Featuring the advantages of precast concrete in road infrastructure.

The precast concrete technology was invented more than 100 years back (1905) by British engineer John Alexander Brodie. In India precast prestressed concrete technology are widely used in bridges, flyovers, viaducts, tunnels etc. The size of construction industry in India is around Rs 2,48,000 crore and precast has only 2 per cent share in relation to the traditional method of construction. Road development is an economic stimulus that creates assets. It is also an essential element for the rapid economic growth, trade and social integration.

One bright spot in Indian highway development is the policy decision taken by government to reduce dependency on bitumen (asphalt), the popular raw material for road construction, in favour of cement (concrete) for all new road projects since 2014. The decision was taken in consideration to the fact that concrete roads are seen to be more durable and thus will bring down the cost of road maintenance significantly. This decision also paves the way for exploring new technologies for faster construction of cement concrete roads, where precast concrete technology takes priority within available options. So let’s have a look on what experts have to say on the advantages of precast concrete in road infrastructure construction.

Time and cost saving technology

K Rajarama Rao, Chief General Manager – Materials, NCC Ltd states, “Prefabrication of any structure component off-site during highway construction or reconstruction offers major time and user cost savings in comparison with traditional cast-in-place methods of construction. Precast road pavement’s technology offers dramatic increase in durability and speeding up construction process. It also brings substantial safety advantages, lower disruption in traffic and increase overall convenience for the road users.”

Modular panels make the construction process safer and more efficient because roadwork can be completed during off-peak hours in windows as short as five hours, reducing the need for time-consuming roadway closures because they are precast, the panels can be fabricated under environmentally controlled conditions, which can result in products with better engineering properties. Workers are developing their skills and knowledge that will improve productivity and quality.

C.N Shridhara, Head-Technical and Marketing, Preca Solutions India Pvt Ltd says, “The precast prestressed slabs for the road pavements will increase durability of roads, drastically reduce the construction time and user costs. It will ease the construction difficulties in remote areas. Even roads can be constructed without compromising quality in remote area where raw materials are not available. Also this methodology lowers the disruption to the movement of traffic while construction. This technology will create every project unique and higher mark up.”

He adds, “Precast elements casted in quality controlled method will reduce the maintenance cost drastically. As the slabs are prestressed, the performance of slabs can be increased by inducing compressive stresses. This will reduce cracking and strengthens the slabs to prevent bending a torquing. This will reduce the repair cycles. At present most of the pavement will damage due to rain water or sewerage water stagnation. As concrete, roads will resist more the water than bituminous pavements.”

K.M Velumani, Proprietor, Velan Concast says, “The rising traffic volumes combined with aging infrastructure, such as roads and bridges have given cause to find a safe, cost effective and efficient solution that would placate everyone involved from the construction workers to the citizens using the varying infrastructure. Precast concrete is a viable solution that has been proven to be cost effective while reducing construction time without sacrificing safety.”

By completing road or bridge construction or restorations faster, not only the construction cost reduces but the costs incurred by individuals and businesses are also reduced.  With increased time in commute, adding to increased petrol, which in turn contributes to air pollution and businesses facing loss in number of working hours, thus affecting productivity, the economic costs are felt across the board.

Quick and invisible repairs in high-traffic areas

Rao feels precast concrete panels can ease congestion at busy intersections and are a good choice for ramps and other locations where heavy traffic presents a challenge during construction. Using the panels can extend the construction season because prefabrication eliminates the need to pour concrete in cold-weather conditions. It has less frequent maintenance. There will be higher economical effectiveness due to mass production of all standardised elements. (Mainly pavement panels and curb elements etc).

Velumani explains, “As proven with the highway rehabilitation project at Virginia in USA, the exit ramp, which needed to be restored, would have taken 100 days to complete using traditional methods and caused major inconveniences with heavy traffic congestions to regular commuters. By using precast panels, the project was successfully completed in 35 nights by closing one lane at a time and opening all lanes to traffic during rush hour. By using precast panels, instead of the traditional cast in place approach, construction time was reduced by two to three times.  Moreover, the panels were ready by driven on the next day.”

Vijay Kalantri, Chairman and Managing Director, Dighi Port Limited said, “Precast concrete pavement systems have drawn greater interest from the highway community over the past decade as a solution for quick and invisible repairs in high-traffic areas. Road-user surveys cite congestion and traffic delays from roadway construction as major sources of frustration for motorists. Traffic congestion also reduces highway capacity and increases delay costs for the travelling public.” Public agencies are challenged to find ways to restore high-volume roadways rapidly with minimal impact to motorists and durable long-lasting repairs.

Precast prestressed concrete technology brings unmatchable durability for the newly constructed road pavements and bridges with the lowest level of disruption to the traffic during its implementation therefore it gains grip in the Indian infrastructure and construction sector. Pankaj Udeshi, Asst. General Manager Procurement, Supreme Infrastructure India Ltd. said, “The precast technology is applicable and needed for both either replacement or rehabilitation of existing bridges and construction of the new ones.”

As traffic volumes continue to rise in the Indian highway infrastructure, its users increase their demands regarding its comfort and quality. As capacities of the construction industry are limited, utilisation of rapid construction methods is becoming necessity. Prefabrication, respectively precasting seems to offer all that is needed in current situation.

Higher pace of construction works to answer the need to cut the time of traffic flow limitation. Innovative planning, subordinates design to the technology, use resources and techniques to accelerate the bridge construction and the maintenance without compromising the safety. Pankaj says, “It is mainly about cutting the construction time, i.e. the limitations to the existing traffic, and about increasing the durability due to the higher quality of the factory-made concrete. Based on that, it does make sense to precast most of the bridge elements – a pile, pier column, pier cap, beam, deck and barrier or railing as well.”

Provides greater control

According to Rao the main advantages of precast concrete over cast-in-situ are, precast pavement panels or elements can be cast and cured in a controlled environment at a precast plant, providing greater control over consistency of the concrete mix, procedures of vibration and proper curing. Precast objects reduce or eliminate curling, strength and air-entrainment problems that are common with conventional concrete paving.

Constructing precast panels in precast plants ensures quality in construction. The environment in which they are created can be controlled so that there is consistency in the mix, proper curing, elimination of curling and air-entertainment and ensuring quality strong products are transported to construction sites.

The non-proprietary precast, prestressed concrete pavement system is aimed at strengthening concrete panels by prestressing them, a technique used in cast-in-place concrete construction for decades. Pretensioning panels during fabrication combined with post-tensioning during installation reduce the incidence of cracking in the slabs.

The proprietary systems use a jointed precast slab assembly with unique design features for installation and transferring load across panels. Damaged areas of pavements can be replaced with precast panels custom built to meet the thickness, cross slope and layout requirements of the project site. Precast concrete pavement systems can be used for single-lane replacements, multiple-lane replacement (an additional lane may be needed to accommodate materials and equipment) or full-width road construction.

Precast road pavement’s technology offers dramatic increase in durability and speeding up construction process.

K Rajarama Rao, Chief General Manager – Materials, NCC Limited

Precast concrete is a viable solution that has been proven to be cost effective while reducing construction time without sacrificing safety.

K.M Velumani,Proprietor, Velan Concast

As the slabs are prestressed, the performance of slabs can be increased by inducing compressive stresses. This will reduce cracking and strengthens the slabs to prevent bending a torquing.

C.N Shridhara, Head-Technical and Marketing, Preca Solutions India Pvt Ltd

Precast concrete pavement systems have drawn greater interest from the highway community over the past decade as a solution for quick and invisible repairs in high-traffic areas.

Vijay Kalantri, Chairman & Managing Director, Dighi Port Limited

The precast technology is applicable and needed for both either replacement or rehabilitation of existing bridges and construction of the new ones.

Pankaj Udeshi, Asst. General Manager Procurement, Supreme Infrastructure India Ltd.