3INTRODUCTIONCellular Lightweight Concrete (CLC) is conventional concrete, where natural aggregate (gravel) is exchanged for the best insulation medium available, namely air, embedded in organic and bio-degradable foam that offers no chemical reaction but solely serves as wrapping material for the air. Consequently CLC behaves, like conventional concrete, in particular concerning curing, hardening and most important “ageing “. CLC infinitely increases its strength by hydration (forming of crystals in cement) as long as exposed to humidity in the atmosphere.For structural (steel-reinforced) application, CLC is used in densities of 1,000 to 1,200 kg/m³, which, due to the billion of micro-sized and uniform air bubbles offer 500 % more thermal insulation and a substantially higher fire-rating than conventional concrete. If a wall of conventional concrete should offer the same thermal insulation as CLC, the wall produced would have to measure 5 times thicker and therefore also use 10 times more material (sand, gravel, cement) to produce. CLC structures in hot climatic zones require only 1/5th energy for air- conditioning when compared to traditional clay-brick structures.
4ADVANTAGESExcellent compressive strength in excess of regular clay bricks / solid blocks, guarantees min.CLC Bricks density is 1000kg/m3 which reduces dead load on structures.Huge saving in foundation and structure savings on beam costs.Optimization of floor space or coverage.Good earth quake resistance properties.Easy handling. Lightweight CLC is easy to transport and stock.Easily cut to custom size requirements on size using basic power- tools.Huge saving of labour. Faster construction directly relates to reduction in labour requirement.
5Highest thermal insulation making cool summers and warm winters. Reduced Air conditioning expenses. AC energy requirements can be 5 times lower than conventional structures.Fire resistant.Non toxic fumes in case of fire.Excellent acoustic barrier. More peace of living, no disturbance from your neighbour’s home theatre.Highly accurate and smooth walls reduction in plastering.Opt for any finish on walls – external plastering, tiling, cladding, internal tiling, dry lining, spray plaster or anything of your choice.Eco friendly.
6COMPARISON OF RCC FRAME QUANTITIES USING BRICKS AND CLC BLOCKS FOR MASONRY WORKS S.NoDescriptionBricks/BlocksCLCSaving (%)1Density of Material1900 kg/m31000 kg/m3-2Weight of building(Incl Masonry)KNKN203ConcreteIn superstructure (excl slab)In foundation and plinthm3198.8 m3150 m3159.6 m322.604SteelSuperstructure (excl slab)Foundation & plinth25.9 M.T27.8 M.T22.6 M.T23.34 M.T12.7019.70
7S.NoDescriptionBricks/BlocksCLCSaving (%)5Plaster15 mm 1250 m220 mm 1250 m20.95 L (12mm)1.16 L (12mm)0.82 L1429.306Shuttering(Reduced sizes of Members)X m20.75 X m225
81CLC BLOCK=13.5 BRICKS500*250*200229*114*70Parameter for 10 m2 wallBrick wallCLC Block MasonryCLC % AdvantageNo. of Units116893%Mortar for Masonry0.58 M30.014 m374%Labour- Skilled.- Un Skilled1.98 Masons3.68 Coolie0.51 Masons1.66 Coolie55%Weight of Wall4485 Kg2000 kg
9RELATIVE COMPARISON OF ALTERNATIVE WALLING MATERIALS S.N.ParametersCLCBurnt Clay Bricks1Basic Raw Materials and Other inputsCement, Sand, Flyash, water & Foaming agentTop agricultural soil, energy2Production process and set-upCan be produced at project site using ordinary concrete mixer and foaming generatorProcessed in specially erected or central brick kilns3Dry Density kg/m340019004UsageInsulationPartition, low rise load bearingRCC ElementLoad Bearing and Non Load Bearing5Pre cast Block Size500 X 250 X 100/200 mm229X114X70mm6Cast-in-placeAny shape & size kg/m3 In density rangeNot Feasible7AgeingGains Strength with age as ordinary concreteMay deteriorate with age
10S No.ParametersCLCBurnt Clay Bricks8Thermal conductivityfor kg/m3for kg /m3for 1000 kg/m30.8119Sound InsulationSuperiorNormal10Ease of WorkingCan be cut, sawn, nailed, drilled11Eco FriendlinessPollution FreeLeast energy requiredCan consume fly- 26% to 33%Process creates smokeUses high energy & waste agricultural land
11TECHNICAL SPECIFICATIONS OF CLC BLOCKS WITH DENSITY OF 1000 kg/m3 Block Size (mm)Block Size (inches)Approximate Weight/block (kg)No. of Blocks / m3600*200*22524*8*92737600*200*20024*8*82441600*200*15024*8*61855600*200*10024*8*41283500*200*22520*8*922.5044500*200*20020*8*82050500*200*15020*8*61567500*200*10020*8*410100
12Because one size doesn't fit all The Nominal dimensions of CLC blocks are 600mm in Length, 200mm in height and can vary from 100mm, 125mm, 150mm, 200mm & 300mm in width. Note: The maximum variation in the length of units shall not be more than 5mm cmd maximum variation in height and width of the unit not more than 3mm & is acceptable as per I. S. Standards. CLC blocks are a substitute for ordinary & dense concrete blocks. This versatile material can be produced to desired specifications in a wide range of densities from 400 kg/Cu. M. – 1800 kg/Cu. M., as per specifications.
13PRODUCTIONCLC is an air-cured lightweight concrete that can be produced at project site, utilizing equipment and moulds normally in use for conventional concrete. CLC, like conventional concrete ages well, increasing its strength by as much as 50% (!) between 28 and 90 days after pouring, As long as CLC draws humidity from the atmosphere it will keep on increasing its mechanical properties.Required EquipmentFoam GeneratorConventional MixersAir CompressorConventional moulds, horizontal/vertical /Trolley
14Raw MaterialFine SandCement (53 grade OPC)Fly AshFoaming AgentMould Releasing AgentWaterCuring of CLC takes place within the same period as conventional concrete. If cast in the evening, the concrete can be demolded next morning. Curing can be speeded up by either heat, steam or chemical (accelera - tors). - As in conventional concrete CLC may also be coloured (adding pigments).
16TECHNICAL SPECIFICATION CLC Bricks are available in 3 grade strengths:Grade A: These are used as load bearing units & have a brick density in the range of 1,200 kg/Cum – 1,800 kg/CumGrade B: These are used as non-Load bearing units & have a brick density in the range of 700 – 1,000 kg/Cum.Grade C: These are used for providing thermal insulation & have a brick density in the range of 400 – 600 kg/Cum.The blocks for masonry work would conform to the stipulations of IS: 2185 (Part-4) : 2008 and those for thermal insulation would satisfy the requirements of IS: 6598 (Part-4) :
18Recommended usage of CLC based on density Density kg/m³: This density is primarily applied for thermal insulation or fire protection. It uses only cement (or little flyash), water and foam and can easily be pumped. Foam generators allow the production of stiff foam for slopes to be applied on roof-tops.Density kg/m³: Is also used for void-filling, such as an landscaping (above underground construction), to fill voids behind archways and refurbishing of damaged sewerage systems. It is also been used to produce building blocks.Density kg/m³: Serves to fore mostly produce blocks and other non-load bearing building elements such as balcony railings, partitions, parapets and fence walls etc.Density kg/m³: Are the most commonly densities for prefab and cast in situ walls, load-bearing and non-load-bearing. It is also successfully used for floorscreeds (sound and insulation plus weight reduction).Density kg/m³: would be recommended for slabs and other load-bearing building elements where higher strength is obligatory.
19APPLICATIONCellular Lightweight Concrete (CLC) is excellent for strong yet light walls, noise insulating floors and leak proof roofs CLC, also known as foamed concrete or cellular concrete is not an autoclaved aerated concrete (AAC) product, it is conventional concrete with a wide range of densities, choice of aggregates and mix designs. It is widely used in the manufacture of single skin lightweight concrete wall panels, employing tilt-up construction. This is an ideal situation for the manufacture of light commercial structures and factories as well as residential housing. With the rise in population and increase in constructional activities considering the improvement in the standard of living the demand for building bricks is increasing day by day.
20ADVANTAGES IN DETAILThe tremendous savings described when using CLC are manifold.Savings in Raw Material:Blocks products reduce dead weight of filler walls in framed structures by more than 50% as compared to brickwork resulting in substantial savings. Due to the bigger and uniform shape of blocks, there is a saving in bed mortar and plaster thickness. Considering that a substantial amount of steel is necessary only to carry the weight of the structure, steel requirement might reduce by hundreds of ton in high rise.Considerably Lower Weight:Weight reduction is obvious in transport, where almost double of volume of building material can be produced; it has an impact on craning, where either larger panel can be taken, or the full capacity in span. Alternatively less re-location of the crane is necessary.
21Thermal Insulation:Thermal Insulation increasingly turns to be the most important issue in the planning and construction of buildings. There are many costly ways of insulation on sandwich structure of a wall, adding the one or another rigid insulation material, with a satisfactory result by computation but not always a sound solution in safety, health or environment. The best solution is, to incorporate thermal insulation in the mix of a concrete, such offered in air-cured CLC.Excellent Acoustic Performance:Blocks has excellent acoustic performance and can be used as effective sound barrier and for acoustic solutions. Hence, it is highly suitable for partition walls, floor screens / roofing and panel material in auditoriums.
22Fire Protection:The air-embedded in the CLC is also instrumental for the high fire-rating. In 1200 kg/m³ density a cm thick wall has a fire endurance of 5 hours. The same delay occurs with a 400 kg/m³ layer of CLC in only 10 cm thickness. CLC is otherwise non-combustible.Sound Insulation:Over the efforts to keep on increasing the thermal capacity of building members, other aspects have been neglected, such as sound insulation. Sound is experienced as air-borne or foot-fall sound (impact).
23Insulated Flooring:As the impact force will not transmit, slabs produced of CLC or topped with a layer of CLC floor screen will prevent any sound being noticed in the room below. Walls of CLC will also serve as sound retaining walls on roads or railway tracks therefore, absorbing the sound and preventing it from bouncing to the other side.Workability:Blocks products are produced in a rectangular shape for internal and partition walls or in shapes as required. The products are lightweight, making them easy to place and secure using less skilled labour. The bricks can be drilled and shaped like wood using standard hand tools, regular screws and nails. It is simpler than brick or concrete.
24Economical Production: Using only fly ash, cement, water and foam, the cost for one m³ of CLC in most cases is less even than for the equivalent volume of conventional concrete. Adding all the described highly appreciated benefits (comprising CLC) to regular concrete, if at all possible, the cost for such regular concrete would probably double but still not reach the overall quality of CLC.Environment Friendly:Blocks products are manufactured with fly ash 100% recycled resource. As a building material, Cellular Lightweight Concrete products conserve fertile agricultural soil. It has a dramatic impact on emission of Green House Gases created during cement manufacturing.
25Lifespan:Blocks products are weather proof, pest resistant and fire proof.Eco Friendly:CLC is remarkably ecofriendly. It saves depletion of the top soil, while at the same time it can actually use flyash – an industrial waste as one of its major constituents. The production process of CLC or its use does not release any harmful effluents to ground, water or air (unlike smoke of brick kilns and ruining of top soil in production of bricks). CLC due to its low weight is ideal for making partition walls. The use of CLC for this purpose will reduce the need for plywood partitions. This consequently will result in reduction in deforestation and will benefit environment.
26EASY TO CHASE WALL FOR ELECTRICITY CONDUITS AND PIPING WORKABILITYEASY TO CHASE WALL FOR ELECTRICITY CONDUITS AND PIPINGCLC is as strong and sustainable as conventional masonry/ brick walls. It is as easy to work with as wood. All CLC products can be easily cut and crafted with common hand tools. It can be cut and insert pipelines easily.
27DESCRIPTIONCellular Lightweight Concrete (CLC) is produced by the mixing of sand, fly-ash cement foam and water in requisite proportion in ready mix plant or ordinary concrete mixer. The mixed slurry is then poured into moulds of pre-cast blocks / structural components / assembled form-work of building elements or over flat roofs for thermal insulation as per I. S.: It is essentially air cured, thus can be produced at project site, utilizing equipment and moulds normally in use for conventional concrete. The foam is produced with the help of a Foam Generator by using a foaming agent. The foam contains isolated air bubbles, which creates million of unconnected tiny voids/cells in the mix resulting in lighter weight of concrete.
28Structural Capability CLC, like conventional concrete ages well, increasing its strength by as much as 50% (!) between 28 and 90 days after pouring, As long as CLC draws humidity from the atmosphere it will keep on increasing its mechanical properties. Curing takes place within the same period as conventional concrete. If cast in the evening, the concrete it could be demoulded the next morning. Curing can be speeded up by heat, steam or chemical (accelerators). CLC is an excellent and competitive material for low -rise, load- bearing construction and outside walls as well as partitioning work in multi –storeyed blocks.
29AppearanceCellular Light-weight Concrete is very light coloured. The addition of foam into the concrete mixture creates millions of tiny voids or cells in the material, hence the name cellular concrete. Although there is no direct path for water to pass through the material, an appropriate coating is required to prevent water penetrating into the CLC material. The quality of CLC production can be controlled accurately at the project site, just like Concrete. The surface finish depend upon the formwork and moulds used during casting.
30Site Precasting Of Blocks Basic advantage and superiority of the technology envisages easy and trouble free manufacturing of the product at the site of work. The product manufactured at the site shall be exclusively for in-house consumption of the project. All the raw materials shall be supplied by the client. Plant, machinery and equipment are optional. With this system the price shall be quite economical due to saving in sales tax and transportation and utilization of all the wastages and breakages at site for filling work and construction of boundary walls etc.
31Contact UsM/s Krishna Ashtech CLC Private Limited Offices:- 12/49, Site-4, Sahibabad Industrial Area, Sahibabad, Ghaziabad, U.P. Site: Vishada Road, Near Vishada Mandir, Badhpura, Dadri, G. B. Nagar Phone: , , Visit on: