2. Relevant process/specification:
Contract and Manufacturer’s specifications
(i) The Project Engineer and Site Foreman the responsible for the field activities
(ii) Safety Officer shall be responsible for ensuring that the necessary work permits are obtained prior to commencement of works and will ensure that the works are being carried out in Safe Manner
(iii) Inspection and testing activities shall be controlled by QA/QC Engineer in accordance with approved Inspection and test plan.
(i) Sweep blast the surface of the crack to remove all loose deposits, debris and other deleterious substances as per manufacturer recommendation.
(ii) Using a marker pen, locate drill position at between 150 and 300 mm centers along the entire length of the crack.
(iii) At drill locations, drill a hole into the concrete approximately 15-25 mm deep using a suitable drill bit.
5. Fixing injection nipples:
(i) Using a long nail, locate steel nipples to the injection points, adds Nitomortar FC to fix the nipples. Secure to the concrete by pressing firmly for a period of 30 seconds. Locate all nipples using a similar method.
(ii) Spacing shall be close enough to ensure that the resin will penetrate along the crack to the next point of injection. This will normally be between 200 mm and 300 mm.
(iii) The surface of the cracks between the nipples shall be sealed with a band of Nitomortar FC, 30 to 40 mm wide and 2 to 3 mm thick.
(iv) The Nitomortar FC shall be allowed to cure for 8 hours at 35°C. At low ambient temperatures the curing time will be extended and the applicator shall ensure that the surface sealant has adequately cured prior to continuing.
(i) Prepare the two components of Nitofill UR 63, low viscosity epoxy resin by pouring the entire contents of the hardener can into the base container and mixing until homogenous.
(ii) Insert the mixed material into the standard injection gun (To be approved by the Engineer). Ensure all the seals of the injection gun are closed.
(iii) One end of the injection hose shall be attached to the lowest packer on vertical cracks or to either end of horizontal cracks.
(i) Commence injection from the lowest nipple. Locate on/off valve to the nipple. Switch the valve on and gradually apply pressure to the gun, filling the crack with Nitofill UR63. Continue applying pressure until resin appears at the next packer location or until no more resin will enter the crack.
(ii) Remove or switch off the valve, remove the gun from the nipple and move on to the next location.
(iii) Continue injecting resin until all nipples locations have been sealed.
(iv) Remove all Nitomortar FC and nipples from the concrete by suitable means not before 6 Hrs.