Special Type of Concrete - Cellular Lightweight Concrete (CLC)
Cellular light weight concrete is used in the production of Cellular blocks, as roof insulation material , for prefabricated panels as structural members for low cost construction.
Cellular concrete like conventional concrete ages well, increasing its strength by as much as 50 % between 28 days and 90 days after pouring. As long as cellular concrete draws humidity from the atmosphere it will keep on increasing its mechanical properties.
Cellular concrete is produced using “Neopor” foaming agent with Natural sand and cement with water.
“Neopor” cellular lightweight concrete can be cast in situ or it can be a pre-cast. It can be cast in bricks for masonry or walls using fly ash in the concrete. The concrete has to be prepared with foam manufactured by foam generating machine and mixed with concrete.
Raw material for the cellular concrete:
The ingredients in the concrete is foam like “Neopor” , Sand , Cement and water.
Type of plant required for making neopor foam :
Neopor Foam generator “BK-8” has to be imported from Germany which can produce approximately 8l/sec (28.8 m3/ hour) sufficient to produce 50-60 m3 of cellular concrete/hour with Noise reducing rotation air-compressor , self-priming side- channel pump, including foam-lance, electr. Control-box and timer, drive 380/400 V, 50 cycles electric motors.
Type of foaming agent
Neopor – 600 Foaming agent is required for the production of highly stable foam. 1 kg of foaming agent with 40 litres of water produces 540 litres of foam.
Neopor foaming agent is based on a protein – hydrolisation. It causes no chemical reaction but serves solely as wrapping materials for the air to be encapsuled in the concrete(mortar).
Some of the physical properties of cellular concrete:
1. Range of densities : 400 to 1800 kg/cum.
2. Compressive strength : 10 kg/cm2 to 250 kg/cm2.
3. Shrinkage behaviour : 0.215 mm/ m with a density of 1200 kg/cum and 0.145mm/m with higher densities.
4. Thermal conductivity : 0.082 to 0.555 (W/mK) and dense concrete – 2.1 (W/mK)
5. Fire rating : non combustible
6. Water absorption : approx. 5 % at a density of 1200 kg/cum no condensation closed cellular structure.
Recommended mix design for cellular concrete based on a mixing volume of 1 cum.
Sand grading : A minimum of 20 to 25 % fine sand ( less than 300 microns is) is recommended for better physical properties.
Cement : Cement used in the production of foam concrete is usually OPC. However blended cements can also be used but blended cement results in slower rate of strength gaining.
Fly ash to an extent of 25 % or more of the mix can also be used in production of cellular concrete blocks and prefabricated elements with density of 1000 kg/cum to 1200 kg/cum.
The mix proportions in such case will be :
Cement (Portland) = 190 kg
Content of air in concrete = 43% approx.
Fly ash = 309 kg
Content of fly ash in solid material : 33% Sand = 430 kg
Content of fly ash in oven dry material : 31% Water = 250 Liters
Wet density = 1179 kg/cum
Foam = 423 Liters
Oven dry density = 1000 kg/cum (approx)
Cellular light weight concrete is used in the production of Cellular blocks, as roof insulation material , for prefabricated panels as structural members for low cost construction.
Cellular concrete like conventional concrete ages well, increasing its strength by as much as 50 % between 28 days and 90 days after pouring. As long as cellular concrete draws humidity from the atmosphere it will keep on increasing its mechanical properties.
Cellular concrete is produced using “Neopor” foaming agent with Natural sand and cement with water.
“Neopor” cellular lightweight concrete can be cast in situ or it can be a pre-cast. It can be cast in bricks for masonry or walls using fly ash in the concrete. The concrete has to be prepared with foam manufactured by foam generating machine and mixed with concrete.
Raw material for the cellular concrete:
The ingredients in the concrete is foam like “Neopor” , Sand , Cement and water.
Type of plant required for making neopor foam :
Neopor Foam generator “BK-8” has to be imported from Germany which can produce approximately 8l/sec (28.8 m3/ hour) sufficient to produce 50-60 m3 of cellular concrete/hour with Noise reducing rotation air-compressor , self-priming side- channel pump, including foam-lance, electr. Control-box and timer, drive 380/400 V, 50 cycles electric motors.
Type of foaming agent
Neopor – 600 Foaming agent is required for the production of highly stable foam. 1 kg of foaming agent with 40 litres of water produces 540 litres of foam.
Neopor foaming agent is based on a protein – hydrolisation. It causes no chemical reaction but serves solely as wrapping materials for the air to be encapsuled in the concrete(mortar).
Some of the physical properties of cellular concrete:
1. Range of densities : 400 to 1800 kg/cum.
2. Compressive strength : 10 kg/cm2 to 250 kg/cm2.
3. Shrinkage behaviour : 0.215 mm/ m with a density of 1200 kg/cum and 0.145mm/m with higher densities.
4. Thermal conductivity : 0.082 to 0.555 (W/mK) and dense concrete – 2.1 (W/mK)
5. Fire rating : non combustible
6. Water absorption : approx. 5 % at a density of 1200 kg/cum no condensation closed cellular structure.
Recommended mix design for cellular concrete based on a mixing volume of 1 cum.
| Density In Kg/Cum | 400 | 800 | 1200 | 1600 |
|---|---|---|---|---|
Material | Weight and Volume | Weight and Volume | Weight and Volume | Weight and Volume |
Sand | - | 420 Kg 160 Lit | 780 Kg 297 Lit | 1130 Kg 430 Lit |
Cement | 300 Kg 97 Lit | 320 Kg 103 Lit | 360 Kg 116 Lit | 400 Kg 129 lit |
Water | 110 Lit | 120 Lit | 140 Lit | 160 Lit |
Neopor Foaming agent | 1.5 kg | 1.2 Kg | 0.9 Kg | 0.6 Kg |
Foam by Volume | 800 Lit | 630 lit | 460 lit | 290 Lit |
Water In Foam | 60 Lit | 46 Lit | 35 Lit | 21 Lit |
Wet Concrete | 470 Kg 1007 Lit | 906 Kg 1013 Lit | 1315 Kg 1013 Lit | 1711 Kg 1009 Lit |
Sand grading : A minimum of 20 to 25 % fine sand ( less than 300 microns is) is recommended for better physical properties.
Cement : Cement used in the production of foam concrete is usually OPC. However blended cements can also be used but blended cement results in slower rate of strength gaining.
Fly ash to an extent of 25 % or more of the mix can also be used in production of cellular concrete blocks and prefabricated elements with density of 1000 kg/cum to 1200 kg/cum.
The mix proportions in such case will be :
Cement (Portland) = 190 kg
Content of air in concrete = 43% approx.
Fly ash = 309 kg
Content of fly ash in solid material : 33% Sand = 430 kg
Content of fly ash in oven dry material : 31% Water = 250 Liters
Wet density = 1179 kg/cum
Foam = 423 Liters
Oven dry density = 1000 kg/cum (approx)
