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The technological scheme of the foam-concrete mixture, which was developed by OOO “IIC” specialists, supposes, in the first place, applying of ready to usage of fine-dust filling materials, such as: limestone or marble powder, dust-loss from the power station, marshalite sands and so on. If to speak about usage of common natural mortar sands, our experience has shown their unfitness for producing foam concrete with reduced density (density type lower then D700) in majority of cases.
However, the main specific feature of developed technology is obligatory usage of certain set of chemical substances and especially designed foaming agent, that allows to solve series of technological problems:
- exclude formation of foam concrete mixture fallouts;
- producing of “hot” mixtures;
- reducing of time for getting necessary plastic strength of the moulded massifs;
- reducing of removable board equipment turnover cycle time;
- increasing of the strength characteristics of the final products
- cement saving.
A question about cement saving has recently arisen very sharply in close connection with breakthrough for cement. While progress in researches works, OOO “IIC” specialists also searched of new low-power-consumption technologies of porous concrete production, using which it’s possible to reduce cement discharge till acceptable from economic point of view level – 150200 kg/m3. During searching works the vibroimpact technology for producing not-cured gas concrete was chosen. After multiple laboratory experiments perspective types of raw materials were sorted out, ways of their preparation were specified, optimization of parameters and modes at different stages of raw materials preparation and making-up of gas concrete mixture was made. Simultaneously samples of necessary nonstandard equipment were manufactured. The principle of controlling vibroimpact with programming parameters of amplitude and frequency was assumed as a basis while designing vibroimpact foundation.
During second half-year 2007 experimental-industrial tests of a new technology were carried out in conditions of actually working production in the city Dolgoprudniy, Moscow region. Several pilot batches of small wall blocks made of not-cured gas-ashconcrete were produced. While they were preparing different parameters of mixture preparation were changed, complex of chemical and aerogenic additives and cement consumption was varied, the time for getting plastic, intermediate and final strength was determined. The issue to find the minimum level of cement consumption while producing blocks with density type D600 with strength class B1,5 was set and solved while using cement ÏÖ500D0 190 kg/m3 from city Stariy Oskol.
Summing up results of all carried out tests, OOO “IIC” proceeds to designing of plant for producing cellular concrete wall blocks using vibroimpact gas concrete technology. ÏÁÇ120À line was taken as a basic.
During modernization process the design of dozing unit and mixer were greatly changed in essence. Besides this the unit for preparation of aluminium suspension and programmed vibroimpact platform.
BRIEF DESCRIPTION OF PLANT FOR PRODUCING CELLULAR CONCRETE WALL BLOCKS USING VIBROIMPACT GAS CONCRETE TECHNOLOGY
Nomenclature of products and their physical-mechanical properties, which were achieved in real operating conditions and provided with received certificates of conformity you can see below:
Density type |
Strength class |
Nominal / Actual parameters mm |
500
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B 1.5
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375 x 200 x 600
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374 ± 1.5 x 198 ± 1 * 599 ± 3
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600
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B 1.2
B 2 |
300 ÷ 200 ÷ 600
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299 ± 1.5 x 198 ± 1 * 599 ± 3
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700
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B 2
B 2,5 |
300 ÷ 188 ÷ 600
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299 ± 1.5 x 198 ± 1 * 699 ± 3
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Design thermal conduction factor ? at equilibrium moisture content 4-6 % for products with density type D500 is 0.11Wt/ (m *K).
Engineering metrics of products, produced with OOO “IIC” are represented in several certificates of Russian Federation. Wall cellular-concrete blocks are unique building material, which possesses as sufficient density, either good heat-insulating qualities. Such blocks are produced out of porous concrete of D500 density type, B1.5 compression strength class. Such strength is enough to construction of 2 floors high bearing walls. Massive and light wall blocks with width 375 mm allow to brick single-layer outside enclosing constructions which possess high level of thermal protection and low level of air permeability. At the same time, additional thermo-insulation is not necessary for them. Resistance to thermal transfer of such walls with finishing is equal Rtr=3.64 m2 kW. Blocks 300 mm width are commonly used in building of single-layer outside walls of public buildings and constructions. Resistance to thermal transfer of such walls with finishing is equal Rtr=2.89 m2 kW.
At present time OOO “IIC” team, having summed up long-term experience of designing and producing of special equipment , proceeds to work on the second tendency – creation of high automated factory with annual capacity of 150 thousand m3 of products, produced from cellular concrete using prospective vibroimpact gas concrete technology. Start-up of such factory is planned to take place already in 2008.