SIST-TP CEN/TR 16443:2013
(Main)Backgrounds to the revision of EN 450-1:2005+A1:2007 - Fly ash for concrete
Backgrounds to the revision of EN 450-1:2005+A1:2007 - Fly ash for concrete
This Technical Report describes the backgrounds to the revision on EN 450-1:2005+A1:2007, Fly ash for concrete - Part 1: Definition, specifications and conformity criteria.
Hintergründe zur Überarbeitung der EN 450-1:2005+A1:2007 - Flugasche für Beton
Contexte de la révision de l'EN 450-1:2005+A1:2007 - Cendres volantes pour béton
Podlaga za revizijo EN 450-1:2005+A1:2007 - Elektrofiltrski pepel
To tehnično poročilo opisuje ozadje revizije standarda EN 450-1:2005+A1:2007, Elektrofiltrski pepel za beton – 1. del: Opredelitev, specifikacije in merila skladnosti.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TP CEN/TR 16443:2013
01-september-2013
Podlaga za revizijo EN 450-1:2005+A1:2007 - Elektrofiltrski pepel
Backgrounds to the revision of EN 450-1:2005+A1:2007 - Fly ash for concrete
Hintergründe zur Überarbeitung der EN 450-1:2005+A1:2007 - Flugasche für Beton
Contexte de la révision de l'EN 450-1:2005+A1:2007 - Cendres volantes pour béton
Ta slovenski standard je istoveten z: CEN/TR 16443:2013
ICS:
91.100.30 Beton in betonski izdelki Concrete and concrete
products
SIST-TP CEN/TR 16443:2013 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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TECHNICAL REPORT
CEN/TR 16443
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
March 2013
ICS 91.100.30
English Version
Backgrounds to the revision of EN 450-1:2005+A1:2007 - Fly
ash for concrete
Contexte de la révision de l'EN 450-1:2005+A1:2007 - Hintergründe zur Überarbeitung der EN 450-
Cendres volantes pour béton 1:2005+A1:2007 - Flugasche für Beton
This Technical Report was approved by CEN on 29 October 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, Former Yugoslav Republic of Macedonia, 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
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16443:2013: E
worldwide for CEN national Members.
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Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 List of relevant references .5
3 General .5
3.1 General and objective .5
3.2 Structure of the report .6
4 Overview of requirements in EN 450-1:2005+A1:2007 and EN 450-1:2012 .6
5 Background for modification of the requirements in EN 450-1 .7
5.1 Definition of fly ash.7
5.2 Co-combustion materials .8
5.3 Loss on ignition . 11
5.4 Free calcium oxide. 13
5.5 Reactive silicon dioxide . 14
5.6 Phosphate . 15
6 Background for the statistical evaluation for assessment procedure by variables . 16
7 Background for modification of test methods in EN 450-1 . 18
7.1 Chemical composition . 18
7.2 Fineness wet/dry . 18
8 Measures within EN 450-1 to assure fly ash quality . 20
8.1 Production process . 20
8.2 Quality control and conformity evaluation technical properties . 21
8.3 Conformity evaluation toxicological and environmental aspects . 21
9 Impact of co-combustion on the release of regulated dangerous substances . 22
9.1 General . 22
9.2 Overruling regulation regarding toxicological and environmental aspects . 22
9.3 Environmental regulations (Leaching) . 23
Annex A (informative) List of abbreviations . 25
Annex B (informative) Generation of fly ash . 26
B.1 The chain from fuel to fly ash, ready for use in concrete . 26
B.2 Ash formation during combustion . 27
Annex C (informative) Overview of tested fly ashes obtained from co-combustion . 31
Annex D (informative) Calculated maximum co-combustion amounts . 33
D.1 Objective . 33
D.2 Method . 33
D.3 Data . 33
D.4 Results . 33
Bibliography . 36
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Foreword
This document (CEN/TR 16443:2013) 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.
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Introduction
Following five years of experience using EN 450-1, it was clear that some clauses need improvement within
the standards. In the existing standards the maximum amount of fly ash from co-combustion was limited to
certain proportions. Experience gained with fly ashes conforming to a European Technical Approval (ETA),
where higher co-combustion amounts were permitted, showed that the requirements in the corresponding
Common Understanding of Assessment Procedure (CUAP) were sufficient guarantee for fly ashes to produce
excellent performance in concretes, mortars, grouts and cements. As agreed in CEN/TC 104, the experience
gained with ETA fly ashes should be incorporated in the revision of EN 450-1.
In this background report it is proved that wider ranging limits and types of co-combustion materials can be
safely applied in the revised EN 450-1. It is also shown that in practice some requirements in EN 450-1 have
been proven to be unrealistic. Improvements have been proposed for the definition of fly ash, the loss on
ignition, free calcium oxide, reactive silicon dioxide and the limits for phosphate.
The conformity procedures have also been evaluated, especially the assessment procedure for inspection by
1)
variables. Based on this evaluation work, modifications are needed for the LOI classes B and C.
The revised version of the standard incorporates the European Technical Approvals (ETA) and EU members
experience gained with fly ash in concrete. The requirements of the revised standard will result in fly ashes
which will perform similarly to those conforming to EN 450-1:2005.
1) LOI – Loss on ignition.
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1 Scope
This Technical Report describes the backgrounds to the revision on EN 450-1:2005+A1:2007, Fly ash for
concrete Part 1: Definition, specifications and conformity criteria.
2 List of relevant references
The following references are covered by the present document:
EN 450-1:2005+A1:2007, Fly ash for concrete — Part 1: Definition, specifications and conformity criteria;
2)
), Fly ash for concrete — Part 1: Definition, specifications and
EN 450-1:2012 (revised EN 450-1
conformity criteria;
EN 450-2:2005, Fly ash for concrete — Part 2: Conformity evaluation;
EN 196-2, Methods of testing cement — Part 2: Chemical analysis of cement;
EN 197-1:2000, Cement — Part 1: Composition, specifications and conformity criteria for common
cements;
EN 14588:2010, Solid biofuels — Terminology, definitions and descriptions.
3 General
3.1 General and objective
Fly ash has been used for many decades in concrete as an addition for its positive influence on workability,
heat of hydration, strength development and durability. After the encouraging pilot projects some decades ago
with positive results, licenses for regular use and later on technical approvals were granted by the national
building authorities, certificates and standards. Today, regulations and standards exist for the use of fly ash in
mortar and concrete.
In 1995, the first EU standard was published, namely EN 450, Fly ash for concrete — Definitions,
requirements and quality control. This edition was followed up by a harmonised standard based on
Mandate M 128 in 2005 (EN 450-1:2005), together with a second standard (EN 450-2:2005), specific for
conformity evaluation.
The scope of EN 450-1:2005 states that fly ashes with percentages of co-combustion material higher than
those covered in EN 450-1:2005, Clause 4 or with other types of co-combustion material are outside the
scope of EN 450-1:2005.
In some countries, the use of fly ash with a higher percentage of co-combustion material was already common
practice and it was not accepted by these countries that these fly ashes, containing higher amounts of co-
combustion and other co-combustion materials, were excluded from CE marking.
It was agreed that European Technical Approvals (ETAs) could be granted for this product according to
Article 8.2 of the Construction Products Directive. The mandate M 128 was updated with the clarification that
fly ash produced with other types than those covered by EN 450-1 and fly ash produced with a percentage of
co-combustion material outside the limits defined in EN 450 (all parts), can be subject to ETAs, in order to
allow these products to be CE marked. The experience gained with the fly ashes conforming to these ETAs
has been used for the next revision of EN 450-1.
Due to the regular five-year revision, WG 4 of CEN TC 104 incorporated the knowledge gained with the fly
ashes conforming to these ETAs with EN 450-1. Other issues for the revision were identified as a lack of
clarity regarding the conformity evaluation and some of the other requirements.
2) In this present Technical Report a reference to the revised EN 450-1 always refers to EN 450-1:2012.
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The objective of this report is to provide insight into the background to the modifications that have been taken
up in EN 450-1:2012 (revised EN 450-1) and of those requirements that have been deleted from
EN 450-1:2005+A1:2007
3.2 Structure of the report
Clause 4 provides an overview of the requirements of EN 450-1:2005+A1:2007 and EN 450-1:2012. In Clause
5 the background for the modifications of the requirements within EN 450-1 is described. Clause 6 gives the
background for the statistical evaluation for assessment procedure by variables, Clause 7, the background for
the required test methods, regarding chemical composition and the determination of fineness. In Clause 8, an
overview how fly ash quality is assured within the production process itself, the quality control system and the
conformity evaluation of toxicological and environmental aspects is given. Clause 9 deals with the impact of
co-combustion on the release of regulated dangerous substances.
More background information about the generation of fly ash can be found in Annex B.
4 Overview of requirements in EN 450-1:2005+A1:2007 and EN 450-1:2012
An overview of the requirements in the revised EN 450-1 is presented in Table 1. The requirements are
related to fresh and hardened concrete. The chemical requirements concern Loss On Ignition (LOI), chloride
(Cl), reactive and free Calcium Oxide or lime (CaO), reactive Silicon Dioxide (SiO ), the sum of SiO + Al O
2 2 2 3
+ Fe O , Magnesium Oxide (MgO) and soluble Phosphorus Pentoxide (P O ). The physical requirements
2 3 2 5
concern (or: are related to) fineness and the maximum deviation of particle density. The performance based
requirements are water requirement, initial setting, activity index and soundness.
In relation to the previous standard, the following changes have been adapted:
The definition of fly ash has been modified (EN 450-1:2012, 3.2).
The permitted amount and type of co-combustion materials have been changed (EN 450-1:2012, 4.1).
The requirement for the lower limit of LOI for category B and C fly ash has been deleted (EN 450-1:2012,
5.2.2).
The requirement for free lime (CaO) has been changed (EN 450-1:2012, 5.2.5).
The amount of total phosphate has been limited by a new requirement (EN 450-1:2012, 5.2.11).
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Table 1 — Properties and requirements of fresh and hardened mortar and concrete
EN 450- EN 450-
Phase Property Unit
1:2005+A1:2007 1:2012
loss on ignition (LOI) class A ≤ 5,0 ≤ 5,0
class B % by mass 2,0 – 7,0 ≤ 7,0
class C 4,0 – 9,0 ≤ 9,0
workability
a e
water requirement % ≤ 95 n.m.
d
≤ 40 (cat. N)
e
fineness fraction > 45 µm % by mass n.m.
≤ 12 (cat. S)
e
soluble phosphate (P O )
mg/kg ≤ 100 n.m.
2 5
initial strength
total phosphate (P O )
% by mass — ≤ 5,0
2 5
development
b e
initial setting min. 2C n.m.
e
sum SiO + Al O + Fe O
% by mass ≥ 70 n.m.
2 2 3 2 3
e
reactive SiO
strength % by mass ≥ 25 n.m.
2
development
e
activity index 28 days ≥ 75 n.m.
%
e
91 days ≥ 85 n.m.
total content of alkalis
e
% by mass ≤ 5,0 n.m.
alkali silica reaction
(Na O equivalent)
2
(ASR)
e
reactive calcium oxide (CaO) % by mass ≤ 10,0 n.m.
e
sulphuric anhydride (SO )
% by mass ≤ 3,0 n.m.
3
c
f
free calcium oxide (CaO) % by mass ≤ 2,5
soundness/
e
soundness mm ≤ 10 n.m.
durability
e
magnesium oxide (MgO) % by mass ≤ 4,0 n.m.
-
e
chloride (Cl ) % by mass ≤ 0,10 n.m.
a
Only applicable for category S fly ash.
b
Initial setting of fly ash cement paste shall not be more than twice as long as the initial setting time of the test cement alone.
c If the content of free lime is greater than 1,0 % by mass, the fly ash shall be tested for conformity to the requirement for soundness.
d The fineness shall not vary by more than ±10 % from the declared value.
e n.m. = not modified.
f If the content of free lime is greater than 1,5 % by mass, the fly ash shall be tested for conformity to the requirement for soundness.
5 Background for modification of the requirements in EN 450-1
5.1 Definition of fly ash
5.1.1 Text of EN 450-1:2005+A1:2007
Fine powder of mainly spherical, glassy particles, derived from the burning of pulverised coal, with or without
co-combustion materials, which has pozzolanic properties and consists essentially of SiO and Al O . The
2 2 3
content of reactive SiO , as defined and described in EN 197-1 being at least 25% by mass.
2
5.1.2 Text of EN 450-1:2012 (revised EN 450-1)
Fine powder of mainly spherical, glassy particles, derived from the burning of pulverised coal, with or without
co-combustion materials, which has pozzolanic properties and consists essentially of SiO and Al O .
2 2 3
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5.1.3 Background
The requirement of reactive SiO has been deleted in the definition of the revised EN 450-1, but still exists as
2
requirement for initial type testing (EN 450-1:2012, 5.2.7).
By definition fly ash has to be derived from the burning of pulverised coal and co-combustion materials. This is
only possible in dedicated boilers where combustion of finely ground fuel takes place in a cloud, with
combustion temperatures of 1 300 – 1 500 °C. This means that ashes from other boilers like grate-fired and
fluidised bed combustion boilers do not meet this definition. In other words, the definition guarantees that
combustion takes place at high temperature, which is high enough to facilitate glass formation in the fly ash.
The definition includes co-combustion, but, in EN 450-1:2012, 4.1, the amount and type of combustion
material are further restricted. Also, as noted in EN 450-1, municipal and industrial waste incineration ashes
do not conform to the definition of this clause. This implies that the fuel always contains coal. Coal contains
mineral matter that will form the glass phase during combustion. Also part of the secondary fuel also contains
mineral matter that contributes to glass formation. On a performance level, the requirement for the activity
index after 28 and 91 days provide enough assurance for a sufficient pozzolanic behaviour of the fly ash. The
presence of the glass phase is further assured by the requirement for the minimum total amount of
SiO + Al O + Fe O (as a main fraction of potential glass forming matter).
2 2 3 2 3
5.2 Co-combustion materials
5.2.1 Text of EN 450-1:2005+A1:2007
Fly ash from co-combustion as defined in 3.2 is obtained from pulverised coal fired simultaneously with co-
combustion materials as listed in Table 1 (Table 2 of this report). The minimum percentage, by dry mass, of
coal (K ) shall not be less than 80 % and the maximum proportion of fly ash derived from co-combustion
c
materials (M) shall not be greater than 10 % when calculated from Formula (1).
Table 2 (Table 1 of EN 450-1:2005+A1:2007) — Types of co-combustion materials
1 Vegetable material like wood chips, straw, olive shells and other vegetable fibres
2 Green wood and cultivated biomass
3 Animal meal
4 Municipal sewage sludge
5 Paper sludge
6 Petroleum coke
7 Virtually ash free liquid and gaseous fuels
5.2.2 Text of EN 450-1:2012 (revised EN 450)
Fly ash from co-combustion as defined in 3.2 is obtained from pulverised coal fired simultaneously with or
without co-combustion materials as listed in Table 1 (Table 3 of this report). The minimum percentage, by dry
mass, of coal (K ) shall be not less than 60 % or 50 % if the co-combustion material is only green wood. The
c
maximum proportion of ash derived from co-combustion materials (M) shall not be greater than 30 % by dry
mass when calculated from Formula (1).
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Table 3 (Table 1 of the revised EN 450-1) — Types of co-combustion materials
Solid Bio Fuels conforming to EN 14588:2010 including animal husbandry residues as
1
defined in 4.3 and excluding waste wood as defined in 4.40, 4.107 and 4.136
2 Animal meal (meat and bone meal)
3 Municipal sewage sludge
4 Paper sludge
5 Petroleum coke
6 Virtually ash free liquid and gaseous fuels
NOTE Other types of co-combustion materials not included in Table 3 (Table 1 of the revised EN 450-1) may be
subject to an ETA.
5.2.3 Background
The classification of secondary fuels has been changed in the revised EN 450-1. The secondary fuels listed in
line 1 and 2 of table 3 have been merged as these are from the same origin and compiled in EN 14588. As
“green wood” is not defined in that report a definition was added in the revised EN 450-1 as:
"3.13
green wood
green wood is wood originating from trees, bushes and shrubs created when processing wood as cross-cut
ends, planings, saw dust and shavings used in the form of dust, chips and pellets".
The minimum proportion of coal has been decreased from 80 % by mass to 60 % by mass. Further, the
maximum proportion of ash derived from secondary fuels has been increased from 10 % to 30 % by mass.
Since 2005, ETAs have been used for testing the technical and environmental suitability of fly ash from co-
combustion for use as addition in concrete. Generated fly ashes from co-combustion exceeding the co-
combustion limits of EN 450-1:2005+A1:2007 were tested according to these ETAs. Before ETAs were
available, Dutch fly ashes from co-combustion were tested according to CUR recommendations (since 1999).
The tested fly ashes are presented in Annex C.
Co-combustion may increase the content of Ca, K, P and Mg in some cases. The other macro elements (Fe,
Al, Si, Na, and Ti) are mainly indirectly influenced by becoming impoverished due to the enrichment of other
macro elements. In most secondary fuels from vegetable and animal origin these macro-elements are present
in low concentrations (ash based), related to coal. The situation in fuels from industrial origin may be different
like the presence of Al, Si, Fe and Ti in demolition wood, Al, Si and P in sewage sludge and Al, Si and Ca in
paper sludge. The revised EN 450-1 contains an adequate set of requirements that covers these influences;
see Table 5. As can be derived from this table the influence of Ca, K, Mg and P is directly covered by at least
one requirement of the revised EN 450-1.
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Table 4 — Requirements for fly ash for fresh and hardened concrete in relation to the effects of co-
combustion
Main influence co-combustion
Phase Requirement of EN 450-1
Ca K Mg P
LOI — — — —
workability water requirement — — — —
fineness fraction > 45 µm — V — —
soluble P O
VV
— — —
2 5
initial strength
total P O
— — — VV
2 5
development
initial setting — — — VV
sum SiO + Al O + Fe O
V V V V
2 2 3 2 3
strength
development
activity index — — — V
Na O equivalent
— VV — —
2
Alkali Silica
Reaction
VV
reactive CaO — — —
SO
— — — —
3
free CaO VV — — —
soundness/
Soundness V — — —
durability
total MgO — — VV —
-
Cl — — — —
Key
VV direct relation between the requirement and the influence of co-combustion
V in-direct relation between the requirement and the influence of co-combustion
— no relation
The test results showed that in nearly all cases, the chemical requirements of the ETA were met with one
exception, which in that case fly ash was rejected for use in concrete. This can be explained by the fact that
the co-combustion amount was adjusted to the chemical requirements or to operational conditions (fuel feed,
slagging, corrosion, etc.). An overview of limiting parameters for co-combustion materials is given in Table 5.
The results showed also that the XRD analyses of fly ash did not provide any extra information for quality
control purposes. In all cases no minerals were identified other than listed in the ETA. Therefore this criterion
was not included in the revised EN 450-1.
For a selection of these fly ashes, concrete specimens were produced to check if the proposed test
methodology is adequate. The performance of the concrete did not show significant influence of co-
combustion. The results are described in several reports and presentations (see CUR, 2003; Sarabèr, 2004;
Sarabèr and Van den Berg, 2005; Sarabèr and Van den Berg, 2006; CTSC, 2008). It was shown that the
performance of fly ash obtained from different co-combustion materials could be explained by the
mineralogical composition of the fly ash and that this could be related to the origin of the co-combustion
material. It was shown that depending on the origin of the fuel high co-combustion percentages are possible
up to 25 % by mass.
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Table 5 — Limiting parameters for co-combustion materials (basis Table 1 of the revised EN 450-1)
Type Limited by
1 Solid Bio Fuels conforming to EN 14588:2010 including animal husbandry residues
as defined in 4.3 and excluding waste wood as defined in 4.40, 4.107 and 4.136.
green wood 1 Co-combustion fuel based
green wood 2 Co-combustion fuel based
green wood 3 Co-combustion fuel based
bark wood reactive CaO
Cacao shells Na O equivalent (K)
2
palm kernels total P O
2 5
2 Animal meal (meat and bone meal)
Meat and bone meal total P O
2 5
3 Municipal sewage sludge
Municipal sewage sludge total P O
2 5
4 Paper sludge
Paper sludge CaO
5 Petroleum coke
a
Petroleum coke —
6 Virtually ash free liquid and gaseous fuels
Industrial HC liquid Co-combustion fuel based
a
Prevented by National environmental regulations.
As already stated, the actual amount of co-combustion material is not only limited by the maximum
requirement for co-combustion, but also by the chemical requirements of EN 450-1. This means that in
practice, the actual amount of coal combustion (K ) will be higher than 60 % by mass and the maximum
c
proportion of ash derived from co-combustion materials (M) will be less than 30 % by mass. To illustrate this,
the maximum amount of co-combustion has been studied in relation to the chemical requirements (KEMA,
2008). The minimum proportion of coal combustion and the maximum proportion of ash derived from co-
combustion materials (M) adjusted to meet the requirements of EN 450-1 by calculating chemical
®
3)
compositions using the "KEMA TRACE MODEL " The study shows that co-combustion of most secondary
fuels will be limited by the chemical requirements or by the definition regarding the fuel based maximum co-
combustion. In Annex D all results are summarised.
5.3 Loss on ignition
5.3.1 Text of EN 450-1:2005+A1:2007
The loss on ignition shall be determined in accordance with the principles of the method described in
EN 196-2 but using an ignition time of 1 h, and shall fall within the limits of the categories specified below:
Category A: Not greater than 5,0 % by mass
Category B: Between 2,0 % and 7,0 % by mass
®
3) KEMA TRACE MODEL is the trade name of a product. This information is given for the convenience of the users of
this Technical Report and does not constitute an endorsement by CEN of the product named. Similar products may be
used if they can be shown to lead to equivalent results.
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Category C: Between 4,0 % and 9,0 % by mass
5.3.2 Text of EN 450-1:2012 (revised EN 450-1)
The loss on ignition shall be determined in accordance with the principles of the method described in
EN 196-2 but using an ignition time of 1 h, and shall fall within the limits of the categories specified below:
Category A: Not greater than 5,0 % by mass
Category B: Not greater than 7,0 % by mass
Category C: Not greater than 9,0 % by mass.
5.3.3 Background
LOI of fly ash is an important quality parameter. LOI may influence several properties of concrete like
workability, interaction with organic admixtures, strength development, durability and visual aspects.
Key
1 LOI(mean) = UL – k · s
a
2 upper limit
3 single result limit
4 Prob.
5 LOI
a
PR
b
CR
Figure 1 — Producer and consumer risk in statistical evaluation
With the introduction of the revised EN 450-1:2005, three categories of LOI w
...
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