Instruction on application of dry fire-resistant mixes of The "Aliter-Aksi" company
Packing
Dry fire-resistant mixes of manufacture of Open The "Aliter-Aksi" company can be packed by various ways:
- mix of all components, including connecting, bagged in the bags laid on the pallet or in big-bag;
- mix of inert components, bagged in bags with an inscription "filler" and fire-resistant cement in packing manufacturer of cement or complex connecting, bagged in bags with an inscription connecting. In this case at preparation of concrete it is necessary to mix a filler with cement or connecting in a proportion specified on a label and in the instruction on application.
Storage
The period of storage of mixes, as a rule, makes 6 months from the date of their manufacturing. In case cement is delivered in packing manufacturer, working life of a mix is determined by working life of cement. For cements of manufacture ' Lafarge Aluminates' ('Ciment Fondu Lafarge', 'Secar-51', 'Secar-71', 'Secar-80') he makes 1 year.
After the specified term before application of a mix it is necessary to check up, whether meet strength characteristics of concrete to the certificate on the given set.
Mixes should be kept in the conditions excluding an opportunity of hit on them of atmospheric precipitation.
Mixing
The amalgamator
For preparation of concrete it is recommended to use amalgamators of compulsory mixing. At use of the usual gravitational amalgamator (the amalgamator of free falling) there can be an education agglomerate a dry material and addition of water in quantity, greater is required, than it is necessary. Application of such amalgamators is supposed only for heat-insulating concrete of series áLAKS with density less than 1,2 g/sm3.
Quantity of added water
The rough quantity of added water is specified in the instruction on application of a mix. It is necessary to mean, that addition of excessive quantity of water leads to decrease in durability and density of concrete. It especially concerns to low-cement to concrete of series áLKORIT. In turn lack of water complicated stacking of concrete.
Time of mixing
Time of mixing depends on intensity of the applied amalgamator. As a rule, it makes:
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for concrete áLKOR
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- 4 minutes; |
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for concrete áLIT-áLKORIT
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- 6 minutes; |
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for concrete áLAKS
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- 3 minutes |
(as unduly long mixing leads to destruction of particles of porous fillers).
Mix is mixing all over again in a dry kind 30-60 seconds. (in order to prevent dusting it is supposed to add thus a small amount of water), then add approximately 80 % from the quantity of water stipulated by the instruction on application. The remained quantity of water moves gradually before reception of a necessary consistence of concrete. As a rule, it meets to that moment when concrete forms large layers.
The consistence of concrete can be checked up by two simple ways:
Generate from concrete a sphere and throw him on height about 30 sm:
if the sphere at falling scatter on parts, quantity of water in concrete is not enough;
if the sphere keeps the form, the contents of water in concrete optimum;
if the sphere blurs, concrete overwetting.
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Influence concrete with submersible vibrator:
if upon termination of vibration in concrete there is not swimming away deepening, the quantity of water in concrete is not enough;
if concrete well flows, his consistence is suitable for stacking by vibration;
if at vibration of concrete on his surface water, concrete overwetting acts.
Stacking of concrete
The dry mixes received by hashing with water concrete should be used prior to the beginning him setting. As a rule, it is recommended to finish stacking of concrete during 30 minutes.
Forms or a timbering should possess sufficient mechanical durability so that at embedment there was no their deformation. Joints of separate elements of a timbering should be tight, otherwise finely divided the part of concrete will follow from a timbering.
If concrete keeps within on the existing or rendered layer made of a fire-resistant brick or concrete, the surface of this layer should be humidified or covered by a layer of a water-proof material.
For reception of concrete with high durability and low porosity he should be well condensed at stacking. As a rule, for this purpose vibration is used. At application needle vibrators it is necessary to move them slowly, not supposing formation in concrete of not swimming away deepenings. At good vibration large concrete agglomerates blur, and on a surface appear fine blister air, concrete as though boils. During this moment vibration should be stopped in order to prevent stratification of concrete.
For insulation concrete of series áLAKS with density less than 1,2 g/sm2 vibration is necessary to force only concrete "leak" instead of to condense it, therefore it should be short-term and not intensive. Sometimes it is possible to be limited embedment without vibration and 'rodding' concrete. Excessive mechanical influences on concrete can lead to destruction of particles by porosity of a filler, especially, vermiculite, that leads to increase in density and heat conductivity of concrete; increases as well the charge of a mix that can lead to its shortage.
If on a surface of concrete the thin layer finely divided connecting fractions is formed, it speaks that concrete overwetting and in the subsequent batters is necessary to lower the contents of water. If the new portion of concrete keeps within on already provibrated layer, the vibrator should be shipped in this layer deeply enough so that both of a layer have well enough incorporated with each other.
At use of external hinged vibrators it is necessary to install them so that vibration extended on all volume of stacked concrete.
At great volume fettle the works, intended for liner the surface should be broken into separate maps. Their size depends on time necessary for filling by concrete of one map. Each next portion of concrete should move on already laid layer prior to the beginning of him setting. As a rule, the size of one map does not exceed 1 g/Í2. After hardening concrete within the limits of a map (as a rule, next day after stacking), the differentiating timbering leaves and made liner the next map. It is convenient to carry out liner, filling maps in chessboard order. Joints formed thus are so-called "working" joints. For performance of "temperature seams", compensating convertible temperature expansion of concrete, before stacking of concrete in the places certain by the project liner, install a compensatory material (usually fibrous).
At temperature of air 15-30 ó disclosing of the form or removal of a timbering can be made in 12-24 hours after embedment. It is possible to count, that concrete has collected sufficient for form removal durability if at percussion a hammer he publishes a ringing sound. At lower temperatures setting and concreting concrete occur more slowly (especially it concerns heat-insulating concrete áLAKS with density less than 1 g/sm3 and low-cement concrete áLKORIT containing less of 1,5 % óÁď). It is necessary to mean, that the longer concrete will be in the form of or a timbering, the above there will be its quality.
At normal temperature concreting concrete, as a rule, comes to the end through 2 - 3 days. During this term it is recommended to not suppose drying of a surface of concrete, covering her damp fabric or spraying water. During this time categorically it is forbidden to subject a product or liner to action of negative temperatures. Term concreting increases at the lowered temperature of air.
Work during the winter period
At work during winter time raw materials should be placed in a room with temperature more than 10 ó at least three days prior to their use. If concrete is put on a metal surface, it also should have temperature more than 10 ó. Before end of process concreting the material should not be frozen. If necessary it is recommended to warm up products by means of warm air. It is necessary to remember, that the below temperature, the proceed setting and concreting concrete more slowly. Some concrete of series áLKORIT containing less 5 % of cement (less (1,5% óÁď) can not harden at all at temperature less than 5 ó. Work with them is supposed only at temperature above 10 ó.
Influence of a low ambient temperature is especially great at manufacturing fine products or thin layers liner, put on a cold surface. It is necessary to note, that hydration aluminidecalcium the cement, occuring at concreting concrete, is exothermal process, therefore in some cases at manufacturing massive products or drawing of layers liner more than 200 mm, concrete of series áLIT and áLKOR (especially made on cement 'Ciment Fondu Lafarge') can be applied by thickness at temperature 0-10 ó.
Work at a heat temperature
At a heat the problems connected with excessively fast setting of concrete (especially it concerns concrete of series áLIT) can take place. In this case it is recommended to prepare batter small volume and to reduce the size of cards to lower time spent for stacking of concrete. Use retardant setting according to the instruction on application is possible. Special attention follow to give humidifying of a surface of concrete within 1-2 days after stacking. It is especially important for thin layers liner, having the greater open surface.
Drying and the first roasting
Prior to the beginning of operation at heats concrete liners should be dried up.
At carrying out of drying and the first roasting it is necessary to be guided by following rules:
constant movement of air through the furnace should be provided so that the allocated moisture left from the furnace;
until the temperature liner will not reach 650 ó, direct hit of a flame on liner should be excluded;
fluctuations of temperature should be reduced to a minimum, distribution of temperature in the dried up unit should be as more as possible uniform, thermocouples should be installed in various places, both on an entrance and on an exit.
Drying and the first roasting should be spent under the certain schedule. The mode of drying depends on thickness and a configuration liners and from a kind of fire-resistant concrete. As a rule, the more thickly liners and concrete is more dense, the drying longer should be spent.
In most cases drying is made on a following mode:
rise of temperature up to 150 ó with a speed no more than 20-30 C/hour and endurance at 150 ó within 1 hour on 10 ÍÍ liners but until to stop allocation pair;
rise of temperature up to 650 ó with a speed no more than 20-30 C/hour for concrete áLAKS, 15-20 C/hour for concrete áLKOR, 10 C/hour for concrete áLIT and áLKORIT;
quotation at 650 ó within at least 1 hour on 10 mm liners;
rise of temperature up to working speed no more than 50 C/hour for concrete áLAKS, 40 C/hour for concrete áLKOR, 30 C/hour for concrete áLIT and áLKORIT.
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