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Hungarian Cement Concrete and Lime Association
Magyar Cement-, Beton- és Mészipari Szövetség

Facts and curiosities about concrete production

Facts and curiosities about concrete production

 

Did you know that ...

...nowadays tconcrete is he most commonly used material after water and dirt, and also the most important building material?

Basically its spread was made possible by the invention and the mass production of the portland cement. The word "portland" comes from the fact that it was developed in England in the middle of the 18th century and its color resembles the rocks on the island of Portland.

...concrete used to be mixed by hand?

Concrete mixing was a demanding physical exercise done by hand, not directly on the floor but on a mixing plate made of a solid material. First, the materials were blended dry three times, then twice more while adding water. For dry mixing, the sandy gravel was measured in a 1 m x 1 m x 1 m sized wooden pile, then a hollow was formed on the top of the pile for the cement. Dry mixing was carried out by overlapping the pile three times.

The wet mixing was done by folding the pile twice more while adding the water from watering pots. The consistency of this mixed concrete was barely earth-moist.

...nowadays concrete misxing is done by specialized entrepreneurs?

High-quality concrete is no longer mixed on-site, but is ordered from companies specialized to concrete mixing. Such concrete is called transportable concrete and can be ordered in transport concrete plants. These plants have everythning required for modern machine mixing that thus theay they have replaced the heavy physical work.

...concrete used to be compressed manually?

Working with concrete was also difficult physical job, as it was made by hand. Earth-moist concrete was moved and poured into the formwork with a wheelbarrow and then compacted with 20-30 cm layers of wooden trunks.

...nowadays working with concrete is mechanized?

Concrete is transported by mixer cars to the building site where pumps are used to move it to the formwork and then it is compressed with vibrators. The surface is being smoothed by vibrating tools, and after-treatment admixtures protect the concrete from drying out.

As a result of the latest development results, the so-called Self Compacting Concrete (SSC) is now used world wide, without any requirement of vibrators.

...the consolidation of concrete lasts for about a month, so its after-treatment is really important?

Instead of watering of concrete, there are more advanced after-treatment admixtures available, which can be applied to the surface of the concrete, creating a thin vapor-barrier film. These materials prevent the evaporation of water in the concrete and provide better results at the same time as the effects of post-treatment admixtures are consistent in time.

...nowadays concrete is not just a mixture of sandy gravel, cement and water?

Concrete attributes can now be set as targeted by using various additives and admixtures. These materials can be mineral powders (limestone, fly ash, granulated slags, silica etc.), various fibers (micro and macro plastic fibers, steel fibers, glass fibers, etc.) and various pigments (colorants).

The most important admixtures are plasticizers and superplasticizers, but air-entrainers, retarders, accelerators, stabilizers and sealing admixtures are also used. With PCE-based granulators, we can produce cast-ready concrete from a slightly earth-moist state without adding additional water.

...we can change the properties of concrete into many directions?

Nowadays we can produce a concrete that is not washed away in running water, so we can work with it under water as well. In case of road constructions, frost and melting-resistant concrete is necessary, which can be produced with the combined with the use of plasticizing and air-entraining admixtures. The construction of tunnels is supported by the so-called shotcrete which is being shot onto the surface with a nozzle. During the summer we use retarding admixtures, and anti-freeze admixtures at WInters. We can also produce floating or  light-structured, watertight concretes with good thermal insulation. The energy industry can also utilize the special properties of concrete, whether it be radiation-protection or heating in the winter, and summer-cooling concrete.

... the history of reinforced concrete started with a boat and a flowerpot?

Concrete is similar to stone and therefore fragile. In order to make it strong and tough iron or steel inserts are inserted. The alkaline medium of concrete prevents them from cossosion.

It was a French farmer named Joseph-Louis Lambot who used the solution called ferro cement for the first time when he applied cement mortar to a chicken crawl net. The boat built with this method was introduced at the World Expo in Paris in 1855. Joseph Monier was a French gardener, who at the 1867 World Expo in Paris exhibited a flowerpot invention. These became patented products for the construction industry only later.

... reinforced iron was introduced to Hungary by Szilárd Zielinszki?

Construction engineer Szilárd Zielinski worked in Paris at the Eiffel corporation. He opened an engineering office in Budapest in 1889, working mainly with iron structures. In 1897 he was appointed as professor the Budapest University Of Technology.  After learning about the patentof French engineer François Hennebique, he was the first who called for and later used reinforced concrete structures in the country.

...concrete is recyclable and regulations are helping this in Hungary?

To ensure sustainable development, it is very important to change our way of thinking about debris of dismantled buildings and structures, and to treat this not as waste but as industrial raw materials.

Since 2005, the Technical Guidelines (BV-MI 01: 2005 (H)) is helping application issued by the Hungarian Federation of fib (International Concrete Association), with the assistance of renowned contributors.

The issue is also addressed by European legislation, 2008/98 / EC was published in 2008. This specifies that waste that is properly recycled is no longer a waste but an industrial raw material.

In the European standardization process, the latest concrete standard (EN 206: 2013) was issued in 2013, which already included concrete recycling regulations. The standard was issued in Hungarian (MSZ 4798: 2016) in 2016, so the technical background of concrete recycling is already available.

...the possibilities of using construction and demolition waste are wide-ranging?

Reclaimed mines, rehabilitated areas, temporary streets in forests, rural or temporary construction sites can all be built by using construction and demolition waste, but they can also be used as a filling material for filling in canals, walls, walking paths, drainage, or sport grounds.

...how a plan for recycling concrete debris looks like?

First, the concrete debris needs to be crushed so that it can be easier handled. In the next step, the debris is divided into fractions and stored separately. After this it is necessary to examine the fractions in the same way as for gravel or crushed stone. Subsequently, it is possible to begin the preparation of the concrete technology plans depending on the installation.

...it is possible to return the concrete without waste?

Solutions are already being used to increase the amount  of the returned concrete by breaking it washing it apart and then reapplying the resulting additive to make concrete again. Washing water can be re-used as well. This method is considered to be advantageous as it does not burden sewers or the environment and 100% of the returned concrete is used as like the discarded concrete coming from the mixing drum when it is flushed.

...that the handling of  construction and demolition wastes happens in several steps?

The proper treatment of construction and demolition wastes is carried out as follows: temporarily storage in a temporary establishment separated by type and then usage in way that helps avoiding significant transport costs. Each type is delivered to a suitable processing plant. The concrete debris is crushed, then sorted by fractions. This is followed by examination and then final usage taking into account their properties.

...that many countries in Europe have achieved significant results in the recycling of construction and demolition waste?

Countries with a leading example of a self-sustaining economy are Germany, the United Kingdom, the Netherlands, Belgium and France. The yearly use of recycled materials in these countries in 2012 exceeded 10 million tons. According to the National Bureau of Statistics, Spain has reduced the amount of construction and demolition waste by almost half (from 42 million to 27 million) between 2007 and 2012. It should be noted, however, that this value is mainly due to the fact that an amendment that entered into force in 2011 excluding hazardous wastes and naturally occurring substances.

... that sustainability was a key aspect of the construction of the Groupama Arena in Budapest?

The contractor has created a waste management plan for the construction site to recycle or reuse the waste resulting from the demolition process as much as possible (more than 75% of it). The filling of all outdoor cladding and more than a quarter of the substrate flooring is made of 100% recycled concrete.

 

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