EPOXY GROUTING FOR REPAIR WORK

REPAIR TECHNIQUE ON CRACKS 

1. PRESSURE INJECTION EPOXY GROUTING

SLAB REPAIR

Procedure for Epoxy Injection Grouting in Concrete Structures:

Surface preparation is the first step in repair of cracks in concrete. The area to be epoxy grouted should be made free from oil, grease, dust and all loose and unsound materials.

Then cracks in concrete is cut open into a ‘V’ groove about 10mm deep by mechanical or manual method. Loose materials are removed by using compressed air. The ‘V’ groove cut is fully sealed with epoxy mortar at least one day in advance before epoxy injection.

Nails are driven into the cracks at 15 cm to 50cm intervals along the crack.

Holes of 7 – 10 mm diameter is then drilled along the cracks and copper or aluminium or polythene pipe pieces of 6 – 9 mm diameter is fixed as grout nipples around the nails and allowed to rest on them.

Epoxy formulation is injected from the bottom most pipe. All other pipes, except the adjacent ones are blocked by wooden plugs. The injection is done using suitable nozzles connected to air compressors or by hand operated modified grease guns. Pressure of 3.5 to 7 kg /cm2 is normally used.

As soon as the epoxy comes out from the adjacent open pipes, they are plugged and the pressure is increased to the desired level and maintained for 2 to 3 minutes. The injection nozzle is then withdrawn and the hole sealed with epoxy mortar.

This operation is repeated for the other pipes also. Any resin that remains or overflows the pipe is scraped off with a metal spatula and the surface cleaned with a rag soaked in non-inflammable solvent.

Due to restriction of pot life, it is advisable to mix only small quantities of epoxy at a time. All proportioning should be by weight and mixing should be thorough.

Low viscosity resins may be adopted for thin cracks. A record of materials used for epoxy grouting should be maintained.