Construction Materials and Engineering - Module III - Lecture Notes
Download as PPTX, PDF20 likes3,955 views
The document discusses various construction materials and methods. It covers topics like masonry, bricks, stone masonry, types of bonds, hollow block masonry, partition walls, modern construction methods, and damp proof courses. Masonry involves arranging masonry units like stone or bricks with mortar. There are different types of bonds used in brick masonry like stretcher bond, header bond, English bond and Flemish bond. Modern methods include framed construction, prefabricated construction and earthquake resistant construction. Damp proof courses are provided to prevent entry of moisture into buildings.
Construction Materials and Engineering - Module III - Lecture Notes
- 1. Construction Materials and Engineering Module - III Shamjith Km shamjithkeyem@gmail.com Department of Civil Engineering Government Polytechnic College Manjeri
- 3. Construction Technology Masonry Modern methods of constructions Damp proof courses Pre stressed concrete Form work Scaffolding, Shoring and Under pinning Plastering and Pointing
- 4. Masonry Art of building the structure using stones, bricks, or concrete blocks. Stone Stone masonry Brick Brick masonry Cement mortar or grout holds the masonry units together.
- 5. Classification of masonry walls 1 Load bearing walls 2 Non-load bearing walls 3 Retaining walls 1) Based on load action
- 6. Load Bearing walls1 Walls which carries loads coming above it If beams and columns are not used, load from roof and floors are transferred to foundation by walls Eg:- Normal house walls Provides structural support Thick walls (Occupy larger area) Good quality stones or bricks should be used
- 7. Non-load Bearing walls2 Walls which does not carry loads coming above it If beams and columns are used, load from roof and floors are transferred to foundation through this frame These walls only support themselves and the weight of the claddings attached. Eg:- Walls in framed buildings, partition walls Provides no structural support Thin walls (Occupy less area)
- 8. Retaining walls3 Wall which holds or retains soil behind it Helps to maintain ground surface at different levels Provides safe space at lower portion Prevents soil sliding
- 9. Classification of masonry walls 1 Stone masonry 2 Brick masonry 3 Laterite masonry 2) Based on material used 3 Composite masonry
- 10. Stone masonry1 Systematic arrangement of laying the stones and bonding together with mortar to form a solid mass Materials required: 1) Stones 2) Mortar
- 11. Brick masonry2 Systematic arrangement of laying the bricks and bonding together with mortar to form a solid mass Materials required: 1) Bricks 2) Mortar
- 12. Laterite masonry3 Systematic arrangement of laying the laterite and bonding together with mortar to form a solid mass Materials required: 1) Laterite 2) Mortar
- 13. Composite masonry4 Systematic arrangement of laying different types of materials and bonding together them with mortar to form a solid mass
- 14. Selection of stone for stone masonry: 1 Availability 2 Ease of working 3 Appearance 4 Strength and stability 5 Polishing characteristics 6 Economy 7 Durability
- 15. Technical terms 1 Natural bed The plane along which the stone can be easily split Direction of bed should be perpendicular to dirn of loading 2 Sill Bottom surface of a door or window 3 Corbel Projecting stone provided to support beam or wall plate
- 17. Technical terms 4 Course A layer of stones or bricks 5 Cornice Course of stone provided at top of wall 6 Coping Course provided at top of wall to protect the wall from rain water.
- 18. Technical terms 7 Spalls Chips of stones used to fill up the empty spaces in masonry 8 Quoins External corners or angles of a wall surface 9 Bond Arrangement of layers by which no vertical joints are formed
- 19. Different types of stone masonry Rubble masonry Ashlar masonry 1. Coursed rubble 2. Uncoursed rubble 3. Random rubble 4. Dry rubble 5. Polygonal rubble 6. Flint rubble 1. Ashlar fine 2. Ashlar rough tooled 3. Ashlar rock (Quarry faced) 4. Ashlar chamfered 5. Ashlar block-in-course
- 20. Rubble masonry Stones of irregular sizes are used Quarry stones with slight modifications are used Strength of rubble masonry depends on 1. Quality of mortar 2. Use of long through stones at frequent intervals 3. Proper workmanship (filling of mortar) Rough or undressed stones can be used Wider joints as stones are of irregular sizes
- 24. Dry rubble masonry4 No mortar used to join
- 27. Ashlar masonry Built from accurately dressed stones Uniform and fine joints of about 3 mm thickness Height of courses = 30 cm Costly Used in basements, bridge piers, abutments, etc
- 28. Ashlar fine All sides and faces of the block are finely dressed with chisel Ashlar rough Bed and sides are finely dressed. Ashlar quarry faced If exposed faces remain undressed Ashlar Chamfered If exposed faces rounded /bevelled at 45o angle
- 29. General principles and specifications 1 Should satisfy requirements of IS specifications 2 Stones should be hard, tough and durable 3 Colour of the stone should be uniform 4 All stones should be laid with their natural bed 5 Stones should be well watered before use 6 Dress according to specification of the work 7 Formation of continuous vertical should be avoided 8 Good quality mortar should be used 8 Chips and broken pieces should not be used
- 30. Brick Masonry Brick Standard size = 19 x 9 x 9 cm Nominal size = 20 x 10 x 10 cm (Including mortar thickness) 1 m3 B.W = 500 Nos Average weight of a brick = 3.5 kg
- 31. Technical terms 1 Stretcher Brick laid with its length parallel to the face of wall 2 Header Brick laid with its length perpendicular to the face of wall 9 19 9 9 Stretcher face Header face
- 32. 3 Bed Lower surface of the brick when laid flat 4 Bed joint Horizontal layer of mortar upon which the bricks are laid 5 Arrises Edges formed by the intersection of plane surfaces of the brick No.of arrises = no.of edges = 12
- 33. 6 Perpends Vertical joints separating the bricks in either transverse or longitudinal direction longitudinal direction Transversedirection Plan view
- 34. 7 Lap Horizontal distance b/w the vertical joints in successive courses. Lap Perpends Min lap length = 𝟏 𝟒 x brick length
- 35. 8 Closer Obtained by cutting a brick lengthwise A) Queen closer Queen closer Queen Closer is placed 1) To avoid continuous vertical joints 2) To close a wall in some length
- 36. 8 Closer Obtained by cutting a triangular portion of brick such that half width and half length. B) King closer King closer King closer is used near doors and windows
- 37. 8 Closer Half width and full length is cutted C) Bevelled closer Bevelled closer Used for splayed brick works
- 38. 8 Closer Full width cutting with 45o/60o with length D) Mitred closer Queen closer Used at corners and junctions 45o/60o 45o/60o
- 39. 9 Bat Cutting the brick across its length No 𝟏 𝟒 brick bat Waste/used as aggregates Half bat or 𝟏 𝟐 bat 𝟑 𝟒 bat
- 40. 10 Raking back A wall terminated in stepped fashion Easy for future working, good appearence
- 41. 11 Toothing A wall terminated in such a way that alternate courses are projected
- 42. 12 Frog Depression/projection to act as a key to hold the mortar Prevent sliding of brick Depth about 10 mm to 20 mm
- 43. 13 Quoin Heavier bricks laid at external corners
- 44. 14 Bullnose Brick moulded with a rounded angle Used for rounded quoin
- 45. 15 Cownose Brick moulded with a double bullnose on end
- 46. Brick bonds Method of arranging bricks in masonry so that they overlap properly and are tied to act as a single unit is called bond.
- 47. Different types of bonds 1 Stretcher bond 2 Header bond 3 English bond 4 Flemish bond 5 Garden-wall bond 6 Raking bond 7 Dutch bond 8 Brick-on-edge bond 9 English cross bond 10 Facing bond A) English garden wall bond B) Flemish garden wall bond (Scotch bond/sussex bond) A) Diagonal bond B) Herring bone bond C) Zigzag bond
- 48. Stretcher bond1 All bricks are laid parallel to wall face Useful for one brick partition wall Minimum thickness = 10 cm
- 49. Header bond2 All bricks are laid perpendicular to wall face Used to lay curved walls (eg: well) Minimum thickness = 20 cm ¾ bat ¾ bat
- 50. English bond3 Alternate courses consist of stretchers and headers Strongest bond H S S S S H H H H H H H S S S S H H H H H HQueen closer Quoin header Quoin stretcher
- 51. English bond3
- 52. English bond3 In every header course, a queen closer is placed next to a quoin header. Each alternate header is centrally supported over a stretcher. Number of mortar joints in the header course is nearly double than that in stretcher course
- 53. Flemish bond4 In every course headers and stretchers are placed alternately. Good appearance SH Queen closer Quoin header Quoin stretcher SH S SH H SH SH S SH H
- 54. Queen closer is placed next to a quoin header in every alternate course. Every header is centrally supported over a stretcher. Types of Flemish bond: 1) Single Flemish bond 2) Double Flemish bond Flemish bond4
- 55. One face only flemish bond, other face English bond Flemish bond4 Single flemish bond Double flemish bond Both faces flemish bond English bond Flemish bond Front Back Good in strength Good in appearence Flemish bond Flemish bond Front Back
- 56. Garden wall bond5 Used for garden works - importance to appearance Maximum height = 2 m Less strength – can’t use to take loads
- 57. Raking bond6 A) Diagonal bond C) Zig Zag bondB) Herring bone bond One-sided diagonal Two-sided diagonal Eg:- paving of bricks Bricks placed in a zig-zag manner
- 58. Brick should conform to IS Specifications Specification for brick masonry 1 Bricks should be immersed in water for a sufficient time to avoid them from absorbing water from the mortar 2 Brick should be laid on their beds with the frogs upward3 4 Brick bats should be avoided as far as possible 5 Maximum height of construction/day is 1.5 m 6 Joint thickness should be thin Wall should be raised uniformly7 Good quality mortar & proper bonding should be confirmed8
- 59. Hollow block masonry Concrete rectangular blocks made using light weight aggregates. Can be used for load baring and non-load bearing members.
- 60. Advantages of hollow bricks Available in regular and uniform size Light in weight – can handle easily – faster construction As block is hollow, there is saving of material As blocks are larger than bricks, number of joints are less. Hence saving of mortar. Rough surface makes plastering easier. Can withstand high temperature – fire protection Rapid execution of work
- 61. Types of hollow bricks Stretcher Blocks1 Laid with length parallel to the face of the wall Corner Blocks2 used at the ends or corners of masonry – doors/window openings
- 62. Types of hollow bricks Pillar Blocks3 used when two ends of the corner are visible Jamb Blocks4 used to provide space for casing members of window
- 63. Types of hollow bricks Partition Block5 Used to build partition walls Lintel Blocks6 used for purpose of provision of beam or lintel beam
- 64. Types of hollow bricks Frogged Brick Blocks7 frog will help the block to hold mortar and to develop the strong bond Bullnose Block8 When rounded edges are needed at corners
- 65. Solid block masonry Heavy in weight Manufactured from dense aggregates Strong – provide stability to structure Used for load bearing walls Available in large sizes compared to bricks Regular size and uniform shape Faster construction
- 66. Interlocking brick masonry Solid blocks having a projection and depression so that they can join together to form a single unit Projection of one block fit into the depression of the next so that they always align perfectly. Holes provided to reduce amount of materials Steel mesh can be used to increase strength Permits water to seep into earth through joints Faster construction and nice appearance Available in different colours and regular sizes
- 67. Partition walls Wall constructed inside the enclosed area It separates various rooms in a building Generally a non-load bearing wall May be upto full floor height/eye level Minimum thickness = 10 cm (Stretcher bond)
- 68. Requirements of partition wall Strong enough to carry its own weight Should be capable of resisting impact Should act as a sound barrier when divides rooms Should be light weight and thin Should be cheap and easy for construction Also need to carry fixtures, fittings and plasterings Should be resistant to fire
- 69. Types of partition walls 1 Brick partitions 2 Clay block partitions 3 Concrete partitions 4 Glass partitions 5 Timber partitions 6 Metal partitions 7 Plaster slab partitions 8 Asbestos cement sheet partitions 9 Strawboard partitions 10 Wood wool slab partitions
- 70. Modern methods of construction Framed construction Prefabricated construction Earthquake resistant construction 1 2 3
- 71. Framed construction1 Frame is a network of footings, columns, beams and slabs Walls constructed within this frame are called as panel walls Whole weight of the structure is transmitted to foundation through this frame.
- 72. Advantages of framed construction Thin panels – increases floor area Greater freedom in planning Partition walls can be changed when necessary Better resistant to vibrations Can be used for unreliable soils – piling, etc Speed in construction Resistant to earthquake Suitable for any number of stories
- 73. Prefabricated construction2 Also known as modular construction Structural components are manufactured in plants which are away from building site Transported to site and then assemble the parts. Can manufacture large quantity of components in less time period.
- 75. Advantages of prefabricated construction Can erect the structure faster Equipment and machinery need not transported Plant casting allows increased efficiency, quality control and greater control on finishes Less affected by climatic factors Division and specialization of human workforce Saving of time and labour Suitable for any number of stories Reduced wastage of materials
- 76. Earth quake resistant construction3 Construction in which it can resist sudden unpredictable ground shakings Effects of earthquake 1. Ground shake 2. Landslides 3. Ground displacement 4. Liquefaction 5. Tsunami 6. Aftershocks
- 77. 1 Continuity should establish in case of additions and alterations 2 Suspended ceilings should be avoided 3 Continuity of construction should be maintained 4 Structure should rest on strong foundations 5 Should provide suitable gap b/w adjoining structures 6 Connections b/w structural & non structural parts need smooth 7 Projections should be avoided as far as possible 8 Proper structural design should be done 9 Better to have light weight structures 8 Symmetrical shaped structures are good10 Requirements of earthquake resistant construction
- 78. Damp Proof Courses (DPC) Dampness is the presence of hygroscopic or gravitational moisture Building should remain dry and free from moisture Dampness reduces strength Dampness give un-hygienic conditions Provision of DPC prevent entry of moisture from walls, floors and basement of a building
- 79. Rising of moisture from the ground Action of rain Exposed tops of walls – eg:- parapet, roofs 1 2 3 Condensation – eg: badly designed kitchen Inadequate roof slope Defective junctions – b/w parapet wall & roof slab 4 5 6 Causes of dampness
- 80. 1 Causes rotting of wood 2 Causes corrosion of metallic fixtures 3 Deteriorate electric installations 4 Deteriorate carpet & furniture’s 5 Causes spots on the floors and walls 6 Causes petting off and removal of plaster 7 Causes bleaching and blistering of paints 8 Causes efflorescence in bricks, tiles and stones 9 Dangerous for the health of occupants 8 Promotes growth of termites durability decreases10 Effects of dampness
- 81. 8 Dampness give rise to breeding of mosquitoes11 Effects of dampness 8 Wall decorations and paints may damaged12 8 Flooring gets loosened due to reduction in adhesion13 8 Electrical fittings get damaged14 8 Floor coverings are damaged15
- 82. Use of DPC Integral Damp proofing Surface treatment 1 2 3 Cavity wall construction Guniting Pressure guniting 4 5 6 Methods of Damp proofing
- 83. Use of DPC1 Provide DPC b/w source of dampness & part of building adjacent to it Materials used : 1. Hot bitumen 2. Cement concrete 3. Plastic sheet 4. Mastic asphalt 5. Metal sheets 6. Stones and bricks
- 84. Integral Damp proofing2 Adding certain water proofing compounds to the concrete mix so that it becomes impermeable Materials used : 1. Publo 2. Permo 3. Silca 4. Snowcem 5. Dr.Fixit
- 85. Surface treatment3 Application of layer of water repellent substances on the surface through which moisture enters Materials used : 1. Calcium and Aluminium Oletes 2. Stearates Pointing & Plastering of the exposed surfaces : 1. Sodium or Potassium silicates 2. Aluminum or Zinc Sulphates
- 86. Cavity wall Construction4 Main wall is shielded by an outer skin wall (water repellent) leaving a cavity b/w the two
- 87. Guniting5 Depositing layer of rich cement mortar by pressure to the exposed surface of walls, pipes, etc. Mortar is shot on clean surface
- 88. Pressure Guniting6 Cement grout is filled in cracks, voids in the structure of building by high pressure This method is effective to control entry of ground water through foundations.
- 89. Concrete and steel Concrete is strong in compressions and weak in tension Steel is strong in both tension and compression
- 90. Pre-stressed concrete A method to overcome concrete’s natural weakness in tension. Used to produce beams, floors or bridges with longer span than with ordinary reinforced concrete.
- 91. Principle of pre stressing An initial load is applied on the structure prior to its use (Like stretching an rubber band and holding inside our hands, then release) Process of induction of compressive stresses in the structure before it is put to its actual use is known as Prestressing
- 92. 1) RCC – Reinforced cement concrete 2) PCC – Prestressed cement concrete
- 95. External or internal pre-stressing Based on type of structure 1 2 Based on method of applying pre-stress Source of prestressing 3 4 Types of prestressing 1. Linear prestressing 2. Circular prestressing 1. Pre tensioning 2. Post tensioning 1. Mechanical 2. Hydraulic 3. Electrical 4. Chemical
- 96. External prestressing When pre-stressing achieved by elements outside the concrete. Tendons lied outside the member
- 97. Internal prestressing When pre-stressing achieved by elements inside the concrete. Tendons lies inside the member
- 98. Pre tensioning
- 99. Pre tensioning The tension is applied to the tendons before casting the concrete After hardening of concrete, tendon cuts, the tension force is released. The tendon tries to shrink back to its original length Concrete resists this shrinking through bond b/w concrete and tendon. Compressive force is induced in concrete Eg: - Electric poles, railway sleepers
- 100. Post tensioning
- 101. Post tensioning The tension is applied to the tendons (located in a duct) after hardening of the concrete. Ducts are placed inside the concrete before casting. After the concrete gets hardened, the tendon inside the duct is tied and anchored against concrete. Eg: - box girders
- 102. 1 Section remains uncracked under service loads 2 High span-to-depth ratios 3 Suitable for precast construction 4 Rapid construction 5 Better quality control 6 Reduced maintenance 7 Suitable for repetitive construction 8 Reduction of formwork 9 Availability of standard shapes Advantage of prestressing
- 103. 1 Prestressing needs skilled technology 2 The use of high strength materials is costly 3 There is additional cost in auxiliary equipments 4 There is need for quality control and inspection 5 Skilled labour needed Limitations of prestressing
- 104. Formwork When concrete is placed, it is in a plastic state An artificial temporary support provided below and around the concrete to hold the fresh concrete in desired shape.
- 105. Formwork materials Commonly made of wood and steel. Plastics and fibers are also used.
- 106. Process involved Assembly and erection Concrete placement Stripping and dismantling
- 107. 1 Serves as mould for concrete structural components 2 Decides accuracy to size, strength and surface finish 3 Holds the self weight of the fresh R.C.C 4 Provides a working platform 5 To support the weight of concrete Functions of formwork
- 108. 1 Easy removal with least amount of hammering 2 Economy-Materials should be cheap and reusable 3 Water proof - Less leakage through the joints 4 Quality-desired size,shape,&finish need to obtained 5 Rigidity against deformations 6 Inside surface of formwork should be Smooth 7 Sufficient Strength to bear DL, LL, labour, etc. 8 Swelling and shrinkage should be minimum Requirements of good formwork
- 109. Modern day formworks 1. Modular construction is used mainly 2. Fast and efficient 3. minimize wastage of concrete 4. Slip form technology used.
- 110. Slip form technology
- 111. Slip form technology A kind of mechanical formwork system suitable for use in casting continual walls of structures. Types of slip form: 1) Horizontal slip form 2) Vertical slip form 3) Tapered slip form Lifting equipments are used to rise the slip form Eg:- Large towers, canals, Chimneys Also called as climbing forms and sliding forms
- 112. PVC forms Available in standard sizes Good in appearance Easy to assemble and dismantle Materials will not stick on it Sufficient water proofing Made of Polyvinyl chloride Light in weight Useful in case of high rise buildings
- 113. Scaffolding To safely support men and materials Temporary elevated platform When height of construction/repair > 1.5 m Usually made of timber/steel
- 114. 1 Single (bricklayers/putlog) scaffolding 2 Double (masons) scaffolding 3 Cantilever (needle) scaffolding 4 Suspended scaffolding 5 Trestle scaffolding 6 Steel scaffolding 7 Patented scaffolding Types of scaffold
- 115. Single scaffolding1 Wall Standards putlog putlog Toeboard Toeboard Ledgers Guard rail hole Raker
- 116. Single scaffolding1 Used mainly for brick works Also called as bricklayers or putlog scaffolding Can’t use for plastering and painting
- 117. Technical terms 1 Standards – Vertical members of scaffold 2 Ledgers – Horizontal members parallel to wall 3 Putlog – supports on ledger and hole in wall 4 Toeboard – to provide working space for workers 5 Guard rail – to protect workers from falling 6 Raker – inclined support to scaffold 7 Transom – Putlogs, but both ends supported on ledgers
- 118. Double scaffolding2 transom transom (Putlogs, but both ends supported on ledgers)
- 119. Double scaffolding2 Used mainly for plastering and painting Also called as masons or independent scaffolding Used for heavy works Two standards will be present
- 122. Trestle scaffolding5
- 123. Steel scaffolding6
- 125. Shoring To support an unsafe structure Temporary supporting structure When addition and alterations need to done on unsafe structures Types of shoring 1. Raking (inclined) shores 2. Flying (horizontal) shores 3. Dead (vertical) shores
- 126. Shoring This is used when stability of structure is endangered due to Timber , RCC, or steel materials are used 1. Removal of a defective portion of structure 2. Unequal settlement during construction 3. To insert underground pipelines
- 127. Raking shores1 Wall plate Needle Cleat Ride raker Raker Hoop iron wire Sole plate Unsafe buildingBraces
- 128. Raking shores1
- 129. Fly shore2 Unsafe buildingSafe building Fly beam Wedge Straining piece
- 130. Dead shore3
- 131. Underpinning Placing of a new foundation below an existing foundation Process of strengthening existing foundation
- 132. Underpinning is used in below conditions 1. When a building with deep foundation is constructed near a building with shallow foundation. (shallow foundation should be strengthened) 2. To protect from excessive settlement of foundation 3. To improve bearing capacity of soils 4. To provide basement to an existing structure
- 133. Plastering Tools used: Normal thickness = 12 mm Gauging trowel, Float, Floating rule, Plumb bob Coats in plastering 1. Rendering coat 2. Floating coat 3. Setting/finishing coat
- 134. 1 Plastering removes unevenness of surfaces 2 Make surface smooth and clean 3 To develop decorative effects 4 To hide defective workmanship 5 To protect from dust 6 To protect surface against vermin 7 To protect from water penetration Objectives of Plastering
- 135. Defects in plastering Blistering Small patches swell out beyond the plane of plastered surface.
- 136. Defects in plastering Cracks Cracks get developed on plastered surface
- 137. Defects in plastering Efflorescence While drying, soluble salts comes out and appear as crystalline white substance.
- 138. Defects in plastering Flaking Formation of very small loose mass on plastered surface.
- 139. Defects in plastering Peeling Plaster from some portion of surface comes out and a patch is formed.
- 140. Defects in plastering Popping/blowing Conical hole formed Infront of plastered surface due to particle which expand on being set.
- 141. Defects in plastering Rust stains Rust stains occur on certain plastered surfaces.
- 142. Defects in plastering Softness Some portion of plastered surface become soft. Uneven surface The surface become uneven after plastering. Different thickness at different locations.
- 143. Pointing For good strength (primary) and appearance Action of filling joints of masonry with rich mortar These spaces are filled up by suitable mortar in the decided shape Joints are raked out to a depth of about 20 mm Mortar used for pointing: L.M or C.M in 1:1 or 1:2
- 144. Types of pointing Flush pointing1 Recessed pointing2 Grooved pointing3 4 Tuck pointing 5 Struck pointing 6 V-pointing Weathered pointing7 Beaded pointing8
- 145. Flush pointing1 20 mm Old mortar Rich Mortar 1:1 or 1:2 Recessed pointing2 Face of pointing is vertical 20 mm Old mortar Rich Mortar 1:1 or 1:2 Channel shaped appearance 5 mm back from face
- 146. Grooved pointing3 20 mm Old mortar Tuck pointing4 Rubbed or keyed pointing 20 mm Old mortar Rich Mortar 1:1 or 1:2 3 mm projection from face 5 mm back from faceSemi-circular depression inwards at mid height groove
- 147. Struck pointing5 10 mm Old mortar V - pointing6 20 mm Old mortar Rich Mortar 1:1 or 1:2
- 148. Weathered pointing7 Old mortar Beaded pointing8 20 mm Old mortar Rich Mortar 1:1 or 1:2 To drain water easily
- 149. 1 Cement mortar and lime mortar 2 Acoustic plaster – for sound treatments 3 Asbestos cement plaster 4 Barium plaster – to prevent radiation 5 Granite silicon plaster 6 Gypsum plaster – white colour 7 Keen’s cement (Plaster of paris + Alum) 8 Martin’s cement (Plaster of paris + pearl ash) 9 Parian cement (Plaster of paris + borax) Materials for pointing 10 Sirapite (Plaster of paris + petroleum)
Editor's Notes
- #2: Engineering structures are composed of materials.