Bricks lecutre
- 1. 10/29/2015 1:51 PM 1 BRICKS Civil Engineering Materials Fall Semester 2014 Department of Civil Engineering Iqra National University Peshawar Civil Engineering Materials
- 2. 10/29/2015 1:51 PM 2Civil Engineering Materials 2 Building Materials • Building stones • Bricks and clay products • Cement concrete • Timber and wood products • Metals and alloys • Paints, varnishes, distempers • Asphalt, bitumen and tar • Plastics and fibers • Glass • Asbestos, adhesives and abrasives
- 3. 10/29/2015 1:51 PM 3Civil Engineering Materials 3 Bricks and Clay Products
- 4. 10/29/2015 1:51 PM 4Civil Engineering Materials 4 Clay Products • Clay Products – Bricks – Tiles – Fire clays and fire bricks – Terracotta – Earthenware – Clay pipes • Bricks – Block of tampered clay or ceramic material molded to desired shape and size, sun dried and if required burnt to make it more strong, hard and durable
- 5. 10/29/2015 1:51 PM 5Civil Engineering Materials 5 Bricks • Commonly it is rectangular in shape – Length = twice width of brick + thickness of mortar – Height = multiple of width of brick – Usual size available in Pakistan is 8¾ x 4¼ x 2 ¾ inches to make it 9 x 4.5 x 3 inches with mortar – Indian Standard size 19 x 9 x 9 cm and 19 x 9 x 4 cm to make it 20 x 10 x 10 cm and 20 x 10 x 5 cm with mortar • Bricks are most common form of structural clay products; others being tiles, pipes, terracotta, earthenware, stoneware, and porcelain
- 6. 10/29/2015 1:51 PM 6CE-107 Civil Engineering Materials 6 Historical Development Began as low walls of stones or caked mud Sun-dried bricks - With the availability of fire became burnt bricks Invention of kilns made mass production of bricks easy Limestone turned into lime mortar replaced mud as mortar In Mesopotamia, palaces and temples were built of stone and sun-dried bricks in 4000 B.C. The Egyptians erected their temples and pyramids of stones by 3000 B.C. By 300 B.C., Greeks perfected their temples of limestone and marble Romans made the first large-scale use of masonry arches and roof vaults in their basilica, baths and aqueducts
- 7. 10/29/2015 1:51 PM 7CE-107 Civil Engineering Materials 7 Historical Development Medieval and Islamic civilizations perfected masonry vaulting to a high degree of development - Islamic craftsmen built palaces, markets, and mosques of bricks and often faced them with brightly glazed tiles Europeans built fortresses and cathedrals using pointed vaults and flying buttresses In America and Asia other cultures were building with stones During industrial revolution, machines were developed to quarry and cut stones, mould bricks, and speed the transportation of these materials to site of building Portland cement came into wide use and this enabled the construction of masonry building of greater strength and durability
- 8. 10/29/2015 1:51 PM 8CE-107 Civil Engineering Materials 8 Historical Development Late in 19th century tall buildings were built, of steel and reinforced concrete (pored into simple forms), economically Development of hollow concrete forms in 19th century averted the extinction of masonry as a building material - Cavity wall, developed by the British during the earlier part of the 19th century also contributed to the survival of masonry as a building material This facilitated the introduction of thermal insulation High strength mortars, high-strength masonry units, and complex shapes of masonry units extended the use of masonry for buildings
- 9. 10/29/2015 1:51 PM 9CE-107 Civil Engineering Materials 9 Historical Development • Through the mid-1800s – Primary Building Materials • Late 1800s – New Products Developed – Ended Masonry’s Dominance • 20th Century Developments – Steel Reinforced Masonry – High Strength Mortars – High Strength Masonry Units – Variety of Sizes, Colors, Textures & Coatings
- 10. 10/29/2015 1:51 PM 1010/29/2015 1:51 PM CE-107 Civil Engineering Materials 10 Adobe • Spanish-American name applied to sun-dried brick and to the clay soil from which the brick is made • Adobe soil is composed of very fine mixture of clay, quartz, and other minerals • Adobe soil has great plasticity when moist, but when dry is so coherent that tillage is almost impossible • Soil is used combined with straw, molded and baked in sun for 7 to 14 days • Used in regions of low rainfall and dampness
- 11. 10/29/2015 1:51 PM 11CE-107 Civil Engineering Materials 11 Civil Engineering Uses • Construction of exterior and interior walls, partitions and boundary walls • Construction of piers, abutments • Construction of footings • Construction of miscellaneous load bearing structures
- 12. 10/29/2015 1:51 PM 12CE-107 Civil Engineering Materials 12 Classification of Bricks Bricks Sun Dried Katcha Un Burnt Burnt Pucca Practice Usage Finish Manufacture Burning Strength
- 13. 10/29/2015 1:51 PM 13CE-107 Civil Engineering Materials 13 Classification of Bricks • Sun Dried, Un-burnt or Kacha Bricks –After molding dried in sun, and are used in the construction of temporary structures which are not exposed to rains. • Burnt or Pucca Bricks –Burnt in an oven called kiln to provide strength and durability
- 14. 10/29/2015 1:51 PM 14CE-107 Civil Engineering Materials 14 Classification of Burnt Bricks Burnt Bricks Practice Usage Finish Manufacture 1st Class 2nd Class 3rd Class 4th Class Common Brick Facing Brick Engg Brick Sand Faced Rustic Hand Made Machine Made Burning Pale Bricks Under Burnt Body Bricks Well Burnt Arch Bricks Over Burnt Strength Class A Class B Classes 350 to 35
- 15. 10/29/2015 1:51 PM 15CE-107 Civil Engineering Materials 15 Classification of Burnt Bricks Field Practice • First Class Bricks – Thoroughly burnt, deep red, cherry or copper color – Straight edges, square corners, smooth surface – Free from flaws, cracks, stones and nodules – Uniform texture & ringing sound – No scratch marks with fingernails – Water absorption 12-15% of dry weight in 24 hours – May have only slight efflorescence – Crushing strength not less than 10.5 N/mm2 – Recommended for pointing, exposed face work, flooring and reinforced brick work
- 16. 10/29/2015 1:51 PM 16CE-107 Civil Engineering Materials 16 Classification of Burnt Bricks Field Practice • Second Class Bricks – Small cracks and distortions permitted – Water absorption 16-20% of dry weight allowed – Crushing strength not less than 7.0 N/mm2 – Recommended for all hidden work and centering of RBC • Third Class Bricks, Pilla Bricks – Under burnt, Soft and light colored producing dull sound – Water absorption 25% of dry weight – Recommended for temporary structures • Fourth Class Bricks, Jhama, Khingar – Over burnt and badly distorted in shape and size – Brittle in nature – Ballast of these bricks used for foundation and floors and as road metal
- 17. 10/29/2015 1:51 PM 17CE-107 Civil Engineering Materials 17 Classification of Burnt Bricks Strength Based • Classes – 350 (35 N/mm2) 125 (12.5 N/mm2) – 300 (30 N/mm2) 100 (10 N/mm2) – 250 (25 N/mm2) 75 (7.5 N/mm2) – 200 (20 N/mm2) 50 (5 N/mm2) – 175 (17.5 N/mm2) 25 (2.5 N/mm2) – 150 (15 N/mm2) • Sub Classes – Subclass A. Tolerance 0.3% in dimensions – Subclass B. Tolerance 0.8% in dimensions • Heavy Duty. Compressive strength > 40 N/mm2
- 18. 10/29/2015 1:51 PM 18CE-107 Civil Engineering Materials 18 Classification of Burnt Bricks • Basis of Usage – Common Brick. General multi-purpose – Facing Brick. Good appearance, color, textured, durable under severe exposure – Engineering Bricks. Strong, impermeable, smooth and hard • Basis of Finish – Sand Faced Brick. Textured surface by sprinkling sand inside mold – Rustic. Mechanically textured finish
- 19. 10/29/2015 1:51 PM 19CE-107 Civil Engineering Materials 19 Classification of Burnt Bricks • Basis of manufacturing method –Hand Made. Hand molded –Machine Made. Wire cut, pressed and molded bricks • Basis of Burning –Pale Bricks are under burnt –Body Bricks are well burnt in central portion of kiln –Arch Bricks are over burnt. Also called clinker
- 20. 10/29/2015 1:51 PM 20CE-107 Civil Engineering Materials 20 Comparison of Stones and Bricks • Stone – Natural material – Heavier – High dressing cost – Costly except in hilly areas – Less porous, good for hydraulic structures – Greater strength – Better heat conductor – Weather resistant – Superior quality stone is monumental and decorative • Bricks – Manufactured from clay – Lighter – Moldable to any shape – Cheaper except in hilly areas – More porous, needs water proof treatment – Reasonable for normal loads – Poor heat conductor – Needs pointing and plastering – Architectural effect is achievable
- 21. 10/29/2015 1:51 PM 21CE-107 Civil Engineering Materials 21 Ingredients of Good Brick Earth • Brick earth is formed by the disintegration of igneous rocks. Potash feldspars, orthoclase or microcline yield clay minerals which decompose to yield kaolinite, a silicate of alumina. On hydration it gives a clay deposit Al2O3. 2H2O called kaolin. • Alumina or clay 20-30% by weight • Silica or sand 35-50% by weight • Silt 20-35% by weight • Remaining ingredients 1-2% by weight – Lime (CaO) – Magnesia (MgO) – Iron oxides – Alkalis (Sodium potash, etc) • Water
- 22. 10/29/2015 1:51 PM 22CE-107 Civil Engineering Materials 22 Ingredients of Good Brick Earth • Silica, Sand – Present as free sand or silicate. Its presence in clay produces hardness, resistance to heat, durability and prevents shrinkage and warping. • Alumina – Fine grained mineral compound. Moldable plastic when wet, becomes hard, shrinks, warps and cracks when dry. • Lime – Acts as binder for brick particles. Reduces shrinkage when present in small amount, excess causes the brick to melt and lose shape.
- 23. 10/29/2015 1:51 PM 23CE-107 Civil Engineering Materials 23 Ingredients of Good Brick Earth • Magnesia – Provides darker yellow color with iron. Usually less than 1%. • Iron Oxide – Helps fusion of brick and provides light yellow to red color to brick. Should not be present as iron pyrites
- 24. 10/29/2015 1:51 PM 24CE-107 Civil Engineering Materials 24 Ingredients of Good Brick Earth • Harmful Substances – Lime in excess or in lumps and pebbles, gravel, etc – Iron Pyrites – Alkalis in excess – Organic Matter – Carbonaceous Materials • Additives – Fly Ash – silicates help in strength development – Sandy Loam – controls drying of plastic soil – Rice Husk Ash – controls excessive shrinkage – Basalt Stone Dust – modifies shaping, drying & firing
- 25. 10/29/2015 1:51 PM 25CE-107 Civil Engineering Materials 25 Operations in Manufacturing of Bricks • Preparation of Brick Earth – Un-soiling – Digging – Weathering – Blending – Tempering • Molding of Bricks • Drying of Bricks • Burning of Bricks
- 26. 10/29/2015 1:51 PM 2610/29/2015 1:51 PM CE-107 Civil Engineering Materials 26 Preparation of Brick Earth • Un-soiling – Removal of top 20 cm organic matter and freeing from gravel, coarse sand, lime etc • Digging – additives spread, soil excavated, puddled, watered and left over for weathering • Weathering – heaps left for one month for oxidation and washing away of excessive salts in rain • Blending – sandy earth and calcareous earth mixed in right proportions with right amount of water • Tempering – kneading of blended soil with feet or with a pug mill to improve plasticity and homogeneity
- 27. 10/29/2015 1:51 PM 27CE-107 Civil Engineering Materials 27 Pug Mill
- 28. 10/29/2015 1:51 PM 2810/29/2015 1:51 PM CE-107 Civil Engineering Materials 28 Manufacturing of Burnt Bricks • Molding – giving right shape – Hand molding • Ground molding. Molded on sand. No frog in bricks • Table molding. Molded on stock boards with frog – Machine molding • Plastic method or Stiff-Mud process. Molded stiff clay bar cut by wire into brick size pieces. Structural clay products • Dry Press method. Moist powdered clay fed into machine to be molded into bricks. Roof, floor and wall tiles • Drying – Removing 7-30% moisture present during molding stage. This controls shrinkage, fuel and burning time. Natural open air driers in shades
- 29. 10/29/2015 1:51 PM 29CE-107 Civil Engineering Materials 29 Brick Molds
- 30. 10/29/2015 1:51 PM 30CE-107 Civil Engineering Materials 30 Table Molding
- 31. 10/29/2015 1:51 PM 31CE-107 Civil Engineering Materials 31 Plastic Molding
- 32. 10/29/2015 1:51 PM 32CE-107 Civil Engineering Materials 32 Strikes
- 33. 10/29/2015 1:51 PM 3310/29/2015 1:51 PM CE-107 Civil Engineering Materials 33 Extruded – Wire Cut Extruded – Smooth Wood Mold Extruded – Raked
- 34. 10/29/2015 1:51 PM 34CE-107 Civil Engineering Materials 34 Method of Drying Bricks
- 35. 10/29/2015 1:51 PM 35CE-107 Civil Engineering Materials 35 Manufacturing of Burnt Bricks • Burning Stages – Dehydration (400-650 °C). Water smoking stage in which water from pores driven off – Oxidation (650-900 °C). Carbon eliminated and ferrous iron oxidized to ferric form. Sulphur is removed – Vitrification (900-1250 °C). Mass converted into glass like substance • Incipient vitrification. Clay just softens to adherence • Complete vitrification. Maximum shrinkage • Viscous vitrification. Soft molten mass, loss in shape, glossy structure on cooling
- 36. 10/29/2015 1:51 PM 36CE-107 Civil Engineering Materials 36 Manufacturing of Burnt Bricks • Clamp or Pazawah Burning – Alternate layers of bricks and fuel encased in mud plaster. – Fuel consists of grass, cow dung, litter, wood, coal dust – Brick layer consists of four to five courses of brick – 25,000 to 100,000 bricks in three months cycle • Kiln Burning – Intermittent kiln. Loaded, fired, cooled and unloaded before next loading – Continuous kiln. Bricks are loaded, fired, dried and cooled simultaneously in different chambers. Example: Bull’s trench kiln and Hoffman’s kiln
- 37. 10/29/2015 1:51 PM 37CE-107 Civil Engineering Materials 37 Clamp or Pazawah
- 38. 10/29/2015 1:51 PM 38CE-107 Civil Engineering Materials 38 Intermittent Kiln
- 39. 10/29/2015 1:51 PM 39CE-107 Civil Engineering Materials 39 Hoffman’s Continuous Kiln
- 40. 10/29/2015 1:51 PM 40CE-107 Civil Engineering Materials 40 Bull’s Trench Kiln
- 41. 10/29/2015 1:51 PM 41CE-107 Civil Engineering Materials 41 Bull’s Trench Kiln
- 42. 10/29/2015 1:51 PM 42CE-107 Civil Engineering Materials 42 Characteristics of Good Bricks • Size and shape – uniform size, rectangular surfaces, parallel sides, sharp straight edges • Color – uniform deep red or cherry • Texture and compactness – uniform texture, fractured surface should not show fissures, holes, grits or lumps of lime • Hardness and soundness – not scratchable by finger nail. Produce metallic ringing sound • Water absorption – should not exceed 20% wt • Crushing strength – not less than 10.5 N/mm2 • Brick earth – free from stones, organic matter
- 43. 10/29/2015 1:51 PM 43CE-107 Civil Engineering Materials 43 Special Forms of Bricks a. Round ended brick b. Cant brick c. Splay brick d. Cornice brick e. Compass brick f. Bull nosed brick g. Perforated brick h. Hollow brick i. Coping brick j. Plinth level brick k. Split brick (Queen closer) l. Split brick (King closer)
- 44. 10/29/2015 1:51 PM 44CE-107 Civil Engineering Materials 44 Specially Shaped Bricks
- 45. 10/29/2015 1:51 PM 4510/29/2015 1:51 PM CE-107 Civil Engineering Materials 45
- 46. 10/29/2015 1:51 PM 46CE-107 Civil Engineering Materials 46 Testing of Bricks • Dimension Test. Sample size 50. 20 pieces selected to determine length, width and height tolerances. • Compressive strength Test. Sample prepared from smooth, parallel face, brick is soaked 24 hours and stored under damp jute bags for 24 hours followed by further immersion in water for three days. Load applied @ 14 N/mm per minute till failure. Maximum load at failure divided by average area of bed face gives compressive strength.
- 47. 10/29/2015 1:51 PM 47CE-107 Civil Engineering Materials 47 Testing of Bricks • Absorption Test. – 24 hours immersion cold water test. • Dry bricks oven dried at 105° ± 5° C • Room temperature cooled bricks weighed W1 • Bricks immersed in water at 27° ± 2° C for 24 hrs • Soaked bricks weighed W2 • Water absorption in % = (W2 – W1)/W1 x 100 – Five hours boiling water test • Oven dried bricks weight W1 • Bricks immersed in water and boiled for 5 hours and then cooled down at room temperature in 16-19 hours • Cooled down weight as W3 • Water absorption in % = (W3 – W1)/W1 x 100
- 48. 10/29/2015 1:51 PM 48CE-107 Civil Engineering Materials 48 Testing of Bricks • Efflorescence Test. Ends of brick kept in 150 mm dia porcelain/glass dish containing 25 mm deep water at 20°–30°C till all water is absorbed – Nil imperceptible efflorescence – Slight deposit covers area < 10% of exposed area – Moderate deposit covers exposed area 10% to 50% – Heavy deposit covers exposed area > 50% – Serious deposits are heavy and powder or flake away the surface
- 49. 10/29/2015 1:51 PM 49CE-107 Civil Engineering Materials 49 Defects of Bricks • Over-burning. Burnt beyond complete vitrification • Under-burning. Burnt less not to cause complete vitrification • Bloating. Spongy swollen mass over the surface due to excess carbonaceous matter and sulphur • Black Core. Due to bituminous matter or carbon • Efflorescence. Grey white crystallization of alkalis on the surface, due to water absorption • Chuffs. Deformation due to rainwater falling or hot bricks • Checks or Cracks. Due to lumps of lime getting in contact with water • Spots. Dark sulphur spots due to iron sulphides • Blisters. Broken blisters due to air entrapped during molding • Laminations. Thin lamina produced due to air entrapped in voids of clay
- 50. 10/29/2015 1:51 PM 50CE-107 Civil Engineering Materials 50 Brick Masonry • Brick sides – Header – Stretcher • Brick Bonds – English • Brick Masonry Patterns – Herringbone – Basket weave – Flemish
- 51. 10/29/2015 1:51 PM 51CE-107 Civil Engineering Materials 51
- 52. 10/29/2015 1:51 PM 52CE-107 Civil Engineering Materials 52 Basic Brickwork Terminology Bed Joint Head Joint Course - horizontal layer of brick
- 53. 10/29/2015 1:51 PM 53CE-107 Civil Engineering Materials 53 Basic Brickwork Terminology Header - Bonds two wythes together Wythe: vertical layer 1 unit thick Soldier - Laid on its end, face parallel Rowlock - laid on face, end visible Stretcher - long dimension horizontal & face parallel to the wall
- 54. 10/29/2015 1:51 PM 5410/29/2015 1:51 PM CE-107 Civil Engineering Materials 54 Joint Color that “Blends” w/ Brick Color
- 55. 10/29/2015 1:51 PM 5510/29/2015 1:51 PM CE-107 Civil Engineering Materials 55
- 56. 10/29/2015 1:51 PM 5610/29/2015 1:51 PM CE-107 Civil Engineering Materials 56 Concave Joints
- 57. 10/29/2015 1:51 PM 5710/29/2015 1:51 PM CE-107 Civil Engineering Materials 57 Raked Joints
- 58. 10/29/2015 1:51 PM 5810/29/2015 1:51 PM CE-107 Civil Engineering Materials 58
- 59. 10/29/2015 1:51 PM 5910/29/2015 1:51 PM CE-107 Civil Engineering Materials 59 Simulated Precast Concrete Lintel (actually a steel lintel supports the assembly)
- 60. 10/29/2015 1:51 PM 60CE-107 Civil Engineering Materials 60 Arch
- 61. 10/29/2015 1:51 PM 6110/29/2015 1:51 PM CE-107 Civil Engineering Materials 61
- 62. 10/29/2015 1:51 PM 6210/29/2015 1:51 PM CE-107 Civil Engineering Materials 62