rehabilitation methods
TRANSCRIPT
![Page 1: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/1.jpg)
REHABILITATION AND RETROFITTING METHODS
AVINASH KUMAR GUPTA
EE TRAINING
TRAINING INSTITUTE
CCW AIR
12/04/2017
![Page 2: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/2.jpg)
GENERAL
1.0 General• Method of repair and selection of repair
material needs consideration Assess the service life of structure based on
technical & economic evaluation.Repair of structural defect to ensure safety of
structure.Protection of the structure from further
deterioration
![Page 3: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/3.jpg)
Objectives of Repair
2.0 Methods of Repair objective• Reinstate the structural integrity by restoring
or increasing strength & stiffness.
• Prevent the ingress of moisture, chloride, CO2 to improve durability.
• Maintaining the aesthetic/ appearance of concrete surface.
![Page 4: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/4.jpg)
3.0 Repair options
Grouting & Crack Repair Patch Repair Replacement of structurally week concrete Replacement of spalled/ delaminated concrete. Replacement of carbonated concrete around steel bar Cleaning & depassivating the corroded steel. Concrete overlays with normal, low/ highly fluid concrete,
latex modified concrete. Jacketing Realkalisation of carbonated concrete Electro chemical removal of chloride from concrete. Water proofing/ protective coating.
![Page 5: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/5.jpg)
4.0 Performance Requirements of Repairs System
Strength, serviceability and durability.Protection of steel.Bond with parent surface.Dimensional stabilityResistance to environmentally induced
damage.Ease of application.Appearance
![Page 6: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/6.jpg)
5.0 Factors to be considered for selection of Repair Method
Type & extent of distress. Location of distress. Environmental exposure. Availability of skill. Availability of time & access. Appearance. Cost.
![Page 7: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/7.jpg)
6.0 Repair Stages
Concrete Removal & surface preparation. Fixing suitable form work. Bond/ passivating coat and repair
application.
![Page 8: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/8.jpg)
6.1 Concrete Removal & Surface Preparation
Completely expose the bar if more than half of has been exposed.
Consult structural engineer if cross section area of individual bar is reduced by 15% or more/ two adjacent bars reduced by 10% or more.
Secure the bars at design location. Sand blast the surface/ Air blast to remove
dust & debris/ low pressure water blasting/ broorming.
![Page 9: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/9.jpg)
Repair procedure for corrosion damaged concrete
![Page 10: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/10.jpg)
6.2 Form Work
• On vertical & overhead surface, if the repair material is likely to sag.
• Ensure no air is trapped on concreting.• Change the contour or provide vent pipes.• Secure form work with expansion anchor.• Form anchors should be pre tested for
slippage.• Preformed foam gasket or cast in place
foam, to provide a water tight seal
![Page 11: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/11.jpg)
FORM WORK
![Page 12: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/12.jpg)
6.3 Applying Bonding coat & Repair application
• Filling of cracks with cement/ resin based grout
• Injecting grout into a mass of dry aggregate.
• Poured concrete.• Pre packed concrete.• Dry packing.• Sprayed concrete.
![Page 13: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/13.jpg)
7.0 Repair Methods Repairs using mortars Dry pack and Epoxy bonded dry pack Preplaced Aggregate concrete Shotcrete Concrete replacement Epoxy bonded concrete Slica fume concrete Polymer concrete system Strengthening concrete by impregnation using vacuum method Thin polymer overlays Thin epoxy overlays Resin/ polymer modified cement slurry injection Protective seal coat on the entire surface Ferrocement Plate bonding RCC Jacketing Propping & supporting Fiber wrap technique Foundation Rehabilitation (Shoring/ Under Pinning) Chemical/ electro chemical methods
![Page 14: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/14.jpg)
7.1 Repairs using mortars7.1.1 OPC mortars• For repairing defects on exposed new concrete
surface.• Defects are small• Shall not be used for old concrete, existing
concrete if cracks extends to first layer of steel bars
• Proportion (OPC + clean sand+ water) same as parent concrete.
![Page 15: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/15.jpg)
7.1.2. Polymer modified cement mortar
7. Repair using mortars• Repairs on exposed old hardened concrete• Thickness less than 50mm• For thicker applications, reinforcing mesh with
U nails• Polymer mixed, as specified in mortar
![Page 16: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/16.jpg)
7.1.3. Epoxy Mortars
• Resin + hardener + sand over epoxy bonding coat over old hardened surface
• High strength & abrasion resistant, water resistant
• Can be in few mms overlays• Places wherea) Difficulty in epoxy bonded concreteb) Depth is < 40mmc) Repair area is small• In layers of 15mm. use mesh when thickness >
15 mm
![Page 17: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/17.jpg)
7.1.4. Dry Pack & Epoxy Bonded Dry Pack
apply bond coatCement + sand (1.2.5) with just enough water to
form ball by hand Pack into placeUse suitable hard wood dowel/ hammerPlaces having small width but deeperNot to be used behind bars
![Page 18: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/18.jpg)
DRY PACKING
![Page 19: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/19.jpg)
7.1.5 Pre placed Aggregate concrete (PAC)
Forcing the grout into mass of clean, graded coarse aggregate densely packed in form work
Massive rebars, under water, shrinkage minimum
Grout (sand, cement, pozzolana, plasticizers, super plasticizers and air entraining agents)
Grouting from bottom Proportioning – Trial mix necessary Best pumpability Use anti wash admixture under water
![Page 20: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/20.jpg)
Preplaced Aggregate
![Page 21: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/21.jpg)
7.1.6 Shotcrete• Pneumatically applied concrete/ mortar
onto a surface• Dry mix/ wet mix• Jetting the mixture from nozzle at high
velocity on to the surface• Use steel fibers/ poly propylene as
specified.
![Page 22: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/22.jpg)
Shotcrete
![Page 23: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/23.jpg)
7.1.7 Concrete Replacement Damaged/ unacceptable concrete
greater than 0.1 m2
Depth greater than 150mm Depth greater than 25mm below bars Concrete in less than 7 days old. No bonding agent to be used
![Page 24: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/24.jpg)
7.1.8. Epoxy Bonded Concrete
When depth of repair is greater than 40mm Fresh concrete is laid over epoxy resin bond in
existing hardened concrete Shear keys also needed + extra bars
![Page 25: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/25.jpg)
7.1.9 Silica fume concrete Silica fume 10% by weight of cement≯ Use super plasticizers Where high strength and low permeably
in required Epoxy bonding agent for depths upto
50mm to 150mm.
![Page 26: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/26.jpg)
7.1.10 Polymer concrete system
MMA (Methyl methacrylate) & vinyl Easter (low flowing viscosity & high strength)
Patches, over lays etc. Polymer + Inhibitors + promoters +
initiator + aggregate primer
![Page 27: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/27.jpg)
7.1.11 Surface impregnation using vacuum Methods.
• Create vaccum• Introducing a repair material (resin of
low viscocity)• Cracks repairs upto 5 micron• Evacution of moisture• Vinyl Ester gel – sealing of joints, water
proofing (It swells in contact with water)
![Page 28: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/28.jpg)
7.1.12 Thin polymer overlays
Improve abrasion resistance Water proofing, protective coating Less than 10 mm thickness One coat of primer One or more coats of sealent Primer (vynil ester resin), initiator &
promoter Sealant (primer + silica + TiO2 + carbon
black)
![Page 29: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/29.jpg)
7.1.13 Thin Epoxy Overlay• Improves abrasion resistance• Water proofing• Overlays in 2 to 3mm• Resin and hardner• Requires protective coating
![Page 30: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/30.jpg)
7.1.14 Resin/ Polymer modified cement slurry injection
![Page 31: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/31.jpg)
7.1.15 Protective seal coat on the entire surface
Prevention of ingress of aggressive gases & liquid (Co2, H2O etc)
Polyurethene, epoxy, alkyds, chlorinated rubber, acrylic emulsions
Water based coatings are preferred over solvent based
![Page 32: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/32.jpg)
7.1.16 Ferro Cement
Thin wall type composite total thickness 12 to 30 mm
Hydraulically cement mortar reinforced with wooven wire mesh
Plasticizers and polymers Wire mesh is nailed to parent surface Protective reinforced membrane
against the vagaries of environment Prevents seepage & leakage
![Page 33: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/33.jpg)
7.1.17 Plate Bonding
Rehabilitation & upgradation of concrete structure
Connecting MS Plates by bolting & gluing with epoxy
Bolts are positioned during construction
![Page 34: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/34.jpg)
PLATE BONDING
![Page 35: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/35.jpg)
7.1.18 RCC Jacketing• Increases the size for slender columns• Composite action (Old + New)• Increases stiffness• Ensure transfer of load to new jacket• Ensure perfect bonding by shear keys &
bonding coat (Epoxy or polymer modified cement slurry)
![Page 36: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/36.jpg)
Column strengthening Concrete jacket
![Page 37: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/37.jpg)
7.1.19 Propping & Supporting
![Page 38: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/38.jpg)
7.1.19 Wrap Technique• Increase the load carrying capacity Bi- directional woven fabric1. Woven fabric presoaked in epoxy applied
over prepared surface after application of epoxy primer.
2. Left to cure at ambient temperature• Subsequent layers Unidirectional E- glass fiber• Pre cut unidirectional E- glass fibre
wrapped over epoxy primer• Excellent barrier to corrosive agents
![Page 39: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/39.jpg)
7.1.18 Foundation Rehabilitation Methods
A. Shoring Raking shores Flying shores Dead shores
![Page 40: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/40.jpg)
RAKING SHORE
![Page 41: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/41.jpg)
Flying Shoring
![Page 42: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/42.jpg)
Dead Shoring
![Page 43: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/43.jpg)
Foundation Rehabilitation
B. Underpinning Underpinning piles Micropiles Proprietary jacked piles Injection of the ground with cement/
chemicals
![Page 44: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/44.jpg)
Underpinning Pile
![Page 45: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/45.jpg)
Micro Pile
![Page 46: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/46.jpg)
Jacked Pile
![Page 47: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/47.jpg)
8.0 Repair/ Rehabilitation Strategies
• Reduction of dead/ line loads• Repair/ strengthening of columns, beams
and slabs• Improving the compressive strength of
concrete• Attending to cracks and joints• Improving masonry structure to resist
earthquake forces• Providing protective cover against the
aggressive deteriorating chemicals.
![Page 48: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/48.jpg)
9.0 Stress Reduction• Reducing of dead/ live loads• Replacing heavy solid partitions with
light weight partitions• Enlarging openings by removing filler
walls• Reducing number of stories• Changing the building use• Span reduction of beam by props
![Page 49: Rehabilitation methods](https://reader035.vdocuments.net/reader035/viewer/2022062523/5a6d8bc17f8b9ab8418b750f/html5/thumbnails/49.jpg)