🧱 Siliceous fly ash for concrete (type II addition) — chemical and physical requirements: loss on ignition in categories A, B, C, chloride, sulfate (SO3), free and reactive calcium oxide, reactive silica, sum of SiO2 + Al2O3 + Fe2O3, alkalis, MgO, phosphate, fineness on the 0,045 mm sieve, activity index at 28 and 90 days, PN-EN 450-1

Construction PN-EN 450-1

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN 450-1:2012 (Polish version), in full (our translation of the Polish card text): “This European Standard specifies requirements for the chemical and physical properties as well as quality control procedures for siliceous fly ash, as defined in 3.2, for use as a type II addition for production of concrete conforming to EN 206-1. Fly ash according to this document may also be used in mortars and grouts. Fly ash produced with other types or higher percentages of co-combustion materials than those provided for in Clause 4 is outside the scope of this European Standard. Provisions governing the practical application of fly ash in the production of concrete, i.e. requirements concerning composition, mixing, placing, curing etc. of concrete containing fly ash, are outside the scope of this European Standard. Where necessary, reference should be made to other European or national standards for concrete, such as EN 206-1”. We read the text of the standard in the preview of SIST EN 450-1:2013 (EN 450-1:2012) from the cover to 5.3.2 (activity index, page 10); we do not have the rest — 5.3.3–5.5 (among others soundness, particle density, setting time, water requirement), Clauses 6–8 (packaging and labelling, sampling, conformity criteria) and Annexes A, B, C and ZA.

ACCORDING TO THE TEXT OF EN 450-1:2012 (foreword, introduction, Clauses 1–5.3.2). The standard was prepared by CEN/TC 104 “Concrete and related products” (secretariat DIN) under a mandate of the European Commission and EFTA; it superseded EN 450-1:2005+A1:2007. Main changes according to the foreword: extension of the permissible content of solid and of liquid and gaseous co-combustion materials, fixed limits for loss on ignition, incorporation of the requirements of EN 450-1+A1:2007 and editorial revision. Test methods for free calcium oxide and for fineness by sieving are given in the EN 451 series. Definitions (Clause 3): fly ash is a fine powder of mainly spherical, glassy particles derived from burning of pulverised coal with or without co-combustion materials, with pozzolanic properties, consisting essentially of SiO2 and Al2O3, obtained by electrostatic or mechanical precipitation from the flue gases of power stations; it may be processed (classification, selection, sieving, drying, blending, grinding, carbon reduction); ashes from municipal and industrial waste incineration do not conform to this definition (3.2). Test cement: Portland cement CEM I of strength class 42,5 or higher according to EN 197-1 (3.3). Activity index: the ratio (in percent) of the compressive strength of standard mortar bars with 75 % test cement and 25 % fly ash to that of bars with 100 % test cement, at the same age (3.5). Co-combustion (Clause 4): proportion of coal at least 60 % by dry mass (50 % if only green wood is co-combusted), proportion of ash from co-combustion materials M ≤ 30 % according to Formula (1), liquid and gaseous fuels ≤ 40 % of total net calorific value; Table 1 lists solid biofuels according to EN 14588:2010, meat and bone meal, municipal sewage sludge, paper sludge, petroleum coke and virtually ash-free liquid and gaseous fuels. Specifications (5.1): the requirements of 5.2 and 5.3 are characteristic values assessed statistically (Clause 8); the test methods of the standard are reference methods — others may be used if they give equivalent results, and in a dispute only the reference method is used. Chemical requirements are expressed on dry fly ash (5.2.1); for the major elements according to EN 196-2:2005, Clause 13, the following modifications apply: sintering with peroxide in a furnace at 550 °C for 60 min (timing from the recovery of the temperature to 540 °C), proceeding even if melting is not clear, decomposition of the evaporation residue with 2,0 g potassium bisulfate instead of the sodium carbonate and sodium chloride mixture. Loss on ignition (5.2.2): according to the principles of EN 196-2 but with an ignition time of 1 h; category A ≤ 5,0 %, B ≤ 7,0 %, C ≤ 9,0 % by mass; the requirement limits unburnt carbon, so it is sufficient to show unburnt carbon within these limits by direct determination according to ISO 10694; note: loss on ignition may affect air-entraining admixtures in freeze-thaw resistant concrete, hence three categories. Chloride as Cl– according to EN 196-2 ≤ 0,10 % (5.2.3); SO3 according to EN 196-2 ≤ 3,0 % (5.2.4); free CaO according to EN 451-1 — above 1,5 % the fly ash is tested for soundness (5.2.5); reactive CaO calculated according to EN 197-1:2011, 3.1, ≤ 10,0 % — with total CaO ≤ 10,0 % the requirement is deemed satisfied (5.2.6); reactive SiO2 according to EN 197-1 ≥ 25 % — in the initial type test of fly ash from co-combustion (5.2.7); sum SiO2 + Al2O3 + Fe2O3 according to EN 196-2 with the modifications of 5.2.1 ≥ 70 % (5.2.8); alkalis as Na2Oeq ≤ 5,0 % (5.2.9); MgO ≤ 4,0 % in the initial type test of fly ash from co-combustion (5.2.10); total phosphate P2O5 according to ISO 29581-2 ≤ 5,0 %, and soluble P2O5 according to Annex C ≤ 100 mg/kg in the initial type test of fly ash from co-combustion (5.2.11); for 5.2.7–5.2.11 fly ash from the combustion of coal only is deemed to satisfy the requirement. Fineness (5.3.1): mass of residue on the 0,045 mm sieve, determined wet according to EN 451-2 or by air jet according to EN 933-10; category N ≤ 40 % and not more than ±10 percentage points from the declared value, category S ≤ 12 % (without the ±10 points limit); in a dispute wet sieving according to EN 451-2 is the reference method. Activity index (5.3.2): standard mortar bars and compressive strength according to EN 196-1; at 28 days ≥ 75 %, at 90 days ≥ 85 %; the test cement is selected by the fly ash producer: Blaine fineness at least 300 m²/kg, tricalcium aluminate 6–12 %, alkalis (Na2Oeq) 0,5–1,2 %; note: the result gives no direct information on the strength contribution of fly ash in concrete and does not limit its use to the mixing ratio of the test. This is where the extract we read ends.

STATUS (cards as of 02.10.2026). The card of PN-EN 450-1:2012 (Polish version) has no “Withdrawn” header — the standard is CURRENT: published 13-02-2014, 34 pages, price group Q, Construction and Building Structures Sector, KT 274 Concrete, ICS 91.100.30, “Introduces: EN 450-1:2012 [IDT]”, directive 305/2011/EU, “Replaces: PN-EN 450-1+A1:2009 – Polish version”. Card of the English version: no “Withdrawn” header, published 22-10-2012, 30 pages. Earlier editions: PN-EN 450-1+A1:2009 (Polish version) — withdrawn 22-10-2012 and replaced by PN-EN 450-1:2012 in the English and Polish versions; PN-EN 450-1:2006 (Polish version) — withdrawn 30-06-2009 and replaced by PN-EN 450-1+A1:2007 (English version). Whether CEN is preparing a new edition of EN 450-1 we did not check — the iTeh catalogue page is built by a script and does not show the status.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 450-1 appears in 53 records at 9 laboratories: AB 054 (23), AB 688 (10), AB 687 (7), AB 550 (6), AB 829 (3), AB 672, AB 713, AB 804 and AB 874 (1 each). In 52 records the entry begins with “PN-EN 450-1”, in one (AB 688, Al2O3 content) with “PN EN 450-1:2012 pkt 5.2.1” — without the hyphen. In the current scopes on the PCA website (read 02.10.2026, scope issues from 12.11.2025 to 22.09.2026) the number appears at all 9 laboratories; at AB 054 part of the scope is suspended at the request of the body (bold italics, from 25.06.2026 to 22.12.2026), but no row with the number 450-1 is set in bold italics. The “Laboratories” tab searches entries BEGINNING WITH “PN-EN 450-1” and shows all 9 laboratories and 52 positions — checked with the tab query on the labcoda.pl production server on 02.10.2026; only the AB 688 record written without the hyphen is not visible.

WHAT THE LABORATORIES TEST (positions in PCA). Object: fly ash (siliceous, for concrete), ashes, wastes with codes of groups 10 01 and 19 01, at AB 688 also fluidized-bed ash and ash from peat and wood, and at AB 687 cements and binders. Loss on ignition (gravimetric method) with PN-EN 450-1 next to PN-EN 196-2 — AB 054, AB 672, AB 687, AB 688, AB 713, AB 829, AB 874 (ranges from (0,01–15,0) % to (0,50–40,00) %). Activity index “calculated” or “pozzolanic activity” next to PN-EN 196-1 — AB 054, AB 550, AB 687, AB 804, AB 829. Water requirement according to Annex B (flow table) — AB 054, AB 550, AB 687, AB 829 (at AB 550 range (90–115) %). Soundness (Le Chatelier ring), initial and setting time (Vicat apparatus) with PN-EN 196-3 — AB 054, AB 550, AB 687. Soluble phosphate as P2O5 according to Annex C — AB 054 (also with PN-EN ISO 6878) and AB 688 (range (1,0–200) mg/kg). Reactive CaO and SiO2 “calculated” next to PN-EN 197-1 — AB 550, AB 687. At AB 688 the number with clause 5.2.1 appears for Ca, Mg, Al, Si by ICP-OES (procedures IB-DPA-25 and IB-DPA-28) and SiO2 by the gravimetric method. At AB 054 the number also appears for insoluble residue and SiO2 (gravimetric method, procedure PB/LC-6).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. For loss on ignition: the standard requires ignition for 1 h, on the principles of EN 196-2 — a result with another ignition time is not a result according to 5.2.2; the category (A, B, C) is chosen by the user of the concrete, not by the laboratory. For chemical composition: everything on dry fly ash; for major elements according to EN 196-2 the three modifications of 5.2.1 apply (550 °C and 60 min, potassium bisulfate) — analysis without them gives numbers that only seem comparable. For reactive CaO: it is a value calculated according to EN 197-1, and with total CaO ≤ 10,0 % the requirement is deemed satisfied without calculation. For fineness: in a dispute wet sieving (EN 451-2) decides, not air-jet sieving (EN 933-10); in category N the deviation from the declared value also counts. For activity index: both mortars must be tested at the same age and with the same test cement, which has specified limits for fineness, C3A and alkalis. For calculations: activity index and reactive oxides are “calculated” in the scopes — the components come from tests according to EN 196-1, EN 196-2 and EN 197-1, described in separate standards.

WHAT WE DO NOT GIVE. We do not have 5.3.3–5.5, Clauses 6–8 (sampling, autocontrol, statistical conformity criteria and single result limit values), Annex A (dangerous substances and radioactivity), Annex B (determination of water requirement for category S), Annex C (method for soluble phosphate) or ZA — we therefore give no requirements for soundness, setting time, particle density and water requirement, no procedure of the annex methods and no conformity assessment criteria.

Method principle

Siliceous fly ash is assessed against chemical and physical requirements expressed as characteristic values: loss on ignition (ignition for 1 h according to the principles of EN 196-2, categories A/B/C) or directly unburnt carbon (ISO 10694), chloride, SO3, free and reactive CaO, reactive SiO2, the sum SiO2 + Al2O3 + Fe2O3, alkalis, MgO and phosphate — on dry fly ash — as well as fineness on the 0,045 mm sieve and activity index (ratio of the strength of mortar with 25 % fly ash to mortar with test cement only at 28 and 90 days, EN 196-1).

Applications

• Siliceous fly ash as a type II addition to concrete according to EN 206-1, also to mortars and grouts — limit: fly ash with other or more co-combustion materials than in Clause 4 is outside the scope
• Loss on ignition of ashes and wastes of groups 10 01 and 19 01 (gravimetric method, next to PN-EN 196-2) — 7 laboratories
• Activity index, water requirement (Annex B), soundness and setting time of fly ash — from 3 to 5 laboratories depending on the property
• Soluble phosphate P2O5 (Annex C) and major elements by ICP-OES in ashes — 2 laboratories

Key parameters

Standard

Standard number

PN-EN 450-1:2012 (wersja polska i angielska; EN 450-1:2012 IDT)

Title (PL)

Popiół lotny do betonu — Część 1: Definicje, specyfikacje i kryteria zgodności

Title (EN)

Fly ash for concrete — Part 1: Definition, specifications and conformity criteria

Step-by-step procedure

1. Sample

   Sampling (Clause 7, EN 196-7) — details NOT GIVEN; chemical requirements on dry fly ash. PN-EN 450-1:2012 current (cards as of 02.10.2026).

2. Loss on ignition or unburnt carbon

   Ignition for 1 h according to the principles of EN 196-2 and assignment of category A (≤ 5,0 %), B (≤ 7,0 %) or C (≤ 9,0 %); alternatively unburnt carbon according to ISO 10694.

3. Chemical composition

   Chloride, SO3 and major elements according to EN 196-2 with the modifications of 5.2.1 (550 °C, 60 min, potassium bisulfate); free CaO according to EN 451-1; reactive CaO and SiO2 calculated according to EN 197-1; total P2O5 according to ISO 29581-2.

4. Fineness

   Residue on the 0,045 mm sieve, wet (EN 451-2) or by air jet (EN 933-10); assessment in category N or S.

5. Activity index and assessment

   Bars of mortar with 75 % cement + 25 % fly ash and with 100 % cement (EN 196-1), compressive strength at 28 and 90 days, ratio in percent (≥ 75 % and ≥ 85 %); statistical conformity assessment according to Clause 8 — its criteria are NOT GIVEN.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Fly ash is a fine dust — work with dust extraction and respiratory protection; furnace for ignition and sintering (550 °C and above); the extract of the standard we read contains no safety warnings
• TECHNICAL NOTE: ash from incineration of municipal and industrial waste is not fly ash in the sense of 3.2, and fly ash with other or more co-combustion materials than in Clause 4 is outside the scope of the standard — results for such materials are not an assessment according to PN-EN 450-1

Frequently asked questions