does pool water used to make a concret mix affect strength? 1

[valuwise]

hi. I am from a construction company. We had a situation where the municipality shut the water supply whilst in the midst of mixing concrete on site. we use a mechanical mixer and it is for a floor slab. NHBRC states that the min strength for a floor based slab is 10mpa. We are mixing a 25 mpa strength.
To complete a section we backwashed aprox 40l water from the clients pool and used it for one mix out of a 300 sq metre slab. When i informed the project manager of what we had done, he is concerned that the chlorine in the pool water might destaibilise the concrete. It is unreinforced concrete, with a mesh inlaid.
Can somebody please advise me wheter this is correct?

 

[valuwise]

ps: it is a residential dwelling, ground floor slab with heavy duty 193 mesh.

 

[Ron]

Shouldn't cause an issue. Yes, the chlorine might be a bit higher than for drinking water, but not inordinately so.

Provided you kept all other parameters the same, strength will not be affected.

The chlorine will not "destabilize" the concrete. The only effect you get from higher chlorine (chloride) is a higher potential for rebar corrosion, which doesn't apply in your case. Don't worry about the mesh...it's probably not doing any good anyway!

 

[JAE]

So this was pool water oozing out of the dead guy's body after you encased him in concrete?

I would second the concern over the higher potential for rusting of your mesh. If the mesh is on the ground - bottom of the slab - where it usually ends up - then no problem. If you chair it high you possibly could get some minor spalling.

 

[nuche1973]

I did an exploratory investigation on a structure that had excessive cracking due to the corrsion of the reinforcing, it was not pretty. However, since you are using mesh, I agree with what was posted earlier: if the mesh is on the bottom = no problem. If it was placed correctly = cracking. Since you're affiliated with the construction company that place the concrete: you would be able to determine where the mesh was placed. Having been a field guy myself, and based on what I have seen, I don't think you're going to have any problems.

There are days when I wake up feeling like the dumbest man on the planet, then there are days when I confirm it.

 

[a2mfk]

Funny stuff... so because the wire mesh was likely not placed correctly, the slab will be BETTER OFF?

 

[concretemasonry]

Was the contractor willing to drink a glass of the water as a prelimiary basic test to see if it was potable?

You never know what is in a pool.

Probably O.K., but it makes the contractor think twice, even in a crisis situation.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[racookpe1978]

There is always a "p" in pool water. 8<)

Seriously, your dilution - at "40l water from the clients pool and used it for one mix out of a 300 sq metre slab - is pretty high.

 

[apsix]

"If it was placed correctly = cracking."

I'll assume this is a joke.

 

[valuwise]

hi guys

wow ! who would have thought it would be this easy to get technical advise Errrr you guys not like that doctor i read about who after treating a patient in flight for a suspected cardiac arrest ,(after being called upon by the fligth captain ) sent him a bill! I KID YOU NOT!
But seriously , I really thank you guys who take your time to answer and assist in finding solutions on this site.
AND yes i would drink from this pool-sparkling blue water and NOOOO no one was buried in the concrete