basic property of Building Material and it's explanation
- 2. overview ● Building materials are basic requirement of construction ● Necessary to know the various types of building materials ● It affects the usefulness, economy and durability of structure To understand better, it is required to know the properties of materials such as… ● Physical properties ● Chemical properties ● Mechanical properties
- 3. Physical properties 1. Density Mass of unit volume of material It means mass (in kg, gm, lb) of unit volume (in m3, cm3, ft3)
- 4. Weight of unit volume of homogeneous material In simple words, ratio of material density with water density Physical properties 2. Specific Gravity
- 5. Mass of unit volume including voids Almost same as first property Physical properties 3. Bulk density
- 6. Ratio of volume of pores and volume of total sample Physical properties 4. porosity
- 7. Ability of the material to absorb water Physical properties 5. Water absorption
- 8. Capacity of material to allow water to pass through it. Means at constant pressure the amount of water passing from unit area. Physical properties 6. Permeability
- 9. Ability of the material to absorb water from the atmosphere water vapour Physical properties 7. Hygroscopicity Hygroscopic Nuclei
- 10. Ability of material to withstand high temperature without deforming or losing load bearing capacity Physical properties 8. Fire resistance
- 11. Specific Heat Take a unit mass and heat it The heat given for 1 degree increase in temperature is Specific Heat Physical properties 9. Thermal properties Thermal Resistivity It is reciprocal of Thermal conductivity Thermal conductivity If time, area, and thickness is unit, Temperature difference between faces is 1 degree, Then the heat transferred is called Thermal conductivity
- 12. Ability of resisting alternate freezing and thawing, without losing mechanical strength considerably, when the material is saturated with water. Physical properties 10. Frost resistance
- 13. Resistance of material against destruction by natural agencies Physical properties 11. Durability
- 14. Ability of the material to resist the size/volume changes. Physical properties 12. Soundness 13. Acoustic property Deals with origin, transmission, absorption and insulation of sound.
- 15. Material’s reaction with gases, water, moisture, salinity, sulphate, and other things Chemical properties which changes its composition, physical state, color, properties etc.
- 16. Mechanical properties Ability to resist various loads safely without deforming Strength
- 17. Material deforms when loaded. If regains original shape and size after load removal that property is called elasticity Mechanical properties Elasticity
- 18. If material does not get original shape and size after load removal, that property is called plasticity. Mechanical properties Plasticity
- 19. Sudden failing of material without considerable deformation Mechanical properties Brittleness
- 20. Tendency to deform more and more under sudden loading without failure. Mechanical properties Ductility
- 21. Resistance to abrasion, wear, scratching Mechanical properties Hardness
- 22. Resistance to wearing due to contact movement between surfaces Mechanical properties Abrasion
- 23. Continuous slow deformation over long term by constant load Mechanical properties Creep
- 24. If Loaded repeatedly in reversed loading condition, material fails at very low stress level is called fatigue Mechanical properties Fatigue Ability to deform without breaking Tenacity
- 26. Quality ● Economical & have required quality ● Not necessary to select always a best material Selection of appropriate materials Strength ● It should just perform safely ● Not necessary to take strongest one Availability ● Should be available easily ● Avoid storage and huge purchase Durability ● Life should be equal to structure ● Should be sufficiently strong to resist forces
- 27. Workability ● Material should be brought to shape and size by with less effort and skills Selection of appropriate materials Transportation ● Try to have locally available material ● No breakage during transportation Climate ● Should suit the climatic condition Appearance ● Should have good view and proper colour
- 28. Modern Technology: Use of new material for economical purpose Selection of appropriate materials Economy : Should cost lesser than other alternatives Speed of construction: Select to construct speedily and easily
- 29. Use of Material for various construction Stone aggregates Lime Bricks, walls, Floor finish, plaster, filling etc. Clay Mortar, Foundation, Flooring, Walls, Plaster, White Washing, etc. Lime Mortar, plaster, foundation, RCC works, floors, precast unit, pipes, paints etc. Cement Foundations, walls, flooring, lintels, columns, slab etc. Stone RCC works, mortar, concrete, foundation, flooring, pavement, plastering etc. Aggregate
- 30. Use of Material for various construction Stone aggregates Lime Furniture Components, truss components, beam columns, form work etc . Wood Foundation, filling, RCC work, plaster, mortar, flooring etc. Sand Building Components, pipes, reinforcements, truss components, furniture components etc. Steel Door, window, ventilation, fittings, tank, pipes etc. Plastic Door, window, fitting, furniture, pipes, tanks etc. Glass
- 31. Use of Material for various construction Stone aggregates Lime Door, window, ventilation, pipes, wires, sections, fittings etc . Aluminium Damp proofing, water proofing, roads, paints etc . Bitumen Pipes, sheets, roofing partition, damp proofing insulations etc . Asbestos
- 32. Clay products Arbaz H Khatuda
- 33. Clay ● Clay is formed by different elements but main constituents are kaolinite and Silica. Kaolinite gives plasticity and silica reduces shrinkage. ● Clay is made by disintegration of rocks due to weathering and chemical actions. ● By adding water it can be shaped in any form, and after burning in kiln, chemical reaction of ingredients makes it hard. ● Bricks, tiles, stonewares, etc are the products of clay that are being used widely in construction.
- 34. Classification of Clay Products China Clay stonewares porcelain etc Brick Clay: ● Bricks ● Tiles ● Earthen Wares Fire Clay: Fire bricks ● Acidic ● Basic ● neutral Bentonite Used as filler material
- 35. Standard Requirements of Bricks Determined By two types of tests : Field Testing and Lab Testing Field Testing ● Testing for Shape and Size : Standard brick size should be 19 cm X 09 cm X 09 cm for full brick 19 cm X 09 cm X 04 cm for half brick Brick should have regular shape, rectangular face, sharp corners and even surfaces ● Colour : Should have uniform bright copper colour. Overburnt is dark red, under burnt is yellowish. ● Texture : Homogeneous, compact, free from voids, cracks, flaws, lumps etc. ● Sound : When two bricks are struck, they should produce ringing sound and should not break. ● Strength : Should not break when dropped from 1 m height. ● Other Tests : Have less than 50% efflorescence. no marks for nail scratching. should have proper frog.
- 36. Manufacturing of Bricks Selection of Clay: Brick Clay Should Contain following Ingredients, ● Alumina: 20-30% → gives plasticity → easy moulding → excess causes shrinkage, warping, too hard bricks. ● Silica: 50-60% → combines with alumina and makes brick hard, strong, durable, prevents shrinkage, warping and pressure provides uniform shape to bricks → excess makes brick porous, brittle and problems in burning. ● Lime: about 5% in powder form → reduces shrinkage → fuses with silica, form hard binding material → gives strength → excess causes melting and deformations → nodules causes disintegration with moisture. ● Iron oxide: 5% desirable → helps in fusing sand → makes brick red → excess causes softness and deformation in burning → becomes dark → shortage causes yellowish color. ● Magnesia: small quantity makes it yellowish and reduces shrinkage → excess causes decay of bricks.
- 37. Harmful ingredients for brick clay ● Lime : Excess lime deforms the brick, nodules causes disintegration in presence of moisture. ● Iron Pyrites: Crystallizes and splits brick into pieces. ● Peebles : Prevents proper mixing → makes brick non-homogeneous, weak, porous. ● Alkalies: Acts as a flux → causes brick to fuse, warp, twist → hygroscopic hence causes efflorescence. ● Organic Matter : Makes brick porous. Manufacturing of Bricks
- 38. 1.Excavation Remove top layer of roughly 150 mm containing leaves, roots, grass, vegetables, peebles etc Excavate earth, break clods, remove peebles, lime, kankar, roots vegetation etc. Manufacturing of Bricks 2.Weathering Sprinkle water over excavated soil spread it in form of heap. Allow to weather for a month. Turn at least twice during weathering. 3.Blending Break the clods, add necessary ingredients. Turn up and down for through mixing, add water if required. 4.Tempering Add sufficient water to make soil homogeneous and plastic. Knead under the feet by men or cattles. Use pug mill for large scale manufacturing.
- 39. Pug Mill ● Top diameter slightly more than bottom diameter. ● Height : usually 2 to 3 m. ● ⅓ height is below in the ground. ● Vertical shaft pivoted in timber bottom. ● Horizontal arms with blades are attached to shaft. ● Rotated by electric or diesel power. ● Clay and water is added from top, and material is mixed. ● Mixture is taken out from opening at bottom.
- 40. Moulding of Bricks Hand moulding ● Metal mould has longer life. ● Dimension are kept 10% more to allow for shrinkage during drying and burning. ● Multiple moulds are also prepared. Ground Moulding ● Suitable on level Ground. ● sometimes plasters ground with sprinkled sand. ● If mould is dipped in water before moulding → slop moulded bricks. ● If fine sand or ash is sprinkled → bricks will have sharp, straight edges → sand moulded bricks. ● Prepared moulds placed on ground → lump of tempered clay dashed in the moulds → pressed to remove hollow voids → surplus is removed by wire frame or sharp plate called strike → mould lifted, brick left on ground → lower faces are rough.
- 41. Moulding of Bricks Table moulding ● Process similar to earlier types, all material is placed on a large table and the moulders stand near the table and mould the bricks. Machine Moulding ● Used for large quantity. ● Better quality bricks with economic cost. ● 2 processes 1. Stiff mud process 2. Dry process ● In stiff mud process, less water is added and forced from the dye to get shape. ● Comes out as continuous ribbon, cut by knife or wire. ● In dry process, very little water added, then filled in mould and pressed by plunger. ● Drying period can be reduced or avoided.
- 42. Natural Drying → Bricks turned on edges and left for 2-3 days to become hard for handling. → Should be protected from sun rays and severe wind. → Then staked in such way that free air circulates in between by keeping gapes in staking arrangement. → Protected from sun and rain. Left for roughly one week depending on weather. Drying of Bricks Artificial Drying Can be of 2 types (1) Hot Floor Dryer (2) Tunnel Dryer → Hot floor dryers are heated by hot flue gases or furnace placed at one end of dryer. → Tunnel dryers are heated by hot air from kilns. → Dryers Can be continuous to load from one end and unload from other or batching type. → Tunnel dryers are economical. → Artificial dryers take less time and used for large scale production, can be continued in rainy season. Necessity: → Bricks gets strong for handling and stacking. → Reduces cracks and distortion during burning. → Saves fuel while burning. It can be (a) Natural Drying or (b) Artificial Drying
- 43. Burning of Bricks burnt in Clamp or kiln. Clamp→ Temporary structure, used for small scale local demand. Kiln→ Permanent Structure, suitable for large scale production. Clamp: ● Trapezoidal shape in plan. ● Shorter side kept slightly in ground. ● Slight slope of roughly 15° is given. ● Local fuel such as cow dung, wood, leaves, placed in layer of 70-80 cm. ● Bricks are placed above in 4-5 layers with gapes for air. ● Repeated layers of fuel and bricks are placed upto 3-4 m height. ● Lower portion is ignited, thickness of fuel is reduced in upper layer.outside is plastered with clay and top is filled with clay. ● Burning is continued for one month and then cooling for one month. Advantage of clamp: → local fuel is used → economical burning → minimum supervision required. Disadvantages of clamp: → non uniform burning, resulting in under burnt, over burnt bricks → slow process → not possible to control fire → final shape is not uniform
- 44. Kiln There are two types: 1) Intermittent kilns 2) Continuous kilns Intermittent kiln: bricks are supplied in it at regular time interval. ● Rectangular structure with thick walls. ● Opening for fuels provided with doors to control firing. ● Doors in short wall for brick loading-unloading. ● Laid in 2-3 rows upto 8-10 layers in height parallel to short wall. ● 2 brick wide space left in between for fuel. ● Top of fuel space to be covered by projecting bricks from upper layer of brick rows. ● After loading of bricks, top is covered by earth to prevent loss of heat.
- 45. Kiln Intermittent kilns Process: Firing : slow firing for first 2-3 days to drive out the moisture, then strong firing by raising doors for flues. Cooling : slow cooling by closing doors for flues upto 8 days, slow cooling prevents cracking of bricks. Unloading : started by removing top earth layer. → quality is better than clamp → some bricks remains unburnt while some at bottom are over burnt → this can be resolved by down draught intermittent kilns where hot gases are forced to move downwards for heating bricks by chimney draughts. → due to close control on firing, evenly burnt bricks are obtained.
- 46. Kiln Continuous kilns: for non stop supply of bricks 3 B u r n i n g P r e - h e a t i n g 2 1 L o a d i n g Air Circulation Path 5 U n l o a d i n g 4 C o o l i n g Air Entry Escape of Air
- 47. Continuous Kiln ● Air is entered from the unloading point, which cools the bricks that comes out. ● Then enters in the kiln to help in burning. ● Then heated air goes to entry portion which pre heats the bricks. ● Lastly, exits from the loading point. ● Direction of air circulation is reversed to direction of production process. There are various types of continuous kilns but most popular are bull trench, hoffman and tunnel kilns.
- 48. Bull Trench Kiln ● Can be full or partially in ground. ● Oval or rectangular shape. ● Divided by dampers. ● Bricks loaded with space for flues. ● Holes are provided at top for inserting flues. ● Movable chimneys are provided on top where raw bricks are loaded. ● Fire holes are closed when burning is ended, each section takes one day to burn bricks. ● Chimney is shifted to next section when burning of other section is started. Favorable points: ● Good quality of bricks ● Non-stop supply ● Saving of drying space ● Saving of time ● Economy in fuel consumption. Against all above, high initial cost and closed Supervision is necessary.
- 49. Hoffman’s Kiln → Circular shape. → It has central chimney, 12 compartment doors and dampers. → Compartments are connected to chimney. → compartments are connected to chimney by dampers and have holes for fuels in powdered form. → cool air enters at 1 where burnt bricks are unloaded. → passes through 12, 11, 10, 9, 8 where burnt bricks are being cooled. → bricks are burnt in 6 and 7 → heated air preheats bricks at 3, 4, 5 → Raw bricks are laid in 2, heated air is passed upward through chimney. → Burning is shifted to 4,5 in next phase. Process will be continued. Favorable point: ● Low fuel consumption ● Saving of time ● Work continued in rainy season ● Good quality of bricks ● Arrangement in limited area ● No extra space needed for drying Against all above, skilled supervision and high initial cost may be overlooked.
- 50. Tunnel kiln ● Continuous in form of tunnel , it can be straight, circular, or oval. ● Rail tracks are provided for trolleys ● Bricks are placed in trolley ● Bricks get dried, preheated before burning ● Bricks are burnt and forwarded for cooling ● Cooled bricks are unloaded
- 51. COMPARISON: CLAMP & KILN Points Clamp Kiln Quality Ordinary Good Production in numbers 25000-100000 per operation More than 200000 in a day Time of cycle 3-6 months About 14 days Structure Temporary Permanent Suitability Limited production Large scale production Production continuity Discontinuous Continuous Fuel Any type of local fuel Selected coal Optimum utilization of fuel Not possible Gases used for preheating Labour Ordinary labourers required Trained person required Cost Low High Control of burning No control Possible Wastage of bricks 35% 10% Operations One at a time All process at a time
- 52. Flow diagram of brick manufacturing Drying Natural or artificial drying Burning Burning in clamp / intermittent kiln / continuous kiln and storing Preparation of clay 1. Removal of top layer of soil 2. Weathering for one month 3. blending /adding ingredients 4. Tempering-kneading of clay Moulding Table / Machine / Ground moulding with/without frog
- 53. Types of brick Queen closer King closer Squint brick Splay/cant brick Plinth stretcher Coping brick Cornice brick Bull nose brick
- 54. Types of brick Double bullnose brick Gutter brick Perforated brick Hollow brick Chequered brick Voussoir brick
- 55. Other types of bricks Refractory bricks: ● can resist high temperature and thermal shocks without yielding. ● Prepared from refractory materials suitable for furnaces operating at high temperature. ● There are three types ○ Acidic bricks ○ Basic bricks ○ Neutral bricks Acidic bricks: fire bricks & silica bricks Fire bricks: ● prepared from fire clay consisting molten silica, alumina and little quantity of fluxes. ● No oxides of calcium, magnesium or iron so no melting at high temperature. ● Classified as high duty, medium duty and low duty. ● Suitable for lining of steel furnaces, reverberatory furnaces and glass making furnaces. Silica bricks: 95% silica + 2% CaO, little fire clay added → High pressure moulding and high temperature burning → compressive strength > 15 N/sqmm → temperature resistance upto 2000°C → joints are bigger due to more expansion → used in steel industry and bessemer converter.
- 56. Basic bricks: Manufactured from magnesite, dolomite, and bauxite and accordingly knowns as 1. Magnesite bricks 2. Dolomite bricks 3. Bauxite bricks Magnesite bricks: oxides of magnesium and calcium with little silica → Magnesium chloride added to improve plasticity → used for lining in bessemer converter, open hearth furnaces, blast furnaces and in metallurgy. Dolomite bricks: prepared from calcined dolomite, carbonate of magnesia and lime → contracts at high temperature. Bauxite Bricks: contains more than 50 % alumina and iron oxides, little silica and fire clay → more shrinkage at high temperature, hence not much popular. Neutral Bricks: Types of neutral bricks are: chrome brick, chrome magnesite brick, forsterite brick,spinel bricks. Chrome bricks: contains oxides of chrome, magnesium, aluminium and silicon, chrome oxide is the main ingredient.they resist corrosion but not satisfactory as refractory bricks. Chrome magnesite bricks: main ingredients are chrome ore and magnesite. These bricks are strong. Forsterite bricks: forsterite is chief ingredient. They have good strength and low shrinkage. Spinel bricks: consists magnesia and alumina, prepared in electric furnace. Neutral bricks are used in furnace where reaction may be acidic or basic.
- 57. Fly Ash bricks: ● Fly Ash is residue of coal burning, available at thermal power plant, becomes cementing material with combined with lime. ● Lime, sand and fly ash is mixed as 1:2:12. ● Paste is obtained by adding suitable amount of water. ● Hydraulic press is used in preparing bricks. ● Curing is done in steam chamber with required temperature and pressure. ● Better in many aspect compared to regular bricks. ● Good shape and size with 10% economical. Sand lime bricks: ● Known as calcium silicate bricks. ● Prepared by 85% sand, 10% lime and little clay. ● Pigments are added for desired colors. ● Manufactured using rotary press, autoclave, and high temperature with humidity. ● Hard, dense, uniform, strong, smooth and free from efflorescence. ● Costly hence not suitable for foundation, furnace. ● Weak in abrasion, most suitable for face work and decoration only.
- 58. Acid Resistant brick: Prepared from clay and low percentage of lime, sand and felspar. They are vitrified in ceramic kiln. Use: chemical plants, sewers conveying effluent and constructions likely to come in contact with acids. Burnt clay facing bricks: These bricks possess more compressive strength. They absorb less water. Have good shape, size, color. Minimum warping and efflorescence. Use: for facing work in area having corrosive atmosphere. Over burnt bricks: Strong compact structure but irregular shape and dark non uniform color, suitable pavement and aggregates for floors, roads etc.
- 59. Laboratory testing of bricks Grades of bricks ● Ordinary bricks: crushing strength ≮ 3.5 N/mm^2 ● Class A bricks: Crushing strength 7-14 N/mm^2 Length tolerance- ± 30 cm Total length of 20 pc - 350-410 cm Width tolerance- ± 20 cm Total width of 20 pc - 165-195 cm ● Class AA bricks: Crushing strength > 14 N/mm^2 Length tolerance- ± 12 cm Total length of 20 pc - 368-392 cm Width tolerance- ± 6 cm Total width of 20 pc - 174-186 cm Following tests are common for bricks ● Crushing strength ● Efflorescence ● Water absorption ● Soundness
- 60. Bricks used in construction First class brick: burnt in kiln - table moulded - standard shape - sharp edges smooth surface - good quality. Use: face work, buildings, dams, roads, bridges etc. Second class brick: ground moulding - kiln burning - slight rough surface - slight irregular shape - edges straight but not sharp and uniform - hair cracks Use: where walls are plastered, more mortar required Third class brick: ground moulding - clamp burning - rough surface - not hard- edges irregular and distorted - dull sound when struck Use: unimportant and temporary works, not suitable for wet climate. Fourth class brick: over burnt bricks with irregular shape - dark non-uniform color - strong but non-uniform Use: road metal, aggregate for foundation.
- 61. Classification by grade Grade-A: compressive strength > 10.5 N/mm^2, water absorption <20%, uniform color - well burnt - table moulded - sharp edges - hard - suitable for external works. Grade-B: compressive strength > 7 N/mm^2, water absorption <22%, table moulded - useful for ordinary work Grade-C: compressive strength > 3.5 N/mm^2, water absorption <25%, soft, can be used for unimportant work, can be used below plinth. Grade-D: over burnt-under burnt, soft, yellowish, can be used as aggregates.
- 62. Other clay products 1. Tiles 2. Earthenwares 3. Stonewares 4. Glazing Tiles: ● Floor tiles ● Roof tiles ○ Pot tiles ○ Pan tiles ○ Flat tiles ○ Mangalore tiles ○ Allahabad tiles ○ Corrugated tiles ○ Guna tiles ○ Encaustic tiles
- 63. Earthenware ● Prepared from clay, sand and crushed pottery. ● Soft and porous but can be made hard and impervious on glazing. ● Terracotta and porcelain are earthenwares. Porcelain: Hard, brittle, non-porous, used for electric insulation, sanitary wares, storage vessels etc. Made by 1. Dry Process: ingredients are mixed and pressed in hydraulic press and burnt in kiln 2. Wet Process: mixed by water forming paste, moulded, dried, glazed and burnt in kiln. Used for electrical goods Terracotta: Porous: sawdust added in making, fire and sound proof, can be chiseled, sawn or nailed. Polished: superior quality, not affected by weather, prepared in kiln then glazed and again burnt in kiln. Used for decoration and ornaments.
- 64. Stoneware Protective treatment, it can be transparent, coloured, opaque. Following are the types ● Transparent glazing ○ Salt glazing ○ Lead glazing ● Opaque glazing ● Refractory clay is used ● Durable, impervious, strong, resists corrosion ● Suitable for sanitary wares, sewer pipes, glazed tiles, WC pan, wash basin, sink, bathtub, etc Glazing