Precast Concrete

By Vinisha , 2nd year , Civil Engineering

Time and tide waits for none. Technologies do justice to these words. The best example is precast concrete. Previously, Constructing a building requires a great period of time. But now in our fast world we can construct a building within weeks and months. This is favored by precast concrete.

Let’s see in detail about precast concrete. In certain places there is only limited availability of space in the construction site so there arises a difficulty for storing the materials and preparing the concrete. Therefore the concrete is cast at factories and assembled together. These concrete can be :plain concrete, reinforced concrete, prestressed concrete. It is the construction product in which the cast concrete in a reusable mould or form. The moulds are made up of Timber, Steel, plastic, rubber or fiberglass.

Precast concrete is the fine aggregate in a mixture the final product approaches the look of naturally occurring rock or stone. Precast concrete are used with an exterior and interior walls. The casting of the concrete is usually performed on the ground level which helps in safety throughout the project

 Many surface finishes are needed to complete the  precast wall panel. Now a days polystyrene is used in precast concrete wall panels. Polystyrene is used because of their lightweight and thermal insulation. In architectural application of precast concrete there are different types according to their size, function and cost. The precast concrete are widely used due to their efficiency and economical quality. The advantages of precast concrete are they are safer and more affordable. The disadvantage may include the need of highly skilled labour for the installation process. Proper connections should be made or otherwise the sections may fail.

These type of concrete are mostly used in agricultural Industries. As they withstand extreme weather and can hold up for many years of constant usage, they are widely used in agricultural field. They are used in bunker silos, cattle feed bunk, livestock slats, livestock watering trough, feed trough, concrete panels.

Precast concrete are essentially checked and structurally designed to withstand both tensile and compressive loads. They are designed to bare constant weights as they are used in making retaining walls, railway sleepers, bridge components, traffic barriers, paving units and steps if staircase. The structural application may also include multi storey car parks, foundation, beams, floor, walls.

The production of precast concrete  elements takes place under controlled conditions  in enclosed factories. This means that tolerances  can be accurately controlled, waste can be minimised, and that a denser, stronger and better quality concrete  can be produced.

Concrete  is cast into forms and left to cure. precast forms are normally made of steel or plywood. Whereas plywood forms are usually limited to about 20-50 castings depending upon the complexity of the form, a virtually unlimited number of castings can be made by precasting using steel forms.

During the manufacturing  process, admixtures  can be included in the concrete. These can be water-reducing, air-entraining, retarders and accelerators (for faster curing time). The purpose of admixtures  is to improve  on concrete quality  in both its fresh and hardened state. Colour pigments can also be added, such as iron oxides (red and brown), chrome oxides (green) or cobalt oxides (blue).

Precast concrete can be bolted together. In order to do this, steel connectors are embedded in the concrete at the time of casting. This must be done with great precision.

They can be grouted or concreted together. In this method, loops of reinforcement  are left protruding out of the precast concrete members. Two members are placed in position, and reinforcement is threaded between the loops. Fresh concrete is then poured around this reinforcement, in a s left for this purpose. Precast concrete are the interesting and essential findings of the Construction world. Therefore, this type of concrete should be encouraged more as they are affordable and quicker in process.

We are moving at a faster pace in the construction industry, new techniques are adapted and implemented every day  techniques like precast concrete are so efficient to all including the organization and the end-users .