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Concrete






Concrete




Concrete is a bonding material, Sand and stone is a building material that is prepared by mixing water at a specific rate.
Cement = Powder
Cement + Water =Paste
Cement + Fine Aggregates+ Water =Mortar
Cement + Fine Aggregates + coarse Aggregates + Water = Concrete

Characteristics of Concrete

 Concrete is used as a construction material considering the following characteristics.
  • Hardness
  • Durability
  • Ability to obtain high Compressive Strength
  • Ability to be cast
  • Non porous
  • Fire resistance
  • Water resistance
  • Economical
  • Low maintenance
  • Aesthetic properties

However, the following disadvantages can be seen in concrete.

  • Tensile strength is weak compared to other construction materials.
  • ductility is very low.
  • Is fragile.
  • Relative to strength
  •  Too heavy

Factors affecting the quality of concrete

  • Quality of raw materials.
  • repertory type.
  • Accurate mixing ratio.
  • Amount of water collected.
  • Proper mixing, transporting and depositing of concrete.
  • concrete compaction and tanning.

Materials used for concrete

Binding Material

 Binding material is created by bonding the material in the concrete.
Ordinary Portland Cement -(OPC) is the most commonly used bonding material for concrete.

Water – cement ratio

 Water is applied to concrete and the weight of the cement is given as a rate. (Or as a percentage of the weight of the cement). This ratio is called the water-cement ratio.










Fine Aggregates











 Completely detachable materials with a mesh of 4.75 mm in size are called subtle aggregates. Fine aggregate for concrete is used in rivers, streams and sand. The use of stone powder as an alternative to Fine Aggregates is also seen in some places,

Fine aggregates used in concrete shall have the following characteristics:

  • Mildew should be in shape.
  •  Not spherical in shape.
  • Should be free of soil, mud, dust or garbage.
  • There should be no chemicals that can harm the strength, durability and reinforcement of concrete.

Fine Aggregates of Functions

  • Available space filling between coarse aggregates
  • Minimizing cracking and shrinking of concrete
  • Fine aggregates To be able to obtain the required strength by changing the rate and to produce concrete,

Coarse Aggregates






Coarse Aggregates

Aggregates larger than 4.75 mm are called Coarse Aggregates. The maximum size of Coarse Aggregates cubes used for concrete varies from 12, 20, 25, 32, 37.5 mm. Coarse aggregates use small pieces of granite. In addition, coarse aggregates can be used, such as gravel and rubber.

 Coarse aggregates used for concrete should have the following characteristics.

  • Lack of decayed spall,
  • Partitioning with sharp edges
  •  Free from reactive chemicals
  • Some grades have been,

Functions of Coarse Aggregates

  • Increasing Concrete Crushing Strength.
  • Formation of Solid and Tough Masses with Cement and Subtle Combinations.
  • Reduce the cost by increasing the volume of the concrete.

Water

For concrete, there are no Salts Drinking water use does.There are several functions in concrete through the use of water to mix concrete. That is,
  • Contributing to the reinforcement of cement by hydration
  • Ease of working. (Mixing, transporting, depositing and compaction of concrete)
  • Minimizing the effect of heat released during the hydration of cement.

Concrete When applying water, it is important to use water at the right water-cement rate. The reason is,

If too much water is applied to the concrete,
That excess water remains in the concrete as free water particles. When the concrete dries, most of the water particles evaporate, resulting in pores in the concrete. Then the concrete takes on a spongy nature and its strength is low. Furthermore, as the water in the concrete increases, the solid constituent of the solid separates and forms segregation. Then the strength of the concrete is reduced.
 If less water is applied to the concrete
 Water is insufficient to cement and react. Because the cement does not react with water completely, the bonding between the aggregates does not occur and the strength of the concrete is weakened.

Admixtures

Various chemicals are added to the concrete mix to improve the quality of the concrete, increase the working ability, and control the performance of the concrete. These materials are called Admixtures.

Functions of Admixtures.

Some of the functions of additives can be stated as follows,
  • Reduce or increase the initial reinforcement time of the concrete.
  • Improving Workability,
  •  Reduce the amount of water applied to the concrete,
  • Reduction of heat exit from concrete
  • Reduce Concrete Shrinkage
  •  Water leak reduction,
In the environment Improving resilience to harmful chemicals

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