What makes cement: composition, proportion, characteristics, types, how to make yourself

Concrete - the foundation of any building structure. Almost every building, located around us, one way or another, was built using cement mortar. Building concreteCreated on the basis of cement for decades withstands multi-ton load, practically without experiencing a negative impact from the outside. Why for many decades was the cement is the most popular building material? Editorial HouseChief.ru try to uncover the most secret formula through which we finally We learn from what it was doing cement and why he is considered one of the most durable materials around world.

Regulations

Cement, like any other commodity, must go through a certification process. There are several guests and building codes, which are to some extent related to the quality of the cement mixture. We list the main ones:

1. GOST 31108-2003 "Cements. Specifications. "
2. GOST 30515-97 "Cements. General technical conditions ".
3. GOST 10178-85 "Portland cement and slag. Specifications. "

Here you can find links to additional acts and regulations, which may be useful in-depth study of the issue.

The chemical composition of cement

By itself, the cement - nothing, as a powder. It is created on the basis of clinker. The composition may contain different ingredients and excipients.

Interesting fact! When the grout hardens, its density not inferior to stone densities. To create the artificial stone used cement, too.

Heating occurs before indicators + 1450 ° C. The structure of the natural components is changing, and it turns out the new substance - clinker. Thereafter, the resulting material is combined with gypsum and milled, resulting in turns familiar to all cementitious powder.

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Mikhail Starostin

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"Here it is the chemical composition of the finished cement powder: 67% of calcium oxide (CaO), 22% silica (SiO2), 5% aluminum oxide (Al2O3), 3% iron oxide (Fe2O3), 3% other constituents."

Main characteristics

Cement main technical characteristic remains its brand, this is the marking to say about such an important characteristic as an indication of the maximum load in kg.

The numbers indicate the maximum rate loadsWhich can withstand the frozen cement. It is called an indicator of the compressive strength. In practice, this value indicates the weight that can withstand the material and it does not collapse. For example, using cement M200 load which can withstand cm³ 1 is 200 kg.

Interestingly, the test cement is allowed only after complete drying, which occurs after 28 days and not earlier. After this test the cement sample is placed in a press and squeezed. The pressure at which it began to break down, and it is a mark. Moreover, the procedure is repeated six times, and then from 4 best indicators calculated arithmetic mean. This is measured in MPa and kg / cm².

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Mikhail Starostin

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"The letter" D "refers to the data of the special additives used in cement. For example, D10 says that the dry mixture was added 10% additives. Due to they are able to give the final structure more strength and frost resistance. "

Cement types for field use

As we have noticed before, the quality of the cement mixture affect different additives. It affects their scope and strength. For example, the samples used in hardy construction of houses and constructions in areas with severe climate, in seismic zones additives are used, the parameters which increase stickiness of the mixture. They, in turn, do not give concrete structures crack.

Interesting fact! In the process of freezing the water contained in the concrete expands and begins to destroy its inside. However, modern technologies allow to improve the degree of hardiness, cement powder in the mineral supplements are made, for example, woody neutralized pitch. They create a strong shell around the water particles.

In most cases, the cement mixture are added various additives, the percentage of which may reach 10 and 20%. For the construction of monolithic buildings use cement brand M500. Such a material higher rate of hardening and strength. Usually it is from such a cement mixture erect overlap and supporting structures.

What makes cement

Typically, cement production plants are being built where there are deposits of limestone and other rocks, which are used in the creation of clinker. The main natural elements of which make cement, are:

• carbonate minerals such as: rock crystal amenable calcination;
• clay materials, as well as the rocks of sedimentary nature of mineral origin. The raw material has a viscosity, is applied at a dry production method.

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When choosing a cement look for indicators such as the fineness. The finer the powder structure, the stronger will be the mixture. "

carbonate rocks

What carbonate rock used in cement production:

• a piece of chalk (Limestone variation) - easily subjected to processing, cheap and versatile;
• marlOr marly limestone. Plus these rocks is that they contain a sufficient amount of moisture, in addition, they contain the necessary pieces of clay;
• limestone raw materials, Shell, characterized by the absence of silicon inclusions. Breed has a pore structure is easily destroyed under the influence of compressive forces;
• carbonate rocks. They are characterized by valuable physical properties.

clay raw materials

To the clay rocks are:

• clayContaining mineral inclusions, swelling when water is added;
• loams - diluted sand fraction;
• shales - strong clay rocks;
• loess - inelastic porous rock with the inclusion of quartz.

corrective additives

Additionally minerals, special plasticizers are used in the production of cement. The most frequently used additive-based minerals containing fluorspar and apatites.

Important! The basis of any binder is cement clinker and 15-20% of mineral additives. That depends on him the fortress of the future of cement and its other characteristics.

How to make cement production

As in any production create a cement mixture occurs strictly on special technological scheme. And consists of the following steps:

1. Creation of clinker. His recall, made of limestone and clay as a percentage of 75 × 25. The mixture was placed in an oven at a temperature of approximately + 1500 ° C occurs composition change. A viscous substance, securely fastening all the granules of clinker. The resulting clinker is cooled in a special refrigeration units.
2. The granules are then further crushed. Grinding takes place in special grinding mills. They are placed there with drums steel balls.
3. To the crushed clinker also add tonkodisperstny gypsum and mineral supplements.

There are different techniques of preparation of raw material. Consider the main ones.

wet method

Wet binding technology involves the addition of water in step grinding, in this case lime is used instead of chalk. This creates a special blend, or blend, which is then re-dried in a furnace, turning into a kind of a glass ball, which is then crushed again. When this cement production cost significantly increases. Believe that the mixture prepared in this way is more robust.

dry method

Dry process - a cheaper option. In this case, in practice, combined two process steps - drying and grinding the mixture. The ball mill guide hot gases, which are carried out dry. Here, the output is the finished powder.

combined techniques

Combined embodiment combines the features of both wet and dry process. Technologies differ in each enterprise. Sometimes, instead of a wet process, permitting the clinker hydration to 50%, using embodiments with decreasing moisture content at this stage, to 18 or 20%. The second method involves the preparation of a dry mixture, followed by moistening of 14%, granulating, final annealing. It all depends on the tasks facing technologies.

How to make cement at home

Despite the apparent complexity of the production of cement and make it their own hands at home possible. It is clear that this option will not be as technologically advanced as the plant and burn it at the required temperature and will not work. However, some tricks we can tell you. Consider one of the most popular recipes for creating the composition, it is suitable for sealing cracks and Tightening. To create a mixture of water, we need lime, stone ash and plain water.

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"Equal proportions of the ingredients are taken when creating the mix."

Another popular recipe is created using a conventional glycerin. To do this, take a lead glot its ground to fine state stoving can be a conventional metal baking. In such a "clinker" is added glycerol. This cement is more like a shoplifter analog.

Interesting fact! One of the most controversial ways to create cement based on blood came up in China. As one of the ingredients used pig blood. Despite the fact that the moral side of the issue raises ethical controversy. It is said that the fortress a cement stone is not inferior.

How to prepare the grout

The usual mortar cement and sand is added in proportions 1: 3. On request, it can be to fall asleep plasticizers.

Soap and detergents added to the mixture can not be, they eventually washed out of the composition and can give rise to cracks. For small cracks alignment suitable preparation of the cement paste without the use of sand. However, as the binder can be any available material. Even the egg yolk. The mixture with the added very little water. Such a mass of leaves virtually no rough edges for the final finishing of joints and unevenness.

From what and how to make cement - video

In order to secure this information, look at the training video, from which make cement.

And if you have questions to the author, ask them in the comments.