|EQUIPMENTS FOR LIGHT CELLULAR CONCRETE - LCC|
Tehnologia de producere a BCU este protejata in Romania prin
BREVETUL DE INVENTIE
Nr. 118746 B/30.10.2003, proprietatea
SC "FOTON 2000 SELF"
SRL BUCURESTI si care
are ca obiect
“ Procedeul de obtinere a betoanelor celulare usoare, fara autoclavizare
( BCU – BCfA ) “......
LCC = LIGHT CELLULAR CONCRETE
LCC = LIGHT CELLULAR CONCRETE
ACC = AUTOCLAVED CELLULAR CONCRETE
LCC is similar to ACC, but involves a different fabrication technology.
The following raw materials and utilities are necessary for producing LCC:
- raw materials: sand, (ash), cement, water, foaming agent
Practically speaking, LCC is a mixture of a mortar (prepared according to the “fabrication recipe”) and a certain quantity of foam, injected with pressure by the central unit.
After the homogenization of these components, LCC has the aspect of foamed concrete, with a viscosityand fluidity alike to sour cream. The pouring of this foamed cement can be made in prints of miscellaneous dimensions, usually chosen so that they are corresponsive to the usual dimensions of the ACC bricks (e.g.600x250x200mm).
The foamed concrete (LCC) can be poured just as well directly into a mould,
for the direct achievement of monolith walls. This choice is advantaging because of eliminating the hand-made costs for five compulsory operations in laying out a building: walling up, plastering, picturing electrical installations, and picturing sanitary applications and carpeting.
Our company insures:
- the delivery of the central unit and foaming agent (in Romanian territory);
- the putting into function of the installation and instructing the catering personal
(totally for free in Romania, with transport and housing prepaid by customer in case of exports);
- permanent technical assistance in order to obtain the optimal fabrication recipes
(for free, by mail, e-mail, or phone);
- obtaining the Romanian Technical Agreement (for free);
- warranty and post-warranty service (with transport and housing prepaid in case of exports ).
The central unit, (any of the presented versions), as well as the walling bricks fabrication technology and the direct pouring into a monolith wall technology are certificated, respectively technically approved by MLPAT>Romania. </040-2001.
As steps in the LCC production process, the following are distinguished:
- preparing the prints for filling (lubricating them with special liquids or residual oil);
- loading the central unit with foaming agent and water in a 2-2,5 percentage;
- loading cement, sand and water into the concrete mixer, according to the fabrication recipe for the desired density;
- homogenization of the mortar into the concrete mixer;
- injecting the foam into the concrete mixer through a pressure hose connected to the central unit;
- homogenization of the mixture (foam and mortar) inside the concrete mixer.
It is good to know that the hardening of this material depends on the environmental temperature.
The bricks (building blocks) obtained after unfolding (after 24 hours) can be delivered in 2 or 3 days after pouring , although it is best the walling to begin after at least 7 days since fabrication.
After the putting into function and establishing the final recipe, our society assumes the obligation of agreeing the product obtained by the beneficiary (on Romanian standards).
The costs involved by obtaining the technical agreement (for Romania) are covered by our company.
In this case, the production of LCC becomes legal to the owner, under the license of FOTON 2000 SELF.
The foaming agent (active and concentrated substance) is an organic product, non-toxic and biodegradable.
One kilo of foaming agent is 12 RON.
The consumption of foaming agent, in order to obtain 1 cubic meter,is specified in the fabrication recipe. It is imported from Italy and can be delivered in any desired quantity.
For obtaining a good quality LCC, the involved raw materials must accomplish the following tasks:
- the sand must have an aggregate grading between 0 and 3 mm, the amount of dusty parts
as small as possible (below 2%) and the amount of silicon dioxide as big as possible;
- the cement, type A II-(X) 32,5 R (Romanian standards), must have no additions;
- the water used to prepare the foaming solution must be as “clean” as possible,
with very small amount of limestone.
For calculating the necessary costs for producing a cubic meter of LCC, our advice is to do this for a density of 800-kg/cubic meter, because this is usually used both for the exterior walls as for the interior ones. So, to the raw materials’ cost, you have to add the foaming agent’s cost (0,74 l * 1,16 kg/l * 12 RON + taxes), electrical energy and water consumption costs and conversions costs. If you quote up, you reach a sum of approximately45-50 USD / cubic meter (including taxes),
which represents 50-60% of the price of a cubic meter of ACC (in Romania).
There are necessary 6 – 10 square meters of pouring surface for 1 cubic meter of LCC (occupied by moulds and access surface).
Productivity is established depending on the concrete mixers’ capacity in usage (you will obtain bigger productions while using higher capacity concrete mixers).
For example, with a small concrete mixer of 150 liters you can produce 1 cubic meter/hour, while with a 500 liters concrete mixer you obtain 2,5-3 cubic meters/hour.
Any type of concrete mixers can be used for homogenizing the mixture of mortar and foam, including concrete-stations or auto concrete mixers.
The necessary volume of foam for producing 1 cubic meter of LCC with a 800 kg/cubic meter density is about 640 liters (c.dm.), meaning 0,74 liters of concentrated foaming agent.
Also, LCC can be poured as an isolating layer.
For being able to analyze the LCC specific features referring to corrosiveness, thermal conductivity quotient and water absorption, we must specify before anything else that the fabrication technology is totally different to the ACC one,
(ACC is the only material, which LCC can be compared to).
For producing ACC, aluminum powder is used; for obtaining its cellular aspect,passing through some chemical reactions with the lime as raw material gives off a certain quantity of hydrogen.
At a microscopic level, each particle of aluminum powder gives off a volume of hydrogen, which creates a bubble (sphere) with a diameter between 1 and 3 mm.
The bubbles of hydrogen migrate to the exterior (because it is not a stable gas in its pure state).
The hydrogen’s migration process to the surface is accompanied by the appearance of some microchannels between holes, set up by expansion.
This aspect is easily detected using the microscope.
ACC is treated in an atmosphere of saturated vapors, in autoclaves at a pressure of 12 atmospheres and a temperature of 197 Celsius degrees, for 16 hours in order to be hardened (brought to maturation).
Regarding LCC, the cellular aspect is realized by injecting the foam bubbles into the sand and cement mortar, without any chemical phenomena.
The lack of microchannels involves a much better LCC behavior regarding the thermal transfer and water absorbency, compared to ACC.
Also, the lack of lime inside the LCC involves the lack of corrosiveness.
As a conclusion, the fact that LCC is a coherent system with spherical bubbles, without microchannels, involves a superior characteristic towards
ACC thermal isolation and water absorbency.
ACC absorbs water both because of the capillary channels and the hygroscope character of the lime used in its preparation.
Another favorable feature of LCC compared to ACC is the behavior towards the plastering mortar;
at ACC, the presence of lime determines a quick absorption inside the plastering mortar, which makes a false hard-setting, determining a big probability of detachment of the ACC bricks from the built-up wall.
In order to realize a high quality plastering, the wall to be plastered is usually primed with mortar drops, which is a supplementary and expensive operation.
The absence of lime in LCC determines an extremely facile adheration of the plastering mortar to the wall, which makes possible to deposit a thinner layer than in the case of ACC.
The superior LCC thermal isolation, compared to the ACC’s, offers the possibility of building thinner walls with the same thermal comfort as the ones obtained with thicker ACC walls.
Ioan Micu Moldovan Nr. 4 A, PIPERA, BUCHAREST, ROMANIA
GSM: (0040) 722-226 073, 722-519 826, 723-166 369
Phone: (0040) 21- 231.68.52, 231.90.54, 231.90.53, Fax: (0040) 21-231 68 51
CF: R4429685, RC: J40 /16735/93
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