Why Precast:

What is Precast, Prestressed and Post Tension Concrete Construction?
Precast concrete technology and methodology has until now not been widely utilised in India.  It has been successfully used for more than 60 years throughout the developed world due to its inherent advantages over conventional construction methods.  Precast concreting is the process by which a single element of a building, bridge, commercial structure (section of wall, slab, beam, column, architectural facades, girders, etc…) can be cast using a mould off-site in a factory setting and then erected at a later date when convenient.  All the required elements are brought to the project site and erected within a specified schedule.  An entire structure, using this methodology can therefore be erected within days to weeks – all while having better quality of workmanship, durability, waterproofing and at a price point which is equal to or less than conventional construction methods. 

Imagine being able to finish an entire floor of your building within one day.  Imagine being able to lay entire sections of bridges in one day.  Imagine being able to offer your customers a product which is far more durable, better in quality and requires lower long term maintenance.  Precast construction techniques and methods are inherently better than conventional construction techniques.  It requires a fraction of the manpower, a fraction of the time, has stricter quality assurance guidelines and even requires fewer material resources.

Prestressed and Post Tension construction both use the same basic design principles.  Both these techniques minimize the amount of concrete required and utilize high tensile strands/cables embedded within the concrete to take the specified loads.  In standard RCC construction methodology, by contrast, steel is primarily used to take the tension forces exerted on the structure since concrete only take compressive forces.  The steel only takes tension once the concrete structure has ‘cracked’ and allowed the steel to take tension.  Prestressed and Post Tension concrete structures require lesser amounts of concrete and steel while allowing for much heavier loading versus standard RCC construction as the entire concrete section is effective in resisting the applied loads.

Prestressed concrete construction is where cables are pulled prior to concreting.  Post Tension construction involves the cables being pulled after the concrete has set.  Both techniques are preferred to standard methods especially when it comes to longer span structures.

icg@icgindia.co.in ICG - Infrastructure Construction Group