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In the 16th environmental department act, the necessity of asbestos elimination was approved and the task was given to a committee by the name of committee of planning the elimination of asbestos in factories.

 

In the second day 1379 of mordad The committee decided to completely eliminate asbestos in 7 years.

 

In the 15th of mordad of 1387 as the deadline had been crossed and the production and use of asbestos had not been stopped, the chief of presidents office issued a letter to the environmental department, by the order of the president,  to stop all asbestos use until a suitable substitute has been found . The director of industrial mines of the industry ministry issued the order in the same day. Considering the pressure by the environmental department to enforce the 16th act of the high council of environmental department, in the 1389 16th day of aban the industry minister issued a letter to the first council of the president to keep using white asbestos only, until a suitable substitute is available and as soon as such substitute is introduced, within 6 months all use of white asbestos will be stopped.

 

In 1390 khordads first, after surpassing the due deadline by nearly 3 years, the environment preservation department issued an order to stop all use and importation of asbestos.

 

In 1390 khordads the 4th, the manager of industrial mine department of industry ministry expressed his concern regarding the closer of factories to the council of industry minister. The labor minister in 1390 tir’s 12th, issued a letter to the president insisting on the permission asked in 1380 aban’s 16th and asked for the act of foundational industry and environment act by the number of 446557 in the 24th day of tir of 1389 to be issued.

 

At the end, the first council of the president issued a letter banning any kind of asbestos use in the process of factories including spare machine parts and construction materials. In this letter the use of asbestos in the production of pressured and sewer pipes was allowed under certain conditions until the 1391 shahrivar’s 31 day and the deadline was announced none renewable.

 

In 1390, baverce co. considering the 20 years of experience in this field and considering the necessity of replacing asbestos in the fiber cement industry started to launch the plan of asbestos free fiber cement sheets in its own concrete pipe factory.

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Fiber cement sheets are consisted of cement and reinforcement fibers and are one of the modern buildings requirements.

  • As cement became popular in building industry as well as its extensive use, cement facades became very popular as well.
  • Since the invention of pre-constructed buildings the idea of fiber cement sheets became stronger because it could be produced at the factory and delivered to the project site to be installed.
  • Considering the weakness cement has in bending and tension strength, the idea of reinforcing it was always discussed. In the late 19th and early 20th century an Austrian engineer by the name of Ludwig Hatschek used asbestos fibers to reinforce cement and build a machine modeled after the paper production machine which injected regular dosses of asbestos to cement dough and produced an excellent material with exemplary qualities by the name of flat asbestos sheets or corrugated cement sheets which was produced and used in all  countries for the past century.
  • Since the last decay of 20th century, considering health and environmental factors, the ban of asbestos use was instructed in international communities. Fiber cement producers decided to  find a substitute for asbestos. The result of the researches by the name of N.T (new technology) was launched and asbestos-free fiber cement sheets were produced.

Fiber cement sheets or boards are produced by Hatschek and the most important difference between them and the old production method is in the materials used, the processing and the technical science involved.

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The difference between the flow-on method and the screen tank production method is in the process of material production on the felt. The concentration of watery materials in this machine is higher and the solid containments of watery materials is more which are directly transferred through the transfer mechanism.

Advantages in comparison to screening tank:

  • The production machinery is simpler and requires less investment.
  • The volume of returned water is lower and the machinery is simpler and takes less space
  • Watery material can form with any kind of accessible fiber and material and there is no special treatment required for keeping the fiber
  • and the matrix on the felt. This is why the production is without complication and easy to do.

Disadvantages of this machine:

  • The vertical and horizontal distribution of fibers is not done properly compared to the screen tank method.
  • Due to the fact that in this machine the layers of the product are less than the screen tank method the strength of products produced in this method are less than products produced by screen tank method.
  • High risk of layer separation due to bigger layer thickness and less resistance against bad geographic situation compared to products produced by screen tank.
  • The production volume is lower than the dual screen tank.
  • High risk of density difference in sheet.

These are the reasons that few fiber cement producers use these method although its simpler.

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The purpose of cellulose preparation, is the production of high flow cellulose in order of fiber expansion without fraction.  This means that the fiber after the expansion becomes thinner. Liquid limit of cellulose is measured by a Canadian Standard, Freeness method or C.S.F, according to the ISO 5267/2 standard with the measurement unit of ml and the Schopper Riegler method of SR according to the ISO 5267/1 standard with the measurement unit of degree or (°). The extent of expansion required is a function of production type. (Flat sheet meant for inner use, flat sheet meant for outer use and corrugated sheets)

Without the appropriate expansion, cellulose fiber has the below disadvantages:

A: fibers are too big and rough to use beside cement. In this situation the tensile strength of the product is low and does not have the necessary area to ensure the ultimate tensile strength in fiber cement sheets.

B: The rough and big fibers can’t keep the necessary amount of water in the screen tank. The mesh cracks of the screen tank is bigger than the cement pieces, sillies and other extra materials. So the big fibers can’t stop the escape of these materials and a large portion of these materials exit the screen tank and cause a considerable amount of trouble in the water cycle use.

C: the excessive amount of cellulose in the plasticity production process causes a decrease in the quality. For example resistance against freezing of fiber cement products can decrease, also particle separation and cement parts from the fiber cement area can occur and cause some problems for the color coverage of the product.

Baverce co. cellulose production process is equipped with the below machinery to prevent the above problems:

  1. Water tank is equipped with water volume controller
  2. Cellulose feeding system including elevator, equipped with load cell.
  3. Cellulose pulper with 8 cubic meter velocity and 75 kv power
  4. Cellulose evacuation pump from the cellulose pulper (Centrifuges type).
  5. Two opening cycle tanks or refining cellulose fibers.
  6. Trash rack
  7. Refiner feeding pump, mohno type, with consistent discharge rate.
  8. 250 kv disc dual refiner to open or refine cellulose fiber
  9. Dual cellulose processing tanks with mixer, by the velocity of 100 cubic meter.
  10. Cellulose transition pump to material building section.
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Cement boards, after completing grasping and curing process, have higher moister than the environment and after being exposed to the dryer, loose some of their moister and have a minor shrinkage and a minor reduction in their dimension like most construction material. So if the cement boards are not properly dried or in other words, their moister has not been reduced enough, after being installed in the structure and being exposed to the fresh air; lose some of their moister and the wrenches attached to the boards cause shrinkage or convexity or concave. This can cause internal tension and lead to cement board rapture from the wrench installation points and cause fracture from the edges of the board.

This is why the cement boards need to be dried and have their moister reduced to an acceptable amount to stop this flaw from happening.

Considering this problem baverce co. has designed, manufactured and launched an oven dryer to place its productions in before delivering it to the customers to prevent such problems occurring before installation.

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The process of fiber cement board grasping is as follows:

1) Grasping in free air:

In free air grasping system, cement hardening and hydration bounds are formed in free air, as in other cement based products. After 6 to 10 hours from the time that sheets crossed through the heating tunnel with the approximate temperature of 50 to 60 degrees and the moister of nearly 100% the products have the appropriate strength for movement. The products are separated from the mould and are placed for at least 21 days in, damp free air inside a lidded space to reach their ultimate strength. In products produced in this manner poly vinyl alcohol (PVA) fibers ensure the arming of cement to ensure the tensile strength of the product.

               2) autoclave grasping:

               autoclave process causes basic changes in hydration materials for example high temperatures causes crystal shape silicate hydrate structures. In fact, the grasping system in free air, silicate hydrate crystals are formed but in very high temperatures in autoclave method the crystal structures are changed and the tobermolit structures are formed and can cause an enhancement in the sheets properties. In this system the cement is mixed with sillies with the approximate ratio of 40% cement and 60% sillies. The initial set is like the previous explanatory method in heat house but the ultimate grasping in autoclave and in the approximate temperature of 180 degree and saturated environment is set by the vapor pressure of 12 loads in which the silicate hydrate is formed. The crystal structure formed gives the product good physical properties which it has tensile tension and so the use of PVA is eliminated. The product produces in autoclave method and after passing the dryer is ready to be delivered to the customer.

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Bedding of installation of ivanet flat sheets:

  1. Wooden or steel beams used for installation must be up to the common code of building construction
  2. Beams must have necessary mechanical properties.
  3. Frame case supporting the flat sheets must be connected to the celling or the floor and the sheets should not tolerate any load because of this connection.
  4. Maximum distance for inner or outer walls for beams is 600 millimeters
  5. Bedding beams should be made in a manner that the edge of the sheets can be placed on them and be completely supported by them.
  6. Width of supporting beams should not be less than 38 mm.

 

To install glazed tile or earthenware (for bathrooms) on ivanet flat sheets below conditions must apply:

  1. Colum beams distance must be decreased to 400 mm.
  2. The distance between horizontal beams must be below 900 mm.
  3. Inner and outer edges and the surface of the sheets must be covered by water-proof concrete caulk
  4. Before installing glazed tile or earthenware make sure that the surface of the sheets are clean and doesn’t have any dust or oil on it.
  5. Use special glazed tile paste and apply it one meter at a time.
  6. Push the glazed tile on the paste to eliminate any air bubbles that may occur in the paste.
  7. The special paste must be made and used according to the instructions made by the manufacturer
  8. To install bathtubs or shower-bathes act according to below details

  

 

Method of installation and adjustment of avanet flat sheets in the façade of the building:

  1. Its recommended that the seam between the sheets on column and horizontal beams be alike or in other words aligned.
  2. It is recommended that the width of supporting surface of the sheets be at least 75 mm so installing wrenches in 20 mm of the sheets be possible.
  3. Horizontal Framing for 10mm flat sheets the maximum distance for horizontal beams must be 800 mm and for 12mm flat sheets it must be 900 mm.
  4. In Vertical framing the maximum distance for beams must be 600mm.

Vertical framing method: 1- seam between sheets 10mm 2- width of supporting surface must be at least 75mm

Horizontal framing: 1-seam between sheets 10 mm 2- the width of supporting surface must be at least 75mm

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Ardoise is a French word with the meaning of Fine – grained metamorphic rock which is made as a thin layer and sheets with smooth surface.

eyvanit Ardoise is produced by undergoing a pressure of 100 to 150 kg/cm² on its surface to be compressed and gain the same properties as natural Ardoise and for this reason mechanical properties and resistance against weathering is more than flat sheets and is closer to the properties of natural rocks.

Ardoise is a light coverage, impenetrable and beautiful that gives a classic look to villas and the façade of the buildings with high gradient.

Ardoise is carefully cut and hole-drilled to decrease installation time.

Ardoise installation tools, packaging details and properties:

Dimensions: 300by600 mm

Thickness: 4mm

Flexural strength: 220 kg/cm2

Number in a box: 10

Number in a pallet: 1020

Number used to cover 1 m2: 17

Number of truss or girder under the frame work: 900 mm

Framing distance under the foundation : 200 mm

Dimensions of wooden beams under the foundation: 30by40 mm

Required fastener: 2 galvanized nails and 1 crampon

Installation details of Ardoise avanet

 

 

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One of the most important reasons of using micro sillies on fiber cement products is the ability to complete the pozzolanic reaction

The word pozzolan comes from the name of ancient Italian city pozzuli in which soft volcano ashes were found that are usually mixed with calcium oxide to produce cement. As it is illustrated in figure 1 pozzolan with lime or calcium hydroxide Ca(OH)2 and water forms the paste of calcium silicate hydrate or CSH. This reaction is similar to the binding part of cement hydration. The hydration of type 1 Portland cement produces about 20% lime. Lime or calcium hydroxide is a week and dissolving material that does not contribute to resistance. The reaction between micro-sillies and the lime produced in hydration process produces paste and causes more resistance.

Figure1- micro-sillies with lime or calcium hydroxide and water produces paste phase of calcium silicate hydrate.

One of the other reasons to use micro-sillies is to fill the microtomic holes in the product:

The infinitely small size of micro-sillies fills the relatively big holes between the cement pieces and causes an increase in the resistance and durability. (Fig2 and 3)

Fig2: filler effect of micro-sillies on microtomic holes in fiber cement boards.

Fig3: the effect of different volumes of micro-sillies use in the bulk and diameter of holes in air cured fiber cement boards.

One of the other reasons to use micro-sillies on fiber cement products is to enhance the bending strength and the density and to reduce water absorbent:

In figures 4, 5 and 6 the effect of micro-sillies on the bending strength, density and water absorbent of fiber cement products are shown. Every 1% increase in micro-sillies use in fiber cement products causes an increase in bending strength by 0.5 Mpa or 5kg/cm2. Micro-sillies also causes an increase in plasticity in green sheets and prevent cracks happening while bending the corrugated sheets.

Fig6: the effect of different percentage use of micro-sillies on water absorbent of fiber cement boards.

Fig5: the effect of different percentage use of micro-sillies on the weight of fiber cement boards.

 

Fig4: the effect of different percentage use of micro-sillies on the bending strength of fiber cement boards.

The last main reason to use micro-sillies is to increase the freeze-thaw cycles of the product:

Freeze-thaw cycles causes expansion in the product which leads to the gradual separation of the layers in fiber cement products. Micro-sillies causes an increase in the cohesion between the layers and increases the freeze-thaw cycles. By increasing the use of micro-sillies by 5% swelling of the product after 700 freeze-thaw cycles in free air decreases by a factor of 1.3. For products which are made by auto claw by increasing the use of micro-sillies by 5% swelling of the thickness of the product after 1000 freeze-thaw cycles decreases by one third of the original amount.

Fig7: the effect of different percentage use of micro-sillies on the swelling of the thickness of fiber cement boards.

Fig8: the effect of different percentage use of micro-sillies on the swelling of the thickness of fiber cement boards produced by auto claw method.

 

 

 

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Today with the development of building technology, using precast materials, according to high possibility of quality control and construction speed, is more welcomed by people more than past. One of this precast materials that is used in inner surface and facade is Fiber Cement Board. According to high flexural strength of Fiber Cement Board, it is used in interior and exterior façade and walls, floor and roof covers.

Fiber Cement Boards have High resistance to fire, they are good sound & heat insulations and waterproofed. Comparing to similar products, Fiber Cement Boards have more resistance to absorption and moisture passage. Although in submerge condition they absorb water and their flexural strength decrease, but after being dried, without any size deformation, the original flexural strength is back,According to the fact that are so smooth, after installation, without being finished, they can be colored, wallpapered or any PVC cover & HPL plate.In the following, you can see the production process
Uses of Fiber Cement Boards:
1-interior cover of building:

Lining inside walls:
Fiber Cement Boards with a density up to 1600 Kg/m^3 could be used in internal space of the building and cover. Due to the high impact resistance of this product and suitable mechanical properties, it could be used in walls of a busy place.According to different varieties in design and colors, the Fiber Cement Boards can be used as décor walls or final covers (without being colored) in offices, residential and business places.Substructure of tile and ceramic in toilets, pools, and very wet locations:According to high water proofing of Fiber Cement Boards and strong adhesion to mortars and tile bonding layers, it could be used as Drywall`s covers in such places.Stepped ceilings:In offices, residential and business places and also wet places like pools and which are possible to humidity or steam contact Fiber Cement Board can be used as stepped ceiling in the form of 60*60 tiles or decorative.
2-dry wall Fiber Cement Board:
Is dry wall with fiber cement plate cover without asbestos or Fiber Cement Board that can be used as interior or exterior walls along with facade. There is no need to use traditional material in the wall.Components in dry wall Fiber Cement Board:
1-Ultimate external cover: Acrylic water based color, textured cover.
2-External cover: Fiber Cement Board due to covering external wall and façade simultaneously.3-
Cushioning4
thermal and sound insulation, water and steam barrier5-Polyurethane insulation, rock wool, poly styrene (heat and sound insulation), water barrier (exterior strap with a one-way layer like tie walk), vapor barrier (internal vapor strap with a normal nylon layer)6-Interior cover: Fiber Cement Board, gypsum board, robiits Plus spray gypsum7-Ultimate interior cover: Acrylic water based color, plastic or oil color, wall paperRun the Fiber Cement BoardAccording to the way of using Fiber Cement Board, which is used as covering or dry wall and well defined in previous sections, the way of running is as following:1-Running dry wall system:in this system, because of in-plane stiffness, if it is executed  as the Seismic performance of the building will not changes in main. Dry wall system contains horizontal and vertical parts as cold rolled steel sheet. Horizontal parts (runners) are installed on two levels, one on the floor and the other one on the ceiling, by hilty nail or screw; and then, The vertical parts (stadia) depending on wall and building’s usage are placed on runners at standard distances. In structuring walls, the stadia is not screwed in runners, but has a free space to play???? , and the connection type is by screwing Fiber Cement Board’s panels. This type of flexible connection between fiber cement board and stadia & runner is will reduce the earthquake force and while the earthquake happens there will not be any extra pressure or reaction force on the structure and it will not affect the seismic behavior of the building. After that structuring is completed, Fiber Cement Board plates are installed on the structure by screw. If needed, seal materials like rock wool, glass wool and poly styrene will be used between Fiber Cement Board’s plates.

2-Introducing Fiber Cement Board wall system:

Fiber Cement Board wall is designed to solve the traditional wall’s problems and complete dry wall’s system. This system, in addition to quick construction and mechanical connection to the building and structure, is stronger than dry installation of similar system and doesn’t have problems such as hollow sound, unsafety, insects penetration in the free space of the wall and…. Fiber Cement Board wall consisted of galvanized stadia runners, are connected to the ceiling and roof by hilty or nails and after placement of mechanical and electrical installations, both side of the wall is covered by Fiber Cement Board. After the Fiber Cement Boards are installed, light weight concrete mixed with cement, granule poly styrene and additives is injected into the wall and at the end the seam between Fiber Cement Board, is covered by sealing and the result is a high quality wall prepared for color or any other polishing.

3-implacemment of the cement board façade (cement board on the façade):
3-1-metall fitting:


Implacemment of the vertical element (wall post) of 40*80 can:Because in most of the buildings curtain walls are made of light materials and beams of the classes are the only structural connection points, wall post is used to make connection between horizontal elements; and because full weight of the facade is on the structure, 40*80 can or the right element -depending on the designer’s calculations- is used.Implacemment of the horizontal element from 40*40 can:Because V&M galvanized profiles are placed vertically, horizontal elements from 40*40 cans are performed on wall posts up to 150 vertically distances. It is necessary to mention that implementing the horizontal elements as a crossroad will help align the substructure.

3-2-Galvanized substructure
:

M galvanized profile: This profile is made from galvanized sheet a thickness of 7 millimeter; and for dimensional control of Fiber Cement Board panels that is made due to moisture changes, is used. This profile is placed between two Fiber Cement Board panels. If this profile is used, seam between panels will remains visible; for covering this steam, A galvanized profile can be used. This profile connects to the metal substructure from the middle part, only by a screw.V galvanized profile: This profile is made from galvanized sheet a thickness of 7 millimeter and is used with M galvanized profile in modular and siding Fiber Cement Board façade’s substructure. According to the fact that the price of this structure is significantly lower than M profile, using this profile will reduce cost of substructure. This profile is screwed to the metal substructure from two sides.
3-3- Installing Fiber Cement Board
Running waterproof insulation (sealer) behind the panels:  Because Fiber Cement Board is totally made by cement, has good compatibility with water and wet environment, but because of using cement in combination and the property of absorbing water when saturated with moisture (directly, with vapor or humidity in the air) expands and when dried, contracts; and tension caused by increasing and decreasing length will cause problems on the connection points (screwed points).  To avoid this problem a special sealer behind the Fiber Cement Board’s panels is used and on the Fiber Cement Board’s panels primer and color will do this duty, to minimize moister absorption.You can also find out more about the installation of eyvanit’s Sheets
Cut in specific dimensions:
Fiber Cement Boards must be cut by cutting table machine to avoid non-homogenization and unbounding cutting location. Avoid cutting by milling machine. Granite blades are suitable for cutting this stuff and other sheets cannot be used.
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