Larsen Toubro Limited ECC Division DLRO WELCOME TO

Larsen & Toubro Limited ECC Division- DLRO WELCOME TO QUALITY IN CIVIL CONSTRUCTION PROJECT PRESENTATION By N. Nirapandian 1

WHAT IS QUALITY? • The totality of features and Characteristics of a product or service that on its ability to satisfy stated or implied need. 2

TOPICS • • • FORM WORK CEMENT REINFORCEMENT AGGREGATE - COARSE AGGREGATE - FINE AGGREGATE WATER ADMIXTURE FLY ASH BRICK CONCRET POST CONCRETE CHECK 3

FORMWORK § MATERIAL § FORMWORK SCHEME § DIMENSIONS § LINE § LEVEL § VERTICALITY/PLUMB § RIGHT ANGLE § CLEANLINESS 4

FORMWORK § DISTANCE BETWEEN ADJACENT MEMBERS § COLUMN AND BEAM JUNCTIONS § LEAK TIGHT JOINTS § CLEANLINESS OF FORM SURFACE § APPLICATION OF FORM RELEASE AGENT 5

FORMWORK DO Ø Follow the schemes given in Formwork manual strictly and avoid misuse of components. Ø Apply form work releasing agent to the form work surface, to prevent absorption of water from concrete and adhesion of concrete and damage when shuttering is removed. The form work releasing agent should be applied before reinforcement is fixed in position. Provide tight joints – use foam sheets to prevent leakage of grouts. Ø Remove shuttering slowly and avoid sudden application of load. Ø Allow specified time before removing shuttering. Follow the de shuttering time specified in contract / Indian standards. 6

COLUMN FORMWORK SYSTEM WALER TIE ROD PROP 7

WALL FORMWORK SYSTEM 8

CEMENT 9

CEMENT PHYSICAL PROPERTIES ( Testing as per IS 4031) § Normal Consistency § Fineness § Specific Gravity § Soundness § Initial and Final setting time § Compressive strength at various ages 3, 7 & 28 -days 10

CEMENT CHEMICAL PROPERTIES ( Testing as per IS 4032 ) § Chemical composition § Heat of Hydration (if applicable) 11

CEMENT CHEMICAL COMPOSITION SI. NO. 1 2 3 4 5 6 7 OXIDES PERCENT CONTENT Lime (Ca. O) Silica (Si. O 2) Alumina ( Al 2 O 3) Iron oxide ( Fe 2 O 3) Magnesia ( Mg. O ) Alkalies ( K 2 O, Na 2 O ) Sulphuric Anhydride (SO 3) 60 -70 17 -25 3 -8 0. 5 -6 0. 1 -4 0. 4 -1. 3 -3 12

TYPES OF CEMENT 1. Ordinary Portland Cement - 33 Grade -confirm to IS 269 - 43 Grade -confirm to IS 8112 - 53 Grade -confirm to IS 12269 2. Portland Pozzolana Cement -confirm to IS 1489 3. Portland Slag cement -confirm to IS 455 4. Rapid Hardening Cement -confirm to IS 8041 5. Sulphate Resisting Cement -confirm to IS 12330 6. Low Heat Cement -confirm to IS 12600 7. Coloured Cement: White Cement -confirm to IS 8042 8. High Alumina Cement -confirm to IS 645213

CEMENT SAMPLING TUBE 14

STACKING & STORAGE OF CEMENT • Storage of cement bags shall be done by completely covered dry and moisture proof godawn. • It should not be stacked directly on ground. • Stacking should be done on wooden blanks at height of 150 to 200 mm from floor level. • Godawn should not have any permanent opening. • Stacking should be done week wise(Batch/lot). • No of cement bag should not be more than 12 in a single stack. • Gap of 300 mm at least should be maintained between stack of different weeks/lots/Batch. • Gap of 450 mm should be maintained between stacks and side wall of godawn. • Gap of 600 mm between two consecutive row of stacks should be maintained. • Sufficient lighting arrangement should be provided in cement godawn for handling the cement bag. 15

CODES GOVERNING REINFORCEMENT BARS § IS 1786 - 1985 § BS 4449 - 1997 § ASTM A 615 – 1984 § EN 10080 § RUSSIAN (GOST) 16

REINFORCEMENT § MATERIAL § CHEMICAL PROPERTIES (TC) § TENSILE STRENGTH § ELONGATION § BEND & REBEND § MEAN PROJECTED AREA § SECTIONAL WEIGHT § WELDABILITY 17

CHEMICAL COMPOSITION OF REBARS AS PER IS 1786 - 1985 18

MECHANICAL PROPERTIES OF REBARS AS PER IS 1786 - 1985 19

ALLOWABLE TOLERANCE ON NOMINAL MASS OF BARS AS PER IS 1786 - 1985 §By using bars of negative tolerance effective savings in cost can be achieved. (The design & construction is based on specific theoretical bar diameter, but the bars are supplied by weight) §If the bars are with plus weight, it means reduced geometrical properties of ribs, which in turn reduces the bond between 20 concrete & steel. And also leads to increase in the project cost.

TYPES OF REBARS § Cold Twisted Deformed (CTD) rebars. § Torsteel Rebars. § Thermo-Processed (TMT) rebars. § Corrosion Resistant (CRS) rebars. § Micro alloyed Steel rebars. § Coated rebars – either galvanized or epoxy coated. 21

ADVANTAGES OF TMT BARS § TMT bars contain lower carbon content & thus exhibit better ductility & weld ability (can be butt welded or lap welded) § TMT bars have better yield strength, tensile strength, and elongation than CTD bars of same grade. § TMT bars display easy bend ability and thus requires less energy for bending & rebending along with superior reverse bending properties. § They possess in built ability to resist loss of strength when exposed to higher temperatures. § They display better corrosion resistance than CTD bars due to absence of cold twisting stresses. § TMT bars are also available in higher strength levels than those listed in the Indian Standard. Use of Fe 500 grade TMT bars can result in saving of more than 15% in steel consumption when compared to CTD bars. 22

REINFORCEMENT § BAR BENDING SCHEDULE § CUTTING/BENDING TO REQUIRED DIMENSIONS § SPACING AS PER REQUIREMENT § LAPS § TYING § COVER/CHAIRS 23

CUTTING & BENDING § Jigs used for manual bending for correct dimensions before going for mass production. § Cutting schedule. § Use of latest revision of drawings & bar bending schedules. § Check bent shape for dimensional accuracy (against a template), bent radius & for signs of fracture. § Always bend the bars by Cold. Bars larger than 25 mm in size may be bent hot at cherry red heat (not exceeding 8500 C) except those bars which depend for their strength on cold working. Hot bars shall not be cooled by quenching. ( Clause 6. 1. 1 of IS 2502 – 1963) § Bundling & labeling bars of identical size, shape & type. 24

METHODS OF JOINING REBARS • WELDING • SPLICING BY SWAGED COUPLER METHOD • SPLICING BY USING THREADED COUPLERS 25

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REINFORCEMENT COVER& COVER BLOCK Cover to reinforced concrete member is the minimum thickness of concrete provided over the reinforcement steel measured from the exposed concrete surface to the closest reinforced steel. The role of concrete in the cover region can be compared to the role human skin plays in protecting the flesh & other parts of the body. Concrete in the cover region protects steel reinforcement in two ways: • By providing dense, strong, impermeable barrier against ingress of moisture, oxygen, chlorides, sulphates, carbon dioxide, & other aggressive gases & chemicals. • By providing passive coating on steel surface. Due to alkaline nature of concrete, this coating prevents corrosion 27 of steel.

REINFORCEMENT COVER AS PER IS 456 - 2000 PERMISSIBLE TOLERANCE FOR COVER Unless specified, actual concrete cover should not deviate from the required nominal cover by +10 mm & there is no negative tolerance. 28

PROTECTION OF REBARS If the work is suspended for a longer period, then the dowel bars left in the first phase have to be protected. The protection can be done by the following methods • By applying a firm coat of neat cement slurry to the exposed reinforcement bars leaving no point untouched. • Apply suitable anti corrosive chemical to guard against corrosion. • Encase the dowel bars in concrete either fully or partly. 29

Reinforcement DO ü ü ü Conduct applicable tests for the reinforcement bars for every lot / as stipulated in the specification Store reinforcing bars under cover, until required to use, kept clear of mud, dirt and oil and preferably stacked by sizes on racks. Use only bars that are free from mud, dirt, oil, grease, paint, loose rust, mill scale and pitting due to corrosion, Slightly oxidized bars are not good for adhesion with concrete; DON’T Don’t use bars with mud and dirt sticking to them. Mud and dirt can be easily washed off with water. Don’t use bars with oil, grease and paint sticking to them. These should first be dissolved in suitable solvents. Don’t use bars with loose rust and mill scale. These can be removed with a wire brush. 30

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