This document discusses various techniques for repairing structures including: - Jacketing and section enlargement to strengthen columns. - Enlarging the compression zone and adding reinforcement to strengthen beams. - Providing overlays or underlays to strengthen slabs. - Stitching cracks in walls and slabs by inserting reinforcing bars across cracks. - Removing corroded concrete and rebar from structures and applying protective coatings. - Repairing domes by removing old plaster, injecting cracks, adding ferrocement layers, and applying waterproofing treatments.

1. ILLUSTRATIONS
REPAIRING OF STRUCTURES
AVINASH KUMAR GUPTA
TRAINING INSTITUTE
CCW AIR
APRIL 2017

2. Strengthening Of columns
• Section Enlargement by jacketing.
• Apply specified bond coat on existing column.
• Bond coat of sunepoxy 368
• M-25 or higher grade of concrete.

4. Strengthening of Beams
• Section enlargement with micro concrete
• Shotcrete self compaction concrete
• Increased flexure strength by enlarging
compression zone and additional reinforcement
in tension.
• Increased shear strength by fixing of stirrup with
epoxy and quartz sand mortar as specified.
• MS Plate bonding
• High strength fiber fabric wrap technique.

6. Strengthening Of Slab
• Provide overlays in case of negative moment
deficiency.
• Provide underlay in case of positive moment
deficiency.
• Increase in stiffness and control of deflection.
• Slabs are safe in shear.

8. STICHING of walls/slab cracks
• Concrete and masonry weak in tension.
• Crack indicate tensile failure of material
• Insert U shaped MS bars in the holes and span
across the crack.
• Grouting the holes with either epoxy or non
shrink grout.(non moving cracks)
• Active cracks are to be filled with flexible
materials like poly- sulphides, bituminous
fillers.

11. BEAM AND COLUMN REPAIR BY
GUNITE/SHOTCRETE

12. TREATMENT OF DEPRESSED FLOOR
IN TOILET/KITCHEN
• Remove all materials and expose the pipes.
• Test the water supply pipes and drainage pipes
for leakages using pressure applying methods.
• Provide 40 mm dia GI spout and CC sloped
flooring with water proofing compound.
• Provide 12 mm thick cement plaster (1:3) with
water proofing on the vertical walls
• Provide two coats of bitumen(85/25)in the
sunken portion.

14. Column Beam Junction

15. Repairs at Beam column junction

16. Beam Column Junction

17. COOROSION IN BARS .
RCC STRUCTURE

18. CORODED BARS REPAIR
• Remove all defective concrete and expose
corroded reinforcing bars to their full
circumference.
• Remove the corrosion from the bars until the
shine.
• Apply anti corrosive protective passivating coat to
protect re –bars.
• Patch with repair mortar or concrete and resurface
to required thickness.
• Apply protective coating and follow up with
decorative painting.

19. JACKETING

20. Column repairs

21. GROUTING

22. Beam Strengthening

23. REPAIR STRATEGY
• Remove all unsound concrete at spalled ,cracked
and hollow sounding areas.
• Expose the full corroded rebars to further depth.
• Remove corrosion by approved manual method
or by sand blasting.
• Treat rebars by a passivating material.
• Shotcreting, microconcreting
• Curing and top coat of alkyd to prevent ingress of
deleterious gases.

24. Beam Repairs

25. CRACK FORMATION, IDENTIFY THE
CAUSE

26. Brick wall Column Junction

27. Jacketing upto foundation level

28. Over Head Tank repair

30. Bridge Repair

31. Roof Repair

32. Water proofing of roofs
• Remove existing treatment.
• Number of rain water pipes to be increased.
• Mark surface cracks. Inject polymer modified cement
slurry through nipples along crack lines.
• Regarding.
• Apply two coats of polymer modified cement slurry
with 20% polymer.
• Apply 20 mm thick polymer modified non shrink
cement plaster with 300 X300 square thread
identation.
• Curing and ponding to check adequacy.

33. FILLING CRACKS

34. Filling Cracks

35. Basement Repair

36. Leak Reapair , Rubber based polymer

37. DOME REPAIR

38. DOME REPAIR, External surface
• Remove old plaster.
• Fix grouting nipples and inject cement based
non shrink slurry.
• Provide first layer of Ferrocement.
• Lay second layer and level upto required level.
• Cure for 14 days.
• Apply anti carbonation treatment in two
layers.

39. Dome repair , Internal surface
• Remove old plaster and clean joints wth brushes.
• Remove corroded steel and replace it.
• Pack with non shrink concrete.
• Repack all exposed masonry joints with non
shrink cement sand mortar. Pressure grout with
nozzles at the dome junction with bottom drum.
• Provide specified layer of ferrocement.
• Cure for 10 days
• Apply two coats of polymer cement water
proofing.