The Constructor

Alternate Building Materials Used in Construction Industry

Gopal Mishra

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Alternate building materials are those which can be used economically by replacing the conventional building materials. Alternate building materials are made from waste products and thus it even minimizes environmental pollutions. alternate-building-materials These alternate building materials can be used when it meets the respective specifications in the code of practice. Here some new materials and technology is discussed as well and a list many alternate materials for foundation, roof and walls are presented with details of each.

New Alternate Building Materials and Technology

Following are the new and alternate building materials used in construction works: 1. ALUMINIUM Applications of Aluminum In Construction 2. Bitumen Materials Advantages Applications 3. Tempered Glass 4. Crumb Rubber Advantage Fiber Reinforced Polymer Glass Fiber Reinforced Plastics Bamboo reinforced plastics Polyester Fibers Ferrocement WALLINGS STABILISED, COMPRESSED EARTH BLOCKS Made of mud stabilized with 5% cement/lime etc. and compacted in the block-making machine with no burning. A good walling material is burnt bricks and is economical, stronger, energy-saving, and simple to manufacture. The soil to be used for the blocks should have the requisite component of clay and silt and sand etc. Soil stabilized hollow and interlocking blocks can provide better thermal insulation. Developed by CBRI/ASTRA/Aurovil/e Building Centre. STABILIZED ADOBE: It is an improvement over traditional adobe or hand-molded and sun-dried mud block in which mud is mixed with a small proportion of cement or lime or broken or cut dry grass as reinforcing media to impart added strength and lower the permeability. It is appropriate in dry climates. Fal-G STABILIZED MUD BLOCKS: These are much stronger with less water absorption and cheaper than cement stabilized blocks. With 5 to 10 percent Fal-G, 30 percent saving in cement could be achieved in addition to the utilization of the waste product like fly ash. These blocks could be manufactured at the village level. Most suitable where well-burnt clay bricks are not available. (Developed by INSWAREB Building Centre) CLAY FLYASH BURNT BRICKS: Produced from fly ash and clay, are stronger than conventional burnt clay bricks, consume less energy, provide better thermal insulation and solve the environmental problem through the utilization of fly ash, and industrial waste. (Developed by CBRI) FLYASH/SAND-LIME BRICKS: Produced from fly ash or sand with lime as a binder, are strong, superior in water absorption and crushing strength. However, this needs autoclaving. (Developed by CBRI/CFRI) FLYASH-LIME-GYPSUM (Fal-G) PRODUCTS: Manufactured by blending fly ash, lime, and calcined gypsum (from a by-product of phosphogypsum or natural gypsum) for making a useful product, named Fal-G, and can be used as a cementitious material for mortar/plasters and for masonry blocks of any desired strength. It can also be used for road pavements and plain concrete in the form of Fal-G concrete. (Developed by INSWAREB Building Centre) CLAY RED MUD BURNT BRICKS: Produced from alumina red mud or bauxite an industrial waste of aluminum-producing plants in combination with clay. Possess all the physical properties of normal clay bricks and solves the problem of disposal of the waste product and environmental pollution. In addition, they have good architectural value as facing bricks due to their pleasing hues of color. Red mud in addition improves the quality of bricks made from inferior soil deficient in clay content. (Developed by CBRI) LATO BLOCKS: These are improved bricks made from lateritic soil and cement or lime. Available in South-West India as large soft rock masses. The blocks are molded under pressure to produce strong and good quality blocks which consume lesser energy than conventional bricks and hence cheaper. They are available in pleasing hues of colors ranging from cream to light crimson. (Developed by CBRI) PRECAST STONE BLOCKS: These are of larger size than normal bricks are manufactured by using waste stone pieces of various sizes with lean cement concrete and enable a rationalized use of natural locally available materials. Shaping stones in this manner, enables speedy construction saves on cement, reduces the thickness of stone walls, and affects overall saving by eliminating plasters on internal/external wall surfaces. Appropriate architectural rendering on exterior surfaces can also be given. (Developed by CBRI) PRECAST CONCRETE BLOCKS: Made to the similar dimensions of stone blocks without large size stone pieces, but using coarse and fine graded aggregate with cement. They have excellent properties comparable to other masonry block, are cheaper and facilitate speedy construction, and especially suitable where good quality clay for brick making is not available. (Developed by CBRI) PRECAST HOLLOW CONCRETE BLOCKS: These are manufactured using lean cement concrete mixes and extruded through block-making machines of egg-laying or static type need lesser cement mortar and enable speedy construction as compared to brick masonry. The cavity in the blocks provides better thermal protection and also does not need external or internal plastering. These can be used for walling blocks or as roofing blocks along with inverted precast tee beams. (Developed by CBRI) FLYASH BASED LIGHTWEIGHT AERATED CONCRETE WALLING AND ROOFING BLOCKS: These are manufactured by a process involving the mixing of fly ash, quick lime or cement, and gypsum, foaming agents such as aluminum powder. These are considered excellent products for walling blocks and prefab floor slabs. (Developed by CBRI/CFRI) PRECAST AERATED/CELLULAR CONCRETE WALLING BLOCKS AND ROOFING SLABS: These are manufactured through the aerated cellular concrete manufacturing process. When used in multistoried structures reduce weight, resulting in more in the economic design of the structure. These components can also be worked and handled easily, have a high fire-resistance rating, and provide better insulation. (Developed by CBRI) RAT -TRAP BOND: This is an alternate brick bonding system for English and Flemish bond. This is economical, strong and aesthetic. 25% of the total number of bricks and 40% of motor the cost of the wall can be saved by using RAT -TRAP BOND. It is simple to build and has better insulation properties. (Developed by Laurie Baker) BAMBOO/TIMBER MAT BASED WALLS (EKRA WALLING): Plastered on either side by mud or cement mortar over bamboo mat placed between horizontal and vertical timber/bamboos as a frame. Are easy to construct, cost less and are popular in hilly areas due to self help. However, these are non-load bearing and need supporting structure. This upgraded traditional technology is a relevant for earthquake view point walling option. (Conventional) COMPOSITE FERROCEMENT SYSTEM: It is simple to construct and made of ferrocement i.e. rich mortar reinforced with chicken and welded wire mesh. These reduce the wall thickness and allow larger carpet area. Precast ferrocement units in trough shape are integrated with R.C.C. columns. Ferrocement units serve as a permanent skin unit and as a diagonal strut between columns. Inside cladding can be done with mud blocks or any locally available material. Ideally suitable for seismic areas. (Developed by HUDCO)

ROOFS

LIFE EXTENDED THATCH ROOFING: It is a self-help, locally available, and environmentally sound option. By treating it with copper sulfate solution, its life can be lengthened to reduce the biodegradability effect. By using thatch in the form of compact panels instead of bunches, its combustibility is also reduced. An additional coating of treatment on the roof surface using phosphorylated spray or CNSL oil also achieves waterproofing, fire resistance, termite proofing, and weathering resistance. (Developed by CBRI/RRL- TVM) COCONUT FIBRE AND WOODEN CHIPS ROOFING SHEETS: Coconut fiber and wood chips or fiber are soaked in water for two hours and water drained off. Later these are mixed with cement and laid over a corrugated mold and kept under pressure for 8 to 10 hours. After demolding, these are cured and dried before use. (Developed by RRL-TVM) CORRUGATED BAMBOO ROOFING SHEET: An innovative roofing material with an up-gradation of traditional material from Bamboo Board. It is eco-friendly, light in weight, strong and durable, and minimal fire hazards compared to thatch and other materials. These sheets can be used for roofing, walling, door and window shutters, and other components in building construction. Sheets are bonded with phenol-formaldehyde resin to which anti-termite chemical is added at the time of mat impregnation. These are termite resistant and fire retardant. COUNTRY TILE ROOFING: Can be less expensive than Mangalore tiles on wood when laid on balli understructure, when molded tiles are made longer and distance between supporting members is increased. (Conventional) GUNA TILE ROOF: Such type of roof is very useful for villages. Its construction is possible only with use of Terra-cotta cones made by village potter and village artisans with nominal cost. Appropriate water-resistant treatment can be given on top. It is cheaper by 30 percent than normal roof. (Developed by CSV) PYRAMIDAL BRICK ROOF: In coastal areas where corrosion of reinforcement is possible construction of such roof is useful. There is no reinforcement in such roof. It is cast with ordinary bricks used with cement mortar/concrete in the form of pyramid. A ring beam is used along the periphery over walls. Such roofs are useful in cyclone prone areas. (Developed by CBRI) CEMENT BONDED FIBRE ROOFING SHEETS: These are made by profitably utilizing coir waste, coconut pith, wood wool or sisal fiber, in combination with cement as a binder for the production of corrugated or plain roofing sheets. These sheets use lesser cement than AC sheets, are 50% cheaper than AC/CGI sheets, lightweight, fire-resistant, waterproof and can be used for sloping roof options. (Developed by CBRI) MICRO CONCRETE ROOFING TILE: These are made of graded cement mortar layer vibrated and formed over sloping mold and cured, used in the pitched roofing system and is less expensive than ACC/CGI sheets ad burnt country tile roofing at all spans. It is appropriate where fired clay tiles are not available and timber supporting skeletal system is costlier. The rafter and purlin system cost lesser by using micro concrete roofing tiles. Further reduction can be made by using ferrocement rafters and purlins. (Developed by ITDG Development Alternatives/Tara Nirman Kendra) STONE PATTI ROOFING: This is a flat roofing system with a sandstone slab (patties) resting over steel or slender RCC section beams. The slabs are laid over with terracing for insulation. It is appropriate where (sand) stone slabs are available and is more economical than RCC slabs. Where larger granite stone patties are available like in Rajasthan, MP, AP the beams are not needed and can rest on walls. Further, the impact load distribution and thermal insulation are obtained by kharanjha distributors and lime terracing on top of it. (Conventional) EXTRUDED STRUCTURAL CLAY UNIT FLOOR/ROOF This is made from extruded structural clay units (HOURDIS), placed between tee sections containing rectangular hollows. These are used along with the precast joist and filler between the precast joint. Results in savings in cost and time over conventional RCC cast-in-situ slabs and also provide better thermal insulation. (Developed by CBRI/SERC) PRECAST BRICK PANELS: This is used in combination with partially precast joists (beams) save in economic use of steel and cement and provide an alternative to reinforced cement concrete roofing/flooring where good quality bricks are available. (Developed by CBRI) PRECAST L-PANEL ELEMENTS: Provide a better alternative to RCC sloping roofs. Water seepage can be eliminated in precast L shaped panels where better quality control is possible. Precasting also result in saving on expensive shuttering. (Developed by CBRI) JACK ARCH ROOF/FLOOR: These are easy to construct, save on cement and steel, are more appropriate in hot climates. These can be constructed using compressed earth blocks also as alternative to bricks for further economy. (Conventional) PRECAST BRICK ARCH PANEL SYSTEM: In this technique, the precast brick arches 50cm x 50cm in size are cast on a platform. These precast arches are placed side by side over the partially precast joist. The haunches between the arches are filled with cement concrete to have a level surface on top. Such roof/floor is 30 percent economical, when compared with conventional RCC also. (Developed by CBRI) FERROCEMENT CHANNEUSHELL UNITS: It provide an economic solution to RCC slab by providing 30 to 40% cost reduction on floor/roof units over RCC slabs without compromising the strength. These being precast, construction is speedy, economical due to avoidance of shuttering and facilitates quality control. (Developed by SERC/Auroville Building Centre) PRECAST PLANK AND JOIST FLOORING/ROOFING: Consisting of precast RC planks supported over partially precast RCC joists with in-situ concrete, suitable up to a span of 4.0 m and ensure 12% overall saving in cost and 20% reduction in construction time. (Developed by CBRI) FUNICULAR SHELLS OVER EDGE BEAMS: It provides a simple and attractive alternative to RCC construction for small to medium spans. These can be used to span square, rectangular or even triangular and non-orthogonal spaces and consist of thin sheet concrete, brick, stones, tiles supported on edge beams. These are cost effective as the required quantity of steel and cement is much less and can be precast avoiding costly shuttering. (Developed by SERC) PRECAST WAFFLE UNITS: Provide speedy construction with an overall saving of up to 10% besides avoiding shuttering work. These consist of precast concrete waffle floors/roof units with nominal reinforcement. The shape is like an inverted trough with square or rectangular in plan having lateral dimension up to 1.2m. Suitable for large spans beyond 6m in either direction, on laying in a grid pattern with reinforcement and cast-in-situ concrete joints between them. (Developed by CBRI) PRECAST CHANNEL UNITS: It is easy to construct a roofing/flooring with an effective saving in cost and time. These units are reinforced cement concrete elements channel-shaped in section and 2.5 to 4.2m long providing for the ceiling that looks like one-way rib beams. (Developed by CBRI) PRECAST CORED UNITS: These are simple to manufacture and provide a speedy and economical flush ceiling. Consist of extruded concrete sections units with circular hollows and can be used upto 4.2 m span. Used for floors or roof in load bearing walls and framed structures. (Developed by CBRI) PRECAST IN-SITU THIN RIBBED SLAB: These are made from precast/in-situ ribs provided at a spacing of 1.2 m with cast-in-situ RC flange. These can be used for floor/roof slab. As the ribbed slab is thin, roof treatment should be provided over the slab for better thermal insulation. It is cheaper and easy to construct in comparison to conventional cast in-situ RCC slab. (Developed by CBRI) FILLER SLABS: These are normal RCC slabs where bottom half (tension) concrete portions are replaced by filler materials such as bricks, tiles, cellular concrete blocks, etc. These filler materials are so placed as not to compromise structural strength result in replacing unwanted and non-functional tension concrete, thus resulting in economy. These are safe, sound and provide aesthetically pleasing pattern ceilings and also need no plaster. (Developed by Laurie Baker) Read More on Building Materials
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