CONSTRUCTION / CONCRETE WORK
Problem no.1: A portion of concrete detached and fallen from the main body of concrete.
Causes
During construction, some portion of bad concrete might have been patch repaired manually which has fallen.
Remdy
Repair such weak patches of concrete by epoxy mortar. See subhead 3-6 for details of such mortar.
Problem no.2: Cracks in r.c.c. Structural Column, Pier.
Causes
Faulty design.
Rusting of reinforcement.
Remedy
Do jacketing to repair deteriorated column, piers. It consists of restoring or increasing the section of an existing member by encasement in new concrete/reinforcement.
Problem no.3: Shaking of bolts and machine base plates during running of Machine.
Causes
Grouting of bolts in grouting pockets is not proper and gap below machine base plate is not sealed perfectly. Hence due to vibration of machine there is a movements in bolts and base plate.
Remedy
Fill epoxy grout in the gaps around bolts and also fill the gap below machine base plate with epoxy grout. See subhead 3-10 for details of grouts.
Problem no.4: Cracks in concrete slab/flooring along construction joints.
Causes
At the location of construction joints left while casting R.C.C. slab, a crack is likely to from in slab and in the flooring above because of shrinkage of old concrete along with the line of construction joint. If the construction joint is left in the middle of the room then this crack will be visible.
Remedies
Leave construction joint at the location of wall so that it becomes hidden below the wall and doesn’t appear unsightly.
At location of construction joint, a polymer based or epoxy based bonding compound can be applied over the old concrete before casting new concrete. This may prevent the crack formation at construction joint. For details of bonding compounds refer subhead 3-5.
Problem no.5: white patches on concrete.
Causes
Building materials and/or water used in mixing/curing of concrete have salts in it. Whenever concrete gets wet, these salts get dissolved in water and appear on the surface and when water evaporates, white deposit appears on the surface.
Acid attack on concrete either through urine, sewage or industrial effluent.
Remedies
During construction, it should be ensured by resting of building material and water that they don’t contain water soluble salts.
Concrete should be protected from acid attack and if unavoidable suitable acid resistant coating can be done over it. See subhead 3-2 for details of protective coatings.
Salts appeared on constructed structure should be continuously removed by brushing.
Problem no.6: Water leakage through small gaps of shuttering plates after casting concrete.
Causes
Gaps are not filled with proper packing material.
Remedy
After filling gaps between shuttering plates by jute bags, mortar, etc., put tarpaulin over the entire shuttering before casting of concrete so that minor gaps/holes are taken care of.
Problem no.7: supporting beams of r.c.c. slab weakened/ccracked.
Causes
Due to miscellaneous reasons.
Remedies
If beam is of structural steel, replace it after giving temporary supports to slab by props.
If beam is of R.C.C. do epoxy pressure grouting as per standard specifications. It will strengthen the beam.
Problem no.8: cement concrete walkway/platform/ramp very slippery.
Solution
Provide cement concrete chequered tiles over the cement concrete surface after hacking it and after applying cement mortar. This will provide required roughness.
Make grooves in the floor in both directions by using floor cutter.
Problem no.9: supporting walls of slab weakened/damaged.
Causes
Due to miscellaneous reasons (e.g. sulphite attack, mechanical damage).
