Regulations for use of geosynthetics for road embankments and subgrades/Geosintetiniu medziagu naudojimo keliu pylimams ir pagrindams norminiai dokumentai/Geosintetiku izmantosanas noteikumi cela uzberumos un zemes klatne/Geosunteetide kasutamise juhised tee muldkehas ja aluspinnases.
Vaitkus, Audrius ; Siukscius, Aurimas ; Ramunas, Vaidas 等
1. Introduction
Geosynthetics is the general term describing the flat or three
dimensional products that contains from at least one synthetic or
natural polymer. These products are used to solve civil engineering
problems. This includes eight main product categories: geotextiles,
geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam,
geocells and geocomposites. These polymeric products are widely used in
the ground structures where high levels of durability are required.
Geosynthetic products have a wide range of applications and are
currently used in many civil, geotechnical, transportation,
geoenvironmental, hydraulic, and private development applications
(Almeida et al. 2013; Al-Qadi et al. 2011; British standard BS 8006:2010
Code of Practise for Strengthened/Reinforced Soils and Other Fills;
EBGEO Empfehlungen fur den Entwurf und die Berechnung von Erdkorpern mit
Bewehrungen aus Geokunststoffen).
Taking road applications, geosynthetics are widely used to improve
soil mechanical properties. This is very common situation when soft
soils are found in subgrade. It allows to reduce the fill soil
thickness, to make the settlements as uniform as possible, to build a
structure on soft soils, to build embankments with steep slopes, to
evade the unwanted mixing of the soils, to increase the embankment
stability, to increase the durability of the structure, to reduce the
building time at same time reducing the C[O.sup.2] emission (Skrinskas
2012; Vaitkus et al. 2012). The other area where geosynthetic products
are widely used is the soil erosion control caused by water flow (Oh,
Shin 2007; Zhuang et al. 2013). Geosynthetic products allow building
embankments in water flood areas, to protect the slopes from washout
caused by ground water or rain water (Rawal et al. 2010). It also allows
to rebuild washed out slopes and to maintain the natural looks of the
slope surfaces. A lot of applications are related with road pavement
structure, high level theoretical analysis and calculations are
performed to evaluate the performance of geosynthetics (Abu-Farsakh et
al. 2014; Gongora, Palmeira 2012; Manivannan et al. 2011; Pasquini et
al. 2013; Sert, Akpinar 2012).
Having such a wide range of geosynthetics usage it is necessary to
have regulations and quality control. Every country using geosynthetic
materials can have its own regulations or, if it belongs to EU, it can
use the regulations that are valid in European Union (EU) (Eiksund et
al. 2002; Wilmers 2002). In general, most of the regulations include the
main descriptions, technical properties, and application areas,
guidelines for design, test methods and selection of the geosynthetic
materials. EU also has a number of standards to control the quality and
performance of the geosynthetic materials--BS 8006:2010; EBGEO; M-Geok E
05 Merkblatt uber die Anwendung von Geokunststoffen im Erdbau des
Strassenbaus mit den Checklisten fur die Anwendung von Geokunststoffen
im Erdbau des Strassenbaues; TL Geok E--StB 05 Technische
Lieferbedingungen fur Geokunststoffe im Erdbau des Strassenbaues testing
of geosynthetic material performance are performed using EN or American
Society for Testing and Materials (ASTM) standards.
2. Possible ways of using the geosynthetics in road construction
While many possible design methods or combinations of methods are
available to the geotextile designer, the ultimate decision for a
particular application usually takes one of three directions: design by
cost and availability, design by specification and design by function.
Geotextile design by cost and availability is very simple. The
funds available are divided by the area to be covered and a maximum
available unit price that can be allocated for the geotextile is
calculated. The geotextile with the best properties is then selected
within this unit price limit and according to its availability.
Intuition plays a critical role in the selection process. The method is
obviously weak technically but is one that is still sometimes practiced.
It perhaps typified the situation in the early days of geotextiles, but
is outmoded by current standards of practice.
Geotextile design by specification is very common and used almost
exclusively when dealing with public agencies. In this method several
application categories are listed in association with various physical,
mechanical and/or hydraulic properties. A specification of this type
that is used by the country road department is given. It has its typical
format, listing the various common applications against minimum or
maximum property values. Different agencies have very different
perspectives as to what properties are important and as to their method
of obtaining the numeric values.
Designed by function consists of assessing the primary function
that the geotextile will serve and then calculating the required
numerical value of a particular property for that function. It is
necessary to evaluate a number of concepts and fundamental principles
when calculating the required numeric value. As an example, let's
take the soil reinforcement.
Reinforcement is incorporated in engineering fill, or inserted into
natural ground either to provide steeper slopes than would otherwise be
possible or to improve load carrying capacity. Reinforcement is also
used to improve the performance of weak soils to support embankments or
other resilient structures. Concepts and fundamental principles in
calculations:
--limit state principals;
--partial factors;
--design loads;
--design strengths;
--fundamental mechanisms;
--soil reinforcing mechanisms in walls and slopes;
--soil reinforcing mechanisms in embankment foundations;
--soil reinforcement interaction;
--soil properties to be considered;
--reinforcing geometry;
--reinforcement bond;
--effects of reinforcement axial stiffness on loads;
--factors affecting tensile behaviour of reinforcement.
3. Regulations for use of geosynthetics
There are lots of regulations issued to control the geosynthetic
materials design and quality. Unfortunately there are not so many
regulations that are widely used, not only in the countries they were
issued, but also in the other European countries.
United Kingdom has its own regulations for geosynthetics called the
British standard. The well-known BS 8006:2010 is widely used. This
British standard contains recommendations and guidance for the
application of reinforcement techniques to soils, as fill or in situ and
to other fills. The standard is written in a limit state format and
guidelines are provided in terms of partial material factors and load
factors for various applications and design lives. This standard is
related with ISO and EN standards valid for geosynthetic materials.
Germany uses the whole system of regulations. At first the EBGEO.
These recommendations were created by German Geotechnical Society. In
Germany, the analysis and design of reinforced fill structures, as well
as the required safety stipulations, are controlled by standard for
geotechnical design DIN 1054:2005 Baugrund--Sicherheitsnachweise im Erd-
und Grundbau--Erganzende Regelungen zu DIN EN 1997-1 and other relevant
standards. These recommendations are based on DIN 1054:2005-01
Baugrund--Sicherheitsnachweise im Erd- und Grundbau and analyses are
performed using the partial safety factor approach. In addition, the
European design standard EN 1997-1 (EC 7-1) Eurocode 7: Geotechnical
Design is also referenced. For quality assurance, the M-Geok E 05 and TL
Geok E--StB 05 are used. It is also related with some ISO and DIN-EN
standards valid for geosynthetic materials.
Poland use harmonized standards that are valid in Europe and also
their own quality control system. They use technical approvals called
"Aprobata Techniczna". This document is controlled by The Road
and Bridge Research Institute which is involved in research and
development projects in the area of construction and maintenance of the
road and bridge structures and facilities, specifically roads and road
bridges, railway subgrades, railway bridges, and underground structures.
However, if the production of building product has been conducted
according to Polish harmonized standard PN-EN, then there is no legal
basis for issuing technical approval of the Road and Bridge Research
Institute.
The situation when having the control system according the
harmonized EN standards and local regulations together is very common in
the whole Europe.
4. Regulations for use of geosynthetics for roads in Lithuania
Lithuania is no exception from other EU countries. All the
standards for geosynthetic materials that are valid in EU are also valid
in Lithuania. Using more and more geosynthetic materials in civil
engineering had led to a need of having not only the EN standards but
also the regulations for geosynthetic materials in Lithuania.
This is made by creating two separate documents. The first is
technical specifications (Technini reikalavimu aprasas --abbrevation in
Lithuanian--TRA) and the second is technical guide (Metodiniai
nurodymai--abbrevation in Lithuanian --MN) for geosynthetics used in the
road soil works.
TRA is made according German technical supply conditions for TL
Geok E--StB 05. This document has three provisions:
1. Geosynthetics, that is used in road soil works, TRA GEOSINT ZD
13 "Geosintetikos, naudojamos zemes darbams keliuose, techniniu
reikalavimu aprasas" expounds the requirements for geosynthetic
materials, used in soil works when building new country roads and
drainage systems. This document is also applied to local roads
(streets), other traffic zones.
2. TRA GEOSINT ZD 13 implements Lithuanian standard LSTEN
13249:2000 Geotextiles and Geotextile-Related Products--Characteristics
Required for Use in the Construction of Roads and Other Trafficked Areas
(Excluding Railways and Asphalt Inclution).
3. Every building product, imported from the EU member country,
from country that has signed the European Economic Area contract, or
from Turkey, can be supplied to the market of Lithuanian Republic
without any restrictions, if it was legally made in EU member country,
country that has signed the European Economic Area contract, or in
Turkey or legally imported into these countries from third parties and
it is allowed to supply it in the market in that country. The free
movement of construction products limitations are allowed if it does not
provide an equivalent level of protection or public safety, business,
animal or plant health and life protection reasons.
This document indicates what test methods have to be specified for
geotextiles and geogrids according the application area. As a basis for
this, the standard EN 13249:2000 was used. Table 1 shows the modified
requirements according the special needs in Lithuania.
This was done in the same way for the geosynthetic barriers (Table
2). In this case, as a basis, the standard LST EN 13361:2013
Geosynthetic Barriers--Characteristics Required for Use in the
Construction of Reservoirs and Dams was used. This document also
describes the minimum parameters of the geosynthetic materials,
durability requirements, explains what EN standards has to be used for
each test of the material, explains the supply conditions, CE
(Conformite Europeenne) marking and Declaration of conformity.
MD is made according German regulations M-Geok E 05 and EBGEO. This
document has 6 provisions:
Geosynthetics, that is used in road soil works, MN GEOSINT ZD 13
expounds the requirements.
1. For geosynthetic materials, used in soil works when building new
country roads and drainage systems. This document is also applied to
local roads (streets), other traffic zones.
2. Geosynthetics, that is used in road soil works, TRA GEOSINT ZD13
is applied together with MN GEOSINT ZD13.
3. Steel reinforcing elements are not included.
4. MN GEOSINT ZD 13 takes unique German and harmonious EU and
international standards and corresponding updates into account.
5. Products from other EU member countries that do not comply with
the conditions stated in these directions together with the tests and
observation made in manufacturers country are assessed as equivalent to
these requirements if they also provides the required safety level: for
work, health and are suitable to use for the same period time.
6. According the original purpose, MN GEOSINT ZD 13 is not suitable
to be as contract basis or as a directive. According the secondary
purpose.
7. MN GEOSINT ZD 13 in parts or transformed can be applied to be a
part of construction, supply and engineering contract.
MN GEOSINT ZD 13 describe the main concepts of geosynthetics,
explains every product in a category that is classified in Fig. 1.
Separation, filtration, drainage, reinforcement, erosion control,
protection and barrier applications are described in details.
Specifications for materials, installation, work description. Design for
reinforced soil and drainage systems. Test methods according EN
standards. This document also has two design examples.
[FIGURE 1 OMITTED]
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
[FIGURE 4 OMITTED]
[FIGURE 5 OMITTED]
The first example shows how to increase the bearing capacity of the
embankment. Special design charts are used or simplify the indication of
the fill soil thickness (Fig. 2). When calculating the required tensile
strength for a geogrid, the long term tensile strength has to be
evaluated:
[F.sub.d] = [F.sub.k,5%]/([A.sub.1] [A.sub.2] [A.sub.3] [A.sub.4]
[A.sub.i][gamma]],
where [F.sub.d]--design tensile strength, kN/m;
[F.sub.k,5%]--tested short term tensile strength, kN/m; [A.sub.1]--creep
partial safety factor; [A.sub.2]--installation damage partial safety
factor; [A.sub.3]--junction and connection partial safety factor;
[A.sub.4]--durability partial safety factor (weathering, chemical and
microbiological effects); [A.sub.i]--in some cases additional partial
safety factors has to be evaluated, as an example dynamic impact from
traffic loads; [gamma]--partial safety factor evaluating tolerances of
the material properties and possible tolerances of the building
geometry.
The second example shows how to calculate the slope to be resistant
to sliding (Fig. 3). There are four collapse types described and
evaluated (Figs 4-7). The first collapse type is slope surface sliding
above the reinforcement (Fig. 4). The second collapse type is exceeding
the passive earth pressure in the bottom of the slope (Fig. 5). The
third collapse type is the reinforcement pull out from the anchoring
trench including the shear stress for the reinforcement and the lifting
forces of the trench fill (Fig. 6). The fourth collapse type is the
failure of the top of the slope (Fig. 7).
By using MN GEOSINT ZD 13, it is the first time the standards LST
EN 13249 and LST EN 13361 are implemented in Lithuania. MN GEOSINT ZD 13
can be adjusted and improved according the tests of geosynthetics,
internal production control and control test results.
5. Conclusions
Creating two separate documents, technical specification TRA
GEOSINT ZD 13 and technical guide MN GEOSINT ZD 13 for geosynthetics
used in the road soil works enabled the design and material supply
control in Lithuania.
[FIGURE 6 OMITTED]
[FIGURE 7 OMITTED]
For technical guide MN GEOSINT ZD 13 include some experience and
examples of EBGEO Empfehlungen fur den Entwurf und die Berechnung von
Erdkorpern mit Bewehrungen aus Geokunststoffen. Because of that
methodical directions became more universal document and for this stage
of regulations for geosynthetics in Lithuania is very useful feature,
because there is still no separate document for geosynthetic material
design.
Technical guide MN GEOSINT ZD 13 additionally has Annex 2 that
shows the dependence between California Bearing Ratio and deformation
modulus ([E.sub.v2], [E.sub.v1], [E.sub.v]). This annex allows the
designer to know soil deformation modulus design values when looking at
the geotechnical investigations where only [E.sub.v] or California
Bearing Ratio values are given.
When presenting the application schemes of use of geosynthetics,
the separation layer was indicated as geotextile and reinforcement as
geogrid or woven geotextile. This has been done due to the fact that
people that use geosynthetic materials would not use nonwoven geotextile
as a reinforcement layer.
These regulations include both types of design methods, design by
specification and design by function.
Technical specification TRA GEOSINT ZD 13 and technical guide MN
GEOSINT ZD 13 for geosynthetics used in the road soil works specify
geotextile and geogrid required properties and test methods according
the application area. It ensures the use of high quality material for
construction and increase life time of road pavement structures.
Caption: Fig. 1. Geosynthetic materials
Caption: Fig. 2. Design chart for subbase layer thickness
Caption: Fig. 3. Reinforcement installation in the anchoring trench
Caption: Fig. 4. Resistance to sliding
Caption: Fig. 5. Exceeding soil resistance in the bottom of the
slope
Caption: Fig. 6. Reinforcement pull-out from the anchoring trench
Caption: Fig. 7. Shear strength of the top of the slope
doi: 10.3846/bjrbe.2014.11
References
Abu-Farsakh, M. Y.; Gu, J.; Voyiadjis, G. Z.; Chen, Q. 2014.
Mechanistic-Empirical Analysis of the Results of Finite Element Analysis
on Flexible Pavement with Geogrid Base Reinforcement, International
Journal of Pavement Engineering.
http://dx.doi.org/10.1080/10298436.2014.893315
Almeida, M. S. S.; Hosseinpour, I.; Riccio, M. 2013. Performance of
a Geosynthetic-Encased Column (GEC) in Soft Ground: Numerical and
Analytical Studies, Geosynthetics International 20(4): 252-262.
http://dx.doi.org/10.1680/gein.13.00015
Al-Qadi, I. L.; Dessouky, S.; Tutumluer, E.; Kwon, J. 2011. Geogrid
Mechanism in Low-Volume Flexible Pavements: Accelerated Testing of
Full-Scale Heavily Instrumented Pavement Sections, International Journal
of Pavement Engineering 12(2): 121-135.
http://dx.doi.org/10.1080/10298436.2010.535534
Eiksund, G.; Want, A.; Rathmayer, H. 2002. Norgeospec, a Proposed
System for Specification and Control of Geotextiles for Separation and
Filtration in Roads in the Nordic Countries, in Proc. of the 7th
International Conference on Geosynthetics. September 22-27, 2002, Nice,
France, 1375-1378.
Gongora, I. A. G.; Palmeira, E. M. 2012. Influence of Fill and
Geogrid
Characteristics on the Performance of Unpaved Roads on Weak
Subgrades, Geosynthetics International 19(2): 191-199.
http://dx.doi.org/10.1680/gein.2012.19.2.191
Manivannan, G.; Karim, M. R.; Gnanendran, C. T.; Lo, S.-C. R. 2011.
Calculated and Observed Long Term Performance of Leneghans Embankment,
Geomechanics and Geoengineering: an International Journal 6(3): 195-207.
http://dx.doi.org/10.1080/17486025.2011.578667
Oh, Y. I.; Shin, E. C. 2007. Reinforcement and Arching Effect of
Geogrid-Reinforced and Pile-Supported Embankment on Marine Soft Ground,
Marine Georesources and Geotechnology 25(2): 97-118.
http://dx.doi.org/10.1080/10641190701359591
Pasquini, E.; Bocci, M.; Ferrotti, G.; Canestrari, F. 2013.
Laboratory Characterisation and Field Validation of Geogrid-Reinforced
Asphalt Pavements, Road Materials and Pavement Design 14(1): 17-35.
http://dx.doi.org/10.1080/14680629.2012.735797
Rawal, A.; Shah, T.; Anand, S. 2010. Geotextiles: Production,
Properties and Performance, Textile Progress 42(3): 181-226.
http://dx.doi.org/10.1080/00405160903509803
Sert, T.; Akpinar, M. V. 2012. Investigation of Geogrid Aperture
Size Effects on Subbase-Subgrade Stabilization of Asphalt Pavements, The
Baltic Journal of Road and Bridge Engineering 7(2): 160-168.
http://dx.doi.org/10.3846/bjrbe.2012.22
Skrinskas, S. 2012. International and Scientific Activities of the
Lithuanian Road Administration Are the Source of Experience, The Baltic
Journal of Road and Bridge Engineering 7(3): 169-172.
http://dx.doi.org/10.3846/bjrbe.2012.23
Vaitkus, A.; Vorobjovas, V; Ziliute, L.; Kleiziene, R.;
Ratkevicius, T. 2012. Optimal Selection of Soils and Aggregates Mixtures
for a Frost Blanket Course of Road Pavement Structure, The Baltic
Journal of Road and Bridge Engineering 7(2): 154-159.
http://dx.doi.org/10.3846/bjrbe.2012.21
Wilmers, W. 2002. The Revised German Regulations for the Use of
Geosynthetics in Road Construction, in Proc. of the 7th International
Conference on Geosynthetics. September 22-27, 2002, Nice, France,
1401-1404.
Zhuang, Y.; Wang, K. Y.; Liu, H. L.; Chu, J. 2013. The Contribution
of the Subsoil in a Reinforced Piled Embankment, European Journal of
Environmental and Civil Engineering 17(S1): s269-s281.
http://dx.doi.org/10.1080/19648189.2013.834599
Received 13 March 2014; accepted 6 May 2014
Audrius Vaitkus (1)([mail]), Aurimas Siukscius (2), Vaidas Ramunas
(3)
(1) Road Research Institute, Vilnius Gediminas Technical
University, Linkmenu g. 28, 08217 Vilnius, Lithuania
(2) JSC VIACON, Perkunkiemio g. 4a, 12128 Vilnius, Lithuania
(3) Dept of Roads, Vilnius Gediminas Technical University,
Sauletekio al. 11, 10223 Vilnius, Lihuania
E-mails: (1) audrius.vaitkus@vgtu.lt; (2) aurimas@viacon.lt; (3)
vaidas.ramunas@vgtu.lt
Table 1. Geotextile and geogrid required properties and test methods
according the application area
Properties Test method Application area
Separation Filtration
Mass per unit area LST EN ISO 9864:2005 S S
Thickness LST EN ISO 9863:2005 H S
Max tensile LST EN ISO 10319:2008 H H
strength (a)
Elongation at max LST EN ISO 10319:2008 S S
load
Joints/seams LST EN ISO 10321:2008 - -
tensile strength
Static puncture LST EN ISO 12236:2000 A A
test (a, b)
Dynamic perforation LST EN ISO 13433:2006 - -
test (a)
Friction
characteristics LST EN ISO 12957-1:20 H H
Creep (c) LST EN ISO 13431:2000 A H
Installation damage LST EN ISO 10722:2000 - -
Long term LST EN 13719:2002 H H
protection
efficiency
Characteristic LST EN ISO 12956:2000 S S
opening size
Water permeability LST EN ISO 11058:2001 S S
normal to the
plane (b)
Water flow capacity LST EN ISO 12958:2000 S S
in their plane
Durability LST EN 13249 Annex B S S
LST EN 14030:2002 or
Resistance to LST EN ISO 13438:2005 H S
chemical
degradation
Microbiological LST EN 12225:2000 H H
resistance
Resistance to LST EN 12224:2000 S S
weathering
Application area
Properties Drainage Reinforceme Protection
Mass per unit area S S S
Thickness S S H
Max tensile A S H
strength (a)
Elongation at max S S S
load
Joints/seams - S/A -
tensile strength
Static puncture A A A
testa, (b)
Dynamic - - H
perforation test (a)
Friction H H -
characteristics
Creep (c) H A -
Installation damage H - -
Long term H H H
protection
efficiency
Characteristic S S S
opening size
Water permeability S S S
normal to the plan
Water flow capacity A A S
in their plane
Durability S S S
Resistance to S S H
chemical
degradation
Microbiological A S H
resistance
Resistance to S S S
weathering
Notes: H--required according standard LST EN 13249 (in Europe);
A--according standard LST EN 13249 required in all application
conditions; S--according standard LST EN 13249 required for
specific application conditions;--not relevant; a--if mechanical
properties (tensile strength and static puncture resistance) in this
table are marked by letter H, manufacturer has to apply the data to
both properties. If only one property is important--tensile strength
or static puncture resistance, it is enough to apply it on the
technical description; b - this test is not relevant for some types
of materials, for example geogrids; c--"S/A"--"S" is relevant for
road constructions, "A" is relevant for reinforcement under
embankments or in steep slopes.
Table 2. Required properties test methods according the application
area for geosynthetic barriers
Type
Properties GBR GBR-C
Mass per unit area A H
Thickness H H
Permeability to liquids H H
Swell index - A
Max tensile strength H H
Elongation at max load A A
Static puncture test H H
Burst strength S S
Peel strength S S
Friction: direct shear test S S
Friction: inclined plane test S S
Foldability at low temperature S -
Thermal expansion A -
Resistance to weathering H -
Microbiological resistance - S
Resistance to oxidation H H
Resistance to environmental H S
stress cracking
Resistance to leaching A S
Resistance to wetting-drying cycles - S
Resistance to freezing-thawing cycles - S
Resistance to roots S S
Test method
Properties GBR GBR-C
Mass per unit area LST EN 1849-2:2010 LST EN 14196:
2004
Thickness LST EN 1849-2:2010 LST EN ISO
LST EN ISO 9863-1:2005 9863-1:2005
Permeability to liquids LST EN 14150:2006 ASTM D 5887
Swell index - ASTM D 5890
Max tensile strength LST EN ISO 527-1:2001, LST EN ISO
10319:2008
Elongation at max load LST EN ISO 527-1:2001, LST EN ISO
10319:2008
(a)
Static puncture test LST EN ISO 12236:2000 LST EN ISO
12236:2000
Burst strength LST EN 14151:2010 LST EN
14151:2010
Peel strength LST ISO 34-1:2011 (b) ASTM D 6496
Friction: direct shear test LST EN ISO 12957-1:2005 LST EN ISO
(a) 12957-1:2005
(c)
Friction: inclined plane LST EN ISO 12957-2:2005 LST EN ISO
test 12957-2:2005
Foldability at low LST EN 495-5:2003 -
temperature
Thermal expansion ASTM D 696-08 -
Resistance to weathering LST EN 12224:2000 d
Microbiological resistance LST EN 12225:2000 LST EN
12225:2000
Resistance to oxidation LST EN 14575:2005 LST EN
14575:2005
Resistance to environmental LST EN 14576:2005 LST EN
stress cracking 14576:2005 (e)
Resistance to leaching LST EN 14415:2004 LST EN
14415:2004
Resistance to - LST EN
wetting-drying 14417:2006
cycles
Resistance to - LST EN
freezing-thawing 14418:2006
cycles
Resistance to roots LST CEN/TS 14416:2006 LST CEN/TS
14416:2006
Notes: GBR--geomembrane; GBR-C--geosynthetic clay liner;
H--required according standard LST EN 13361 (in Europe);
A--according standard LST EN 13249 required in all application
conditions; S--according standard LST EN 13249 required for specific
application conditions;--not relevant; (a)--using specimen type
5A, when test speed is 100 mm/min; (b)--edge specimen without
groove, when test speed is 50 mm/min; (c)--internal junctions of
GBR-C can be evaluated during shear test; (d)--this parameter is not
evaluated because GBR-C must be covered immediately after
installation; (e)--suited for GBR-C, if GBR-C is in composite with
GBR.
