Cement is ... Composition, characteristics, types and manufacture of cement

At all times, people for their needs were engaged in construction, starting with ancient buildings and ending with modern technical masterpieces. In order for buildings and other structures to remain reliable, a substance is needed that will not allow the constituent parts to disintegrate separately.

Cement - a material that serves for a bunch of building elements. Its application is great in the modern world. It is used in various spheres of human activity, and the fate of all structures depends on it.

History of occurrence

Knitting materials began to be used in ancient times. At first it was unbaked clay. Due to its simplicity of reception and prevalence, it was applied everywhere. But because of weak viscosity and stability, clay gave way to heat-treated materials.

In Egypt, the first quality building materials were obtained. This is lime and gypsum. They had the ability to harden in the air, so they were widely used. These building materials met the requirements until navigation began to develop. A new substance has become necessary, which would resist the action of water.

In the XVIII century was invented material - romantsement. It is a product that can harden in both water and air. But the increased development of the industry required more high-quality materials and astringent properties. In the XIX century, a new substance for binding was invented. It was called portland cement. This material is used to this day. With the development of mankind, new requirements are imposed on astringents . For each industry uses its own brand, which has the necessary properties.

Composition

Cement is the main component of the construction industry. The main components in it are clay and limestone. They are mixed together and heat treated. Then the resulting mass is ground to a powder. A gray, fine mixture is cement. If it is mixed with water, then the mass will eventually become like a stone. The main feature is the ability to harden in air and resist the effects of moisture.

Preparation of cement slurry

To ensure that the building mass is of the required quality, the composition should include at least 25% of the liquid. Changing the ratio in any direction leads to a decrease in the performance properties of the solution, as well as its quality. Seizure occurs 60 minutes after the addition of water, and after 12 hours the mixture loses its elasticity. It all depends on the air temperature. The higher it is, the faster the mass will harden.

To obtain a solution, sand is needed, in which cement is added. The resulting mixture is thoroughly mixed and filled with water. Depending on the work performed, the solution can be ordinary or enriched. The first consists of proportions 1: 5, and the second - 1: 2.

Types and manufacture of cement

At the moment, many varieties of binder are made. Each has its own degree of hardness, which is indicated in the stamp.

The main types are:

• Portland cement (silicate). It is the founder of all kinds. Any brand uses it as a foundation. The difference is the amount and composition of additives that give the cement the necessary properties. The powder itself has a gray-green color. When adding liquid, it hardens and becomes firm. It is not used separately in construction, but is used as a basis for creating composite materials.
• The plasticized composition reduces costs, has the ability to remove the mobility of the solution and perfectly resists the effects of cold.
• Slag cement. This is the result of crushing clinker, blast furnace slag and adding active additives. Used in construction for the preparation of mortars and concrete.

• Aluminous. Has a high activity, setting speed (45 minutes) and solidification (complete occurs after 10 hours). Also, a distinctive feature is increased resistance to moisture.
• Acid-resistant. It is formed as a result of mixing quartz sand and sodium silicofluoride. To prepare the solution, sodium liquid glass is added . The advantage of this cement is its resistance to acids. The disadvantage is a short service life.
• Color. Formed by mixing portland cement and pigment substances. Unusual color is used for decorative works.

The production of cement consists of 4 stages:

• Extraction of raw materials and its preparation.
• Firing and obtaining clinker.
• Grind to a powder.
• Addition of necessary impurities.

Methods of production of cement

There are 3 methods that depend on the preparation of raw materials for heat treatment:

• Wet. With this method, the required amount of liquid is present at all stages of cement production. It is used in situations where the main components can not participate in the process without the use of water. It is a chalk with a high content of moisture, plastic clay or limestone.

• Dry. All stages of the manufacture of cement pass with materials containing a minimum amount of water.
• Combined. The production of cement includes both wet and dry methods. The original cement mixture is made with water, and then it is filtered as much as possible using special equipment.

Concrete

This is a building material that is formed by mixing cement, filler, liquid and the necessary additives. In other words, it is a solidified mixture, which includes gravel, sand, water and cement. The concrete differs from the mortar with its composition and filler dimensions.

Classification

Depending on what kind of bonding material is used, the concrete can be:

• Cement. The most common form in construction. The basis is Portland cement, as well as its varieties.
• Gypsum. Has increased strength. As a binder material is taken plaster stone.
• Polymeric. The basis is polyester resins. Suitable for work on horizontal and vertical surfaces. It is an excellent material for finishing and landscape works.
• Silicate. The binding material is lime and siliceous substances. In its properties it is very similar to cement and is used in the manufacture of reinforced concrete structures.

Depending on the purpose, the concrete can be:

• Normal. It is used in industrial and civil construction.
• Special. Found its application in hydraulic engineering structures, as well as road, insulation and decorative works.
• Special purpose. It is concrete, resistant to chemical, thermal and other specific effects.

The cost of cement

Manufacturers produce products packaged by weight. Weight of bags of cement is 35, 42, 26, and 50 kg. It is most profitable to buy the last option. It is most suitable for loading and allows you to save on packaging. Depending on the object on which repairs will be carried out, cement of different brands is used, having its own cost. When paying for each bag of cement is taken into account. Its price is fixed and can fluctuate depending on the seller's requirements.

Before you start to calculate the monetary costs, you need to decide on one more nuance. Sometimes you can see an ad, which shows the cost below the standard. Do not fall for such a trap. In such cases expensive cement is diluted with cheaper. Winning several rubles, you will lose the quality of the building material.

Take one 50 kilogram bag of cement. The price of M400D0 will be 220 rubles. The cost of others can vary, but on average this is:

• M400D20 - 240 rubles.
• M500D0 - 280 rubles.
• M500D20 - 240 rubles.

If you want to use only a couple of bags of cement, then it is most profitable to buy them in the nearest store for the sale of building materials. And if you need a large amount, you should contact the manufacturer.

Cement consumption

Before performing any construction work, the question arises as to how much cement is needed and what consistency the solution should be. Ideally, strength should be maintained and the proportionality of the components should not be exceeded.

When responsible and serious work is to be done, mixing cement and sand "by eye" is unacceptable. If you do not spare the binding material, then at high volumes it will cost a huge amount of money.

So how much cement is needed for the work? The construction norms (SNiP) will help to answer. Here, all the factors affecting the production of the mixture are taken into account. Focusing on the brand of the composition and considering all the factors, you can clearly learn the rate of cement consumption per 1 cubic meter of solution.

The main feature that many developers do not take into account is that cement is distributed in voids between sand particles. Remember that the composition has activity. With long-term storage in the room, brand 500 in a few months will be 400. Therefore, when buying, you should always ask for a certificate with a release date.