SIST-TP CEN/TR 16349:2012

Framework for a specification on the avoidance of a damaging Alkali-Silica Reaction (ASR) in concrete

This Technical Report gives guidance for avoiding a damaging Alkali-Silica Reaction (ASR) in concrete.

Rahmen für eine Spezifikation für die Vermeidung von Alkali-Siliciumdioxid-Reaktionen in Beton

Cadre d'une spécification destinée à prévenir les dommages causés au béton par l'alcali-réaction

Okvir za specifikacijo za preprečevanje alkalno silikatne reakcije (ASR) v betonu

To tehnično poročilo določa sisteme prevzemnega vzorčenja enotnih vzorčnih načrtov za kontrolo po opisnih spremenljivkah in kontrolo po številskih spremenljivkah. Načrti s številskimi spremenljivkami so v obliki »accept-zero«, tj. serija, katere vzorec vsebuje enega ali več neskladnih izdelkov, se ne sprejme (V tem tehničnem poročilu se izraz »neskladni izdelek« nanaša na izdelke iz plemenitih kovin, pri katerih je masni delež plemenite kovine manjši od nominalnega masnega deleža). Za načrte s številskimi spremenljivkami se običajno zahtevajo manjši vzorci kot za načrte z opisnimi, vendar mora vsebnost plemenite kovine pri vseh vzorčenih izdelkih presegati nominalno vsebnost najmanj za določeno vrednost. Namen tega tehničnega poročila je zagotoviti sheme in postopke »accept-zero« za zagotavljanje zgodnje mejne vrednosti dolgoročnega odstotka neskladnih izdelkov iz plemenitih kovin na trgu (tj. odstotek izdelkov, ki pridejo na trg in pri katerih je delež plemenite kovine manjši od nominalnega) z najmanjšimi možnimi velikostmi vzorcev. Po tem tehničnem poročilu je zgornja mejna vrednost 1,47 % neskladnih izdelkov. Namen se doseže na tri načine: a) velikost vzorca se zmanjša, ko se skupno število sprejetih izdelkov v vseh serijah od zadnje zavrnitve poveča; b) če je kakovost ves čas visoka, je pod določenimi pogoji mogoč prehod iz vzorčenja po opisnih spremenljivkah na vzorčenje po številskih spremenljivkah; c) pri vzorčenju po številskih spremenljivkah se lahko velikost vzorca dodatno zmanjša s prehodom iz metode neznanega standardnega odklona (metoda »s«) na metodo znanega standardnega odklona (metoda »ó«), če obstaja dovolj dokazov, da je standardni odklon postopka stalen. To tehnično poročilo je oblikovano za uporabo pod pogoji, ko: d) so izdelki podobne vrste, imajo podobno maso in nominalno vsebnost plemenite kovine in je vse dobavil en dobavitelj; OPOMBA: Če se kateri od teh dejavnikov razlikuje, se mora to tehnično poročilo uporabiti posebej za vsako kombinacijo vrste, razpona mase, nominalne vsebnosti plemenite kovine in dobavitelja. e) se stroški dobavitelja za označevanje finosti povečujejo s številom pregledanih izdelkov in stroški pregleda posameznega izdelka; f) pri vzorčenju po opisnih spremenljivkah ni možno točno določiti, ali so vzorčeni izdelki skladni glede vsebnosti plemenite kovine ali ne; g) je pri vzorčenju po številskih spremenljivkah vsebnost plemenite kovine po masi za vsak vzorčen izdelek neprekinjeno merljiva (običajno v tisočinkah, izražena kot realno število), vsebnost plemenite kovine od izdelka do izdelka pa je porazdeljena po normalni porazdelitvi, vsaj do bližnjega približka; h) je pri vzorčenju po spremenljivkah po metodi »ó« standardni odklon postopka stabilen.

General Information

• Status: Published
• Public Enquiry End Date: 30-Dec-2011
• Publication Date: 18-Jun-2012
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: BBB - Concrete, reinforced concrete and prestressed concrete
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 20-Apr-2012
• Due Date: 25-Jun-2012
• Completion Date: 19-Jun-2012
• Ref Project: CEN/TR 16349:2012 - Framework for a specification on the avoidance of a damaging Alkali-Silica Reaction (ASR) in concrete

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CEN/TR 16349:2012
01-julij-2012
2NYLU]DVSHFLILNDFLMR]DSUHSUHþHYDQMHDONDOQRVLOLNDWQHUHDNFLMH$65YEHWRQX
Framework for a specification on the avoidance of a damaging Alkali-Silica Reaction
(ASR) in concrete
Rahmen für eine Spezifikation für die Vermeidung von Alkali-Siliciumdioxid-Reaktionen
in Beton
Cadre d'une spécification destinée à prévenir les dommages causés au béton par l'alcali-
réaction
Ta slovenski standard je istoveten z: CEN/TR 16349:2012
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
SIST-TP CEN/TR 16349:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 16349:2012

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SIST-TP CEN/TR 16349:2012


TECHNICAL REPORT
CEN/TR 16349

RAPPORT TECHNIQUE

TECHNISCHER BERICHT
April 2012
ICS 91.100.30
English Version
Framework for a specification on the avoidance of a damaging
Alkali-Silica Reaction (ASR) in concrete
Cadre d'une spécification destinée à prévenir les Anwendung von Qualitätsregelkarten bei der Herstellung
dégradations causées au béton par l'alcali-réaction von Beton


This Technical Report was approved by CEN on 14 February 2012. It has been drawn up by the Technical Committee CEN/TC 104.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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, Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16349:2012: E
worldwide for CEN national Members.

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CEN/TR 16349:2012 (E)
Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Alkali-Silica Reaction (ASR) .5
3 Elements of specifications .5
4 Characterisation of environment .5
5 Precautionary measures appropriate to concrete .6
5.1 General remarks.6
5.2 Use of cement with a low effective alkali content .7
5.3 Use of slag, fly ash, silica fume or other pozzolana (in cement or as an addition) .7
5.4 Limiting the effective alkali content of the concrete .7
5.5 Verification of the suitability of a concrete mix in a performance test .8
5.6 Use of a non-reactive aggregate combination .8
6 Summary .8
Bibliography .9



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Foreword
This document (CEN/TR 16349:2012) has been prepared by Technical Committee CEN/TC 104 “Concrete
and related products”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This Technical Report is partly based on the recommendation of RILEM TC ACS (Part 1 of AAR-7) [6].

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Introduction
This Technical Report has been prepared by the Joint Working Group (JWG) on Alkali-Silica Reaction (ASR)
that was set up by the chairmen of CEN/TC 51, CEN/TC 104 and CEN/TC 154 and composed of
representatives from CEN/TC 51, CEN/TC 104, CEN/TC 154 and RILEM TC ACS.
The following is a list of the members of the JWG on ASR:
Name Represents
Michel Delort CEN/TC 51
Christer Ljungkrantz CEN/TC 51
Tom Harrison CEN/TC 104
Christoph Müller CEN/TC 104
Philip Nixon (until 2009) CEN/TC 154
Robert Gossling (from 2010) CEN/TC 154
Jean-Marc Vanbelle CEN/TC 154
Terje F. Ronning RILEM
Ingmar Borchers (VDZ) Guest

In CEN member countries, ASR has been recognised as a problem in concrete structures since the
1970s.Consequently, a number of countries have established provisions to avoid a damaging ASR. These
provisions are currently set out in national guidance documents and specifications.
Provisions vary in the different CEN member countries and depend on local experiences; some member
countries have not yet found the need to set up specifications.
The JWG was established to review the situation and to see whether it is possible to go further in providing
pragmatic and unified economic European specifications for the avoidance of a damaging ASR in concrete.
The JWG concluded that, unless there is any sound scientific explanation of a damaging ASR which can be
used uniformly all over Europe, it is premature to have harmonised classes for alkali-reactivity of aggregates
and provisions for avoiding a damaging ASR on a European level. Additionally, safety margins are determined
at national level and are related to the reliability at which a damaging ASR will not occur. Nevertheless, a
framework for the specification of the avoidance of a damaging ASR in concrete can be given.
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1 Scope
This Technical Report gives guidance for avoiding a damaging Alkali-Silica Reaction (ASR) in concrete.
2 Alkali-Silica Reaction (ASR)
Alkali-Silica Reactions in concrete are a result of reaction between the alkaline pore solution in concrete and
reactive mineral species (as reactive silica and silicates) in the aggregate. The reaction leads to the formation
of a gel that can absorb water and exert an expansive force on the concrete. In certain conditions, these
reactions can lead to damaging expansions and cracking in the concrete. For such damaging expansion to
occur, all of the following conditions must be present simultaneously:
 a critical amount of reactive mineral species;
 a sufficiently high alkali hydroxide concentration in the pore solution;
 a sufficient supply of water.
Effective specifications to avoid damage from the reaction are based on ensuring that at least one of these
conditions is absent.
NOTE Another type of reaction between reactive mineral species in the aggregates and the alkaline pore solution,
which has been reported (e.g. from Canada and China), is the alkali-carbonate reaction. As alkali-carbonate reaction has
not been recognised as a significant problem in Europe, it is not covered by this Technical Report.
3 Elements of specifications
In order to promote the sustainable use of locally available materials, it is important to tailor the precautions to
the environment that the structure is exposed to as well as to local experience in building practice. Based on
these principles, specifications for avoiding a damaging ASR in concrete are given within the following
structure:
a) characterisation of the environment (environmental category):
1) degree of saturation of the concrete with water;
2) alkali supply;
3) further aggravating factors.
b) undertaking recommendations for precautionary measures appropriate to concrete, depending on the
environmental category.
4 Characterisation of environment
When all the necessary compositional factors are present, the likelihood and extent of damaging alkali-silica
reaction is dependent on the environment. Three levels of categorisation of environment are therefore
appropriate:
 E1: the concrete is essentially protected from extraneous moisture;
 E2: the concrete is exposed to extraneous moisture;
 E3: the concrete is exposed to extraneous moisture and additionally to aggravating factors, such as
de-icing agents, freezing and thawing (or wetting and drying in a marine environment) or fluctuating
loads.
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More details on the factors affecting the environmental categorisation are given in Table 1.
Table 1 — Environmental categorie
...