EN 680:2005

SLOVENSKI STANDARD
01-maj-2006
Nadomešča:
SIST EN 680:2001
Določanje krčenja avtoklaviranega celičastega betona zaradi sušenja
Determination of the drying shrinkage of autoclaved aerated concrete
Bestimmung des Schwindens von dampfgehärtetem Porenbeton
Détermination du retrait de séchage du béton cellulaire autoclavé
Ta slovenski standard je istoveten z: EN 680:2005
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 680
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2005
ICS 91.100.30 Supersedes EN 680:1993
English Version
Determination of the drying shrinkage of autoclaved aerated
concrete
Détermination du retrait de séchage du béton cellulaire Bestimmung des Schwindens von dampfgehärtetem
autoclavé Porenbeton
This European Standard was approved by CEN on 26 October 2005.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
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, 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
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 680:2005: E
worldwide for CEN national Members.

Contents Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Principle.4
4 Apparatus .4
5 Test specimens .5
5.1 Sample .5
5.2 Shape and size of the test specimens.5
5.3 Number of test specimens .5
5.4 Preparation of test specimens .6
5.5 Measurement of dimensions of test specimens and determination of their volume.6
5.6 Conditioning of test specimens.7
6 Testing procedure.7
6.1 Drying storage in a climate at (20 ± 2) °C and (45 ± 5) % relative humidity and
determination of length changes and variations of mass.7
6.2 Drying of test specimens at (105 ± 5) °C .7
7 Test results.8
7.1 Calculation of relative length change.8
7.2 Calculation of moisture content .8
7.3 Determination of the conventional reference value of drying shrinkage .8
7.4 Determination of the total value of drying shrinkage.9
7.5 Calculation of the dry density.9
8 Test report .9

Foreword
This European Standard (EN 680:2005) has been prepared by Technical Committee CEN/TC 177
“Prefabricated reinforced components of autoclaved aerated concrete or light-weight aggregate concrete with
open structure”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2006, and conflicting national standards shall be withdrawn at
the latest by June 2006.
This document supersedes EN 680:1993.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
1 Scope
This Euopean Standard specifies a method for measuring the relative length changes due to drying (drying
shrinkage) of autoclaved aerated concrete manufactured according to EN 771-4 or prEN 12602. The
shrinkage characteristics determined according to this method are the following: The conventional reference
value of drying shrinkage is the relative length change between two specified moisture contents. The total
value of drying shrinkage is the relative length change due to drying from the saturated state until reaching
constant length under specified climatic conditions. Other drying shrinkage values may be determined
between other parameters to meet other specified national requirements.
2 Normative references
The following referenced documents are indispensable for the application of this European Standard. For
dated references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 678, Determination of dry density of autoclaved aerated concrete
EN 771-4, Specification for masonry units — Part 4:Autoclaved aerated concrete masonry units
prEN 12602, Prefabricated reinforced components of autoclaved aerated concrete
3 Principle
Prismatic test specimens are cut from products from new production. For conditioning they are saturated in
water at (20 ± 2) °C for a period of at least 72 h and then stored in sealed plastic for a period of (24 ± 2) h.
Subsequently they are dried in air at (20 ± 2) °C and (45 ± 5) % relative humidity (drying period under
reference shrinkage storage conditions) until constant length is reached.
At the end of the conditioning period and in suitable time intervals during the drying period the length changes
and the mass of the test specimens are determined.
Finally, the test specimens are dried to constant mass at (105 ± 5) °C in order to determine the dry density of
the autoclaved aerated concrete and to enable the calculation of the moisture content of the test specimens at
each measuring date from the difference between the mass in the actual moist state and the dry mass.
A graph relative length change versus moisture content is plotted, and from the curve the conventional
reference value of drying shrinkage, ε , is determined as the relative length change between the two
cs,ref
moisture contents 30 % by mass and 6 % by mass.
Where the total value of drying shrinkage is required, the relative length change of the test specimens from
the end of the conditioning period until reaching constant length under reference shrinkage storage conditions
at (20 ± 2)° C and (45 ± 5) % relative humidity shall also be measured.
4 Apparatus
a) saw with rotating carborundum or diamond blade or other equipment for cutting test specimens;
b) balance, capable of determining the mass of the test specimens to an accuracy of 0,1 %;
c) callipers, capable of reading the dimensions of the test specimens to an accuracy of 0,1 mm;
d) container, for immersion of the test specimens under water;
e) temperature and moisture controlled room or cabinet, capable of maintaining a temperature of (20 ± 2) °C
and a relative humidity of (45 ± 5) % for storing the test specimens during the drying period and for
performing the measurement of length changes (see note);
f) measuring apparatus (comparator) for measuring length changes of test specimens.
Any suitable measuring apparatus may be used provided the following requirements are met:
 Length changes shall be measured in the longitudinal axis of the test specimens.
 Positive contact shall be established with the gauge plugs attached in the centres of the end faces of
the test specimens.
–5
 Measurements shall be performed with an accuracy of ∆L/L ≤ 10 , where ∆L is the variation in
gauge length and L is the initial length of the test specimens between the gauge plugs.
 Measuring apparatus shall have sufficient range to allow for variations in the actual length of various
test specimens.
 Means shall be provided for checking the measuring apparatus at each measuring date against an
invariable reference.
g) gauge plugs, to be applied on the end faces of the test specimens, made of corrosion-resistant metal and
shaped in such a way that a reliable positive contact with the measuring apparatus used is ensured.
h) ventilated drying oven, capable of maintaining a temperature of (105 ± 5) °C.
NOTE The room according to e) need not necessarily be humidity-controlled. Alternatively, during the drying period,
the test specimens may be stored in a closed container under the specified climatic conditions. For the reference
conditions the specified relative humidity of (45 ± 5) % in the container can be obtained by means of saturated potash
solution (KCO ).
5 Test specimens
5.1 Sample
The sample for the preparation of the test specimens shall be taken in such a manner that it is representative
of the production to be investigated.
In the case of prefabricated reinforced components the test specimens are prepared from the components
themselves. Alternatively, they may be taken from prefabricated nonreinforced components of the same
mould.
5.2 Shape and size of the test specimens
The test specimens shall be prisms with a cross-section of 40 mm × 40 mm and a length to suit the length of
the measuring apparatus, but not less than 160 mm.
5.3 Number of test specimens
The test set, taken from either prefabricated reinforced components, from prefabricated nonreinforced
components of the same mould or from nonreinforced masonry units, shall consist of three test specimens.
Whenever possible, one test specimen shall be prepared from the upper third, one from the middle and one
from the lower third of the component or of the masonry unit in the direction of rise of the mass during
manufacture (see Figure 1).
Key
1 Direction of rise
Figure 1 — Sampling scheme
5.4 Preparation of test specimens
The test specimens shall be cut by means of a rotating carborundum blade or other equipment. They shall not
contain any reinforcement. All surfaces shall be plane and clean.
The longitudinal axis of the test specimens taken from a reinforced component or from an unreinforced
component of the same mould shall be perpendicular to the direction of rise and preferably in the longitudinal
direction of the reinforced component. The longitudinal axis of the test specimens taken from unreinforced
masonry units shall be perpendicular to the direction of rise and preferably in the vertical direction of the unit
corresponding to the height of the unit.
Test specimens may be prepared from samples which have previously been used for other tests, provided
that they are cut at least 150 mm from an area where visible damage or changes to the normal structure and
appearance have occurred.
Gauge plugs according to 4g) for measuring length changes shall be firmly attached to the centres of the end
faces of the test specimens using an adhesive such that the adhesive does not influence the result.
NOTE  For the determination of the moisture content of the autoclaved aerated concrete according to 7.2 it is necessary
to know the mass of the gauge plugs and of their fixation (adhesive).
5.5 Measurement of dimensions of test specimens and determination of their volume
The initial dimensions of the test specimens shall be measured to an accuracy of 0,1 mm, using callipers.
Width and thickness shall be measured – between the longitudinal middle axes of opposite longitudinal
surfaces – near both ends and in the middle of the length.
The length L shall be measured along the longitudinal middle axes of two opposite longitudinal surfaces.
The volume V of the test specimens shall be calculated by multiplying the mean values of thickness, width,
and length measur
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