UNIT-II MATERIALS AND CONSTRUCTION[A] BASIC CONSTRUCTION MATERIALS Materials Cement Brick, Stone Natural & Artificial sand Reinforcing steel – mild, tor & high tensile steel Concrete types– PCC, RCC, Prestressed & precast Introduction to smart material Recycling of materials . . for reinforcement concrete and fabrication of steel doors.used in mortar or concrete Bricks and stones – for masonry work. windows. sand. Steel.Basic materials and their uses Basic materials used in construction are cement. stone and steel Cement –As a binding material Sand. fixtures and fastners . bricks. Cements Cement binder a very fine in size Compose of various ratio of chemical When water is added to the cement. a hydration reaction occurs. producing a solid gel that bond the aggregate particle •3CaO+Al2O+SiO2+3CaO+SiO2+4CaO • +Al2O3+Fe2O3+other minerals 7 . fineness-OPC-Surface area not less than 2250cm2/gm 2-setting timeInitial setting time-30min Final setting time-3 to 6 hrs 3-compressive strength -3days-16N/mm2 7days-22 N/mm2 4-soundness-not more than 10 mm .1-CEMENT a) b) lime stone + clay physical properties of cement 1. but higher strengths 2CaO .g. Al2O3 Slowly during hydrationAl2O3 •3CaO . SiO2 Strength Rapid setting but low strengths •2CaO . Al2O3 9 Time . 3CaO .Cements The composition on the cement helps determine the rate of curing and the final properties of the concrete e. SiO2 •3CaO . Al2O3 and 3CaO . Cements The concrete is expected 28 days for nearly complete curing Some additional curing may continue for years Types of cement Type 1: General purpose Type 2: Low rate of heat generation. moderate resistance to sulphate Type 3: Rapid setting Type 4: Very low rate of heat generation Type 5: Good sulphate resistance + = 10 . Cements Reaction Cement Sand Aggregate •Hydration reaction occur 3CaO . xH2O + heat 3CaO . xH2O +Ca(OH)12 + heat Water 11 . SiO2+xH2O -> Ca2SiO4 . SiO2+ (x+1)H2O -> Ca2SiO4 . Al2O3+6H2O -> Ca3Al2(OH)12 + heat 2CaO . less resistance to chemical attack 2-rapid hardening Portland cement-after 3 days it is same as 7 days strength of OPC 3.bridges & foundation & more resistant to sulphate attack-decoration & architectural finish.types of cement A) Portland cements- 1-ordinary Portland cement-all types of constn.it is costly 6-white and colored cement .low heat cement –slower rate of reaction 4-sulphate resisting cement5-portland blast furnace slag cement-used for dams. B) Super Sulphate cement-resistant to sea water C) Natural cement.not used D) High alumina cement-it is not attacked by carbon dioxide therefore for manufacture of RCC pipes Field testing of Cement . Uses of Cement OPC is used for preparation of cement mortar & constn of bldgs 2) Manufacturing of tiles 3) Used as a base in paints 4) White & coloured cement uesd in plastering & decorative finish 5) Sulphate resisting cement is used in constn of surfaces exposed to sulphate action 6) construction of highway slabs 1) . 2-BRICK properties of brick 1-size and shape 2-water absorption 3-strength-35 kg/cm2 4-colour . . Manufacture of bricks Selection of site Preparation of clay Moulding of bricks Drying of bricks Burning of bricks . TYPES OF BRICKS 1) 2) 3) 4) 5) first class second class third class uses of bricksIn masonry work Flooring material Constn of roads First class bricks used in face work of the bldg Broken bricks used as a aggregate in lime concrete . stone blocks. The rocks quarried from quarries is called as stone. stone aggregates. which a solid portion of earth crust. stone flags. stone lintels. Quarried stone may be in the from of stone slab. . Stone has to be properly dressed & shaped before it is used at the place of work.Stone Stone is always obtained from rocks. and durable Angular aggregate particles provide strength due to mechanical interlocking between particles More surface on angular particles may form voids or cracks The large size of aggregate is preferred Aggregate particles should not be larger than about 20% of the thickness of the structure or it will cause the holding defect 20 .Aggregate Gravel & Rock Aggregate must be clean. strong. Sedimentary rocks. unstratified rocks.Stratified rocks. metamorphic rocks. calcareous rocks Classification based on hardness of the stones:Very hard rock.Classification of rocks Geological classification:.Igneous rocks. Physical classification:. medium rock and soft rock. . hard rock. laminated rocks Chemical classification:. argillaceous rocks.Siliceous rocks. road metalling & also used as a aggregates Lime stone slabs used for flooring.roofing Granite:-for bridge abutments. TajMahal .Uses of stones Broken stones & stone chips are used in foundation. Quartzite is used for rubble masonry. for floor of buildg. Railway ballast & road metal Stone blocks are mainly used In walls & for ornamental facing work.for extreme superior work eg. piers & kitchen ota Marble :. paving. Sand Sand 23 . formed due to decomposition of sandstones due to various weathering actions. . river beds.75mm size sieve) & coarse sand( that retain on IS. 4. Natural (obtained from pits.75mm size sieve) Increases volume of mortar & makes the mortar economical.Sand It is a form of silica (siliceous+ argillaceous). shores)& artificial sand (by crushing of stones) Fine sand (sand which pass through IS.4. angular & coarse Sand should be free from clayey materials It should free from salts The grains should be of durable minerlas .Requisites for Good Sand 1) 2) 3) 4) The gains should be sharp. Coarser sand used for face plastering for external walls.Uses of sand In cement mortar for stone. Used in PCC. & in Prestressed conc. . RCC. brick masonry & plastering work. & channel sections . structures (Fe415 & Fe500)) & High tensile steel: (used in prestress conc.0. forgeable & weldable.) used in construction. T. ductile. Generally mild steel: (designated as Fe250.25% Steel is highly elastic. malleable. Steel is of diff.STEEL It is an alloy of iron & carbon. containing carbon. costruction. Yield strength in N/mm2).25 to 1. sections like I. O. Tor steel: used in RCC. ie. . . tanks. windows & doors. Tor steel. tubes.used as distribution steel in RCC. Non structural components like stairs. beams in the form of various sections. . Mild steel. grills.used as main steel in RCC. High tensile steel cables used in prestressed conc. Girders. ducts etc.Uses of steel Structural material in trusses. In fabrication of steel pipes. 6-CONCRETE CEMENT+SAND+COARSE AGGREGATES+WATER It is workable mixture which can be easily transported. Properties of concrete depends upon properties of ingredients. . placed & compacted to attend maximum strength. Concretes Common construction material Strong hard but brittle Heavy and can not be recycle All ingredients compose of diminishing raw material 32 . Concretes Concretes = a particular composite in which both the particular and the matrix are ceramic material Concretes = Portland Cement + Sand +Aggregate (A cementation reaction between water and the mineral in cement provide a strong matrix and good compressive strength) Cements Sand Aggregate 33 . Properties of Concrete The water cement ratio 34 . Properties of Concrete The amount of air entrainment 35 . improves workability of concrete . but – cause lower strength 36 .minimise problems with shrinkage and freeze thaw conditions.5% (sometimes up to 8%) by volume of the concrete may be trapped by air The entrained air .Properties of Concrete The amount of air entrainment A small amount of air is entrained into concrete during pouring 1-2. Concrete Construction 37 . retaining walls. conc.Grades of concrete M10 1:3:6(culvert. work) M20 1:1. floors) M15 1:2:4(for general RCC.5:3(water tank & bridge construction) M25 1:1:2(heavily loaded RCC. structures) M30 and above (heavy structures) . Classification of concrete 1-Plain cement concrete (PCC) 2-Reinforced cement concrete (RCC) 3-Precast concrete 4-Prestress concrete -Pre-tensioning -Post-tensioning . . It has good weathering resistance property. It has good resistance to abrasion.1-Plain cement concrete (PCC) It is a mixture of cement. fine+coarse aggregates & water The proportion of these ingredients depends upon grade of mix required & for requirenent of particular job The PCC is strong in compression & weak in tension. flooring base gravity dam & retaining walls In . Base for foundation. Used in foundation masonry.Uses of PCC. stresses are transferred from one material to another material. Equally strong in tension & in compression Due to bonding between steel & concrete. Minimum M20 grade of concrete is required for the construction .Reinforced cement concrete (RCC) Mixture of concrete with steel. footing etc Construction of multistoried buildings Construction of road pavements Construction of water. hydraulic structure . Concreting for general work like beam.Uses of RCC. oil tanks. bridges. column.concrete pipes Machine foundations Marine structure. slabs. Precast concrete Concrete which is cast in separate forms before they are placed in position It may be casted at building site or some distance from building site Then with help of equipments & cranes they are transported on site. Simplest form of precast concrete are hollow & solid concrete blocks for the construction of external & internal walls. . Reinforced and Pre-post-stressed Concrete Concrete for construction material Reinforced Concrete Pre-stressed Concrete Post-stressed Concrete 45 . Uses of precast concrete For casting various building elements such as beam. column. bridge girder. slabs. bridge pier & concrete piles . Pipes. water tank etc. For manufacturing of compound poles. electric poles Fabrication of RCC. ) This is a reinforced concrete in which concrete is subjected to compressive stress before the external load applied to conteract tensile stress caused in concrete due to external loads Used for M30 & above grades of concrete. Prestressing is of two types.C.1)Pre-tensioning 2) post-tensioning Prestressing force is applied with the help of hydraulic jacks.Prestressed Concrete (P.S. . In this the tendons are given the required tension after the concrete has attained desired strength. 2) .1)Pre-tensioning In this the tendons are prestressed in place before concrete is poured. Post-tensioning. piles .Uses of Prestressed Concrete (P.) Girders for bridges Beams for larger spans Railway slippers Electrical poles Used in constn of nuclear power stations.C.S.steel plants . ADVANTAGES 1) 2) 3) It permits the use of large spans with shallow member even when heavy loads are encounted High quality materials are used The size of structural member are reduced . . which is hollow or solid.Precast blocks The cement concrete blocks which are cast in rectangular shape mould. Durable. & having High strength . Strong.Uses of pre-cast blocks For light weight structure In partition walls As size of precast block is more it required less material & hence economical. & PSC. works . also used for grouting Concrete Cement+fine aggregates+coars aggregates+water +water Used for RCC.Difference between mortar & concrete Mortar Cement+fine aggregates+water Mortar used for masonry work & plastering works. alloys & polymers change their shape with response to heat. . Eg. fluids that changes its viscosity with respect to electric or magnetic stimuli.Introduction to smart material Smart materials are the materials which have the capability to respond to change in their condition o the environment to which they are exposed Photocromatic material that change in colour with response to light. Different smart materials Piezoelectric material Electrostrictive material Magnetostrictive material Shape memory alloy Optical fibres . Asphalt Asphalt is bitumen. Bitumen is the organic binder. 56 . Asphalt mix is composite of aggregate and bitumen. composed of HC with low melting point thermoplastic polymers and oils. Asphalt Mix The aggregate use as in the concrete that should be clean and angular. A 57 B . Aggregate should have distribution of grain sizes to provide a high packing factor and good mechanical interlock between aggregate grains. Operation of Asphalt Mix 58 . Asphalt construction 59 . Electrostrictive material This material has same properties to that of piezoelectric material. but only the change is that mechanical change is equal to square of electrical field . Piezoelectric material . Magnetostrictive material When subjected mechanical field this material under goes mechanical strain . .Shape memory alloy When subjected to thermal field it undergoes some thermal shape change. temperature. . electric & magnetic field.Optical fibres Fibres that use intensity. frequency to measure strain. phase. Applications of smart materials Used in aircrafts & space crafts to measure vibrations & excessive deflections. Smart concrete used in smart structures to detect smaller cracks. Catalytic materials that increase or decrease the rate of reaction All senser materials that can detect signals & adjust sensitivity according to environment Noise control . Because of this supply of fresh material required can be reduced And ultimately reduce environmental pollution .Recycling of material Recycling is the process in which we can utilize the material left on construction site or demolition of structure. 1) Crushed concrete used for road base.general fill or pavement aggregate 2) Asphalt pavement can be crushed & recycled back into asphalt or in hot mix asphalt plant 3) Metal can be melted down & uesd for metal products 4) Bricks can be used in base material in water proofing treatment . Woods Most familiar materials to mankind. Not a high-technology materials but fantastic. The only material that can be reproduced and give oxygen to human. Woods is very strong but yet lightweight. 68 . clearly reveals an nual growth rings.Woods structure Wood surface •portion of a round cross section. or the surface you would see if you were to view the outside of a log Tangential Surface . Cross sectional •cutting along a radius of a round cross section Radial Surface 69 •cutting at a tangent to the growth rings. Raining season High water time Summer season Lower water time 70 .Woods structure Annual Ring trees grow in both diameter and height during growth periods that are interrupted by periods of rest. and similar defects. if not predried. will dry while in use under uncontrolled conditions giving rise to warp. Water must be removed to provide void space for preservatives if wood is to be treated for prevention against fungal attack.Woods VS water Water caused negative effect to wood Wood. twist. Wet wood is susceptible to attack by decay and stain fungi. bow. 71 . 9% 4.3% 2.7% Longitudinal Shrinkage Radial Shrinkage Tangential Shrinkage L R T T R R T 72 .7% to 12.1% to 7.1% to 0.Wood shrinkage Wood is an anisotropic material (having different properties in 3 dimensions) Three Dimensions in which Wood Shrinks = = = 0. m-2 ) Tensile radial (MN.m-2 ) Compress // fiber (MN.m-2 ) Maple Oak Pine 108 78 73 8 6 2 54 43 33 10 6 3 73 .Mechanical Properties of woods Wood strength depends on density Given a high efficiency when subject to tensile strength parallel to the fiber direction Wood species Tensile // fiber (MN.m-2 ) Compress radial (MN. m2.Comparison of the specific strength Specific strength (SF)= strength/density Material Clear wood Aluminum 1020 steel Copper Concrete SF strength (kg.s-2 ) SF modulus (kg.4E4 0.m2.9E4 74 .7E4 1.4E4 2.s-2 ) 178 127 50 38 15 2.7E4 2. Wooden house 75 . Unit-II Chapter no-4 Sub structure or foundation . P.C.Components of Substructure 1) Foundation 2) Plinth3) D.-Layer between substr & superstr . for piles=2 to 6 & for rocky strata=5 to 10 .S.5 to 2.foundation Definition of foundation Bearing capacity ultimate bearing capacity:.It is the capacity of soil before to failure in shear Safe bearing capacity= ultimate bearing capacity/ factor of safety F. For footing= 2 to 3.O. for temporary structure=1. Sketch of foundation . Functions of foundation 1) To support the str 2) To distribute the load over a wide spread area to prevent buildg frm any movement 3) To prevent unequal settlement 4) To increse the stability of str. 5) To transfer the load to thw sub soil Settlement of foundation Vertical downward movement of structure. Settlement is mainly due to change in volume. Amount of settlement is different for diff. soil & stata Eg. Clay soil settlement is more, Hard rock less settlement is there. Settlement of foundation Vertical downward movement of structure. Settlement is mainly due to distortion of soil or change in volume. Amount of settlement is different for diff. soil & stata Eg. Clay soil settlement is more, Hard rock less settlement is there. S. .Types of settlements 1)Uniform settlement _ It will not cause any damage to str.but excessive settlement will damage undergroung utility services like water supply.drainage lines.telephone & electric cables 2) Differential settlement – The diff in magnitudes of settlement at any two points is known as D. Uniform settlement . Differential settlement . Causes of settlement Loose soil strata below foundation Excessive expansion & contraction of swelling soil (Black cotton soil) Excavation & pile driving in neighboring construction Lowering of water table due to earthquake . Causes of Failure of foundn settlement of sub soil 2) Withdrawal of Moisture from sub soil 3) Horizontal movement of soil mass 4) Atmospheric action 5)Transpiration of trees & shrubs 1) Unequal . Types of foundation Shallow & deep foundation . Grillage foundation .TYPES OF SHALLOW FOUNDATIONS 1.Cantilever or strap Footing 6.Wall Footing/Strip footing 3.Isolated Column Footing/Pad footing 4.Mat or Raft Foundation 7.Spread Footing 2.Combined Footing 5. Deep foundation . 1.Spread Footing Are used to distribute concentrated load from the superstr over a wide area so as to enable the soil bed to provide safe support . 2.Wall Footing/Strip footing Used for light strs such as garden walls or compound walls 1) Simple footing 2) Stepped footing . circular or sloped depending upon distribution of load .buildings It may be square.C.Isolated Footing/Pad footing These are used to support individual column.rectangular.3. It is most commom used in modern R.C. Isolated Footing . Isolated Footing . 4.Strap footing/Cantilever Sometimes it is not possible to provide footing exactly below the column due to its projection beyond the column in that case seprate footing is provided for interior & exterior column . Strap footing . 5.Combined Footing When loads on adjacent columns are very high or bearing capacity of the soil is less then two columns are grouped together to form combined footing. load is same then use rect combined footing When Combined Footing Combined Footing Raft or mat Foundation Mat or raft is a heavily reinforced inverse slab placed over the entire area using heavily beams from column to column Is used when bearing capacity is so less Is used when heavy load on the foundation .6. Raft or mat Foundation . Grillage foundation Is suitable when load from the steel columns is very heavy & bearing capacity is so less .7. Grillage foundation . DEEP FOUNDATION . End Bearing pile -When piles transfer the load of bldg to a grater depth Friction pile .Pile foundation 1) 2) A pile is defined as a slender column capable of transferring the structural load to the deep underlying layers.When piles transfer the load by means of skin frictionwithout any end . Pile foundation . [B] SUPERSTRUCTURE It is the part which is above ground level . footing.g.basement & foundn .g.roof.Superstructure 1) Structural component above plinth upto top 2) Transfers load from upper part to sub str 3) e.beam floor Substructure 1) Structural component below plinth uoto footing 2) Transfers load received from superstr to foundn 3) e. TYPES OF CONSTRUCTION 1-Load bearing structures 2-Framed structures 3-Composite structure . 1-Load bearing structures In this the load of the str is transferred through the walls Economical upto 2-4 storeys Is used when hard strata is available at shallow depths E.of storeys increases wall thk also increases & reduces carpet area .Shaniwarwadwa in pune COEP-these are stone walls If no.g. . Load bearing structure . 2. Constructed more than 100 storeys Used when hard strata is not available at shallow depth.beam. Speed of constn is fast .column & footing to the underlying soil.Framed structure Load transferred through a frame of slab. Framed structure . 3.Composite structure The outer walls of load bearing type where as column & beams provided internally Is used for industrial sheds or warehouse where span is so large . Composite structure . . TYPES OF LOAD 1.Dead load 2.Live load 3.Wind load 4.Earthquake load TYPES OF LOAD material 1.Dead load-load of material in the constn of bldg, self wt of diff P.C.C. comp.Dead load is calculated by R.C.C multiplying its volm by Bricks unit wt.of material Steel Stone masonry Brick Unit wt(KN/m3) 24 25 22 78 22 18 2.Live load It is movable load acting on the str.furniture.i. is considered in design og bldg dpending upon the type of bldg .e.L.equipment & machinery Minimum L. 00 5. in KN/m3 2.00 4.Workshop Minm L.Sr No Type of bldg 1 2 3 4 5 6 Residential Office Bank & reading room Class room .00 7.00 .Assembly hall Dining hall.Store room factories .45 3.00 2.L. 3. .Wind load Is considered in tall bldgs P=kv2 P=Wind pressure in KN/m2 K=Coeff of wind velo. Earthquake load 4.of str G= gravitatational acccln .Earthquakeforce Α = w.α/g = accln due to earthquake =1/20g to 1/20g W = wt.4. forces foeces .Q. Resist E.Q.Sr No Load bearing 1 2 3 4 Comparison betn Load bearing & framed str framed str Hard strata at shallow Suitable for any strata depth Allowed Upto 4 storeys Slow & time consuming constn Economical upto 2 storeys Multistoreyed Fast & speedy Economical upto multisoreyedstoreys 5 It can not resist E. Masonry Types 1) Brick 2) Stone . . . (min 100mm) Less durable Less costly & easy to construct Higher wall thk.Sr No Brick 1 Stone Used brick & mortar for Used stone & mortar for constn constn Lesser wall thk.(300mm) More durable Costly & skilled Labor is required 2 3 4 . Fundamental requirements of masonry 1) It should be strong enough to carry the load 2) It satisfies the I.for durability & strength 3) Proper bonds to be maintained while laying masonry 4) It should be in level 5) Thk should be such that it will offer resistance to water current .S.