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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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Concrete pipes in sewage system, specifications, standards

 

General information about concrete pipes

 

Concrete sewer pipes that are used in collection network and sewage and rain’s water transfer lines are in two types; simple and armed. It should be noted that sewage with non-circle cross section is not mentioned in this discussion. Installing concrete pipes with a diameter of 1000 mm produced by baverce company.Concrete pipes standards:There are different standards for production and application of concrete sewer pipes. here are some of the most important standards in the following; which does not mean that producing concrete sewer pipes is limited to these standards; but means that most of the countries in the world have provided some standards about and use valid standards and cite this standards.-standards no. DIN 4032 and DIN 4035 for producing concrete pipes and accessories.-Standard no. ASTM C14M and ISIRI 8906 for producing armed concrete sewer pipes in 5 classes |, ||, |||, |V, V-Standards no. ASTM C655M and ASTM C506M for producing armed concrete sewer pipes-Standard no. ASTM C443M for connection between concrete sewer pipes with plastic ring
Application of concrete pipes
Concrete sewer pipes in different diameter have a lot of use in connection network, transfer lines and also sewer pomp lines. Today with the development of petrochemical industries and wide production of poly ethylene, the use of concrete pipes –specially in a diameter up to 400 mm; which is about 80% length of swage pipes in average – have reduced and poly ethylene have replaced them. Concrete sewer pipes in to simple and armed types, in different size with a diameter between 400 and 2450 mm produced by vibration and press method. Armed concrete sewer pipes are so suitable for collecting rain and sewer.The amount of bar needed for concrete sewer pipes production depends on tube thickness and diameter, The more thickness and diameter of the pipe, the more the rebar should be used to increase the resistance of the tube.Simple concrete sewer pipes with a diameter up to 900 mm are producible, but using them in a stomach more than 600 mm is not normal, without making this point limiting this.
Production of concrete pipes
Concrete sewer pipes should be produced based on one of the valid standards, with equipment and special machines in factories and with proper quality control; and should be tested before being transported to workshop.Production of concrete pipes in a workshop is not allowed under no circumstance and this kinds of pipes should not be used for sewer connection network. Simple and armed concrete sewer pipe classify in 5 classes |,||, |||, |V, V based on standard. This classification is based on maximum pressure for crushing stone which naturally affects The pipe’s depth and the sub-grade’s type. For producing concrete sewer pipes, sulfate resistance cement is used
Simple concrete sewer pipes
As said before, simple concrete sewer pipes to a stomach up to 900 mm is producible but in Iran simple concrete sewer pipes don’t have a diameter more than 600 mm. Advices in different Iranian publications number- 146A institute water engineering standard design, also didn’t recommend using simple concrete pipes with a diameter more than 600 mm. according to installation terms and bearing tube pressure while transportation, the length of each concrete pipe is Limited.
Armed concrete pipes
Armed concrete sewer pipes according to their class, have one or two layer of bar. Bars are frame made in factories and installed in form. Bars basket is made by machines the length of each armed concrete sewer pipes is normally 2 or 2.5How to carry produced armed concrete sewer pipes
Armed concrete sewer pipes are normally build in two ways
1-The concrete is poured into the tube and vibrated to be dense concrete; then extricated and released in a wet place to become stiff and hard
2-Loose plastic concrete is poured into the rotating steel tube with a gutter with a small slope. The concrete will be thrown to the tube walls, in the beginning the coarse grains collapses to the bottom of the steel tube and fine-grained concrete (mortar) sticks to the wall. Because the steel tube rotate regularly; the coarse grains will be thrown to the walls and put in the mortar.
Processing with vapor
Acting with vapor is done by injecting vapor. Armed concrete sewer pipes can be put in vapor processing room. The tube must be released in the room for a specific time and temperature to obtain the desired resistance. The processing room must be designed in a way that vapor could circle around the body of the tube and be safe from any suction caused by external air flow.
Concrete pipe jacking
Pipe jacking doesn’t have any disturbance for underground pipes installation. This is a very efficient method for long and short pipe’s lines (in 150 meter distance between jack establishment stations) and for pipe passing under main ways, roads and rail; which is much more efficient than other ways. Nowadays because of population increase, the close proximity of the apartments, buildings and urban facilities, and the resulted in traffic; pipe jacking is an efficient and suitable replacement for the old ways.Specifications of pipe jacking tube1-The pipes are produced according to standard ASTM-C76.2-Pipes have gasket metallic ring 3-Pipes comes in 350 units and made by anti-sulfate cement4-Inside the pipe is covered by poly ethylene page or GRP; depending on the costumer’s commands5-Pipes are produced from size 1000 to 2400Baverce company’s concrete pipe jacking are produced from 600 to 2400 diameter special metallic ring.
Corrosion and protection covers of concrete pipes
Concrete sewer pipes should be made with anti-sulfate concrete, but this case doesn’t mean that it will protected from corrosion
Protection cover of the external surface of the pipe
If the soil of the installation site of pipes was corrosive or the pipe touches the corrosive groundwater, protection cover for the external surfaces is necessary. Protecting external surface of the concrete pipes in order to protect them from penetration of corrosive materials and destruction of rebar layers has more importance.Protecting external surface of concrete pipes depending on the corrosiveness of the water and soil path can be in different ways; interchanging the surrounding corrosive soil with suitable non corrosive soil such as mixed river path or sandy soil, or tar felting external surfaces. Banding strip and lathering is not common or necessary. If the external surface of the pipe is going to be covered in the workshop the contractor must do the whole operation according to the design information and the standard way of using the materials in the protection cover and the consulting engineer
.3-2-7-3 protective cover of the internal surface of the pipe
Existence of H2S gas on top of the liquid in the sewage produces acid and according to the time, temperature, flow amount and the amount of sulfate in the sewage, cause corrosiveness in the internal surface of the pipe specially on the top part. Because the amount of liquid changes all the time, most part of the pipe is in danger of corrosiveness and normally, about 15 percent of the internal surface of medium and large pipes is covered by the liquid and doesn’t face the danger of corrosiveness of H2S gas. For sub sewer pipes in medium and big cities the diameter is less than 400 mm and make most length of the network the above number is less than 15.Best thing for protecting internal surface of the sewer pipe nowadays, is using poly ethylene plates which will be put in the pipe during the production. This plates will be put and covered in the concrete by the tentacles which are in one side of the plate. In the connection site, with prediction of extra edge on one side of the tube and cutting the tentacles behind them, extra part of the tube will be on the internal edge of the front tube, connected and will be welded by the special device to integrate the cover of the pipe lines. Welding this plates in the connection site normally is available for pipes with a diameter of 400 mm or more and so this covers are used for pipes with a diameter more than 400 mm.
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