Concrete Crank Injection 3

[CivilEQuinn]

Hi all. My first post, but I've enjoyed reading many other posts and answers. I have a question of my own:

We are repairing cold joint horizontal cracks on a number of dolphins on a river. The river is subject to tidal motions which put the cracks a few feet below the water line at high tide and in the dry at low tide.

My question is which method of repair is best? The spec. is instructing us to use epoxy injection yet I've got a few different views from a couple subs. One says a polyurethane injection material would be more appropriate. While another is saying that why even bother injecting because the joint will just crack again due to the nature that it is a cold joint in the first place.

Thanks

 

[CivilEQuinn]

haha, thats CRACK repair, not crank.

 

[BigInch]

Epoxy!!!!

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[Ron]

Epoxy. If these are old cracks, you might also want to inject a volatile solvent (acetone, MEK, Toluene) into the crack before the epoxy to clean it a bit and achieve better adhesion. You have to be careful though...potential for spills, contamination, and fire.

 

[Blackhorse007]

yeap epoxy is the way, but because of the tide you might want to consider epoxy tt can cure under water?

 

[LittleWheels]

Being in the tidal zone, you have potential reinforcement corrosion. Sealing the cold joint would be prudent.

Epoxy injection will give a structural repair but generally has little flexibility or ductility - it may crack through the epoxy or adjacent to the epoxy, depending on forces (impact?) and conditions. Polyurethane injection is a flexible repair.

Talk to an injection repair manufacturer (of both materials) for some reasonable advice about your specific situation. A good specification and good material application will be required to produce a durable repair.

 

[4wilmar]

There was a flexible vinlyester injection resin on the market which swells tight when exposed to water. I have used it with good success on concrete reservoirs in the middle east. A bit expensive and difficult to mix as there are several components, but it is probably your best bet to keep the salt water away from the rebar if you expect the cracks to remain water tight. Make sure you get the salt water grade or it won't swell.

I generally prefer an internal injection method rather than a surface injection. By that I mean that the sub moves off the crack a few inches and drills into the structure at a 45 degree angle in order to intersect the crack near the middle of the member. Injection resin is then pumped into the holes and forced out the surface of the crack so you know you have good penetration.

Use a good subcontractor familiar with injection methods
if you expect the job to be done right.
Good luck

 

[adina1977]

Hi there! my first post also. Try using a fast setting repair mortar, like Xypex Patch&Plug, can be applied on low tides, preparation of the joint to be treated is not so complex, works on wet surfaces. Check xypex.com. After the enclosure was established, U can grout the remaining of the joint using cement grout with additives at low presure. Leave also some drilled drains to check the filling. good luck!!!