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Concrete Technology

Concrete technology deals with the study of concrete properties and its practical applications. Construction material composed of cement, fine aggregates and coarse aggregates mixed with water that hardens with time are known as concrete. Type of cement which is commonly used for the production of concrete is Portland cement. Concrete is used for the construction of foundations, beams, columns, slabs, and other load-bearing elements in building construction. Based on the binder used, concrete can be classified in many different ways. For example: if the concrete is made of asphalt binder, then it is called asphalt concrete which is used for road construction. If concrete is made of hydraulic, nonhydraulic and polymer cement, then it is hydraulic concrete, nonhydraulic concrete and polymer concrete respectively. Ability to gain strength in water is concrete differ. Various types of cement are used for concrete works which have different properties and applications. Some of the types of cement are Portland Pozzolana Cement (PPC), rapid hardening cement, Sulphate resistant cement, etc.

To obtain required strength in concrete, materials are mixed in specific proportions as grade specified follows: M5, M10, M20, M30 grade, etc. where M signifies Mix and number 5,10,20, etc. as their strength in MPa. The important role which influences various properties such as workability, strength and durability is water-cement ratio. The adequate water-cement ratio is required for the production of workable concrete. When water is mixed with materials, cement reacts with water and hydration reaction starts. This reaction helps ingredients to form a hard matrix that binds the materials together into a durable stone-like material. Concrete can be formed in any shape.

Concrete is mixed in proportion with respect to cement quantity. Based on the mixes, concrete can be divided into two as follows:

  • Nominal Mix: It is used for normal construction works such as small residential buildings. The most common nominal mix is in the proportion of 1:2:4.
  • Design Mix: Concrete for which mix proportions are finalized based on various lab tests on cylinder for its compressive strength. These design mixed offers economy on use of ingredients.

Hand mixing and Machine mixing are the two methods used after suitable mix proportions are known.

There are two types of concrete construction as follows:

  • Plain concrete construction: Concrete is poured and cast without the use of any reinforcement. Only concrete is used for construction when a structural member is subjected only to the compressive forces and not bending.
  • Reinforced concrete construction: Concrete is used with reinforcements to withstand tension forces structural member as it is very weak compared to compression. E.g. residential buildings, dams, roads, bridges, etc.

The construction steps are:

  1. Selecting quantities of materials for selected mix proportion
  2. Mixing
  3. Checking of workability
  4. Transportation
  5. Pouring in formwork for casting
  6. Vibrating for proper compaction
  7. Removal of formwork after a suitable time
  8. Curing member with suitable methods and required time.

Various topics can be studied in this subject are listed as follows:

  • Materials for making concrete
  • Concrete properties
  • Structure of concrete
  • Advanced cementitious composites
  • Concrete fracture mechanics
  • Non-destructive Testing in concrete engineering
  • Future and development trends of concrete
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