One of the most popular materials in the construction industry is concrete. Without it, to some extent, virtually no construction, whether it is an industrial scale or a private sector. With the development of technologies, there appeared varieties of concrete with a certain set of characteristics. For example – expanded polystyrene concrete, which is gaining increasing popularity among consumers.
- Expanded Polystyrene concrete – raw material base, properties
- Varieties, characteristics of EPScrete, application
- Manufacturer of EPS concrete
- Subscribers’ Experience
Expanded Polystyrene concrete – raw material base, properties
Expanded Polystyrene Concrete (EPScrete, EPS concrete or lightweight concrete) is a particularly lightweight concrete with a porous structure, produced on the basis of a cement binder, with a porous granular aggregate (expanded polystyrene). The acceptable bulk density of the granulate – 15 kg per cubic meter of concrete, under special conditions up to 20 kg / mᶟ. The size of the granules (fraction) depends on the brand and class of concrete and varies in the range 0.7-5.5 mm, maximum – 10 mm (heat-insulating PSB of low grades).
Also, air entraining agents and various modifying additives are added to the solution, improving the properties of both the mixture, in the process of application, and of the ready-made concrete during operation. Air-entraining additives are necessary to impart a porous structure to the cement stone, not only due to polystyrene balls but also through the formation of closed air cells.
In addition, they prevent the floating of the granules, ensuring uniformity of the solution and preventing its stratification into fractions.
And given the constant increase in energy prices, an increasing number of builders, when selecting wall materials, pay attention to the insulating capacity of the enclosing structures of relatively small thickness (about 30 cm). In addition to low weight and the ability to retain heat, expanded polystyrene concrete has other positive properties:
- Fire resistance – despite the large volume fraction of polystyrene in the composition, is a low-combustible material, as the granules are inside the cement “case”.
- Biostability – not affected by pathogenic microflora (mould, fungus), does not rot.
- Sound insulation – air pores and polystyrene granules extinguish the sound, together with thermal insulation is obtained and noise insulation.
As for the shortcomings, there are often accusations of increased hygroscopicity, the complexity of post-treatment, lower strength and lower vapour permeability than conventional concrete. But it is rather the properties of the material, not its drawbacks, the waterproofing and finishing protect water from moisture, the mass of materials for such bases is on sale, and the strength is selected based on the task. If you do not try to build a load-bearing wall of a heat-insulating material, the house will not collapse. Low permeability, typical for all derivatives based on polystyrene, is offset by a good ventilation system.
Varieties, characteristics of expanded polystyrene concrete, application
Depending on the formula and the proportions of the incoming substances in the solution, several varieties of EPS concrete are obtained, with different brand values, these characteristics determine the scope of application.
- Thermal insulation expanded polystyrene concrete – used for insulation of load-bearing and frame structures, attics and roofs).
- Heat-insulating structural EPScrete – used for jumpers above door and window apertures, in heat-efficient external walls as non-filling filling.
- Structural and heat-insulating EPS concrete – used in the manufacture of long bridges above the apertures, as a wall material for load-bearing walls in low-rise construction.
- Prefabricated products of EPScrete – wall blocks, slabs, reinforced concrete elements, manufactured on special equipment.
- Monolithic expanded polystyrene concrete is a stale or factory solution used in various structural elements (pouring floors, screeds, floors on the ground, walls). The ratio of density, strength and scope of monolithic EPScrete is similar to the parameters of the previous variety. In recent years, among private traders, the construction of monolithic houses made of expanded polystyrene concrete is becoming more popular.
The compressive strength class, the tensile strength and the frost resistance grade (the number of freeze-thaw cycles without changing the characteristics) of expanded polystyrene concrete directly depend on its density. Quartz sand is added to the solution for the production of thermal insulation and structural and heat-insulating varieties. Together with the increased proportion of binder, this allows achieving high density and strength. The most important characteristics that affect the scope of application are shown in the table.
Manufacturer of expanded polystyrene concrete
The technology for the production of EPS concrete was invented and tested in the fifties and sixties of the last century but then did not receive the wide application. This was explained both by the rather costly production cycle and by the insufficient strength of the resulting stone, which did not reach the standards of that time. Yes, and there was no such need for insulation, everywhere built brick or panel houses, without thinking about such “high” categories as thermal conductivity and energy efficiency.
Today, polystyrene has significantly fallen in price, the grade of the stone has increased, blowing agents and modifiers can be bought in almost any construction shop, and the energy saving parameters of the family nest directly affect the budget. Therefore, the popularity of EPScrete has increased dramatically.
The production of expanded polystyrene concrete is possible both on an industrial scale, in profile enterprises, and in the handicraft version – with their own hands for their own construction.
But if you can mix a common product with a shovel in the trough, some manage to fill dozens of basement cubes in this way, then it is necessary to have a concrete mixer to prepare the PSB. The composition and proportions of the solution depend on the density (mark) to be obtained. For example, it can be such a recipe.
To ensure that the mixture is as homogeneous as possible, it is important not only to correctly select the ratio of binder, fillers and additives but also the sequence of loading into the drum. In most cases, the following algorithm is justified:
- Loading polystyrene foamed granulated, pouring a small amount of water (1/10 part) with modifiers;
- Stirring the contents (30-60 seconds), so that the granules are moistened;
- The introduction of cement (and sand, if we are talking about heat-insulating structural and structural EPS concrete);
- Introduction of water (8/10 parts) with a modifier;
- The introduction of the rest of the water with the air-entraining admixture diluted in it (finished foaming agents, liquid soap, dishwashing agents);
- Stirring the solution for 3-5 minutes until a homogeneous, workable mixture is obtained.
It is common to pour a monolith into a removable or non-removable formwork, a pit, as well as pouring screeds, rough floors and creating heat insulation contours. Since granules and pores are a weak protection from shrinkage and cracking, it is recommended to use fibre as a reinforcing additive if these phenomena are critical for the design.
Our subscribers also had time to evaluate the advantages of lightweight concrete on polystyrene filler, consider the two most common methods of application – insulation and floors on the ground.
One of our subscribers used a heat-insulated monolithic EPScrete of their own for all their designs.
An ordinary concrete mixer, instead of tar, woody saponified – a simple liquid soap, it is not only easier to buy a five-liter canister in any hypermarket, but also with a solution with such an additive, according to the sensations of the craftsman, “better wettability and workability”.
There was no task of obtaining a self-supporting or bearing monolith, only a heat-insulating one, so the density is minimal. Perhaps it makes sense to slightly change the proportions by increasing the share of cement, but for four and a half years of operation and such polystyrene showed itself perfectly. Pieces from the trial pouring and to this day “specially lying in the yard under the rain and snow, but no deterioration in the characteristics is not seen, the fragments do not crumble, do not crumble, do not crawl.”
Instead of the XPS layer and heavy concrete, we use expanded polystyrene concrete: sand preparation at least 200 mm, polyethene film 100 μm, EPScrete D400, 100 mm layer. At the planned soft finish coating on top of expanded polystyrene concrete – bulk floors or a cement-sand screed of a small thickness. You can order a ready-made mortar or do it yourself, purchasing only polystyrene foam and polystyrene foam and tar sapwood.