What is cement?

Cement is a fundamental material in construction, known for its ability to bind and harden other materials. It"s a key ingredient in concrete, which is used to build everything from sidewalks to skyscrapers. But what exactly is cement, and how does it work?

Fundamentally, cement is a finely ground powder composed of various minerals, mainly limestone and clay. It experiences hydration, a chemical reaction, when combined with water. As a result of this reaction, the cement hardens and binds the components together to form a strong, long-lasting structure.

Cement comes in a variety of forms, each designed for a particular use and set of environmental circumstances. The most popular kind is called Portland cement, after the English island of Portland’s limestone cliffs. Other varieties include high-strength cement, which is intended for buildings that must support heavy loads, and white cement, which is used for decoration.

Because of its strength and versatility, cement is a necessary material in the construction industry. Gaining a basic understanding of cement can help guarantee the success of any project, no matter how big or small.

What is cement

"Cement" is a word that many have heard. You can find the definition of this term in specialist sources. Cement is an inorganic dry powder that is essential to the construction industry. It is created by firing a lime-clay mixture at a high temperature that has these ingredients in specific amounts. The resultant building material has unique properties of operation.

Its characteristics alter when water is added:

• it becomes viscous (paste-like consistency);
• acquires a dark gray tint;
• accelerates hardness in an airy and humid environment;
• turns into an artificial stone.

Everyone who has worked with cement has been persuaded time and time again that it is a reasonably strong building material. In terms of hardness, the artificial monolith is on par with natural stone.

The construction material has a long past. The sources contain no trustworthy information regarding cement. It is unknown who invented it first. It’s also challenging for historians to provide a definitive response to the query of where cement was invented. Excavations and scientific research have led to numerous studies of ancient cement. When did it come into being? Scientists made an effort to respond to this query. They concluded that the information existed well before our time. Samples discovered in various nations support this. They included volcanic ash, lime, and gypsum.

The processes used to produce cement evolved over the centuries. Reduced strength binding agents eventually became obsolete. They were swapped out for fired clinker and unique moderating ingredients.

The main component of concrete is cement, which serves as the glue that keeps everything together. It is created by heating a mixture of clay, limestone, and other materials in a kiln to create clinker, which is subsequently ground into a fine powder. Cement is a necessary ingredient for construction projects involving everything from buildings to bridges because it reacts with water to form a paste that becomes stronger and harder. Gaining an appreciation for the strength and longevity of concrete structures requires an understanding of cement and its properties.

Composition

The building material’s complete chemical formula is rather intricate. It includes the following ingredients:

• calcium oxide in the amount of 67%;
• silicon dioxide in the amount of 22%;
• aluminum oxides about 5%;
• iron oxide, the content of which is 3%;
• modifying components – no more than 3%.

The following components form the foundation of the building material:

clinker made from clay and limestone. Strength properties depend on the quality of the clinker. Clinker is the main component produced by heating a lime-clay composition in a rotary kiln. During firing, clay-containing raw materials and limestone materials melt to form granules saturated with silica. Then the clinker is fired again and crushed to a powdery state;

[adsense2]

• components of mineral origin. The introduction of special additives expands the scope of application, improves performance characteristics, and imparts the necessary properties. Granulated slags, crushed shale materials, pozzolanic ingredients, and crushed lime are added. The regulatory documents governing the composition of the building material contain information on the content of various chemicals in mineral components;
• special additives and auxiliary components containing calcium sulfate. Adding these ingredients does not affect the rate of moisture absorption and the duration of use of the working mixture. Changing the concentration of calcium sulfate, which is part of the modifiers, allows you to regulate the duration of the hydration process within the required limits. For this, gypsum powder is added.

Special additives are added to the main components listed above to strengthen the cement composition’s resistance to high temperatures, acids, alkalis, and harsh environments. In addition, additives improve adhesion to steel reinforcement, boost moisture resistance, and modify cement mortar mobility.

Main characteristics

Cement’s properties are related to how it is used. The following attributes are governed by the existing standard:

• strength properties. They vary for cement compositions of different grades. Strength is determined by a laboratory method by compressing a reference sample of the hardened mixture. Strength control according to the requirements of the regulatory document is carried out in three stages: after two days, as well as after one and four weeks after pouring. The parameter value is measured in megapascals. The digital value of strength corresponds to the grade of cement composition;
• setting time. The parameter characterizes the time period during which the plastic properties of the cement mixture change. A properly prepared solution begins to harden a couple of hours after pouring in the hot season. In the autumn, the hydration process can take 8-10 hours. The setting time at zero temperature increases sharply and can be 15-20 hours. The introduction of additives allows you to regulate the setting speed;
• resistance to the effects of negative temperatures. This characteristic is called frost resistance. It characterizes the ability of the hardened cement mass to withstand deep freezing with subsequent thawing over many cycles. At the same time, the integrity of the massif and strength characteristics must be maintained. The cause of destruction is an increase in the volume of water saturating the pores. The introduction of additives increases the frost resistance threshold;
• density. The parameter characterizes the mass of a powdery substance in one cubic meter of material. Freshly prepared cement composition has the lowest specific gravity. During long-term warehouse storage, the material cakes, and during transportation, it is compacted. In this case, the density increases. The characteristic depends on the size of the crushed clinker. Average value is 1.3 t / m3.

Among other qualities, the following can be observed:

• hygroscopicity. The degree of water absorption differs for different brands;
• grinding size. Determined by sifting through a sieve;
• corrosion resistance. Improved by introducing special additives;
• shelf life. It depends on storage conditions and the permissible humidity level.

After extended storage at high humidity in a warehouse, quality declines. A certificate of conformance, which attests to the product’s quality, should be noted when buying building materials.

Types of material

Different types of cement materials are used in the construction industry, and they vary in the following parameters:

• composition;
• concentration of ingredients;
• presence of special additives;
• purpose;
• properties.

The types of Portland cement that are differentiated are as follows:

• fast-hardening. Contains additives of mineral origin, which reduce the duration of strength gain. Used for accelerated construction activities and the manufacture of reinforced concrete structures;
• sulphate-resistant. The main advantage is resistance to the effects of sulphates, achieved by reducing calcium aluminates in the clinker. Used for structures operating in a humid or aggressive environment;
• hydrophobic. Contains surface-active components that significantly reduce hygroscopicity. The result of introducing additives is increased mobility, ease of laying the solution. The material retains its properties at high humidity;
• white. It is easy to distinguish from other cement compositions. Has a light gray color, does not contain titanium oxides, iron and manganese salts. Used for finishing activities;
• color. Contains special pigments of organic and inorganic origin, added to the clinker material before grinding. Colored compounds, for example, yellow cement, are used for finishing activities;
• pozzolanic. Resistant to sulfates, hardens quickly at elevated temperatures. Autoclave treatment significantly increases strength characteristics. Designed for use in soil as well as in damp environments;
• plugging. Produced exclusively for sealing wells in gas and oil developments. Provides reliable insulation from groundwater, resistant to pressure and temperature. Gains strength at the initial stage of hardening.

Based on the ingredients lime, slag, and clay, the following cement compositions are created:

• slag. Gains strength slowly. Used in the hydraulic engineering industry and port construction;
• slag-lime. Characterized by slow hardening. Used for plastering and masonry;
• alumina. Refers to refractory materials. Characterized by corrosion resistance, as well as moisture impermeability.

Take the building material’s intended use and operational characteristics into account when selecting a material for a particular task.

How cement is obtained – manufacturing technology

The following procedures are part of the manufacturing process:

1. Development of limestone, gypsum and clay deposits.
2. Crushing of mined materials.
3. Drying of crushed raw material mass.
4. Obtaining limestone-clay slurry.
5. Firing of raw materials to obtain clinker granules.
6. Crushing clinker to a powder consistency.
7. Dosage and mixing of components.

Various technologies are employed, distinguished by the sludge preparation technique:

• Dry. Drying and crushing are carried out in a grinder into which heated air is pumped up. The finished fraction has the required humidity;
• Wet. Provides the use of chalk. It is crushed in a wet state, then the shiht is fired and crushed;
• Combined. Combines the features of previous methods, depending on the equipment used in the technological cycle.

At the moment, producers favor a dry process of production.

The use of cement

The scope is fairly broad in both civil and industrial construction:

• Production of reinforced concrete products:
• construction of foundations;
• construction of the walls of buildings;
• performing plaster work;
• filling the screed;
• Making tiles.

Furthermore, the material finds extensive application in the construction of roads, bridges, and hydraulic engineering.

Marking features

There are two ways to mark data for classification:

• according to the European classification according to GOST 31108-2003, various types of cement are assigned the CEM marking with a digital index from 1 to 5;
• according to state standard 10178-85, each type of cement composition has a letter index – PC, SPC, BC.

For instance, depending on the kind of additives used, Portland cement produced in accordance with European standards is labeled CEM 1 or CEM 2. PC stands for similar material that is produced in accordance with the national standard. Slag Portland cement can therefore be designated as CEM 3 or SPC. For the benefit of cement product manufacturers, both regulatory documents are currently in force.

Aspect	Description
Definition	Cement is a fine powder that acts as a binder, used to set and harden materials in construction.
Main Component	The primary ingredient in cement is limestone, which is combined with other materials like clay and sand.
Production	Manufactured by heating limestone and other components to a high temperature to form clinker, which is then ground into a fine powder.
Types	Includes Portland cement, rapid-hardening cement, and low-heat cement, each with specific uses and properties.
Uses	Commonly used in concrete, mortar, and grout for building structures, bridges, roads, and other infrastructure.
Setting Process	Cement reacts with water in a process called hydration, which causes it to harden and gain strength over time.
Environmental Impact	Production of cement releases significant CO2, making it a focus for sustainable development efforts in construction.

In contemporary construction, cement is an essential component that is used to create concrete, the foundation of many buildings that we see today. It is an essential component of construction projects ranging from houses to bridges to skyscrapers due to its capacity to bind materials together and provide strength and durability.

Because of its adaptability, cement can be used for a number of tasks, such as laying foundations, plastering walls, and creating masonry mortar. Because of its special chemical makeup, it can harden and become stronger over time, guaranteeing a sturdy and long-lasting construction.

We can better appreciate cement’s influence on our surroundings when we are aware of its significance and applications. Cement is an essential element that supports every aspect of our daily lives, from the roads we drive on to the buildings we live in and work in. Whether you work as a professional in the construction industry or are a do-it-yourself enthusiast, understanding cement will improve your projects and make sure they last.

Video on the topic

Galileo. Histories of inventions. Reinforced concrete

How to mix DURABLE CONCRETE? What is CEMENT and concrete? CHEMISTRY of concrete and cement production

WHAT IS CEMENT ⚠️⚠️⚠️☝️☝️☝️⚗🧪

Cement – What is it made of .Discovery channel

Cement

How cement is made. Technology of production of Belarusian cement