wall moisture problem that explodes you know why?

[sen-no-sen]

For concrete irons: normally the fittings do not rust (or no longer) in healthy concrete, when they rust, it is only when there are microcracks, which happens when the concrete is of poor quality in particularly if it is exposed to salt water: it then seeps into the irons and causes it to rust ...

Absolutely correct, further rusting the metal expands which increases the size of the cracks ... a real vicious circle ...

To come back to the humidity problem it is sometimes necessary to make drains to channel excess water ... from work in perspective.

[hic]

Who hasn't had humidity problems ??
In the photos it reminds me of memories !!

I do not understand Spanish, apart from guessing, but [b] clearly, it is a promotional site to sell devices and wall treatments against humidity, SPAM type, Spanish!

dedeleco

why ventilate a wall,
if we have not dealt with the problem of water that is outside the wall.

the bursting
it's a mechanical problem due to a sequence
wetting and drying,
- contraction dilation

[Obamot]

For concrete irons: normally the fittings do not rust (or no longer) in healthy concrete, when they rust, it is only when there are microcracks, which happens when the concrete is of poor quality in particularly if it is exposed to salt water: it then seeps into the irons and causes it to rust ...

Exactly, further rusting the metal expands which increases the size of the cracks ... a real vicious circle ....

... no, not at all!

oiseautempete should have read the links he posted. Irons in concrete are VOLUNTARILY already rusty, BEFORE pouring concrete. Reason why they are exposed to bad weather and to the open air on building sites. Otherwise we would not put them in the open air and they would be delivered with already a layer of anticorrosion protection "factory" ... See they would be in stainless steel!
We just need the reinforcements to "hang" as well as possible to the concrete so that they can do their job as well as possible. A stainless steel would be smooth and would float in the concrete ... And there would be no optimal transmission of the forces in the elements supposed to absorb them and distribute them statically ...

"It should be noted that upon contact with the initial rust, the hydration of the cement is disturbed: a transition zone is locally formed, beyond which the concrete has more homogeneous characteristics" [...] Concrete mixing water therefore allows products to be formed around the steel, that protect it by passivation. More precisely, under the rust, a frame is covered with a thin protective layer of white products, based on ferrite and calcium hydroxide.

Thus, the chemistry of concrete is so made that one takes advantage of "natural chemical reactions" to take advantage of them in order to passivate the rust in the process, while improving adhesion (and this, in order to these allies instead of being a disadvantage!)

It should be noted that in a "healthy" concrete there is no progression of corrosion (or in totally negligible ratios) otherwise it should be feared that all the reinforced concrete buildings are a danger for the inhabitants ... This is obviously absolutely not the case.

[dedeleco]

Completely agree with Obamot, the rusted iron on the surface adheres better to the concrete, (the paint too), and the alkaline concrete blocks any additional rust, otherwise the bridges would fall apart quickly!
But the concrete on the surface too leached by water becomes acid, cracks and the irons then rust by bursting the cement, especially on the surface, if they are too close to the surface (less than 1 to 2 cm), defect classic.

The subject is not the irons that rust, but the water in damp walls that are often old and destroy themselves, as if they exploded with gases coming out of the water according to eng-avenir.fr !!
In my opinion the dissolution of the salts (like calcite) of the wall followed by migration with the water in the wall, then its evaporation on the surface or in their drying system (aeration and electro-migration with low tension) dapply crystals of these salts which, when they solidify, have the force to push the walls of the wall which block them and make them crack, especially if the wall covering is not very solid (plaster, lime).
It should be noted that the humidity in the walls by pure capillarity should not go up by more than 20cm, theoretically, because the capillary force with fine pores of the micron does not allow more!
We see this on a concrete block in the water!
However the water rises much more in reality !!
We see that it goes up much more (meters) especially in poorly ventilated environment, like a cellar.
The cause is not capillarity, nor water flowing by gravity (poor drainage), but repeated evaporation and condensation in the porous wall linked to small variations in temperature and humidity in the wall, between the top and the bottom and the outside and the inside, (like the rain which conducts the water on the mountains) which can go up high as long as the wall is not ventilated enough to let out this water vapor (cellar). The dissolved salts with migrate and deteriorate the wall, especially during their drying!
In early winter, the earth warmer than the wall which cools with the cold outside air, causes the evaporation of the water from the earth and its condensation in the colder porous wall much higher, making it very humid, even without external humidity, other than soil.
This phenomenon can even give the impression that a drainage is falsely insufficient !! The solution is a waterproof film under walls and slabs, often forgotten in old houses (or never put because plastic did not exist more than 80 years ago !!).

The permanent and strong drying with these devices, leads to a perpetual migration of the salts with the water which dries, and their deposit which deteriorates much faster the wall on the surface as the photos show.
In my opinion it is almost inevitable to accelerate these deposits with these drying systems, especially since they dry well !!

[eng-avenir.fr]

To revive the debate in 1st bravo for the explanations and this link on concrete scrap. Indeed the scrap is systematically rusted before being coated with concrete.
What I found that any element that is coated with concrete there is always a tiny space, which often creates cracks, which is logical because they do not have the same power. If we take a concrete block wall, we install an integrated concrete post there we will have a micro crack over time, that's why I will suggest to architects to lay a fiber on all concrete junctions, because over time the weak point dissociates, and we meet cracks which feeds the rainwater inlets.
So we find humidity, and that's the cycle.
I see that dedeleco toasted me is good, because we are joining our points of view

[eng-avenir.fr]

Theory and logic are two things that are very different from each other, compared to what dedeleco says.
To talk about something that I know very well, if you eliminate humidity through the devices that dry you systematically eliminate the rise in salt, because experience with confirmation. I installed the appliances 1 year ago in a renovated house in Spain because the client had, according to its architect, made decorative partitions on 1 m high, it took 2 years to see the humidity and the salts this once again, so the solution was the devices, and now everything is painted the humidity in the wall is around 60%. I speak as a professional in the field and not as certain who does not know how to install a drill bit and make a hole.
I will ask the client to send me pictures

[Obamot]

Well, at the same time without theory and without logic (which must necessarily meet with practice) a "Professional in the field" should be able to answer the basic question !?

It seems that some people speak of frameworks like holes in Emmental cheese ...! And then in a castle where are the BA walls?

You must first know that in the building, the main danger comes from what men do! It is one of the most accident-prone workplaces, both in severity and frequency ...

Reason why it is very important not to improvise, or say anything when trying to make a link between:

Probable cause / s -> in problems intrinsic to construction defects, potentially capable of endangering its structure, such as:
- possible cancer of the concrete and its degradation.
- possible crack / s updating the reinforcements and the concrete structure itself and causing, in rare cases, an acceleration of its degradation and weakening by corrosion of the reinforcements.

And effects:
- real danger to the structure.

If this scenario is proven, it would be necessary to know to what extent the structure is reached and which part is in danger and "to be treated" without delay ... For that it is necessary to make resistance measurements using a dynamometer. This is the b_a ba.

But before that, we should perhaps start wondering why we use reinforced concrete in construction and why we place reinforcements and where exactly?

1) Concrete is used first of all because it resists extraordinarily well and by nature to vertical loads, that is to say "compression" (therefore no danger of problem with reinforcements in the walls, they are absolutely not the ones who "do the job").

2) the reinforcements are there - in particular - to distribute the static loads and to absorb / contain the tensile / extension forces (precisely the weak point of the concrete). And this mainly in the slabs towards the wall supports and in their center to avoid "buckling" and of course the foundation footings (I deliberately leave aside civil engineering works - public works - bridges and roadways, which are specific cases).

Morality: the danger of intrinsic defects in BA are almost zero (such as cracks in the walls due to the very nature of concrete, and not to exogenous causes which should be resolved by proper drainage). As long as you don't have cracks that appear in the center of the slabs (ceiling side) or towards the wall supports (floor side) ... there is not much to worry about for the structure of the building (again these areas must be directly accessible / visible on the raw cement side ...). The best remaining measurements at places and following the best practices, do at densito ... (There are also other techniques depending on the case, such as infrared photos, laser ... etc). On the other hand, a deterioration of the cement / concrete in the walls is a possible indication of a bad mixture or poorly perverted concrete. And then we have to examine the problem to see if other parts of the construction are not weakened because of this. This is not a problem to be taken lightly.

Subject to the measurements made on the construction to ensure its resistance, all this tells me that in the case of load-bearing walls, in no case a problem of embrittlement of the reinforcement coating would be at the center of a problem presenting a danger (and if it was a question of the slabs, it is a very rare case since being out of contact with any direct humidity, ditto for the foundations which are always oversized and well protected from frost and humidity by the drains which are around).

So there is a priori pawdé pwoblem ...

Ah, and participate in a forum even consult "pros" to ask questions, does not make us "Professionals". A "pro" is either trained by "companionship" in the field by "confirmed companions" (if it exists in BA I doubt ...) or by training leading to a diploma. This does not detract from the merits of those who make a living in the building thanks to their experience. Safety first: you just have to know what your areas of expertise are and be wise enough to stick to them ... Continuing professional training is also a good way to adapt your knowledge according to the evolution of techniques . Have a good day!

[eng-avenir.fr]

Concrete is not 100 years old, http://fr.wikipedia.org/wiki/Histoire_du_b%C3%A9ton
and what some say seems to me founded.
Not so long ago we were talking about testing the fiber to replace the reinforcements, or is this process?
Note that for bridges they are equipped with optical fiber because engineers doubt the reliability over time of concrete.
I saw that on a TV show Les Constructions de l'Estrême.
To return to the binder in the old castles it was a mixture of clay which assembled the stones, therefore no waterproofing, and impossibility to create an external drainage, but if you think about it, I look at the castles which are on high points, they have natural drainage yet we find moisture by capillarity, how do you explain that?
I imagine a big piece of sugar, which by a natural need is filled with water without having regulation, because the humidity we need but with a moderate rate 50/60% no more if not soaked gradually , and the materials lose their power and at least we unwind and there too we find weakness.
Knowing that we humans are on the same level.

Our planet is going to be more and more destabilized, concerning the building materials, I sound the alarm bell and I ask that we do not do the same stupidity as with asbestos.
Let’s not be satisfied with a concrete product that we think is irreproachable, and if we made a serious mistake!
If tomorrow I built a house, it would be of wood and glass, its platform in pozoulane now its support,
I will reflect .......... [/ Url]

[Obamot]

Not so long ago we were talking about testing the fiber to replace the reinforcements, or is this process?
Note that for bridges they are equipped with optical fiber because engineers doubt the reliability over time of concrete.

... I still said that I was not talking about civil engineering works like bridges and roads. It is a discipline in its own right, although related to my training, I do not know it thoroughly ... A priori there are also vibrational phenomena depending on the scope ...

I saw that on a TV show Les Constructions de l'Estrême.

We have no perspective, what proves that it will last longer? Now other materials can absorb the stresses to replace steels, but at what price and with what reliability? You can also create special mixes. But what about professional training on construction sites. The day this happens, the question will have to be reviewed ... Why not!

To return to the binder in the old castles it was a mixture of clay which assembled the stones, therefore no sealing, and unable to create exterior drainage, but if you think about it, I look at the castles which are on high points, they have a natural drainage yet we find humidity by capillarity, how do you explain that? I imagine a big piece of sugar, which by a natural need is filled with water without having regulation, because the humidity we need but with a moderate rate 50/60%

Mouarf ... Drainage was popularized by a certain Henry French in the XNUMXth century who would have been a farmer, but in the Middle Ages we already knew about drainage, since tile factories already produced porous pipes for this use. Besides, we even drained the vineyards at that time, still the agricultural world it seems ... Terracotta walls we knew how to do in the time of ancient Egypt where we were already draining the roads intended to receive heavy charges ... to allow the construction of the pyramids ... As well as around the granaries, to prevent it from germinating ...

There is no drainage without a drain. And there are several things in a drainage apart from the pipes: starting with the nature of the ground (that's true) but there are also aggregates of different particle size, up to sandy soils ...

I imagine a big piece of sugar, which by a natural need is filled with water without having regulation, because the humidity we need but with a moderate rate 50/60% no more if not soaked gradually , and the materials lose their power and at least we unwind and there too we find weakness.

Mmm no ... We did not build a castle in a year ... as we manage to do today in BA

So they had plenty of time to find out what type of soil they were going to install the construction in ... They quickly saw if it was soaked with water ...

Knowing that we humans are on the same level.

Our planet is going to be more and more destabilized, concerning the building materials, I sound the alarm bell and I ask that we do not do the same stupidity as with asbestos.
Do not be satisfied with a product the concrete that you think is flawless

Pfff ... Concrete is the oldest building material on the planet. Nature has used it itself since time immemorial, even before man appeared. Sandstone is a "natural concrete", made up of a mixture of sedimentary rocks and aggregation of sand grains ... All produced by the ebb of the oceans ...

So there is no more "natural" and "sustainable" than concrete, somewhere ...

[dedeleco]

I look at the castles which are on high points, they have a natural drainage yet we find humidity by capillarity, how do you explain that?

Humidity is found everywhere, even at the top of Everest or Mont Blanc, at the top of castles on rocky peaks, yet perfectly drained !! Yes !!
but not by capillarity, (it only makes the water rise by 20cm for pores around the micron, like for a breeze block immersed in water or a blotter in ink !!)
Plants, the same, manage to have a little water in their roots and live near good drainage ditches after several months of drought !!

The mechanism is that of repeated evaporations and condensations inside the earth slightly porous to gases (cracks) and due to small temperature differences in a soil without ventilation which would evacuate this humidity to 100% more or less a little.
Humidity can thus rise tens of meters above the water table.
The basic mechanism is the same as that which rains at the top of the mountains, by evaporation of water from the oceans and condensing in raining clouds, for differences in temperature and pressure!
The only difference is that it occurs underground with the differences in temperature, day, night, summer, winter, varying with the depth underground, and the concentration of dissolved earth salts, even at low concentrations.

I wrote it:

The cause is not capillarity, nor water flowing by gravity (poor drainage), but repeated evaporations and condensation in the porous wall linked to small variations in temperature and humidity in the wall, between the up and down and outside and inside, (like the rain that conducts water over the mountains) which can go up as long as the wall is not ventilated enough to let out this water vapor (cellar ) ...

In early winter, the earth warmer than the wall which cools with the cold outside air, causes the evaporation of the water from the earth and its condensation in the colder porous wall much higher, making it very humid, even without external humidity, other than soil.
This phenomenon can even give the impression that a drainage is falsely insufficient !! .

In fact the earth is like a distillation column with repeated condensing evaporations !!
http://fr.wikipedia.org/wiki/Distillation

The process uses the difference in volatility (ability to evaporate according to temperature) between the constituents in order to separate them: the most volatile has a lower boiling temperature than the least volatile, etc.

The salts of the dissolved earth more or less change the volatility of the water, partially fixing it and letting it evaporate elsewhere.
http://wwwens.uqac.ca/chimie/Thermochim ... HAP_8.html

See this thesis among others:
http://ethesis.inp-toulouse.fr/archive/ ... ghaier.pdf
and study of salt transfer, which occurs as long as the repeated evaporations and condensations are repeated below the drying points, which protect above all what is above, very dry !!