The North Dakota Department of Transportation (NDDOT) in the US is using overlay, a new cost-effective technique, to improve load carrying capacity and enhance safety in road rehabilitation projects.

Concrete overlay, which is also referred to as white topping, is applied by placing a 6in-8in layer of concrete on an existing asphalt roadway to make it long lasting, smoother and withstand heavy traffic volumes.

Highway 2, north of Williston, is amongst the North Dakota roadways that see heavy truck traffic and are being repaired using overlay.

Work on Highway 2, of which NDDOT awarded to Washington-based ACME Concrete Paving, is expected to be completed by the start of October 2012.

ACME Concrete Paving vice president Robert Seghetti said that roads built with the concrete overlay technique require less maintenance and have a lifespan of more than two decades outside of Williston, while within the city it is expected to last for around ten years due to stop-and-go traffic.

The overlay technique has previously been used on roadways across the state and found to be cheaper in providing long-term solutions to rutting problems, particularly at intersections.

The North Dakota Department of Transportation assistant materials and research engineer Clayton Schumaker said that concrete overlay is a relatively new technique that is proving to be an ideal solution for many roadways in western North Dakota.

"With so much traffic, specifically truck traffic, in this part of the state, the concrete overlay will provide a roadway that can withstand the high traffic volumes, while bringing down project costs," Schumaker added.

According to NDDOT, executing the concrete overlay strategy together with other processes, allows it to cater to the increasing traffic needs in the region, along with providing a safe and efficient transportation system.