Unconventional materials


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Unconventional materials

  2. 2. WHAT IS UNCONVENTIONAL? Anything which is not aligned with the general trend or set of rules. Unconventional materials include those materials which are not common construction materials. These may be recycled materials, reusable scraps like boxes, cans, pipes etc. However several materials have come up which is a modification of the existing ones like AAC, WPC etc. The materials covered further are  Pervious Permeable Concrete  Hempcrete  Wood composite polymer  Autoclaved Aerated Blocks  Fiber Reinforced concrete  Polymer modified mortar
  4. 4. INTRODUCTION Hempcrete is a combination of chopped hemp and binder comprising of natural hydraulic lime and a small amount of cement. It is firm and self insulating. Hempcrete is suitable for uses such as timber frame infill, insulation and, with the addition of aggregate, floor slabs. Hemp is a renewable biomaterial and lime is an abundant quarried material.
  5. 5. ADVANTAGES  It is carbon negative and the obvious choice for buildings aiming to achieve a low carbon footprint and the highest sustainable building code levels.  It regulates the temperature and humidity of a building; in some cases completely eliminating the need for heating and cooling systems, resulting in huge energy savings.  The addition of hemp fibres not only improves the strength and flexibility, it also increases the thermal properties of the plaster and so is an excellent way of adding some insulation to your wall.
  6. 6.  It is extremely flexible and breathable which makes it suitable for use in them restoration of old 'solid wall' construction buildings and ideal as a 'wattle and daub‘ replacement in timber-framed buildings. It is also suitable in ecological new builds as it can be applied to a variety of substrates e.g. wood fibre boards, wood wool boards, straw bale.  It is fire and termite resistant, lightweight and forms a hard wall surface yet is vapour permeable to help reduce humidity and prevent condensation.
  7. 7. BENEFITS OF HEMP OVER OTHER MATERIALS  It grows several metres within months. It grows 4m within 100-120 days.  It is versatile - it can be used to produce several products most are non- toxic, bio-degradable and renewable.  It is 10 times stronger than cotton, it naturally repels weed growth and hemp has few insect enemies which means it requires no herbicides and few or no pesticides whereas cotton requires enormous pesticide use.  It can be used as clean biomass. It has more potential as an energy source than any other crop.
  8. 8. Given the right conditions, it is resistant to rot, is fireproof, waterproof, weather resistant and importantly provides insulation. Hemp lime plaster is easy to use and can be applied in much thicker coats than conventional lime plaster hence offering labour savings! It is also much lighter than sand plasters and so has transport savings to.  The addition of hemp fibres dramatically improves the compressive and flexural strength of the product which make its more durable and stronger that other lime plasters.  made from a natural, renewable plant fibre (instead of depleting a natural aggregate resource).
  9. 9. APPLICATIONS Walls – Timber frame infill
  10. 10. Insulation – retrofit against existing walls
  11. 11. Floor slab
  13. 13. WOOD POLYMER COMPOSITE/ WOOD PLASTIC COMPOSITE (WPC): INTRODUCTION WPC (Wood Polymer Composite), a promising and sustainable green material is being evolved as a fundamental product for India, after being well adopted by the world. During WPC process, polymers are reinforced by incorporating the wood powder and fibres discharged from mills and factories as well as agriculture residues. WPC production is a 100% safe manufacturing practice, releasing no air or water pollution and having no process waste of materials. WPC is a highly eco-friendly product having no formaldehyde emission. The conceptualization of WPC is based on the ‘Cradle to Cradle’ approach where the material is recycled at the end of its cycle to produce a new cradle (new) product. The resultant is minimization of solid waste content and conservation of natural resources. Hence cost, energy and depletion of the core materials are reduced considerably.
  14. 14. MATERIALS UTILIZED IN WPC: Wood and plastics (virgin or recycled) with various types, grades, sizes, and conditions are the main materials utilized in WPC production. WPC is composed mainly from a plastic matrix reinforced with wood and other additives sometimes are added using the appropriate processing procedures. WPC utilizes polyethylene and they classified the types of plastic used in WPC as follow: polyethylene (83%), polyvinyl chloride (9%), polypropylene (7%), others (1%). Wood flour is obtained from wood wasted from wood processors. It should be from high quality and free of bark, dirt, and other foreign matter. Moreover, species are mainly selected based on regional availability of high quality flour and color. Pine, oak, and maple are the most common used in the United States. Additives should be added to the mix because the majority of the WPC physical and mechanical properties are depending mostly on the interaction developed between wood and the plastic which is increased by additives
  16. 16. ADVANTAGES •THE REAL ALTERNATIVE TO EXOTIC HARDWOODS: Exposed to the elements, the lifecycle of wood, whether soft or hardwood, is limited. Wood is vulnerable to UV radiation, humidity, fungal growth or insect attack, and requires regular treatment to delay greying, splitting, splintering or the spread of rot. Wood plastic composite provides an appealing alternative: rot proof and durable, it is guaranteed splinter-free and non-slip, it will not split or crack, and is resistant to insects and fungal infection. •A SUSTAINABLE BUILDING MATERIAL: Manufactured using processes designed to protect the environment, a board in wood plastic composite is ecologically sound. The wood fibres are mainly recycled pine. The resin component – recycled polypropylene – is a fully recyclable, environmentally-neutral plastic, widely recognised as a non-toxic substance. These raw materials – both wood and plastic – are all sourced from the recycling industry. •DURABILITY: AN ESSENTIAL QUALITY: 1. WEATHER RESISTANT: WPC is used in very diverse climates, and under difficult conditions where exposure to extreme heat and sunshine, or constant humidity, are the norm. 2. EXCEPTIONAL DENSITY: While hardwood will gradually succumb over time to weathering and hostile outdoor conditions, the extrusion process used in the manufacture condenses the material irreversibly. The subtle intricacies of the technology and the resins used form a perfect adhesive, without the addition of any glue or solvent.
  17. 17. APPLICATIONS WPC is used in both outdoors and indoors: • Decking, • Swimming pool surrounds, • Walkways, Steps, • Outdoor furniture or panelling, • Screens or louvered shutters, • Wood flooring or wall coverings, • Cladding, • Garden arbors or pergolas. The WPC boards, accessories and fixing clips reduce laying times to half those required when installing hardwood decking or support structures. Using standard tools, even the most inexperienced installer can produce straight, neat cuts without splintering. The boards are supplied with an ingenious system of invisible clips for easy laying and rapid dismantling, (if required) minimising the number of screws needed. These clip fasteners allow the structure to expand and shrink while maintaining firm but elastic contact between the boards and their supporting structure. The stainless steel screws we strongly recommend are black. INSTALLATION
  18. 18. Wood composite polymer is manufactured by sevral market companies including ECOSTE(India), EINWOOD(Dubai, Malaysia), JELUPLAST (Germany) etc. Costing of one of them is as follows:- ECOSTE WOOD COMPOSITE POLYMER  18 mm thick : Rs. 140/sq. ft  12 mm thick : Rs. 90/sq. ft  6 mm thick : Rs. 40/sq. ft
  20. 20. INTRODUCTION : In conventional concrete, micro- cracks develop even before structure is loaded because of drying shrinkage and other causes of volume change. When the structure is loaded, the micro cracks open up and propagate. The development of such micro-cracks is the main cause of inelastic deformation in concrete. However, research has shown that the addition of small, closely spaced and uniformly dispersed fibers, to concrete substantially improves its static and dynamic properties. These fibers offer increased resistance to crack growth, through a crack arresting mechanism and improve tensile strength and ductility of concrete.
  21. 21. Fiber reinforced concrete can be defined as a composite material consisting of cement mortar or concrete and discontinuous, discrete, uniformly dispersed fibers. The continuous meshes, woven fabrics, and long wires or rods are not considered to be discrete fibers. The inclusion of fibers in concrete and shotcrete generally improves material properties including ductility, toughness, flexural strength, impact resistance, fatigue resistance, and to a small degree, compressive strength. The type and amount of improvement is dependent upon the fiber type, size, strength and configuration and amount of fiber.
  22. 22. TYPES OF FIBRES : A fiber is a small discrete reinforcing material produced from steel, plastic, glass, carbon and natural materials in various shapes and sizes. A numerical parameter describing a fiber as its Aspect Ratio, which is defined as the fiber length divided by an equivalent fiber diameter. Typical aspect ratio range from 30 to 150 for length dimensions of 0.1 to 7.62 cm. Typical fiber diameters are 0.25 to 0.76 mm for steel and 0.02 to 0.5 mm for plastic. STEEL FIBRES : Steel fibers have been extensively used in overlays of roads, pavements, airfields, bridge decks and floorings subjected to wear and tear and chemical attack. The main problem encountered in the use of steel fibers is the tendency of the fibers to ball or cling together during mixing. This leads to non-uniform dispersion of fibers. Incorporation of steel fibers also decreases workability of concrete.
  23. 23. Glass Fibres : These are produced in three basic forms (a) rovings (b) strands (c) woven or chopped strand mats. Major problem in their use are breakage of fibers and the surface degradation of glass by high alkalinity of the hydrated cement paste. However, alkali resistant glass fibers have been developed now. Glass fiber reinforced concrete (GFRC) is mostly used for decorative applications rather than structural purposes.
  24. 24. Plastic Fibres : Fibers such an acrylic, aramid, nylon, polyproplylene and polyethylene have high tensile strength but low Young’s Modulus thus sharing inability to produce reinforcing effect. However, due to their high ultimate elongation, their addition to concrete have shown better resistance to cracking, reduced crack size and higher impact strength. Their use in concrete is gaining popularity due to numerous advantages. Carbon Fibres : These fibers posses high tensile strength and high Young’s Modulus. The modulus of rupture of an aligned carbon fiber reinforced cement composite with 8 % fiber volume can be as high as 1623 kg/cm². The composite also possesses high fatigure resistance. The use of carbon fibers in concrete is promising but it is costly and availability of carbon fibers in India is very limited. Mineral Fibres : Asbestos fiber has proved to be the most successful fiber, which can be mixed with OPC. The composite has considerably high flexural strength. The maximum length of asbestos fiber is 10 mm but generally fibers are shorter than this.
  25. 25. CLASSIFICATION ACCORDING TO VOLUME FRACTION ƒ Low volume fraction(<1%) ƒ Moderate volume fraction(between 1 and 2%) ƒ High volume fraction(greater than 2) LOW VOLUME FRACTION ƒ The fibers are used to reduce shrinkage cracking. These fibers are used in slabs and pavements that have large exposed surface leading to high shrinkage crack. ƒ Disperse fibers offer various advantages of steel bars and wiremesh to reduce shrinkage cracks: –(a) the fibers are uniformly distributed in three-dimensions making an efficient load distribution; –(b) the fibers are less sensitive to corrosion than the reinforcing steel bars, –(c) the fibers can reduce the labor cost of placing the bars and wiremesh.
  26. 26. MODERATE VOLUME FRACTION ƒ The presence of fibers at this volume fraction increase the modulus of rupture, fracture toughness, and impact resistance. These composite are used in construction methods such as shotcrete and in structures that require energy absorption capability, improved capacity against delamination, spalling, and fatigue. HIGH VOLUME FRACTION ƒ The fibers used at this level lead to strain- hardening of the composites. Because of this improved behavior, these composites are often referred as high-performance fiber-reinforced composites (HPFRC). In the last decade, even better composites were developed and are referred as ultra-high-performance fiber- reinforced concretes (UHPFRC).
  27. 27. ADVANTAGES OF FIBRE REINFORCED CONCRETE • Reduction in shrinkage and cracking : Research has shown that high fiber count (number of fibers per unit volume), reduces the effects of restrained and drying shrinkage cracking. The addition of polypropylene fiber also reduces crack width significantly. After cracking, the fibers transfer tensile stress across cracks and act to confine crack tip extension so that many fine (hair line) cracks occur instead of fewer larger cracks. • Improved Bond Strength The fibers exhibit improved mechanical bonding as a direct result of cement matrix penetrating the fibers network. This feature is called pegging. • Fatigue strength and endurance limit : One of the important attributes of FRC is the enhancement of fatigue strength as compared to plain concrete. The addition of polypropylene fibers, even in small amount has increased the flexural fatigue strength. • Better Toughness : Addition of fibers improve post-crack behaviour and energy absorbing capacity of concrete. The ability to absorb elastic and plastic strain energy and to conduct tensile stresses across cracks is an important performance factor for serviceability of concrete. Fibers have significant influence on post- crack load carrying capacity of concrete..
  28. 28. Conclusion : Based on the test of one hundred and ninety five specimens made with the available local materials, the following conclusions can be derived: 1. No workability problem was encountered for the use of hooked fibers up to 1.5 percent in the concrete mix. The straight fibers produce balling at high fiber content and require special handling procedure. 2. Use of fiber produces more closely spaced cracks and reduces crack width. Fib- ers bridge cracks to resist deformation. 3. Fiber addition improves ductility of concrete and its post-cracking load- carry- ing capacity. 4. The mechanical properties of FRC are much improved by the use of hooked fibers than straight fibers, the optimum volume content being 1.5 percent. While fib- ers addition does not increase the compressive strength, the use of 1.5 percent fiber increase the flexure strength by 67 percent, the splitting tensile strength by 57 per- cent, and the impact strength 25 times. 5. The toughness index of FRC is increased up to 20 folds (for 1.5 percent hooked fiber content) indicating excellent energy absorbing capacity. 6. FRC controls cracking and deformation under impact load much better than plain concrete and increased the impact strength 25 times.
  30. 30. BACKGROUND Developed in Sweden in the 1920s in response to increasing demands on timber supplies, AAC is a lightweight manufactured building stone. Comprised of all natural raw materials, AAC is used in a wide range of commercial, industrial, and residential applications. Autoclaved aerated concrete is a precast product manufactured by combining silica (either in the form of sand, or recycled flyash), cement, lime, water, and an expansion agent - aluminum powder, and pouring it into a mold. During this process, the hydrogen gas that escapes creates millions of tiny air cells, rendering the concrete with a strong cellular structure. THE MANUFACTURING PROCESS Air bubbles are created by a chemical reaction between the hydration products and the aluminum.
  31. 31. FEATURES Weather and earthquake resistant  Long lasting  Acoustically absorbent  Economical  Fire resistant  Energy efficient Autoclaved Aerated Concrete is about one-fifth the density of normal concrete blocks.
  32. 32. BENEFITS Reduces the dead load Ensures less usage of steel and concrete Requires lesser number of joints Ensures a smooth and accurate masonry profile Allows less thickness of plaster  Imparts thermal, sound insulation, fire resistant and earthquake resistant properties. Minimizes waste and pollution  Consumes 50% lesser energy than that needed for manufacturing concrete  Well suited to withstand fires earthquakes and other natural disasters.  Cost effective APPLICATIONS (a)a view showing the use of AAC as an infill material substitute of the original stone infill AAC can be shaped to confirm to any design and can accommodate almost any detail. AAC is excellent for all buildings.  AAC can be used for interior partitions, load bearing walls, back-up walls, firewalls, stair enclosures, elevator shafts, column wraps, shafts and chutes. (b) a view from the outside showing the application of the exterior cement based plasters over the timber framed structure with AAC infill.
  33. 33. a) close view to the application of AAC inside the timber framed structure b) the timber framed wall with AAC infill after the repair work  INSTALLATION Blocks are made to very exacting dimensions and are usually laid in thin-bed mortar that is applied with a toothed trowel, although more conventional thick-bed mortar can be used. AAC has low compression strength. The use of mechanical fasteners is not recommended, as repeated loading of the fastener can result in local crushing of the AAC and loosening of the fastener. There are proprietary fasteners that are specifically designed to accommodate the nature of the material by spreading the forces created by any given load. Conventional thick-bed (10mm approx.) mortar can be used with AAC.
  34. 34. TECHNICAL INFORMATION SERIAL NO. PROPERTIES SPECIFICATIONS 1. Size 600x200x75-300 2. Compressive strength 4-5 n/sq. Mm 3. Dry density 500-600 kg/cubic m 4. Fire resistance 2-6 hours 5. Sound reduction index 45 db for 200 mm thick wall 6. Thermal conductivity 0.16 w/m deg. C CONCLUSION Due to its relatively low consumption of readily available raw materials, excellent durability, energy efficiency, relative cost effectiveness, and ability to be recycled, AAC is well deserving of its “green” designation.  COST The cost of AAC is moderate to high . It is about 1.5 times higher than regular concrete. AAC is competitive with other masonry construction but more expensive than timber frame. Lack of competition in the marketplace makes consumers highly dependent on one manufacturer.
  36. 36.  Features • It is used as a coating for walls and ceilings • Application can be be manual or sprayed by machine • It can be applied directly on a concrete surface. No hacking is required • Only water needs to be added, easy to mix and application is much faster. • It is a highly tensile adhesion strength and hence higher bonding with the base material . • Does not require any water curing. • It is pre mixed and hence hassle free, involving no cumbersome mixing of cement and sand at site. • The application can be thin as 2-3 mm or as thick as 8-10 mm depending upon the requirement. • It can be used as a crack filler for external walls in repairing old plastered surfaces, in repair of shrinkage cracks in parapet walls, in repairs after plumbing/electricl works etc.
  37. 37. MIXING  It is very important that it is thoroughly mixed with water before use. It is advisable to use a mechanical stirrer for uniform and thorough mixing.  Take a clean vessel or bucket without any holes or cuts. Pour some water in it to ensure that no powder gets stuck to the bottom. Add the required quantity of polymer modified mortar powder.  Mixing Ratio - The amount of clean potable water required is approximately 25% to 30% of the weight of the powder, depending upon the thickness of the product to be applied. Water is to be incrementally added in stages, to get a smooth, uniform, workable mix. Allow ample time for initial mixing.  Ensure that no powder is left unmixed at the bottom of the vessel.
  38. 38. METHOD OF APPLICATION  It can be applied on the surface manually with a trowel.  After thoroughly mixing the mortar, apply the first coat on the moistened wall surface uniformly, going upward from the bottom. This will ensure minimum wastage and a proper finish.  The thickness of the coating should be 3 mm (1/8 inch).  Allow the surface to dry for at least 3 hours and then apply the second coat.  Leave the surface to dry completely.  For higher thicknesses, a number of subsequent coats can be applied to achieve the surface in plumb.  Leave the surface to dry (preferably overnight for 10-12 hours) before subsequent application .
  39. 39. METHOD OF APPLICATION  No water curing is required  Prepare only the required quantity of mortar and use it within 2 to 3 hours of mixing with water. Do not add extra water.  Do not apply under direct sunlight or in temperatures higher than 35°C. If the application is done under direct sunlight, necessary measures like covering the surface with net and water curing after two hours should be undertaken.  In case of ordinary day bricks or hollow blocks where the undulation is high, plastering is essential.  It may be applied over plaster in a thickness of 2 to 4 mm, depending on the surface undulation for leveling.
  40. 40. AREAS OF APPLICATION  Residential buildings, commercial complexes, basements, parking areas etc.  It can be directly used on surfaces made from fly ash bricks, concrete blocks, AAC blocks etc.  In the case of ordinary day bricks or hollow blocks, where the undulation is high, plastering is essential over which it may be applied up to 2 to 4 mm thickness depending on base plaster.  Repairs and renovation of old concrete and plastered surfaces
  41. 41. Polymers improve mortars in four main ways: 1. More extensive cement cure. Cement/concrete strength depends on proper curing, a chemical reaction (hydration) between water and cement that causes crystals to grow and wrap around the mix components. During the early stages of cure (roughly the first five to seven days), there must be enough water to maintain the hydration process or the cement/concrete will not harden properly. Polymers reduce the rate of water evaporation, allowing the crystal structure to keep growing and building strength during these critical early curing stages. This reduced water evaporation is especially important in thin applications, where the surface area for evaporation is high, relative to the volume of the mortar.
  42. 42. 2. Improved workability. Polymer modification noticeably improves application characteristics, making the mortar more fluid and easier to handle and apply. Certain polymers also prolong the hydration period, which can increase working time, an important characteristic in hot climates. 3. Improved adhesion. Polymer modifiers act as an adhesive to enable the modified mortar overlay to stick to a variety of surfaces such as concrete, masonry, brick, wood, rigid polystyrene and polyurethane foam, glass, and metals 4. Improved strength and durability. Cured polymer-modified mortars generally have improved tensile strength, flexural strength, impact and abrasion resistance, water resistance, and chemical resistance versus unmodified mortars. Also, the polymer in the mortar helps restrain micro-crack propagation, which improves the overall toughness of the mortar.
  43. 43. BENEFITS  Highly economical. Eliminates the lengthy, cumbersome process of  transporting individual materials and mixing on site.  Saves time and labour as it is pre-mixed, requiring only water to be mixed at site.  Consistent and assured quality, as it is pre-mixed.  No water curing required.  No crack formation during drilling or plumbing work.  Does not flake when in contact with moisture.  Cement based, ensures better bonding with the substrate.  Allows subsequent application of putty or paint just 24 hours  after application.  Provides better breathability for walls.  Can be applied over moist surfaces.  Highly durable.  Excellent crack-filling properties
  45. 45. Pervious concrete is a special concrete with a high porosity used for concrete flatwork that allows the water from precipitation or other sources to pass through thereby ensuring the recharge of ground water. 1. It allows rainfall to be captured and to percolate into the ground. 2. It reduces storm water runoff. 3. It recharges groundwater 4. It supports sustainable construction DEFINITION
  46. 46. BENEFITS OF PERVIOUS CONCRETE 1. Reduces storm water runoff 2. Eliminates the need for detention ponds and other costly storm water management practices. 3. Replenishes water tables and aquifers. 4. Allows for more efficient land development 5. Minimizes flash flooding and standing water 6. Prevents warm and polluted water from entering our streams
  47. 47. FEATURES 1. the maximum size of coarse aggregate may be either 10 mm or 20mm with designed porosity of 15-25% 2. The compressive strength of concrete is 3-18Mpa. The size of pores is in the range of 0.5 = 0.8mm. 3. Helps in storm water management system. It has lower life cycle cost sowing to good strength and excellent durability. 4. The maintenance of pervious is cheap and easy. 5. Pervious concrete has a 15-25% void structure and allows 3–8 gallons of water per minute to pass through each square foot—accounting for far more than is generated during most rain events.
  48. 48. APPLICATIONS 1. Sidewalks 2. Residential streets 3. Paths and walkways 4. Residential driveways 5. Light duty & commercial parking areas 6. Transit & pedestrian areas 7. Watersheds & wetlands 8. Low impact applications
  49. 49. ADVANTAGES 1. Reduced development cost a)Smaller capacity storm water drainage b)Lower investments for rainwater harvesting 2. Reduces overall runoff from an area and also reduces total amount of pollutants in runoff. 3. Help maintain growth of trees deposits aving 4. Reduces pooling of water and hence glare at night 5. Has unique surface finish and enhance tractions which provides better skid resistance to light traffic at the time of rainfall.
  50. 50. INSTRUCTION FOR USING 1. Prepare properly compacted sub grade 2. Place 8”-24” open grade stone(pebble) base 3. Place pervious concrete of appropriate thickness over the base course 4. Curing to be started within 24h and should be continued for at least 7days.
  51. 51. COST 1. Cost 8”thick pervious concrete pavement$3.20/sf material + $3.50/sf labor = $6.70/sf 2. 6”thick concrete cement pavement (comparable)$2.34/sf material + $3.00/sf labor = $5.34/sf therefore, +/-25% premium
  52. 52. 1. No reinforcing steel….not as structurally sound 2. Works best on flat sites 3. Installation • Certified installers needed • Sets up fast • EXACT water content is critical 4. Soils and loads must be right 5. Maintenance (not much more than other surfaces, but different) DRAWBACKS
  54. 54. THANK YOU!!!