used. In production organomineral additives mix various substances in a certain proportion.
In addition to the listed characteristics, plasticizers are divided by the type of effect on the cement-sand mortar when adding:
- Additives modifying effects. These plasticizers can significantly increase the strength of concrete, give structures increased frost resistance, moisture resistance and corrosion resistance. Improving performance is accompanied by a decrease in material consumption;
- Additives to increase the strength of concrete of lower grades;
- Additives that make it possible to work with cement-sand mortar at low temperatures;
- Superplasticizers that allow you to transport the finished mixture over long distances at elevated temperatures;
- Additives that ensure the retention of air bubbles in the concrete mixture to obtain special grades of microporous concrete, which are used for casting structures operating in conditions of frequent and sharp temperature fluctuations;
- Plasticizers, which, due to the fluidity and plasticity of the solution, fill the formwork with thick reinforcement;
- Additives that give the solution an increased viscosity and are used to prepare stucco mixtures.
Which plasticizer is better for concrete depends on the situation and design requirements of the project.
What can replace a plasticizer for concrete
For personal housebuilding, the use of professional plasticizers is often not justified because of their high cost, but the need to give the solution the necessary qualities remains, and therefore many home craftsmen prepare a plasticizer for concrete with their own hands.
There are several proven recipes for making a plasticizer for cement mortar with your own hands:
- Slaked lime. This material makes it possible to increase the elasticity of the mortar for masonry bricks or blocks, improves adhesion, protects the structure from the harmful effects of microorganisms. Fluff lime is often used as an additive in a solution based on slaked lime.
- Liquid soap. Detergent compositions, including washing powder, make the solution more plastic and extend the period of concrete rising.
- PVA glue. It is used, if necessary, to increase the strength of concrete products, as well as to obtain higher water resistance characteristics.
The most important issue in the preparation of a solution with a plasticizer at home is the observance of proportions. How much to add plasticizer per cube of solution to get the desired result? The following instructions will avoid errors and prepare a quality solution.
When using fluff as a plasticizer, it is necessary to add this material while mixing the dry ingredients of the solution. Usually, in order to achieve the required qualities of concrete, lime requires about 20% of the amount of cement. Such a volume is sufficient to obtain a plastic, mobile solution, which will work much easier.
If this additive is supplied in the form of a thick, pasty material, it is necessary to dissolve it with water to the consistency of milk, and add to the already mixed dry components.
There is another option for using lime in a pastry form: the cement needed to prepare the total volume of the solution is mixed with half of the lime, and the second half is mixed with the full volume of sand. After thorough mixing, both parts are combined and mixed again, adding water to obtain the desired consistency.
For all recipes, only slaked lime must be used.
When using detergents to improve the quality of cement-sand mortar, it must be remembered that these components are added exclusively at the very beginning of mixing the mixture. If soap solutions are added to an already prepared solution, foam may appear, which will significantly impair the strength characteristics of the finished product.
It is impossible to use detergents as plasticizers above the recommended proportion, since there is a risk of efflorescence on the external part of the structure, which is the reason for premature destruction of concrete. In addition, this phenomenon leads to a decrease in frost resistance and water resistance of the structure.
To obtain a high-quality solution, it is enough to add 200 ml of liquid soap or other detergent to 50 kg of cement, no more than 150 grams of washing powder will be required for the same volume of cement.
Adding PVA glue is recommended in a diluted state in the ratio to cement as 1 to 50.
Instructions for mixing the solution with plasticizer
The main condition for obtaining a solution with the required qualities is to strictly follow the dosage of the plasticizer in the mixture. It is also important to follow the sequence of additives.
Detergents and washing powder are added in diluted form at the stage of preparation of the cement-sand mixture. Slaked lime is mixed with dry fractions and only after a homogeneous mixture is obtained, water is added. Polyvinyl acetate is diluted with water and added to the finished mixture.
For plasticizers manufactured in the factory, the instructions for use should be followed.
Popular manufacturers and prices
The most affordable plasticizers available on the domestic market include the following brands:
- Hardplast. The products of this company make it possible to achieve high plasticity of the mortar, fight against delamination of concrete, and also increase the waterproofing properties of structures. The cost of the material is about 100 rubles per package with a capacity of 10 kg;
- Dock Plast. This manufacturer also produces affordable plasticizers for cement-sand mortars. Additives produced under this brand make it possible to obtain increased moisture resistance and frost resistance of concrete. Its main purpose is to increase the life of the product. The cost of 10 kg of a package is about 120 rubles;
- Superplast. It is used for concrete intended for work in aggressive environments. Allows to improve water resistance and corrosion resistance. A package of 15 kg is sold within 150 rubles;
- D5. It is used to prevent the appearance of cracks in the concrete base, works great in areas with high humidity. The cost of a bag of 15 kg does not exceed 150 rubles.
The successful use of these plasticizers depends on the exact adherence to the guidelines that govern the ratio of the material to the components of the cement-sand mortar.