Nearly 1.5 million sq. yd.—200 lane miles—already in Korea combine diamond grinding and grooving for a smoother profile and reduced noise levels
South Korea has a small land area, but many cars. In recent years, South Korea has undergone an aggressive highway-building campaign, resulting in a sophisticated network of state-of-the-art roadways, many of which involve miles of tunnels. Throughout South Korea’s history, the country’s mountainous terrain and numerous waterways made road travel arduous. Because of the topography, Korea’s road network contains numerous tunnels and bridges. Roadways in Korea can be classified into three types:
• Expressways—administered by the Korea Expressway Corporation (KEC) (constructs and operates an expressway network in the Republic of Korea and internationally) or private corporations
• National Roads—administered by The Ministry of Land, Infrastructure and Transport
• Local Roads—administered by local governments
According to an article posted by “Korea.net”, improvements to the road network began in the 1960s. With milestones like the 1970 Gyeongbu Expressway—its completion and enhanced access to it providing growth in Korea’s economy. A virtuous cycle began, and today, travel times across Korea have shortened dramatically, and by 2020, a national circular road network with seven horizontal and nine vertical trunks will be completed … [and] will make it possible to access an expressway from any part of the country in half an hour.
Andrew Lee, Planning and Management General Manager-Hexacon Inc. (road pavement construction and facility maintenance construction co.), told Tunnel Business Magazine, “According to the KEC, in the last 10 years, Korea’s tunnel mileage has tripled. For expressways currently under construction, tunnels represent 43% of their length, with long tunnels—3 km (1.86 mi or more)—comprising 16%. Because expressways are owned and maintained by a corporation, drivers must pay to use them, in turn the corporation must be highly responsive to the needs of its customers and provide a high level of service. Road owners are expected to provide expressways that are not only free of congestion, but are comfortable and clean.
An innovative surface treatment developed in the United States — the Next Generation Concrete Surface (NGCS)— has been widely employed in Korea to maintain a safe, smooth driving environment inside the tunnels. Developed at Purdue University between 2006 and 2008 by the International Grooving & Grinding Association (IGGA) and the American Concrete Pavement Association (ACPA), NGCS was designed to reduce noise levels without tires losing their grip on the road surface—NGCS is the quietest non-porous concrete surface available. Using a combination of diamond grinding and grooving on the concrete surface to achieve this, NGCS surfaces are smoother and flatter than ordinary pavements, and they have a consistent profile with a predominantly negative texture, absent of positive or upward texture elements.
In 2014, with assistance from its Research Institute, the Korea Expressway Corporation completed an NGCS pilot project. Since then, their research and implementation of NGCS has grown steadily. Today, NGCS is used throughout South Korea and all new expressway tunnels that are 2 kilometers (1.24 miles) or more in length have NGCS. Use of the surface is now expanding to national highways and local roads. There are nearly 1.5 million square yards (200 lane miles) of NGCS in South Korea.
The climate of Korea is very dynamic. It can experience temperature differences of down to -12°Celsius (10°Fahrenheit) in the winter and up to 38°Celsius (100°Fahrenheit) in the summer. The average annual precipitation is about 1,300 mm (51 in.), causing a lot of rain and snow. Managing roads under these severe conditions presents a challenge. Currently, most NGCS in Korea has been installed in tunnels, but the surface is rapidly being applied to earthwork and bridges because of its various advantages such as safety, smooth driving, and preserving pavement in these severe conditions.
John Roberts, Executive Director-IGGA said, “The NGCS and its smooth, low noise, high friction surface is a perfect fit for the road building and maintenance challenges we see across South Korea.” The IGGA is proud to be a part of the solution helping the Korea Expressway Corporation and Hexacon to employ new cutting-edge technologies to meet these challenges for the people of South Korea.
For the ConstructionPros.com article titled “Pavement Surface an Important Consideration in Korea’s Long Tunnels”, please go to: https://tunnelingonline.com/pavement-surface-an-important-consideration-in-koreas-long-tunnels/
For the Korea.net article “Through Mountains and Over the Sea; K-ROADS”, please go to: http://www.korea.net/NewsFocus/Travel/view?articleId=102713
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