Concrete Overlays

The need has never been greater for engineered strategies to preserve and maintain the nation's pavements. With shrinking budgets, ever increasing traffic volumes and loads, and the critical emerging focus on infrastructure sustainability, highway agencies and local road consultants and municipal bodies are being asked to "do more with less" in managing their pavement networks.

Agencies need to be proactive, sustainable pavement mountainous and rehabilitation strategies that last longer and at reasonable costs. In many situations, concrete overlays or similar to "Thin White Toppings" represent such strategies. They offer cost effective, versatile, short-and long-term solutions for the full range of concrete, asphalt, and composite pavements needs. In addition, they contribute to more sustainable construction practices by preserving pavement service for several decades beyond original service life.

Many concrete overlays have been in service for decades, extending the life of the original pavement structures for 30 years or more! Because concrete distributes the traffic loads over a wide area, the underlying pavement does not experience highly concentrated stresses. As long as the original pavement remains stable and uniform, a concrete overlay can be placed, replaced, or recycled as needed for maintenance and or rehabilitation cycles.

In this manner, the concrete overlay systems can be sustainable for 100 years or longer. Rather than removing and reconstructing on year on year basis adding top coats which give away within weeks of facing rains or heavy traffic conditions, a concrete overlay effectively returns its original investment within 2-3 years of the differential cost and does away with yearly maintenance and suffering to the general public and saving a lot for nations spending.

There are several genuine benefits of the Concrete Overlays:

1) Concrete Overlays consistently provide cost effective solutions. Rupee for Rupee they are one of the most effective long-term maintenance and rehabilitation options for the existing pavements with distress.

2) Concrete Overlays can be constructed quickly and continently as

a) The existing pavement does not need to be removed.

b) Simple operations of surface milling or scarifying is enough for "bonded overlays"

c) Few or no pre-overlay repairs are necessary or even desirable in most cases.

d) Concrete Overlays are placed better using TRTP Fixed Form with Gang Mounted Vibrators or such machines with normal construction practices.

e) Many concrete overlays can be opened to traffic within 3-4 days to traffic from date of placement.

f) Accelerated construction practices can be used throughout the normal construction season.

3) Concrete Overlays are easy to repair.

4) Concrete Overlays are durable rehabilitation tool and most cost effective option

5) Concrete Overlays can survive in and of themselves, as complete preventive maintenance or rehab solutions, or can be used in conjunction with spot repairs of isolated distress.

6) Concrete Overlays enhances pavement sustainability by improving surface reflectance, increasing structural longetivity and enhancing surface profile stability.

Concrete Overlays

A recent event has carried this feature at a heavily trafficked junction near Electronic City where with the joint inputs of Ultratech and ACC and the vital study by their team and the approval of the Bruhat Bangalore Mahanagar Palike a 4 lane road stretch of almost 10,000 SQ. Mtrs with equipment from Allen Concrete Pavers (USA) a leader in Fixed Form Paving technology with more than a dozen machines performing at various sites in India was selected for this sensitive task. The project has been successfully executed to the satisfaction of the general public and the inspection agencies too. Once the outcome is quantified and commercial considerations weighed against the age old practice of asphalt top coats and repeated costs etc are tabled, it is expected to save the agency enough to divert funds to more creative infrastructure needs while the Concrete Overlaid pavements meets the best ride quality and almost nil involvement of rehab for years to come is a new chapter herald by the citizens of Bangaluru.

NBMCW March 2011