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Seminar on Causes, repair and prevention of building cracks


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Edit 14/09/2015: Hi everyone, I have been busy lately so couldn't send you the ppt through mails. I am now allowing everyone to download it from here so that it is convenient for you people. Share it and do comment if you download. Regard.:)

Here is the Seminar on Causes, repair and prevention of building cracks.

Published in: Education

Seminar on Causes, repair and prevention of building cracks

  2. 2. Causes of building cracks1. Chemical reaction in construction materials.2. Climatic condition of the nature.3. Foundation movement & settling of building.4. Environmental stresses.5. Bad quality materials.6. Wrong method of construction.
  3. 3. Cause of Crack- Shrinkage Excessive Water The quantity of water used in the mortar mix can cause shrinkage. Prevention- Use minimum quantity of water required for mixing according to water cement ratio. Quantity of Cement As a general rule, the richer the mix is, the greater the shrinkage/drying will be. Prevention- Do not use excessive cement in the mortar mix.
  4. 4. Shrinkage (contd…)Curing The hardening of cement takes place, causes reduction in moisture and creates shrinkage. This causes cracks in concrete work. Prevention – -Proper curing should be started as soon as initial setting has taken place -Must be continued for at least seven to ten days.
  5. 5. Cracks due to shrinkage
  6. 6. Foundation Movement andSettlement of Soil also causecracksLarge differential settlement of foundation due to any of following causes:- Unequal bearing pressure under different parts of the structure. Bearing pressure being in excess of safe bearing strength of the soil. Low factor of safety in the design of foundations. Local variation in the nature of supporting soil.
  7. 7. Diagonal Cracks in Wall Wide at bottom and narrow at topCauses:-Differential settlement due to expansion of clayey soil byabsorbing water.Remedies:-• Foundation should be deep.• Plinth protection should be provided.
  8. 8. Vertical crack in long wallCause:-Due to no expansion joint at proper intervals.Remedies:-Leave expansion/contraction joints at regular intervals.
  9. 9. Vertical Cracks at Junctions of wallsCauses:-Improper bonding of cross walls by not leaving proper keys in the mainRemedies:-Both walls must be properly bonded by proper toothing.
  10. 10. Cracks in panel walls in R.C.C. framed structuresCauses:-R.C.C. beams are not free to deflect.Remedies:-Gap should be left between top of panel wall and can be filled with weak mortar
  11. 11. Horizontal Cracks in the top most storey below slabCauses:-Deflection of slab and lifting up of the edge.Remedies:-Adopt Bearing arrangements of slab.
  12. 12. Diagonal Cracks in Panel walls in R.C.C. framed str.Causes:-Deflection/ movement of R.C.C. structure.Remedies:-Walls should not be built properly tightly to the cloumns.
  13. 13. Repair of cracks A. Repair cracks giving hollow sound - Remove plaster applying proper cut. - Prepare the surface thoroughly. - Apply fresh cement mortar and finish the surface. B. Repair cracks if it is solid without hollow sound - Clean cracked portion of all loose materials and fill crack seal sealants in cracked portion. Finally finish the surface according to adjoining area.
  14. 14. Epoxy Injection
  15. 15. HOW TO PREVENT CRACKSIN BUILDING1. Drainage arrangement should be made around the building to minimize water entry in the foundation.2. Avoid construction of wall on filled up soil.3. Avoid trees grow too close to building & compound walls.
  16. 16. GENERAL MEASURES FORPROTECTION OF CRACKS1. Selection of materials.2. Specification for mortar & concrete.3. Good construction practices.4. Weather effects.