Supply of Aerocrete Blocks Production Lines СОТАБЛОК (CELLBLOCK)
Specialists of the Open Joint Stock Company «the PZSP» designed, made and adjusted high-technology aerocrete blocks production line. Today the PZSP has up-to-date, highly productive aerocrete blocks production technology of autoclave production and with the help of reliable local equipment manufacturers it can establish production and supply of lines into all regions of Russia. And not only this.
General Information about Autoclave Aerocrete
Energy resource price rise and searching of ecologically safe materials leads builders all over the world to use of autoclave aerocrete — up-to-date, ecologically safe, power efficient material. Aerocrete — is an artificial rock porous material which main manufacturing components are sand, water and lime. Gas forming additive during reaction with these elements creates porous structure. Due to autoclave treatment at temperature of +180 °С and pressure up to 14 bar material strength increases and shrinkage decreases in several times.
The reason of high power efficiency of aerocrete is the fact that heat conductivity of constructional-heat-insulating aerocrete is 3–4 times less than of brick and ceramsite concrete, it may be used in single-layer filler structures in all climatic zones. By heat engineering indexes such exterior walls correspond new normative requirements of energy saving in newly built houses which allows to decrease walls mass in 2–4 times and decrease labor expenditures at their making in 2 times. Autoclave aerocrete itself has unique characteristics due to high porosity and use of ecologically safe materials for aerocrete items production, that’s why in the scale of building materials comfortability it takes the second place after wood.
Figure 1. Comparison of heat conduction coefficient of some kinds of dry materials, Wt/mK
Aerocrete has the widest application in the modern world — beginning from building of small constructions, bathhouses and garages to building of monumental cottages and high-rise monolith-skeleton-type buildings with unrestricted number of storeys (using aerocrete for building of bearing walls). Besides, aerocrete is used for thermal sanation of buildings, building on of existing houses and in many other spheres.
All this allows to say that the demand for aerocrete items in Russia and abroad is at the initial level. To satisfy the full demand it is necessary to built pants and workshops for production of autoclave aerocrete in all regions.
Production of Autoclave Aerocrete at Line СОТАБЛОК (CELLBLOCK) of PZSP: Technologies and Advantages
Production of autoclave aerocrete has a lot of advantages comparing to production of other building materials. Raw materials for production (water, sand, lime, cement) are wide spread and ecologically safe. Raw materials consumption per product unit is rather small, which provides minimum material consumption of production. Power intensity of autoclave aerocrete production is more than two times lower than power intensity of clay brick production — and this means heat and electric energy consumption, and also reduces carbon oxides exhaust in the atmosphere.
Figure 2. Energy resources consumption for production of 1 m3 of building items
Aerocrete of autoclave production method is manufactured from mixture of natural raw materials: sand, cement, quicklime, water and small quantity of aluminum powder.
As a result of chemical reaction of lime and aluminum powder the mixture is foamed, and pores of different size are formed inside filled with air. The following main stages of production of autoclave aerocrete may be divided:
Figure 3. Approximate share requirement of main raw materials (without water) for production of autoclave aerocrete
Mixture is prepared in automatic mode. Components in specified proportion are supplied into mixer, where they are mixed according to the set program to cream mixture.
Mold Filling and Solid Monolith Molding
Ready mixture is replaced into molds, filling them by half. At the same time mold with mixture undergoes shocking to improve porous structure. Lime starts slaking discharging heat — for one and a half hour mixture temperature reaches 80 degree Celsius. Aluminum reacts with lime, discharging free hydrogen and it lifts this mixture which fills the mold completely. Under high temperature concrete starts curing; spherical cells formed by free hydrogen turn into filled with air pores (finished product is for 80% consists of small pores with diameter from 1, 5 to 3 mm). Structural porosity of aerocrete blocks is conditioned by strictly kept technology and process automation.
After solid monolith rise it undergoes preliminary curing to reach strength necessary for cutting.
Solid Monolith Cutting into Items
After preliminary curing the line unbutton the assembled mold and already cured but soft enough solid monolith of cellular concrete is cut horizontally and vertically by thin strings into blocks.
Items Steaming in Autoclave
Then cut solid monolith is placed into autoclave where, thermal and moist treatment takes place at temperature 190 С and steam pressure of 12 atmospheres. Minerals providing strength of cellular concrete are formed under these conditions.
It should be noted that use of controlled autoclave process allows receiving concrete with the determined necessary level of characteristics. These characteristics are the same in any point of finished product. Autoclave treatment of aerocrete is realized not only to accelerate mixture curing process. The main point of the treatment is that in autoclave at temperature of +190 °С and pressure up to 14 bar a new mineral is formed in aerocrete — tobermorit. Due to this strength of material increases and, which is the most important, shrinkage decreases in several times.
Due to its characteristics the autoclave concrete has more methods of application. Cellular concrete of autoclave curing has reduced fracture strength and increased cold resistance. Autoclave treatment allows in shorter periods of time to get items of high strength.
Technological line «Сотаблок» (Cellblock) with capacity of 255 m3/day (90 000 m3/year)
Figure 4. Technological line diagram
Figure 5. Thermal chamber
Figure 6. Cutting section view
Figure 7. Tilter № 1: mold taking off from the solid monolith
Figure 8. Tilter № 2: solid monolith turning into horizontal position
Figure 9. Pick-and-place system
Figure 10. Patent for Invention
Video (in Russian)