Crack injection repair to concrete structures

Scope of work:

Injection of dead cracks with low viscosity 2 components epoxy resin in order to repair the concrete structures.

PREPARATION FOR INJECTION WORK

• 14mm holes must be drilled along the crack path between 200 – 300 mm centres. The holes must be deep enough to receive the ‘metal pipe sleeves’ (approx. 20mm)

• Insert Sika ‘metal pipe sleeves’ into all the holes and epoxy into position using Sikadur 731

• Clean the concrete surface adjacent to the crack with a wire brush or sandpaper.

• Wipe down the concrete with a clean rag to remove any dust and loosely adhering particles.

• The cleaned surface is then sealed using Sikadur 731 applied by a spatula or trowel.

CRACK INJECTION

• Following the curing of the Sikadur 731 (minimum of 12 hours at 30oC) the epoxy injection can commence.

• Starting from one side or the lowest point of the crack a Sika ‘nipple’ is screwed into the first pipe sleeve and Sikadur 752 injected into the crack until the epoxy is seen to ooze from the adjacent pipe sleeve, this pipe sleeve is then sealed with a nipple, continue to inject the current port until refusal (epoxy resin can not be injected more) and then start the injection of the adjacent port and so on. This procedure is continued in the sequence indicated until all have been completed.

• Beginning at the first nipple filled, the nipple is removed and checked for incomplete filling. If any of the pipe sleeves are found to be incompletely filled, the injection of Sikadur 752 must recommence from the previous pipe sleeve to the one found incomplete until full and the nipple replaced. This checking process is continued (without interruption) along the crack until all have been checked.

• After a curing time of 12 hours the sleeve and nipples are trimmed off with an angle grinder or other suitable equipment.