Geosynthetics: Update from Korea

The infusion of geosynthetics in Korea has been accomplished in a relatively short time. A look at potential growth, research, and markets.

By Han-Yong Jeon

1. Introduction

The geosynthetics industry in Korea is a promising field for investment and development. Many types of domestic geosynthetic products are produced and their applications and end uses are widely enlarged every year. Although the geosynthetics-related history in Korea is not long, the infusion has been accomplished in a relatively short period, particularly as far as geosynthetic usage and applications are concerned.

The types of geosynthetics produced and used in the domestic market include: geotextiles, geomembranes, geogrids, PBD (prefabricated board drain), and GCLs (geosynthetic clay liners). The application fields for these products are mainly in the areas of soft soil reinforcement, soil retaining walls, waste landfills, road and subway construction, tunnel and earth dam construction (Korea Nonwoven Industry Association, 2004). The technologies relating to Korean geosynthetics (raw materials, manufacturing processes, testing and evaluation, design and installation, etc.) come mainly from the United States, Europe, and Japan.

In this manuscript, I would like to simply introduce and review the overall and current situation of geosynthetics in Korea, based on the recent technology circumstances of Korean geosynthetics to consider the principle of international geosynthetics technology transfer.

2. Potential growth of geosynthetics

2.1 History of geosynthetics applications

Traditional geotechnical and civil engineering structures have long histories in Korea but there is no evidence that geosynthetics were used until recently. It was suggested that the Japanese used geosynthetics, in this case woven geotextiles, as reinforcement materials in the fields of roads and runways, earth dams, etc. in the 1920s, but we cannot confirm this officially.

It is known that the Korean government used woven geotextiles as protection materials in the breakwater construction on A-San and Nam-Yang areas for the first time in 1971. In 1979 and again in 1983, geotextiles were used as asphalt overlay materials in the fields of highway construction between Seoul and Pusan, and between Sunchun and Pusan. After this, many types of geosynthetics were used in the fields of soft soil reinforcement, waste landfill construction, road pavements and construction, breakwater construction, embankments, beach protection, retaining walls, stabilization of steep soil slopes, erosion control, and tunnel construction.

The amount of geosynthetics used in Korea has increased every year and new materials have been developed consistently since 1996. Despite this situation, geosynthetics-related construction is not as widespread as traditional civil engineering materials such as concrete, steel, etc. Many engineers and design firms are simply unaware of geosynthetics and their potential for lower costs or completely new applications.

The Korean economy is recovering since the second half of 1999 and the demands for geosynthetics are increasing gradually with the stability of the economy. Imported geosynthetics from the U.S. and Europe are increasing slightly at a uniform rate. The paper of Lawson and Cowland illustrates that the position of Korea is in the middle level of the geosynthetics developing Asian countries.

Typical products and manufacturing processes of domestic geosynthetics are itemized in Table 1. There are no significant differences from the kinds of products among Korea and other advanced countries of North America and Europe in this regard. The types of geosynthetics currently produced in Korea include: geotextiles, geomembranes, geogrids, GCLs (geosynthetic clay liners), PBD, geofoam (EPS expanded polystyrene), geopipe, geonets, and geocomposites. Table 1 represents the current state of domestic geosynthetic products.

2.2 Developments of geosynthetic products

(1) Geotextiles

Nonwoven geotextiles of staple fibers having width: ~8.6m, weight per m²: ~3500g/m² are produced by needle-punching methods and spunbonded nonwovens of filament fibers with ~600g/m² are produced by spunbonding method. Woven geotextiles of split polyester and polypropylene yarns having length ~3m are produced by weaving. The range of their design strength is 4~50 ton/m.

For woven geotextiles, high drawn split yarns (; ~3,000 denier) are used as warp and weft yarns and rapier or air-jet weaving machines are used to make woven geotextiles. Recently, the requirement of low elongation (~10%) woven geotextiles are increased to improve the resistance against fracture in installation fields. The smart polymer resins for this purpose are developing and modifying the manufacturing process of woven geotextiles to give the low elongation. For nonwoven geotextiles, staple fibers and filaments of polypropylene, polyester or recycled polyester with/without carbon black are used as raw fibers and needle punching and spunbonding methods are used to make nonwoven geotextiles. Specially designed manufacturing lines were established to produce 8.5m width, 3,500g/m² needle-punched nonwovens.

(2) Geomembranes

HDPE smooth type geomembranes are widely used in Korea. Also, small amounts of EVA geomembrane are used in special-end usages as water-barrier materials. Recently, textured geomembranes were developed and currently tests are in progress. The main end use of HDPE geomembranes is as liners for waste landfills. The range of thickness is 1.0~2.0mm. HDPE is also used as a waterproofing sheet in the fields of tunnel and subway construction.

For smooth type, HDPE geomembranes with UV stabilizers and antioxidants are the main geomembranes in Korea. Extrusion type with T-die and blown type with circular-die manufacturing processes are used to produce geomembranes. Thickness of at least 2mm must be used for waste landfills, based on revised regulations by the Ministry of Environment in 1999. Therefore, research on geomembranes to improve the seam properties is currently ongoing. For textured type, spray-on (impingement) type textured geomembranes to improve the frictional properties between soil and geomembrane have been developed and the testing of their frictional properties is ongoing.

(3) Geogrids

Fabric-type geogrids (aka, soft geogrids) of high-tenacity polyester yarns are the types mainly produced. Either PVC or acrylic resin is used as a coating agent. In 1999, glass fiber geogrids were developed and currently tests are in progress. The fabric type geogrids are used in the fields of soil retaining walls and steep slope soil retention. The glass fiber geogrids are used as reinforcement materials in road construction. Fabric type geogrids, by using high-tenacity polyester yarns and glass fibers, are produced domestically with PVC and acrylic resin used as coating resins.

(4) GCLs

GCLs are generally geotextile-type with staple fiber needle-punched nonwoven, bentonite/woven, or nonwoven geotextile, and—to a lesser extent—bentonite+adhesive/HDPE geomembrane type. Specially designed GCLs are produced to prevent the bentonite loss. Both powder and granular type bentonites are used. The bentonite is imported from the United States, Russia, China, or Australia.

GCLs are mainly used as a composite liner with geomembranes for slopes of waste landfills. They are also used as waterproofing materials in tunnels and subway construction. GCLs are produced by the needle punching method and bentonite mixed with adhesive/HDPE geomembrane type GCLs are produced by calendaring. Special composition of GCL layers and binder are used to prevent the fluid loss of bentonite.

(5) PBD

Prefabricated board drains (wick drains or plastic drain boards) are routine products produced in Korea and also imported. They are used to rapidly consolidate soft soil materials. Nonwoven heat-bonded geotextiles are used as filters. The plastic cores are manufactured domestically using polypropylene. PBD is very common since more than 60% of the west and south areas of Korea consist of soft soils. Many industrial complexes will be constructed in these areas. To strengthen these soils, a large amount of PBD will be used for many years into the future.

(6) Geonet composites

For geonet composites, non-woven geotextiles are used on both surfaces. They are used for drainage in waste landfills.

(7) Miscellaneous

Some geosynthetics, such as geofoam, geopipe, and geosynthetic sheet drains, are used for special end uses in various types of construction. Nonwoven geotextiles used as filters along with polypropylene cores are bonded by heat bonding methods. Currently, research on biodegradable filters and plastic cores is ongoing to prevent soil and surrounding environmental pollution. Biodegradable, smart PBDs with excellent drainage performance are being developed.

3. Regulations, specifications, and standardization

Currently, regulations, specifications, and standard testing methods of geosynthetics are the hottest issues in Korea because some specifications for designing with geosynthetics are confusing to set the minimum values of geosynthetic performances. This situation must be clearly solved, to adopt the international standard test method to be considered for Korean special-installation circumstances.

Ministry of Environment—geosynthetics for waste landfills
Ministry of Construction and Transportation—geosynthetics for general construction
Korea Highway Corporation—geosynthetics for transportation

The Korean government is adopting similar standards as Korean industry. They use both ISO and ASTM International standard test methods involving different types of materials. For geosynthetics, specific properties and circumstances of geosynthetics have been taken into consideration beginning in 1998.

Most standardized geosynthetic-related test methods were adopted from JIS (Japan Industry Standard). However, a new standardization project by the Korea Industry Standards group (including geosynthetics) is ongoing from 1998, in accordance with international standards such as ISO and ASTM International. But between two international standards, ISO standard test methods, regulation of geosynthetics in Korea is strongly influenced by special task forces in different installation fields. Therefore, many regulatory standards are adopted for different installation fields on a project-specific basis.

Currently there are no specific organizations to develop specifications, accreditation, or certification of geosynthetics in Korea except the Agency for Technology and Standards. This agency is undertaking the preparation and organization of these geosynthetic activities. The following organizations are related to specifications, accreditation, and certification of geosynthetics in Korea:

(1) Specifications

Agency for Technology and Standards
Ministry of Environment
Ministry of Construction and Transportation
Korean Standards Association

(2) Accreditation

The Korea Laboratory Accreditation Scheme (KOLAS) is the governmental accreditation body established Dec. 8, 1992, and administered by the Korean Agency of Technology and Standards(KATS). KOLAS has been actively participating in the international activities relating to testing, calibration, and inspection in conjunction with the Asia-Pacific Laboratory Cooperation (APLAC) and the International Laboratory Accreditation Cooperation (ILAC).

KOLAS signed Asia-Pacific Laboratory Cooperation Mutual Recognition Arrangement (APLAC MRA) in Sydney on Oct. 23, 1998 for testing, and May 22, 2001 for calibration. Since then, members of the APLAC MRA have expanded to 20 bodies from

KOLAS is also a signatory to the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement (ILAC MRA) which was signed in Washington, D.C., on Nov. 2, 2000. It now involves 46 member bodies from 37 economies. The ILAC arrangement will provide technical underpinning to international trade by promoting cross-border stakeholder’s confidence and acceptance of accredited testing and calibration results.

KOLAS operates in accordance with the requirements of ISO/IEC 17025, calibration and testing laboratory accreditation system/general requirements for operation and recognition, and is providing accreditation service for testing and calibration laboratories as well as inspection bodies.

The mission of KOLAS:

Provide national accreditation for competent laboratories and inspection bodies.
Encourage establishment and development of laboratories, inspection bodies and related facilities in Korea.
Promote mutual recognition with other accreditation bodies.
Promote international acceptance of test results and inspection reports produced by accredited organizations to facilitate trade.
Cooperate and collaborate with other accreditation bodies.

In addition to KOLAS accreditation, FITI/GSI Korea obtained GAI-LAP accreditation in 1999.

There are also numerous geosynthetics accreditation tests available in Korea on behalf of FITI/GSI-Korea, including 66 ASTM International, 8 ISO, and 3 GRI.

(3) Certification

Currently, there is no organization or institute giving geosynthetic certification in Korea. Private certification reports by Korean consultants, professors, researchers from private or public institutes, geotechnical consultants—or test reports from foreign geosynthetic laboratories—provide a part of geosynthetic certification. In the future, FITI/GSI-Korea should undertake a more significant role of certification of geosynthetics in Korea. FITI/GSI-Korea conducted a pilot certification project of uni-axial geogrids of Samyang Co.(Korea), in accordance with GCI-PCP of the Geosynthetic Institute (USA) during 2004–2005. The results were reasonable and future efforts are envisioned.

4. Korean research and development vs. international needs

Training and education programs in geosynthetics have been supervised by the Korean Geotechnical Society (KGS) from 1987 to 2000. Since 2001, the KGS has supervised most of academic programs of geosynthetic related conferences in Korea. These programs present geosynthetic types and manufacturing, testing methods, applications, and case histories. The focus of these programs is usually on design and installation rather than manufacturing and testing of geosynthetics. Three to four seminars and conferences on geosynthetics are held in Korea per year. For seminars, the special title is selected to be related in geosynthetic installation and some presentations and discussions are available.

Recently, Korean Geosynthetic Society–IGS Korean Chapter held the Asian Regional Conference for geosynthetics, GeoAsia 2004, and this successful conference motivated more geosynthetics activity in Korea. For conferences, special divisions are selected, such as: geosynthetics manufacturing, testing and evaluation, case histories, etc. Many papers are presented in each session. The supervising organizations for geosynthetic related seminars and conferences in Korea are as follows:

Korean Geotechnical Society–Division of Geosynthetics
Korean Society of Civil Engineers
Korean Geosynthetic Society–IGS Korean Chapter
Korean Fiber Society
FITI GSI-Korea/GSRL (INHA University)
GS-ATRA (GeoSynthetic Application Technology Association)
Geosynthetics Research Committee of KOSEF (Korea Science and Engineering Foundation)

Research topics and interests regarding geosynthetics in Korea are the same as those in the United States, Europe, and Japan. Most of the geosynthetic related geotechnical and environmental engineers, professors, and researchers undertake similar research. Also, worldwide information, data, and technical papers on geosynthetics are available in Korea. The main research fields involving geosynthetics are the application, design and assessment of soil retaining walls, waste landfills, roads, railroads, and runway construction, as well as soft soil reinforcement.

Research on geosynthetic regulations and standardization is ongoing by GSRL (Geosynthetic Research Laboratory), Division of Nano-Systems Engineering, INHA University, and testing methods is ongoing by FITI/GSI-Korea. Research on design, installation, and assessment of geosynthetics is under the Korea Institute of Construction Technology and Highway Research Center of the Korea Highway Department.

5. Lessons learned from forensic analysis of case histories applicable to specific areas

There are several areas presenting problems for geosynthetics in Korea. Some typical case histories include:

5.1 Environmental fields

Most waste landfills are constructed between valleys because of limited area. Therefore, they have steep slopes and many rough stones, and are in the category of canyon landfills (Photo 1). The problems that have occurred with this application include:

Failure of geomembranes due to imperfect seaming
–Destruction of waste-landfill system and pollution of surrounded soils
Degradation of polypropylene nonwoven geotextiles due to UV attack
–Decrease of tensile strength and elongation
Bentonite loss from GCLs
–Decrease of water-barrier properties

5.2 Geotechnical fields

Application examples of geogrids to the geotechnical field are the case of segmental retaining wall (Photo 2). For this case, many reduction factors influencing the long-term strength of geogrids must be considered, but specifically high reduction factors were adopted in Korea because of installation concerns. Therefore, high factors of safety must be reflected in design using geogrids and relatively high costs will be incurred even though the system is quite stable. There are no considerations of reduction factors for high rainfalls and drainage systems in design. Situations of inadequate drainage are very dangerous in rainfall seasons.

5.3 Transportation fields

For the application of geosynthetics to soft-soil reinforcement, road and railroad construction, geotextiles are used as reinforcement but they are subjected to high tensile stresses (Photo 3). This is the cause of failure of woven geotextiles by differential settlement and thus attempts to use glass fiber geogrids are ongoing.

6. Market analysis of geosynthetics

Production of domestic geosynthetics in Korea is represented in Chart 1. Here it is seen that the order of production is geotextiles > geomembranes > PDB > geogrids. Chart 2 shows geosynthetic end uses, and illustrates that the order of geosynthetic end uses is reinforcement > drainage/filtration > water barrier > separation.

Geosynthetics design aids in Korea are highly oriented to the geosynthetic properties of task forces that are required for installation rather than the suitability of geosynthetic application. It is not felt to be reasonable for geosynthetic development and advancement to do this. It is clearly recognized that standardization, regulations, and certification of geosynthetics must be developed to improve the situation in Korea.

Both domestic and imported geosynthetics are used in many geotechnical and environmental fields. For domestic geosynthetics, the large companies make use of their own trade routes from manufacturing to marketing. Most middle and small companies make an alliance (a kind of consortium) to supply and sell the required geosynthetics as necessary. On the other hand, imported geosynthetics are supplied through distributors and representatives located in Korea.

There are two types of purchasing and contracting agreements using geosynthetics in Korea. One is government supply and the other is individual supply. The former is an undertaking of the Supply Administration for the Republic of Korea and it occupies the largest portion. The latter is controlled by individual companies and occupies a relatively smaller portion. The final type of government supply is determined by turnkey type organizations. The results of this situation affect all kinds of contracting. The domestic construction fields utilizing geosynthetics are as follows:

Soft soil reinforcement—Nonwoven and woven geotextiles, PDBs, etc.
Soil retaining walls—Nonwoven geotextiles, geogrids, etc.
Waste landfills—Nonwoven geotextiles, HDPE geomembranes, GCLs, geonet composites etc.
Tunnel construction—Bentonite mixed with adhesive/HDPE geomembrane type
Subway construction—Bentonite mixed with adhesive/HDPE geomembrane type
Road and railroad construction—Nonwoven and woven geotextiles, geogrids etc.
Miscellaneous—many types of geosynthetics associated with various end uses

Han-Yong Jeon, Ph.D., GSRL (Geosynthetics Research Laboratory), Division of Nano-Systems Engineering, INHA University, Incheon, Korea.

References

Industrial Fabrics Association International (2005), 2006 GFR Specifier’s Guide.

Korean Geosynthetics Society (2005), Proceedings of 2005 Fall KGS Conference.

Korea Federation of Textile Industries (2005), Proceedings of KITEX 2005.

Korean Nonwoven Industry Association (2005), 2005 Annual Report of KNIC.

Korean Geotechnical Society–Division of Geosynthetics (2000), Proceedings of 2000 Special Seminar on Geosynthetics, September 22, Seoul, pp. 1-92.

Lawson. C, and Cowland J. (1999), “The Future for Geosynthetics in Asia”, Proc. of the 13th GRI Conference; Geosynthetics in the Future: Year 2000 and Beyond, pp. 380-390.

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