Strengthening Column Using Micro Concrete Jacketing
- Remove entire plaster to reach parent concrete surface if the column is plaster.
- Now by tapping with a light hammer, identify of loose concrete portions are present. After identifying & marking, remove loose concrete by using breaker machine attached to a suitable chisel.
- The concrete surface sounds to clean of any loose particles, dust, oil etc. And make rough with an angle grinder.
- 14 mm Dia. & 75 mm deep holes drills in the column concrete at 1000 mm c/c in a staggered manner using drilling machine to fix the shear connectors.
- Clean Holes using air blower and shear connectors of 10 mm Dia. A 75 mm long HYSD bars to fix using Masterflow 935 or equivalent high-performance resinous fixing and anchoring compound.
Fixing Reinforcement Steel
- Cut and bend HYSD bars of 12 mm Dia.
- HYSD bars are in position and tack weld/anchor to the existing steel in place.
Fixing of Formwork & Pouring of Micro concrete
- Make shuttering ply and silver wood according to the size of the jacket.
- Cut 100 mm dia hole in the slab, on the face of the column to facilitate the pouring of micro concrete.
- Place and fixed around the column keeping in mind the required thickness of the jacketing.
- Make formwork joint to be watertight using POP.
- Single component readymade Micro concrete Masteremaco 346 of BASF in 25 kg bag to emptied in a small drum. Two-third of recommended water to the mixed using measuring jar. Mix well for about two minutes using stirrer attached mixing machine. Add 50% by weight of 5mm down clean aggregates into the mixed Micro concrete.
- Add one-third of water and mix it for one minute till homogeneous mix obtain.
- Before pouring of Micro concrete make the surface pre-wet by spraying water.
- Pour manually to form-work.
- Remove after 12 to 16 hours / next day. And cover column immediately with hessian cloth and sprinkle with water for curing.
- Curing to carry out for next three days.
People carrying out the surface preparation and jacketing should wear PPE like helmets, safety shoes, safety belts, Nose Mask, ear plugs, safety goggles.