CEN/TS 772-22:2006
(Main)Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of clay masonry units
Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of clay masonry units
This Technical Specification specifies a method for determining the freeze/thaw resistance of clay masonry units that are declared by the manufacturer as meeting the requirements for HD units and as suitable to be subjected to severe (F2) exposure.
Prüfverfahren für Mauersteine - Teil 22: Bestimmung des Frost-Tau-Widerstandes von Mauerziegeln
Diese Technische Spezifikation legt ein Verfahren zur Bestimmung des Frost-Tau-Widerstandes von
Mauerziegeln fest, die nach Angaben des Herstellers die Anforderungen an HD-Ziegel erfüllen und sich für
stark angreifende Umgebungsbedingungen (F2) eignen.
Metode preskušanja zidakov – 22. del: Ugotavljanje odpornosti proti zmrzovanju/tajanju opečnih zidakov
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2006
0HWRGHSUHVNXãDQMD]LGDNRY±GHO 8JRWDYOMDQMHRGSRUQRVWLSURWL
]PU]RYDQMXWDMDQMXRSHþQLK]LGDNRY
Methods of test for masonry units - Part 22: Determination of freeze/thaw resistance of
clay masonry units
Prüfverfahren für Mauersteine - Teil 22: Bestimmung des Frost-Tau-Widerstandes von
Mauerziegeln
Ta slovenski standard je istoveten z: CEN/TS 772-22:2006
ICS:
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN/TS 772-22
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
June 2006
ICS 91.100.15
English Version
Methods of test for masonry units - Part 22: Determination of
freeze/thaw resistance of clay masonry units
Prüfverfahren für Mauersteine - Teil 22: Bestimmung des
Frost-Tau-Widerstandes von Mauerziegeln
This Technical Specification (CEN/TS) was approved by CEN on 21 March 2006 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 772-22:2006: E
worldwide for CEN national Members.
Contents Page
Foreword .3
1 Scope.4
2 Normative references.4
3 Principle.4
4 Symbols.4
5 Apparatus.4
6 Materials .5
7 Preparation of specimens.5
8 Construction of test panel.6
9 Procedure.8
10 Evaluation of results .10
11 Test report.10
Annex A (normative) Types of damage possible in the freeze-thaw test .12
Annex B (normative) Determination of water absorption.16
Annex C (normative) Measurement of heat transfer rate .17
Foreword
This Technical Specification (CEN/TS 772-22:2006) has been prepared by Technical Committee
CEN/TC 125 “Masonry”, the secretariat of which is held by BSI.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and United Kingdom.
1 Scope
This Technical Specification specifies a method for determining the freeze/thaw resistance of clay masonry
units that are declared by the manufacturer as meeting the requirements for HD units and as suitable to be
subjected to severe (F2) exposure.
2 Normative references
The following referenced documents are indispensable for the application 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.
EN 771-1, Specification for Masonry Units — Clay Masonry Units
3 Principle
A panel of clay masonry units is assembled either from units which have been immersed in water for a
prescribed period of time and which are separated from one another by a specified rubber jointing material or
from units and rapid hardening mortar which when sufficiently hardened is immersed in water for a prescribed
period of time. The panel is subsequently cooled for a specified period and the water near to one face is
repeatedly thawed and refrozen. Damage caused by the freezing and thawing action is assessed and used to
determine the freeze/thaw resistance of the bricks.
4 Symbols
m is the mass of the specimen after drying, in grams (g)
d
m is the wet mass of the specimen, in grams (g)
w
w is the water absorption of an individual specimen, in mass percent (%)
m
5 Apparatus
An appropriate testing machine capable of generating the freeze-thaw cycles specified in clause 8.3 and
ensuring unidirectional freezing and thawing through one face of the units.
Several different designs of testing machine are suitable all of which use a fan to circulate air in the machine.
It is important that the machine circulates the air such that the flow is essentially parallel to the face of the
panel under test.
A water tank, made of plastic or steel.
°
A drying oven capable of maintaining a temperature of 105 °C ± 5 C and of providing forced air circulation.
A weighing instrument capable of weighing specimens to an accuracy of 1 g.
A heat flow meter suitable for carrying out the calibration procedure. A suitable heat flow meter can be
constructed by bonding an electrically heated resistance mat of appropriate rating to an aluminium plate of the
same shape and size, typically 2 mm thick × 200 mm × 400 mm and a sheet of extruded polystyrene foam
100 mm thick (see Figure 1). The polystyrene sheet should be of sufficient size to fill the opening in the
cabinet which is normally occupied by the test panel of masonry units. The aluminium plate, which shall be
painted matt black, is sealed to the centre of this opening with a thermocouple attached to its external surface
at the approximate centre of the plate. The heated mat is connected to a continuously variable transformer
with a means of measuring current and voltage.
Dimensions in mm
Key
1 Insulation 3 Matt black aluminium sheet
2 Electric resistance mat 4 Foam rubber
Figure 1 — Heat flow meter
6 Materials
Foam rubber with closed pores 10 mm ± 2 mm thick and which does not absorb water during the test.
High alumina cement
Sand with a maximum grain size of 1 mm
7 Preparation of specimens
7.1 Sampling
The method of sampling shall be in accordance with EN 771-1. Sufficient units shall be sampled in order to
2 2
construct a panel with a face which has a surface area of between 0,25 m and 0,5 m .
7.2 Preliminary examination of specimens
Each unit shall be numbered and examined. Any existing defects shall be noted. The descriptions given in
Table 1 and shown diagrammatically in Annex A may be used for guidance. Only defects with a damage
type 4 and above need be recorded.
7.3 Conditioning of Specimens
Water absorption may be determined using the method described in Annex B.
If the construction method described in 8.2 i.e. with rubber joints is to be used, then each unit is placed in the
tank of water at room temperature. That water is to be in contact with all faces of the unit and this may be
achieved by the resting of the units on small pads which act as spacers. The units are left submerged for 7
days.
If the construction method described in 8.3 i.e. with mortar joints is to be used, the conditioning of the test
panels shall be in accordance with 8.3.2.
8 Construction of test panel
8.1 General
Test panels may be constructed using either foam rubber or mortar as jointing materials. However in
cases of dispute the jointing medium should be the same as that upon which the declaration of the
freeze/thaw category was based.
NOTE Current scientific knowledge indicates that the results from tests carried out using rubber or mortar for
panel construction are, within the natural variation of results, the same.
All faces of the panel except that exposed to freeze/thaw cycling conditions shall be enclosed in a close fitting
jacket of extruded polystyrene foam with a density of less than or equal to 50 kg/m . The minimum thickness
of the jacket shall be 50 mm at the back and 25 mm around the perimeter of the test panel. The joint between
the polystyrene outer wall and the test panel shall be finished so that melt water is prevented from running
behind the test panel. This may be achieved by placing a layer of the foam rubber around the perimeter of the
test panel.
8.2 Rubber Joints
Remove the units from the water and assemble them into a panel using the closed pore foam rubber
(10 mm ± 2 mm thick) as a jointing material. The units shall be arranged so that the vertical joints in one
course are approximately above the centre of a whole unit in the course beneath it (stretcher bond). Half units
at the ends of courses shall be turned so that the uncut end of the unit (header) forms part of the face of the
panel to be exposed to the freeze-thaw cycles. Sufficient units shall be used to construct a panel measuring
2 2
between 0,25 m and 0,5 m .
It is important that water does not enter the panel at the interfaces between the masonry units and the foam
rubber. This may be prevented by lightly precompressing the panel horizontally and vertically using “T” bolts
or eye bolts or similar which may be tightened by hand.
A typical panel is shown in Figure 2.
Dimensions in mm
Key:
1 Insulation 5 Mortar or rubber joint
2 Stretcher 6 Intimate contact between insulation and brickwork
3 Header 7 Wooden jacket
4 Area for location of thermocouple (shaded)
Figure 2 — Typical test panel
8.3 Mortar Joints
8.3.1 General
Test panels shall be constructed from units and a rapid setting high alumina cement mortar with a cement:
sand ratio of 1: 4 by volume. A typical panel is shown in Figure 2. The units shall be arranged so that the
vertical joints in one course are approximately above the centre of a whole unit in the course beneath it.
Half units at the ends of courses shall be turned so that the end of the unit forms part of the face of the
panel to be exposed to the freeze-thaw cycles. The mortar joints shall be finished with a steel tool to give
a flush or bucket handled finish as shown in Figure 3. Sufficient units shall be used to construct a panel
2 2
measuring between 0,25 m and 0,5 m .
NOTE There are advantages and disadvantages associated with both jointing mediums. Mortar is more realistic
but requires the laboratory to have available a skilled mason and a means of lifting whole panels when they are
saturated. Rubber joints may need sealing to prevent failures on the bed faces but are more easily assembled and
can if necessary be dismantled after fewer than 100 cycles. It is also easier to freeze and thaw bricks the individual
water absorption of which is known.
8.3.2 Conditioning of Test Panels
The test panel shall be allowed to cure in ambient laboratory conditions for 3 days and then completely
immersed in a tank of water at room temperature for 7 days.
1 1
2 3
Key
1 Masonry unit
2 Flush finish to mortar joint
3 Bucket handled finish to mortar joint
Figure 3 — Joint Finish
9 Procedure
9.1 General
The test regime for mortared panels should commence within 30 minutes of removing the panels from the
soaking tank. If this time is exceeded up to a maximum of 4 h then steps shall be taken to limit the
evaporation of water by protection with thermoplastics sheeting. If 4 h is exceeded then the panel shall be
replaced in the immersion tank for a minimum of 20 h and a maximum of 24 h. When the panel is installed
in the apparatus it shall be preconditioned before the freeze/thaw cycling commences by spraying the face
of the panel with a flood coat of water at ambient temperature at a rate of 6 ± 0,5 l/min.metre width of test
panel for 15 min ± 1 min. Ensure an unbroken flood coat of water through the use of a linear nozzle array
at the top of the vertical test panel. Ensure that water does not enter the panel through the top of the panel.
The test regime for rubber panels should commence within 2 h after removing the samples from the
soak
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.