At all times, people have been building for their own needs, 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 individual parts to disintegrate.
Cement is a material that serves to bind building elements. Its application is great in the modern world. It is used in various fields of human activity, and the fate of all structures depends on it.
History of occurrence
Binders have been used since ancient times. At first it was unbaked clay. Due to its ease of obtaining and prevalence, it was used everywhere. But due to its low viscosity and stability, clay has given way to heat-treated materials.
The first quality building materials were obtained in Egypt. This is lime and gypsum. They had the ability to harden in air, due to which they were widely used. These building materials met the requirements until they began to developnavigation. A new substance was needed that would resist the action of water.
In the 18th century, a material was invented - romancement. This is a product that could harden both in water and in air. But the increased development of industry required better materials and binding properties. In the 19th century, a new binding agent was invented. It is called Portland cement. This material is still used today. With the development of mankind, new requirements are imposed on binders. Each industry uses its own brand with 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 subjected to heat treatment. Then the resulting mass is ground to a powder state. The gray fine mixture is the 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 moisture.
Obtaining cement mortar
In order for the building mass to be of the required quality, the composition must include at least 25% liquid. Changing the ratio in any direction leads to a decrease in the operational properties of the solution, as well as its quality. Setting occurs 60 minutes after adding 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 production of cement
At the moment, many varieties of binder are being produced. Each has its own degree of hardness, which is indicated in the brand.
The main types include:
- Portland cement (silicate). It is the foundation of all kinds. Any brand uses it as a foundation. The difference is the amount and composition of additives that give cement the necessary properties. The powder itself has a gray-green color. When liquid is added, it hardens and hardens. It is not used separately in construction, but goes as a basis for creating composite materials.
- Plastified compound reduces costs, has the ability to remove the mobility of the solution and excellent resistance to 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. It has high activity, setting speed (45 minutes) and hardening (complete occurs after 10 hours). Also a distinctive feature is increased resistance to moisture.
- Acid resistant. Formed by mixing quartzsand and sodium silicate fluoride. To prepare the solution, sodium liquid glass is added. The advantage of such cement is resistance to acids. The disadvantage is a short service life.
- Colored. Formed by mixing Portland cement and pigments. The unusual color is used for decorative work.
Cement production consists of 4 stages:
- Extraction of raw materials and its preparation.
- Roasting and obtaining clinker.
- Grinding to powder.
- Addition of necessary impurities.
Cement production methods
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 cannot participate in the technological process without the use of water. This is chalk with a high moisture content, plastic clay or limestone
- Dry. All stages of cement production are carried out with materials containing a minimum amount of water.
- Combined. Cement production includes both wet and dry methods. The initial cement mixture is made with water, and then it is filtered to the maximum using special equipment.
Concrete
This is a building material that is formed by mixing cement, filler, liquid and necessary additives. In other words, it is a hardened mixture, which includescrushed stone, sand, water and cement. Concrete differs from mortar in its composition and aggregate size.
Classification
Depending on which binder is used, the concrete can be:
- Cement. The most common type in construction. It is based on Portland cement, as well as its varieties.
- Gypsum. Possesses the increased durability. A gypsum stone is taken as a binder.
- Polymer. Based on polyester resins. Suitable for work on horizontal and vertical surfaces. It is an excellent material for decoration and landscaping.
- Silicate. The binder is lime and siliceous substances. By its properties it is very similar to cement and is used in the production of reinforced concrete structures.
Depending on the purpose, concrete can be:
- Regular. Used in industrial and civil construction.
- Special. It has found its application in hydraulic structures, as well as in road, insulation and decorative works.
- Special purpose. It is concrete resistant to chemical, thermal and other specific influences.
Cement cost
Manufacturers produce products packaged by weight. The weight of bags of cement is 35, 42, 26, and also 50 kg. It is best to buy the last option. It is the most suitable for loading and saves on packaging. Depending on the object,which will be repaired, various grades of cement are used, which have their own cost. When paying, each bag of cement is taken into account. Its price is fixed and may fluctuate depending on the requirements of the seller.
Before you start calculating cash costs, you need to decide on one more nuance. Sometimes you can see an ad that shows a price below the standard. You should not fall into such a trap. In such cases, expensive cement is diluted with cheaper one. Winning a few rubles, you will lose the quality of the building material.
Take one 50 kg bag of cement. The price of the M400D0 brand will be 220 rubles. The cost of others may vary, but the average is:
- M400D20 - 240 rubles.
- M500D0 - 280 rubles.
- M500D20 - 240 rubles.
If you need to use only a couple of bags of cement, then it is most profitable to buy them at the nearest building materials store. And if you need a large quantity, then you should contact the manufacturer.
Consumption of cement
Before performing any construction work, the question arises of how much cement is needed and what consistency the mortar should be. Ideally, strength should be maintained and the proportionality of the components should not be exceeded.
When responsible and serious work is ahead, mixing cement and sand "by eye" is unacceptable. If you do not spare the binder, then with large volumes it will cost huge amounts of money.
So how much cement is needed for the work being done? Building codes (SNiP) will help answer. It takes into account all the factors that affect the production of the mixture. Focusing on the brand of the composition and taking into account all factors, you can clearly find out the cement consumption rate per 1 cubic meter of mortar.
The main feature that many developers do not take into account is that the cement is distributed in the voids between the sand particles. Remember that the composition has activity. If stored indoors for a long time, a 500 grade will become a 400 after a few months. Therefore, you should always ask for a certificate with the date of issue when buying.
