Degradation of the concrete

Service Description

Degradation of the concrete

I always thought that the concrete is a very durable, inexpensive element and despite the latest statistics in view of cement production, the concrete is also ecological. In the years when I was a student, I used to be obsessed with the mechanical strength or resistance in tine of the concrete, but I realized that I did not ask myself the right questions. I did not understand how a 2000-year old concrete can have a better state than a concrete for 50 years.

We feel that 2000 years ago there was made something special to the concrete and that we no longer can do, but things are not like this. The reason I described the thread of thought is that, very often, I find erroneous reasons for degradation of concrete, such as the manufacturer’s fault, the quality of the cement even the quality of the steel.

How the concrete is made?

The concrete, and here we are talking about the concrete with Portland cement has a structure more or less simple. It is composed of cement, sand, pearl (larger sand with size of 2-5 mm), aggregates (stones with sizes between 5 mm and 32 mm) and water. The cement dust is a bunch of cement grains.

These grains have some very small dimensions (between 2 micrometers and 90 micrometers) if you find cement particles larger than they are probably more stuck together.

When the water comes into contact with the cement grains that you can see above,the grains begin to develop thousands of feet and they begin to cling with these feet to everything they find around, including other cement grains.

Therefore, when we leave a bag of cement in the rain,it begins to harden, without the possibility of soaking these feet once they became hard. Now I am going to explain why a concrete to which more water is added is weaker than a concrete to which less water was added.

How to stop the degradation of the concrete

There are three important elements that we must look at when we are talking about the degradation of the concrete like we must consider the exposure to the environment, namely, to which environment the concrete that we are talking about is exposed. It can be a pillar of a pontoon at sea, in salt water or it is a piece of concrete inside a building that is never exposed to a chemical or harsh environment and it is never exposed to the bad weather.

The second element that I want to talk about is the type of concrete. Each concrete has a particular destination and we do not have to replace one type of concrete with other. When we go to the concrete plant to order the concrete we must ask for the right product.

We will use a type of concrete for each type of structure. For foundation we use a type of concrete, for the pillars other type and so on. For the septic tank or for the underground building will be used a very special concrete because the exposure to the environment and also the direction of the mechanical pressures are different.

It can also be used a normal tone but its strength will not be so good and in some cases it may even come to collapsing of the element made of reinforced concrete or plain concrete.

The last important aspect which must be taken into account is the carbonation of the concrete. This aspect is often misunderstood and of course that its effects are misunderstood and maybe even totally ignored.

I feel compelled to explain what the concrete carbonation is and how it can affect a structure. In the process of the manufacture of the cement we have a very high quantity of carbon dioxide emissions.

These carbon dioxide is released into the air and it is considered a pollutant factor with which I totally agree to, but the poured concrete starts an reverse irreversible reaction that it is beginning to combine with the carbon dioxide from the air, in other words there is a chemical process which in time will result the absorption of the carbon dioxide from the air until saturation. The concrete becomes weaker by the day if it is exposed to the air of the atmosphere or any medium which contains the carbon dioxide.

Therefore it is called the carbonation of the concrete, due to the carbon dioxide and or better-said to the carbon of the carbon dioxide.

The carbonation is due to the fact that, in the presence of the carbonate ions (from air), calcium ions (from concrete) form calcium carbonate precipitates. The calcium carbonate is slightly soluble.

In concrete, all the components of calcium are dissolved and form the calcium carbonate, and this calcium carbonate is nothing more than a calcium salt and the best example I can give is the school chalk. The calcium carbonate from concrete never reaches to that purity and neither to that colour of the school chalk because the concrete contains aggregate and sand and they do not subdue to the carbonation. In the atmosphere there is a substantial amount of CO2. Gaseous carbon dioxide can not react directly with the hydrates from the cement paste. It must be such as the carbon dioxide to be dissolved in water and to form the carbonate ions which will react with the calcium ions of the water located in the pores of the concrete mass.

In conclusion, to protect the concrete we must primarily shelter it against the water, especially the salt water. Not only concrete must be protected from the salt water, also the steel from inside or outside of the concrete. We must choose the suitable cement for the final destination of the concrete for a better durability and we have to be careful with how we pour it.

House Refurbishment in London. New Build in London.

Flat Refurbishment in London. New Build in London.

House Extension and Refurbishment in London.

Loft Conversion and Refurbishment in London.

House Renovation and Refurbishment in London.

Office Refurbishment, Shop Refurbishment in London.

Bathroom and Kitchen Refurbishment in London.

Electricians and Plumbers in London. Refurbishment London.

Kitchen Furniture Fitting in London. Cleaning in London.