How to fix 7m long crack in concrete slab?

[pm50]

there is an expansion crack in our slab. It is partly filled with a rubbery substance (partially removed).  In one small section the edges of the joint have crumbled. We bought an aluminium strip from a Bunnings. It has a strip down the middle to go into the joint.  We glued it in place with a strong glue. Seemingly there was insufficient surface for the glue to hokd the strip in place the length of the aluminium strip. So - how to repair the hole in the expansion joint. How to stick the aluminium in place. 

 

[JacobZ]

Hi @pm50,

Welcome to the Bunnings Workshop community, it is wonderful to have you with us.

Unfortunately, a T-shaped cover strip is going to struggle to bond to a gap this wide because, as you have said, there is insufficient surface that is solidly contacting the glue. You would be better off using some aluminium angle and gluing it to the damaged side of the expansion joint using Sikaflex 11FC Purform.

I'd suggest you start by removing the sealant that remains, before installing the aluminium angle. This can be done with a utility knife. Ensure you wear gloves, long protective clothing and eye protection to reduce the risk of lacerations.

You can then fill up the expansion joint with the same Sikaflex 11FC and smooth it off with a putty knife to create a nice smooth finish.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob