Concrete "Cancer" problems?

RedSnapper


Joined: 12/08/2008
Posts: 540

Message Posted:
29/06/2010 22:15

Is the concrete mix supplied by the builders and developers approved or does it have a standard rating to meet. I was wondering if it has had any technical tests done on it prior to sale or pouring. Are the constituents from a good source or is it sand off the beach? My place had a section of concrete drop or blow off to reveal a rusting reinforcement bar. I sealed it back up with filler and the place is only three years old...

ataturk


Joined: 09/09/2008
Posts: 712

Message Posted:
29/06/2010 23:53

A rusting reinforcement bar means that water has penetrated the concrete meaning it is not water proof.

rowlo



Joined: 12/10/2008
Posts: 4796

Message Posted:
30/06/2010 00:20

most reinforcing bars are rusted before any concrete is poured , the bars are made of steel , not stainless steel ,ie look at a rail track , its all rusted , apart from the top ,where the actuall train runs ,most probable answer is , when the concrete was poured into the shutters , it wasnt vibrated properly , vibrating the concrete brings excess water in the mix to the top and can be skimmed off, if not vibrated water will always find a way in or out , resulting in your problem , most concretes are water proof by the way if they are being used in construction .

keithcaley



Joined: 13/06/2008
Posts: 2521

Message Posted:
30/06/2010 08:45

I spoke to a UK builder about this, and he said that the absolute minimum treatment of steel 'Rebar' should be shot blasting, followed by some 'passivation' treatment to stop the surface rusting

In TRNC, as far as I can see, NO treatment whatsoever is performed - as Rowlo says, the bars are rusty when they go in

Rusting (oxidation) takes place in the presence of water and oxygen, the 'vibrating' process, if carried out PROPERLY will remove air pockets (oxygen) and avoid forming cavities, which would themselves weaken the structure.

There will be enough moisture from rising damp (which is almost 100% guaranteed, given the construction methods here) to react with the steel and any residual oxygen - forming RUST

Rust occupies more space than the original steel, and the consequent expansion is what 'blows' sections of concrete off - concrete which has never properly bonded to the steel itself, due to the rust coating...

This will happen to most of the properties here, in time.

dublinderm


Joined: 26/09/2009
Posts: 538

Message Posted:
30/06/2010 11:26

Could the problem be with the concrete itself?



An unapproved and untested sand could contain PYRITES. This naturally occurring chemical compound would cause the concrete to 'blow' in the manner described.



In the UK & Ireland where most construction will use blocks and mortar, this problem will normally only affect poured floors and foundations. This can be catastrophic to the building with the floor continually pushing outwards and moving the walls with it. There have been a number of high profile cases around the Dublin area lately with many billions of Euro at stake in law suits.



In NC and Turkey of course poured concrete is used for floors, walls and all parts of the building. This means if pyrites are present, the problem could be much bigger indeed.



Sorry if this worries you.



DD

malsancak


Joined: 23/08/2009
Posts: 2874

Message Posted:
30/06/2010 11:35

"Is the concrete mix supplied by the builders and developers approved or does it have a standard rating to meet. I was wondering if it has had any technical tests done on it prior to sale or pouring"

Living down from a place where concrete is produced I used to watch the man sling the ingredients in and fill up the mixing lorries. It was a one man show. Now what do you think the answer to the question is? That's why NO KOCAN, NO MONEY! By the time a kocan is available to be transferred all the problems will show themselves and your surveyor can confirm whether you should go ahead with the purchase. What, no surveyor I hear you say!

Sandcastle


Joined: 16/03/2009
Posts: 215

Message Posted:
30/06/2010 16:36

I am shocked to learn about the steel bars used being treated inthe UK!



Having had several extensions over the years all the steel laid on the floor before conrete has been rusty. Have watched several new builds recently too and so have they!



Or am I missunderstanding something?

Bladerunner


Joined: 10/01/2009
Posts: 204

Message Posted:
30/06/2010 20:23

Steel is always rusty used in construction

Attila


Joined: 27/06/2010
Posts: 23

Message Posted:
30/06/2010 20:46

I remember rusty steel going into construction in the early 70s. The buildings stand as good now as they did then. The rust on the steel used is not very thick. Most of Cyprus is dry so it will be fine. If you are building near a stream, then cover both the inside and the outside of your foundations with tar and you will have no problem

RedSnapper


Joined: 12/08/2008
Posts: 540

Message Posted:
30/06/2010 22:28

5 and 6, this is what was playing on my mind and thankyou all for your input. When i lived in Alicante there was a problem with some concrete batches that resulted in rapid deterioration of several buildings. They started bleeding rust from the edge of the balconies and some of the balconies had been cast wrong and held rainwater and eventually had acrow props put under them. They said the sand was fron a pit that had hit a salt seam. Once on a visit to the defences in Jersey the guide said the Nazis built the fortresses well and rejected much of the sand from the beaches as tests proved it also far too salty, the defences still mostly stand! I wondered if NC had sand pits and where the cement came from. I have seen the big stone quarry over the other side of Buffavento.

Attila


Joined: 27/06/2010
Posts: 23

Message Posted:
30/06/2010 23:31

Unless things have changed recently sand and gravel always came from river beds, never from the beach. As far as I know Cement comes from Besparmak mountains. Before you know it, it will become Birparmak Mountains.