Chapter 3: NESTEM

NESTEM

NESTEM is a geotextile/geogrid material for use in reinforced earthwork and is fabricated using a continuous impregnation process (Fig. 3.56). Glass fibers are soaked in a corrosion-resistant thermosetting resin system such as a vinylester or polyester to form a grid-like structure without significant dimensions in the thickness direction.

Fig. 3.56. Schematic of the NESTEM process.

The material, which has high tensile strength and stiffness and is extremely light, has excellent chemical resistance and has been shown to have extremely good long-term potential under harsh field conditions. Figure 3.57 shows a schematic of the layout and grid spacing of the material. Standard specifications for the five commonly available varieties are listed in Table 3.19.

Fig. 3.57. Schematic layout of NESTEM structure.

Table 3.19
Specification for Standard Grades of Glass Fiber Reinforced NESTEM Elements
Specification			Grade of NESTEM
	GB5	GB8		GB10	GB15	GB22
Weight (g/m²)	260	420		510	850	960
Tensile Strength (Ton/m): L	5	8		10	15	20
T	2.5	4		5	7.5	10

Key: L=Longitudinal; T=Transverse

The glass fiber reinforced thermoset resin based composite has a fiber volume fraction of 50% and generally contains a black pigment or carbon black to increase UV resistance. NESTEM is available in rolls of 30 m length and 1 m width. As seen in Fig. 3.58, NESTEM can be used to reinforce the road subgrade, where it prevents rutting of the road surface, constrains irregular settlement of soft ground and prevents cracking of the road.

Fig. 3.58. Use of NESTEM in road subgrades.

Fig. 3.59. Use of NESTEM in road widening.

NESTEM is also used for stabilizing embankments during the widening of roads, where space constraints can result in the use of very steep slopes (Fig. 3.59). Its use in embankment slopes and reinforced walls is shown in Fig. 3.60. It is easy to place and is fairly easily overgrown by vegetation. It serves as an anchor for strata and offers sufficient frictional resistance between the soil and the layers of NESTEM to stabilize surrounding soil strata/layers.

Fig. 3.60. Use of NESTEM in embankment slopes and reinforced soil walls.

Table 3.20 represents a partial list of projects using NESTEM conducted from 1989 to 1993.

Table 3.20
Examples of Projects using NESTEM
No	Date	Project Name	Project Site	Client	Specification
1	10/1989	Nippondenso Co., Ltd. Nukata Test Course	Nukatabe County, Aichi Prefecture	Nippondenso Co., Ltd.	Reinforced embankment, Slope 1:1.8, H = 12 m
2	12/1989	The Tokyo Electric Power Co., Ltd., Kashiwazaki Atomic Power Plant	Kashiwazaki City, Niigata Prefecture	The Tokyo Electric Power Co., Ltd.	Reinforced soil wall Slope 1:0:3; H = 3 m
3	12/1989	Public Works Research Institutes, Ministry of Construction, reinforced retaining wall experiment	Tsukuba City, Ibaraki Prefecture	Public Works Research Institute, Ministry of Construction	Reinforced soil wall Slope 1:0:1; H = 5 m
4	5/1990	ITJ Second Stage Earthworks	Yamaguchi City, Yamaguchi Prefecture	ITJ Co., Ltd.	Reinforced soil wall Slope 1:0:3; H = 7 m
5	5/1990	Daini Den Den Aomori Route, Tsugaru Station	Tsugaru County, Aomori Prefecture	Daini Den Den Co., Ltd.	Reinforced soil wall Slope 1:0:2; H = 3 m
6	5/1990	Tokin Lakeside Hill, First Regulating Reservoir	Tokin City, Chiba Prefecture	Toso Urban Development Co., Ltd.	Reinforced soil wall Slope 1:1:0; H = 4.5 m
7	7/1990	Arigawa Dam Gensekiyama Covering Works	Setana County, Hokkaido	Hokkaido Development Agency	Reinforced soil wall Slope 1:0:5; H = 5 m
8	9/1990	KDD Ouchibata Relay Station	Yamaguchi City, Yamaguchi Prefecture	KDD Co., Ltd.	Reinforced soil wall Slope 1:0:3; H = 8 m
9	9/1990	Tokin Lakeside Hill Second Regulating Reservoir	Tokin City, Ibaraki Prefecture	Toso Urban Development Co., Ltd.	Reinforced soil wall Slope 1:1:0; H = 4.5 m
10	10/1990	Izu Amagi Earthworks	Ito City, Shizuoka Prefecture	Mori Residence	Reinforced soil foundation
11	12/1990	Nosu Street Widening Works	Hachioji City, Tokyo Prefecture	Tama Town Development Office, Tokyo Prefecture	Reinforced soil wall Slope 1:0:2; H = 2 m
12	2/1991	Ninomiya Town, Ishiki Nakazato Land Readjustment Project	Ninomiya Town, Kanagawa Prefecture	Ninomiya Town, Ishiki Nakazato Land Adjustment Association	Reinforced soil wall Slope 1:1:0; H = 5.5 m
13	4/1991	Narita New Marketing Center	Narita City, Chiba Prefecture	Sanki Co., Ltd.	Reinforced soil wall Slope 1:0:3; H = 6.5 m
14	4/1991	Izu Amagi Earthworks	Ito City, Shizuoka Prefecture	Mori Residence	Reinforced soil foundation Reinforced soil wall Slope 1:0:5; H = 5 m
15	5/1991	Tokiwa Highway	Niizu City, Niigata Prefecture	Japan Highway Public Corp.	Reinforced base course (temporary road); L = 50 m
16	7/1991	Natori Multi-Purpose Gym	Natori City, Miyagi Prefecture	The Tohoku Electric Power Co., Inc.	Reinforced embankment Slope 1:1:5; H = 23 m
17	7/1991	Hakusan Senyo Kougen Skiing Ground	Ishikawa County, Ishikawa Prefecture	Hakusan Lake Highland Co., Ltd.	Reinforced soil wall Slope 1:0:3; H = 8 m

Table 3.20 (cont.)
Examples of Projects using NESTEM
No	Date	Project Name	Project Site	Client	Specification
18	7/1991	Daini Den Den Higashi Kanasaka Second Route, Shimizudera Relay Station	Higashi Chikuma County, Nagano Prefecture	Daini Den Den Co., Ltd.	Reinforced soil wall Slope 1:0:5; H = 7.5 m
19	12/1991	Tamura, Okiyado Land Readjustment Project	Tsuchiura City, Ibaraki Prefecture	Ibaraki Prefecture	Reinforced base course
20	1/1992	Itabashi #5 & #6 Embankment & Revetment Works	Itabashi Town, Tokyo Prefecture	Arakawakaryu Work Office, Ministry of Construction	Reinforced soil wall Slope 1:0:5; H = 3 m
21	2/1992	ITJ Yamaguchi-Miyazaki Microwave Route, Hatakura Wireless Station Project	Nakatano Town, Miyazaki Prefecture	ITJ CO., Ltd.	Reinforced soil wall Slope 1:0:5; H = 11.5 m
22	3/1992	Tokiwa Highway Niizu Works	Niizu City, Niigata Prefecture	Japan Highway Public Corporation	Reinforced base course (temporary road) L = 632 m
23	4/1992	#6 Embankment & Revetment Works	Itabashi Town, Tokyo Prefecture	Arakawakaryu Work Office, Ministry of Construction	Reinforced soil wall Slope 1:0:5; H = 3 m
24	4/1992	Aizu Nanbu Agricultural Irrigation Project, Okawa Driving Channel Improvement Works	Hongo Town, Onuma County, Fukushima Prefecture	Aizu Irrigation Work Office, Tohoku Regional Agricultural Administration	Reinforced soil wall Slope 1:0:5; H = 5.6 m
25	5/1992	ITJ Yamaguchi-Miyazaki Microwave Route, Kotsikiyama Wireless Station Project	Ogori Town, Yoshiki County, Yamaguchi Prefecture	ITJ CO., Ltd.	Reinforced soil wall Slope 1:0:3, 0.5; H = 8 m
26	7/1992	Hachinohe Sawazato Road Improvement Works	Hachinohe City, Aomori Prefecture	Hachinohe Town Development Office, Industrial Relocation and Coal Production Areas Promotion Corp.	Reinforced soil wall Slope 1:0:5; H = 7.5 m
27	12/1992	Nihon Shokusei Central Research Institute	Tsuyama City, Kagawa Prefecture	Nihon Shokusei Co., Ltd.	Reinforced soil wall Slope 1:0:5; H = 6 m
28	1/1993	Takamatsu Airport Vestige Land Works	Takamatsu City, Kagawa Prefecture	Kagawa Prefecture	Reinforced base course
29	3/1993	Miyaoku Dam Temporary Road Works	Ouda Town, Nara Prefecture	Nara Prefecture	Reinforced soil wall Slope 1:0:1; H = 3.5 m

Published: November 1998; WTEC Hyper-Librarian