ce803

8/3/2019 CE803

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Civil Engineering Department, TIST

Arakkunnam, Ernakulam

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RepairPartial improvement of the degraded ordeteriorated strength of a building

Int roduc t ion

Ret rofi tt ingStructural strengthening of a building to apredefined performance level whether or notthere is any damage.For EQ, Terrorist attack, Higher loads etc

Col-beam joint retrofit

Rehabilit at ionA functional improvement by replacement ofextensively deteriorated, damaged or missingfeatures using traditional or substitutematerial.

Rehabilitation of a hotel

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RemouldingReestablish on a new usually improved basisor make completely new.

Remoulding stone block

M any F ederal, St at e, and County G overnments have found rehabili t at ion of exist ing St ruc t ure s t o be more cost effec t ive compared t o t he ent ire demolit ion and replaceme ntof t he exist ing st ruc t ure.

Rest ora t ionA reconstruction or reproduction of anexisting or ancient building to bring it backto its original state.

Restoration of a light house

Int roduc t ion cont d..

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A . Repair M at erial s and M et hods

A1 . Repair M et hodology

Depe nds ony Repair mat erial sy Cause of failure/ de t eriora t iony Locat ion of sit ey T ype of st ruc t urey

Economy

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A 1 . 1 Based on M at erial sA1 . 1 . 1 . Polymer Concre t e

pat ching on ver t ical, overhead and horizo nt al surface s;st ruc t ural crack repair and sealing;st ruc t ural bonding and grout ing;underwa t er and splash zone repair s and cont rol;

expa nsion j oint s ealing.By Polymer impregnat ion in concre t e

Polymer s, monomers, sty re ne, polyest er s

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A1 . 1 .2. Epoxy g routs , mort ar s & coat ings

Rapid sett ing mort ar s-Use on grade, above and below grade on concrete-Highway overlays and repairs-Structural repair material for concrete roadways,parking structures, bridges, dams and ramps

-Full depth patching repairs

Fiber-rei nforced repair mort ar s- Bridges, parking garages and tunnels- Manhole, wet well, sewer and lift station repairs- Where high durability is needed- Vertical and overhead repair of concrete and masonry- Piers, navigation locks, dams, sea walls and other marinestructures

Polymer-modified ceme nt -ba sed mort ar-Horizontal and vertical surfaces- Repair bug holes and honeycombs- Leveling and resurfacing distressed concrete- Provides consistent color and texture

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Epoxy past e-Structurally repairs cracked concrete- For slabs, walls, patios, driveways, parking garages and any structures

Polyure t hanes injec t ion syst ems- Cracks in tanks- Tunnels- Pipes- Basements- Pools- Any structure where water intrusion must be stopped

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y a quick-setting concretey used primarily for bridge deck overlays.y the latex improves an already very low permeabilityy helps to protect the steel in the bridges.y the rapid set cement in the concrete allows thebridge to return to normal surface and traffic usewithin 4 hours of final finishing .

A . 1 . 1 .3. Lat ex M odified Concre t e(Rapid Set Latex Modified Concrete ) (RSLMC)

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A 2. Iss ues Relat ed t o M at erial t ech nology

J ustification of High costSuperior strength,Long term life cycle behaviorMinimum or nil maintenance

micro structural properties monitored to get the macro behaviorresults.

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A 3. Desired Proper t ies of Repair M at erialM inimum de sired charac t eri st ics

characteristics examplesHigh performance, high durability,low maintenance cost

Composites, blockcopolymer, highperformance concrete.

Easiness of usage, increase

productivity, reduce constructioncycle time

High flow self- leveling

concrete/mortar, setcontrolling materialsReduced sensitivity for size,storage & substrate conditionssuch as temp., moisture, place ofapplication etc.

Epoxy compounds

Environmental friendly (which donot emanate toxic or irritatingfumes during service.)

Infrared system of repair

Having less density or unit weight(usage will not add to the dead

weight of the substrate.)

Aerated repair materials

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Environment al frie ndly repair syst em

Infrared system of repairThe Infrared processHeat the existing wearing course of a road, footpath or any otherasphalt surface using infrared technology.Infrared patchingrecycle of Surface Course (wearing course), Binder Course (base

course) and underlying bituminous materials where the materialsare heated in-situ using an Infrared recycler, scarified by handusing a rake, liquid rejuvenation binder added to the existingmaterials and fresh asphalt or similar approved material addedbefore compaction

Environmentally Friendly ²

All existing materials recycled in repair, nodisposal to landfill , the process createsminimal noise, other than a roller forcompaction

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A4 . M at erial s for RepairMaterial Examples Advantages/

disadvantagesPortland cement basedmaterial

Portland cement mortar,portland cementconcrete

Causes shrinkage, crackingand eventually failure ofthe repair work

Resin based products(epoxy resin)

Normal grade epoxyLow viscosity epoxyNormal grade epoxymixed with sand

For bondingFor crackwidth<=0.1mmFor grouting andpatchwork

Polymer modifiedcement products

Acrylic polymer products Increased plasticity&hence reduction inshrinkage stresses

Micro concrete Type A normal strengthType B high strength

Achieve high earlystrength & hence suitableto apply in complicatedlocations

Fibre reinf cementcomposites

Long service life, can beapplied without stoppingthe func of the bldg/stru

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A5 . New Repair Syst em / Produc ts

New products are being developed keeping in mind that they shall bestronger, lighter, durable and economical.Some products & their place of application etc is given.

product component uses

FRP Composites high strength fibers(such as glass, andcarbon) embeddedin a resin matrix

wShear Capacity Improvement,Flexural Capacity Improvement ,wCompression Capacity Improvement ,wBlast Mitigation ,Seismic UpgradeswCrack Control,New Slab Penetrations

FRP composite

bars

Corrosive environment, in structures

subjected to severe weather or deicing salts

Highperformanceconcrete

Micro structureproperty

High rise bldg. col., offshoreplatforms, heavy duty floors withcongested reinf., pavements

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product component usesSpecialadmixtures(airentrainingagents)

water based solutions(vinsol resins)

wimproves the freeze-thawdurability, more workable , Reducesbleeding and segregation

Superplasticizers

Delayed releasemechanism (Poly-

Carboxylic Ethers)

Advantageous for repair work,Impart excellent Fluidity at low

dosage, High strength and durabilityShrinkagereducingagent

Reduces surfacetension even after theconc hardens & hencereduces shrinkage

general repair work and bondingapplications, virtually eliminatecracking in high value flooring

Viscositymodifyingagent

provide pseudo plasticflow (viscosityreducing)

For self consolidating concrete,under water concreting

Retarders delays the set of thesurface of concrete

For concreting operations in directsun, wind, high temp, or low relativehumidity

New Repair Syst em / Products Cont d..

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product component usesCorrosioninhibitingadmixtures

Calcium nitrite wEpoxy coating is mosteffective in corrosiveenvironment

High performancecementatioussystem

Chemically bonded ceramics(CBC), densified systemcontains ultra fine particles(DSUP)Belite cement or sulfoaluminate cement

Are micro defect free(MDF), very strong & dense

Injectionmaterials

Reduces surface tension evenafter the conc hardens &hence reduces shrinkage

To restore the structuralstability, to protect thereinf. From misture, to stopwater & air from enteringthe structure


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concrete that meets special performance and durability requirementsin terms of mechanical properties, volume stability and longer life insevere environmental conditions to which the concrete is exposedduring its service life.

H IGH PERFORMA NCE CONCRETE

Polycarbox ylat e Et her Impart excellent Fluidity at low dosage ,IS : 9103 ² 1999, High strength anddurability, Maximum W/C Ratio 0.35 ,Very low slump loss factor

SUPER PLA

ST ICIZ ERS

Visct rol and Eucon AB S - These viscosity-modifying admixturescontrol bleeding and segregation in self-consolidating concrete. Whenmaterials are not an optimum gradation, viscosity modifiers maintainhomogenous concrete

VISCISI TY M ODIF YI NG A GENT S


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