Presentation on theme: "“BOND STRENGTH INCREASE CORROSION RESISTANCE OF STEEL REBARS”"— Presentation transcript:
1“BOND STRENGTH INCREASE CORROSION RESISTANCE OF STEEL REBARS” 18th AUGUST, NEW DELHIPRESENTATION ON“BOND STRENGTH INCREASE&CORROSION RESISTANCE OF STEEL REBARS”By Use ofNANOPRETREAT ™ Rust Resistant Compound and Bond Strength Increaser…
2Introduction Corrosion of Steel is a matter of global concern Rusting of steel is noticed in every type of construction – structures, RCC, factory sheds, bridges etcProtective steel coatings now available have a few limitationsIt is noted that all buildings and MS structures in coastal areas need repair after 7-8 years of construction!
7THE CORROSION CYCLE Rust expanding on uncoatedsteel surface Cracking near concrete-steel interfaceMore cracking of concrete with high pressure by corrosion productConcrete separates from steelEventually causing spalling
8- An Anti-Rust Compound NANOPRETREAT- An Anti-Rust Compound
9The PRODUCTCoated rebars and MS structures show nearly 100% bond strength increaseCoated steel can be painted, powder-coated & electroplated very wellEasy to use - paint, spray or dip methodsExcellent Corrosion Resistance propertiesNon-toxicWater-based patented formulationInorganic in natureEco-Friendly (Complies with ROHS standards)Non-inflammableCoated structures stable even at -196o to +400o C0.5 to 2 micron coat thickness , so practically no change in gauge of substrate
10PROTECTS STEEL : nanopretreat prevents corrosion in 3 ways:- Stops Formation of free Fe 2+ & Fe 3+ ions by formation of insoluble micro crystals all over the surface.Forms a Fine and Tenacious coat on the Surface of Steel. There by stopping Ingress of Water.Fights Against Atmospheric Pollution.
11BASIC DATA: Viscosity = 13 seconds @30º Celsius Sp. Gravity = 1.12 gm/ccPh. Value:Conforms to ROHS Standard (Reduction of Hazardous Substance - DIRECTIVE 2002/95/EC)nanopretreat does not contain Lead, hexavalent Chromium, Mercury, Cadmium, polybrominated Biphenyls & diphenylethers.
12What happens on application of nanopretreat? When nanopretreat ™ is applied on a steel surface there is a formation of millions of nuclei on activated surface. And coat is "generated" through the surface in due course and becomes inseparable part which is stable through temperature range from +400º to -196º Celsius.
13Reasons for increasing “Bonding Strength” of the coating construction rebars with concrete Application of nanopretreat forms DENSE FOREST of micro-crystals on TMT rebar surface.This dense forest acts as ‘Activator’ for crystal formation.the coating also acts as a cement crystallisation accelerator around the coated TMT Rebar.This process helps hydrated cement crystal to form ‘crystal-crystal’ contact instead of ‘metal – crystal’ contact. Homogenous attraction between two different crystals is always greater.Nanocoat prevents rusting of rebars even in cases of fine cracks that are commonly found in RCC .
15In case of RCC beam ..the compression load is taken by concrete and tensile load is taken by steel when beam is loaded .These compression stresses in concrete and tensile stresses in steel act as a balancing couple to counteract the applied load but this happens only when there is perfect grip between steel and concrete. Hence bond strength is important.If such bonding strength between the concrete and steel is not achieved, it happens just as a steel rod is pierced into an over sized bore of concrete. which ultimately decreases power and strength of beam and consequently collapse.LOADBEAMSTEEL REINFORCEMENT
16Bonding & Role of nanopretreat When the regular rebars come in direct contact with moisture and water, that results in direct corrosion on the surface of steel rebar which separates the rebar and the bonding cement slurry ,that ultimately results into bond or grip stresses. So "stress transfer phenomenon" cannot take place. Hence the beam looses its strength and becomes demolished even if sufficient reinforcement is provided .The nanopretreat ™ prevents all such recurrences only because nanopretreat prevents rusting process and keeps bond stress intact.Present coatings available in the market are in the form of thin layer of epoxy and polymers which cause a loose coat between steel and concrete (construction wants bond of concrete with steel and not with other lose film) ,over which during loading condition, rebar gets separated from concrete hence there is decrease in bond stresses but the nanopretreat ™ applied on steel rebar provides rust resistance as wel as good bond stress as steel guard acts as a part and parcel of steel.
17HEAT RESISTANT: crystals steel surface Image of athe coatinged steel sample - magnified 1000 times. The white particles are the densely formed crystals on the steel surface on applying Steel Guard -the coating.
18crystalsThe steel sample shown was heated to 400o C and hammered. The sample was chiseled to remove coating from the surface of steel and observed under the microscope. Crystals visible show efficacy ofthe coating
19ECO-FRIENDLYIn view of the present Environmental Concern all over the world nanopretreat is an appropriate application as it does not contain any environmental hazardous substance of any kind.
20Nanoptrtreat Performance Study Report DFT : MICRONSIMPACT TEST :250 Kg Passed.BEND TEST : 170 Kg Passed.SCRATCH RESISTANT : 5 Kg Passed.SALT SPARY : 120 Hours passed.'Steel Guard nanocoat'
21To conclude….the crystal arrangement on the TMT rebar after coating is so close and interwoven that water and gases cannot penetrate through the coat thus preventing rust.In addition, it helps in developing massive and tenacious bond with concrete, improving strength and life of the construction
22for your kind Attention. Thank Youfor your kind Attention.