Fly ash from modern coal-fired power technologies: Chloride ingress and carbonation of concrete

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Abstract

The Paper investigates low-lime fly ashes produced from modern coal-fired power technologies (developed to enhance efficiency/lower emissions) including, NOx reduction, co-combustion, supercritical steam and oxy-fuel combustion, and their effects on chloride ingress and carbonation of concrete. Earlier work indicates that some of these influence fly ash properties, but they mainly follow typical behaviour found for the material (consistence and compressive strength) in concrete. Both accelerated and normal type exposure tests were carried out on a range of practical w/c ratio concretes (also enabling interpolation for comparisons at equal 28 day strength). The test fly ash concretes were evaluated against (i) those containing three reference fly ashes covering a range of fineness and (ii) corresponding studies on fly ash concretes from the 1990s. The results show that there was an influence of fly ash fineness, reflected in reactivity/porosity (measured on mortar), and aspects of chemistry on chloride ingress, but there appeared to be minor material effects on carbonation. Comparisons with the 1990s data indicate similar behaviour for the materials between studies for both properties. A relationship was also identified for the product of reactive alumina and sub 10 µm contents of the modern fly ashes and chloride resistance of concrete.
Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalMagazine of Concrete Research
Early online date20 Mar 2019
DOIs
Publication statusE-pub ahead of print - 20 Mar 2019

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Coal Ash
Carbonation
Coal
Fly ash
Chlorides
Concretes
Aluminum Oxide
Steam
Mortar
Lime
Compressive strength
Interpolation
Alumina
Porosity

Cite this

@article{e0b35f8a17c045329603e4c2cf2ec49f,
title = "Fly ash from modern coal-fired power technologies:: Chloride ingress and carbonation of concrete",
abstract = "The Paper investigates low-lime fly ashes produced from modern coal-fired power technologies (developed to enhance efficiency/lower emissions) including, NOx reduction, co-combustion, supercritical steam and oxy-fuel combustion, and their effects on chloride ingress and carbonation of concrete. Earlier work indicates that some of these influence fly ash properties, but they mainly follow typical behaviour found for the material (consistence and compressive strength) in concrete. Both accelerated and normal type exposure tests were carried out on a range of practical w/c ratio concretes (also enabling interpolation for comparisons at equal 28 day strength). The test fly ash concretes were evaluated against (i) those containing three reference fly ashes covering a range of fineness and (ii) corresponding studies on fly ash concretes from the 1990s. The results show that there was an influence of fly ash fineness, reflected in reactivity/porosity (measured on mortar), and aspects of chemistry on chloride ingress, but there appeared to be minor material effects on carbonation. Comparisons with the 1990s data indicate similar behaviour for the materials between studies for both properties. A relationship was also identified for the product of reactive alumina and sub 10 µm contents of the modern fly ashes and chloride resistance of concrete.",
author = "Michael McCarthy and Hamza Yakub and Laszlo Csetenyi",
note = "Acknowledgement is given to the Engineering and Physical Science Research Council (Doctoral Training Award) and the UK Quality Ash Association and its members for funding the research described.",
year = "2019",
month = "3",
day = "20",
doi = "10.1680/jmacr.18.00543",
language = "English",
pages = "1--13",
journal = "Magazine of Concrete Research",
issn = "0024-9831",
publisher = "Thomas Telford",

}

TY - JOUR

T1 - Fly ash from modern coal-fired power technologies:

T2 - Chloride ingress and carbonation of concrete

AU - McCarthy, Michael

AU - Yakub, Hamza

AU - Csetenyi, Laszlo

N1 - Acknowledgement is given to the Engineering and Physical Science Research Council (Doctoral Training Award) and the UK Quality Ash Association and its members for funding the research described.

PY - 2019/3/20

Y1 - 2019/3/20

N2 - The Paper investigates low-lime fly ashes produced from modern coal-fired power technologies (developed to enhance efficiency/lower emissions) including, NOx reduction, co-combustion, supercritical steam and oxy-fuel combustion, and their effects on chloride ingress and carbonation of concrete. Earlier work indicates that some of these influence fly ash properties, but they mainly follow typical behaviour found for the material (consistence and compressive strength) in concrete. Both accelerated and normal type exposure tests were carried out on a range of practical w/c ratio concretes (also enabling interpolation for comparisons at equal 28 day strength). The test fly ash concretes were evaluated against (i) those containing three reference fly ashes covering a range of fineness and (ii) corresponding studies on fly ash concretes from the 1990s. The results show that there was an influence of fly ash fineness, reflected in reactivity/porosity (measured on mortar), and aspects of chemistry on chloride ingress, but there appeared to be minor material effects on carbonation. Comparisons with the 1990s data indicate similar behaviour for the materials between studies for both properties. A relationship was also identified for the product of reactive alumina and sub 10 µm contents of the modern fly ashes and chloride resistance of concrete.

AB - The Paper investigates low-lime fly ashes produced from modern coal-fired power technologies (developed to enhance efficiency/lower emissions) including, NOx reduction, co-combustion, supercritical steam and oxy-fuel combustion, and their effects on chloride ingress and carbonation of concrete. Earlier work indicates that some of these influence fly ash properties, but they mainly follow typical behaviour found for the material (consistence and compressive strength) in concrete. Both accelerated and normal type exposure tests were carried out on a range of practical w/c ratio concretes (also enabling interpolation for comparisons at equal 28 day strength). The test fly ash concretes were evaluated against (i) those containing three reference fly ashes covering a range of fineness and (ii) corresponding studies on fly ash concretes from the 1990s. The results show that there was an influence of fly ash fineness, reflected in reactivity/porosity (measured on mortar), and aspects of chemistry on chloride ingress, but there appeared to be minor material effects on carbonation. Comparisons with the 1990s data indicate similar behaviour for the materials between studies for both properties. A relationship was also identified for the product of reactive alumina and sub 10 µm contents of the modern fly ashes and chloride resistance of concrete.

UR - https://discovery.dundee.ac.uk/en/publications/e0b35f8a-17c0-4532-9603-e4c2cf2ec49f

U2 - 10.1680/jmacr.18.00543

DO - 10.1680/jmacr.18.00543

M3 - Article

SP - 1

EP - 13

JO - Magazine of Concrete Research

JF - Magazine of Concrete Research

SN - 0024-9831

ER -