Precast construction has been adopted fairly widely in infrastructure projects like tunnels, bridges, flyovers, railway sleepers, Metro projects etc. However, their adoption in construction of buildings has been limited so far. This is set to change as many developers, contractors as well as other companies have invested or planning to invest in plants for manufacture of precast elements specifically for buildings. Some of the leading suppliers of these precast concrete manufacturing equipment include Putzmeister, EBAWE, Elematic, Weckenmann and Spiroll.
The main driver for using precast concrete is increase in speed of construction.Further, precast concrete also allows for strict quality control and usage of only those products that have passed the required tests. Manufacturing of precast concrete products off site is much safer since manufacturing can be done at ground level and a standard factory setup facilitates an orderly work environment. Moreover, construction sites using precast concrete can manage with limited labour. There is no manpower required for cutting and bending steel, pouring concrete etc. Facilities for labour can also be commensurate with the requirements of the lower manpower deployed. There are other savings in terms of plastering and finishing. Walls made of precast concrete can be directly painted upon or painted with minimal preparation work. Hollow slabs used for wall construction can effectively insulate enclosed space from noise and heat. There are provisions for incorporation of insulation in prefab components as well.
Currently, the most common precast concrete products include walls, beams, floors, roof, staircases etc. These are traditionally referred to as ‘components’. These components need to be assembled or installed on site. Usage of components is quite prevalent now. Another precast product are ‘panels’. These are components that can be used to form the building envelope, internal partitions, load bearing walls etc. Usage of prefab panels is still quite limited in India among users. Brick/blocks along with mortar are still the preferred choice due to ease of construction with them. Finally, there are ‘volumetric’ components which consist of three dimensional units that can be directly used or combined on site; such as a small house. Usage of volumetric components is also very limited in India as of now. As the penetration of prefab construction increases, more complex products are likely to be made off site. The precast technology already available now can enable design and manufacture of complex structures; giving required variety for architects to feel unconstrained by it.
One of the main concerns of users is that construction done using prefab components is not continuous. Various components are assembled on site and connected using bolts, fasteners, couplers, ties, loops, sockets etc. Experience in other countries has shown that if connectors used are of good quality, there is no need for worry on this front. Leading companies like Peikko, Halfen, and BWG Bohr among others supply such connectors.
Another concern is the high capital investment and consequent higher price/cost of products manufactured using precast technology. Here, it is important to look at the total life cycle costs of using precast technology including savings in time, better finish, lower labour requirement, better safety etc.
Usage of precast concrete requires users to adopt different practices. For example, precast components need to be transported on site by mechanical means. It calls for a whole new approach towards construction. It is not just about replacement of in-situ placement of concrete by precast concrete. We can expect precast concrete products to increase their penetration in the Indian market within the foreseeable future.
Some of the developers and contractors who have invested in plants for manufacturing precast products include: –
• Amrapali Group, Noida (NCR)
• Supertech, Delhi
• Sobha Developers, Bangalore
• L&T Construction, Chennai
• Shapoorji Pallonji Engineering & Construction, Mumbai
• Brigade Enterprises, Bangalore
• B. E. Billimoria & Co., Mumbai etc.
Some of the companies which have entered the market for precast products for buildings are: –
• Precast India Infrastructure Pvt. Ltd., Pune: http://www.precastindia.co.in/
• Shree Polymers, Chennai: http://www.shreeprecastconcrete.com/
• Sai Preethi Precast, Tamil Nadu: http://saipreethiprecastbuilder.com/
• Preca Solutions India Pvt. Ltd., Hyderabad: http://www.preca.in/
• Magicrete Building Solutions Pvt. Ltd., Surat: http://precast.magicrete.in/
• Precast Buildcon India, Hyderabad: http://www.precastbuildcon.com/
• VME Precast, Chennai: http://www.vmeprecast.com/
• Malar Energy & Infrastructure, Trichy: http://malarinfra.com/