ISO 19044:2024
(Main)Test methods for fibre-reinforced cementitious composites — Load-displacement curve using notched specimen
Test methods for fibre-reinforced cementitious composites — Load-displacement curve using notched specimen
This document specifies the test method for the load-displacement curves of fibre-reinforced cementitious composites (FRCC) by three-point loading of notched prisms. The main purpose of this test is to evaluate the tension softening curve of FRCC. NOTE 1 Both crack mouth opening displacement (CMOD) and load point displacement (LPD) are specified as the displacement in load-displacement curves, but measurement of both might not be necessary. Either can be selected depending on the purpose of measurement. NOTE 2 Three-point bending test using notched specimen generally provides higher results than those observed in four-point bending test, in which the fracture occurs at the weakest point of the specimen.
Méthodes d'essai des composites à base de ciment renforcés par des fibres — Courbe de déplacement de charge utilisant un échantillon entaillé
General Information
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Standards Content (Sample)
International
Standard
ISO 19044
Second edition
Test methods for fibre-reinforced
2024-12
cementitious composites — Load-
displacement curve using notched
specimen
Méthodes d'essai des composites à base de ciment renforcés
par des fibres — Courbe de déplacement de charge utilisant un
échantillon entaillé
Reference number
© ISO 2024
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Test specimen . 2
5.1 Geometry .2
5.2 Fabrication of specimen .2
5.3 Loading of specimen .3
6 Test equipment . 3
6.1 Testing machine .3
6.2 Loading apparatus .3
6.3 Measuring device for load .4
6.4 Measuring device for CMOD .4
6.5 Measuring device for LPD .5
7 Test procedure . 5
8 Calculations . 6
9 Test report . 6
Annex A (informative) Method of estimating tension softening curve . 8
iii
Foreword
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This document was prepared by Technical Committee is ISO/TC 71, Concrete, reinforced concrete and pre-
stressed concrete, Subcommittee SC 6, Non-traditional reinforcing materials for concrete structures.
This second edition cancels and replaces the first edition (ISO 19044:2016), which has been technically
revised.
The main changes are as follows:
— in Clause 2, the normative reference has been updated;
— in Clause 4, the list of symbols has been updated;
— the legend for Figure 1 has been edited;
— A.7 has been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
International Standard ISO 19044:2024(en)
Test methods for fibre-reinforced cementitious composites —
Load-displacement curve using notched specimen
1 Scope
This document specifies the test method for the load-displacement curves of fibre-reinforced cementitious
composites (FRCC) by three-point loading of notched prisms. The main purpose of this test is to evaluate the
tension softening curve of FRCC.
NOTE 1 Both crack mouth opening displacement (CMOD) and load point displacement (LPD) are specified as the
displacement in load-displacement curves, but measurement of both might not be necessary. Either can be selected
depending on the purpose of measurement.
NOTE 2 Three-point bending test using notched specimen generally provides higher results than those observed in
four-point bending test, in which the fracture occurs at the weakest point of the specimen.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 1920-3:2019, Testing of concrete — Part 3: Making and curing test specimens
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
fibre-reinforced cementitious composite
FRCC
concrete or mortar containing short discrete fibres that are distributed in matrix
Note 1 to entry: Fibres include chemical fibres (metallic fibres, inorganic fibres, synthetic fibres, and so on) and
natural fibres.
3.2
ligament
area above the notch subject to fracture
3.3
notch
cut for the initiation of fracture
4 Symbols
Symbol Unit Description Reference
a mm depth of notch 5.1
b mm width of ligament 5.1
D mm depth of cross section of specimen 5.1
h mm height of ligament 5.1
L mm overall length of specimen 5.1
n mm width of notch 5.1
S mm loading span 5.1
t mm thickness of knife-edge 6.4
k
5 Test specimen
5.1 Geometry
Specimens shall be prisms of square cross section with a notch at the mid-length as shown in Figure 1.
a) The cross sectional size of the specimen shall be fixed with two types for the ease of operating as
follows: 150 mm × 150 mm and 100 mm × 100 mm. The side length of the cross section of the specimen
shall be equal to or larger than three times the fibre length.
The specimens with different dimensions provide different test results even if the same FRCC is used.
These test results should not be compared.
b) The overall length of the specimen (L) shall not be less than 3,5 D.
c) The notch depth (a ) and notch width (n ) shall be 0,3 D and not more than 5 mm, respectively.
0 0
Key
1 The arrows show the direction of casting.
Figure 1 — Specimen
5.2 Fabrication of specimen
a) The maximum aggregate size shall not be larger than 1/4 of the side length of the cross section of the
specimen.
b) Moulds specified in ISO 1920-3:2019, 5.2.1 shall be used.
c) FRCC shall be placed in one placing sequence without joints. In case of flowable FRCC, pouring toward
the axial direction from the one side of the mould is recommended. The internal vibrator and compacting
rod/bar shall not be used.
d) The notch shall be cut using a concrete saw when the FRCC has developed sufficient strength.
The notch should be cut in one side that faced the side of the mould. The casting surface becomes vertical
one for loading. It is not necessary to cut the edges of the notch to specific forms, as the edge shape
scarcely affects the test results.
e) The number of specimens shall be not less than six. The tolerances of specimens are ±0,5 % for a side of
section.
f) The mass of each specimen shall be measured to the nearest 0,05 kg.
5.3 Loading of specimen
a) Specimens shall be subjected to testing in a condition immediately after completion of the specified
curing procedure.
b) The direction of loading shall be perpendicular to the direction of casting of the specimen.
c) The loading span, S, shall be 3 D. The tolerance of the loading span is ±2 %.
6 Test equipment
6.1 Testing machine
A testing machine capable of operating in a controlled manner, i.e. producing a constant rate of displacement
(CMOD or LPD), and with sufficient stiffness shall be used.
6.2 Loading apparatus
In order to eliminate torsional action on the specimen, the loading block and one of the supports shall be
rotatable around their axes in the direction of the specimen axis. Both supports shall be hinged with rollers
in order to avoid any restraint on the deformation until the specimen completely ruptures.
Both supports should be movable, as the horizontal movement of the specimen is restrained at the loading
block. Inserting multiple rods under both supports as shown in Figure 2 is a simple and effective solution
for a movable mechanism. In order to ensure the absence of horizontal restraint, it is advisable to press
the specimen lightly by hand before applying any load to confirm smooth movement of the specimen in the
horizontal direction.
Key
1 machine head
2 load cell
3 round bar
4 specimen
5 roller
6 round bar ϕ = 20 mm to 30 mm
Figure 2 — Loading apparatus
6.3 Measuring device for load
The load shall be measured using a load cell with an accuracy of 1 % of the estimated peak load or better.
The load cell shall be fixed to the testing machine.
6.4 Measuring device for CMOD
The CMOD shall be measured using a clip gauge with an accuracy of 1/500 mm or better. If clip gauges cannot
be directly attached to the notch, knife-edges are used. The thickness of the knife-edges (t ) to which the clip
k
gauge is attached shall be not more than 5 mm (Figure 3). If the knife-edges are used, measuring position of
CMOD shall be indicated in the test report. Also, if the inverse analysis is conducted, the measuring position
should be considered.
Knife-edges, which should be made of metal, should be attached as
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