Why Concrete Is Considered As Strong Building Material
Reinforced concrete alias reinforced cement concrete, or RCC is extensively used in construction projects. It comprises of steel bars known as reinforcement bars, or rebars. The concrete has great strength against compression, it is cost-effective and the steel has good strength against tension. So, this combination can improve the efficiency of construction work.
HOW TO MAKE CONCRETE
Initially, create a mould, known as formwork, it will have the liquid concrete and give it the form and shape as per requirement. Now, based on the drawings of structural engineer and places in the steel reinforcement bars, bind them in exact position with wire. The tied steel is known as a reinforcement cage. Once the steel is positioned properly, the concrete can be produced by mixing cement, sand, stone chips in different sizes, and water in a cement mixer, and the liquid concrete can be poured into the formwork unless the right level is attained.
The concrete gets solidified quickly, but requires a month to attain its full strength. So, it is normally propped up until that period. Through this time period, the concrete should be cured, or drenched with water on its surface, that is necessary for the chemical reactions within to progress correctly.
The proportions of each ingredient in concrete should be retained properly. The process is known as concrete mix design. A good mix designer will begin with the properties which are required in the mix, then consider various factors, and arrange a detailed mix design.
A site engineer gives order for a diverse type of mix for a various purposes. As for instance, while casting a thin concrete wall in a hard-to-reach area, a mix that is more flowable than stiff should be ordered as the liquid concrete can outflow by gravity into each corner of the formwork.
It is recommended to apply a standard mix for most construction projects. The standard mixes range from M20, M30, M40 concrete, where the number indicates the strength of the concrete in n/mm2. So, M30 concrete contains a compressive strength of 30 n/mm2. A standard mix also indicates the maximum aggregate size. Aggregates belong to the stone chips used in concrete. For M30 / 20 concrete, M30 concrete with a maximum aggregate size of 20mm will be required.
Concrete that is cast in place in its mould is known as cast-in-situ concrete. Concrete members cast in a concrete factory and then supplied to site are known as precast concrete.
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TYPES OF CONCRETE
The followings are the common types of concrete :
High Strength Concrete:
The compressive strength is considered as the most fundamental and vital property of concrete. Concrete that contains a compressive strength of 40Mpa (5,800 psi) is known as high strength concrete.
High Performance Concrete:
High-performance concrete is identified depending on performance conditions like high durability, high strength, and high workability. High-performance concrete (HPC) is created with proper selection and proportioning of its ingredients like cement, sand, gravel, cementitious materials ranging from fly ash; silica fume; and slag, and chemical admixtures for example high range water reducing admixtures.
It is formed with small, lightweight aggregates, like small balls of styrofoam (thermocole) or with inclusion of foaming agents to the mix of concrete. Lightweight concretes contain low structural strength, and frequently utilized in non-structural elements. For instance, aerated autoclaved concrete (AAC) blocks are utilized for constructing walls.
Self Consolidating Concrete or Self Compacting Concrete:
Sprayed Concrete or Shotcrete:
The concrete can be sprayed onto a surface to develop a solid, irregular coating. Under this system, the concrete is not poured into a form or mould. It is directly sprayed onto a surface, and is applied in infrastructure projects and to patch up old, cracked concrete surfaces. Shotcreting is also known as guniting.
Water resistant concretes contain fine particle cement replacements which resist water to infiltrate. These are very effective for construction under the ground, like basements, and various water retaining structures like water tanks and dams, as well as marine structures like jetties and bridges.
Micro Reinforced Concretes:
These types concretes comprise of small steel, fibreglass or plastic fibres that considerably change the properties of concrete.