The performance of Fly ash and Metakaolin concrete at elevated temperatures

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Ordinary concrete is generally considered to have satisfactory fire resistance but when it comes to high strength concrete it shows extensive damage or even catastrophic failure at elevated temperatures. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with Fly ash (FA) and Metakaolin (MK) at elevated temperatures. Variables of the test program include partial replacement of cement with MK from 5% to 20%, FA from 20% to 60%, temperatures from 27 °C to 800 °C and two types of cooling methods (in air and water). The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability and water sorptivity tests. Mass loss at elevated temperatures was also determined. Moreover, quantitative analysis of the SEM images on selected concrete specimens was performed using Image Pro-plus software. Test results showed degradation in the mechanical and durability properties of HPC at elevated temperatures. Quick cooling produced greater loss in compressive strength than slow cooling. This is because of the effect of thermal shock which was more pronounced at 400 °C. From the standpoint of durability, all mixes showed major increase in charge pass and sorptivity values in between 400 °C and 600 °C. Therefore, 400 °C could be regarded as the critical temperature for change in the properties of HPC. Quantitative analysis of the SEM images of Interfacial Transition Zone (ITZ) indicated that pore area fraction increased with the increase in temperature. This resulted in the degradation of microstructure and affected the strength and durability of concrete. In general, at temperatures (400 °C and above) FA20 showed better performance while MK mixes (MK10 and MK20) showed higher degradation in terms of durability. This gives an indication that MK mixes should be used with care especially in structures which may be subjected to temperature of 400 °C and above.

Original languageEnglish
Pages (from-to)67-76
Number of pages10
JournalConstruction and Building Materials
Volume62
DOIs
Publication statusPublished - Jul 15 2014
Externally publishedYes

Fingerprint

Coal Ash
Fly ash
Concretes
Durability
High performance concrete
Temperature
Cooling
Degradation
Compressive strength
Fire resistance
Scanning electron microscopy
Water
Thermal shock
Chemical analysis
Chlorides
Cements

Keywords

  • Compressive strength
  • Elevated temperature
  • Fly ash
  • Interfacial transition zone
  • Metakaolin
  • Thermal shock

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)

Cite this

The performance of Fly ash and Metakaolin concrete at elevated temperatures. / Nadeem, Abid; Memon, Shazim Ali; Lo, Tommy Yiu.

In: Construction and Building Materials, Vol. 62, 15.07.2014, p. 67-76.

Research output: Contribution to journalArticle

@article{43f7f38e038145b78c9d06bc781187aa,
title = "The performance of Fly ash and Metakaolin concrete at elevated temperatures",
abstract = "Ordinary concrete is generally considered to have satisfactory fire resistance but when it comes to high strength concrete it shows extensive damage or even catastrophic failure at elevated temperatures. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with Fly ash (FA) and Metakaolin (MK) at elevated temperatures. Variables of the test program include partial replacement of cement with MK from 5{\%} to 20{\%}, FA from 20{\%} to 60{\%}, temperatures from 27 °C to 800 °C and two types of cooling methods (in air and water). The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability and water sorptivity tests. Mass loss at elevated temperatures was also determined. Moreover, quantitative analysis of the SEM images on selected concrete specimens was performed using Image Pro-plus software. Test results showed degradation in the mechanical and durability properties of HPC at elevated temperatures. Quick cooling produced greater loss in compressive strength than slow cooling. This is because of the effect of thermal shock which was more pronounced at 400 °C. From the standpoint of durability, all mixes showed major increase in charge pass and sorptivity values in between 400 °C and 600 °C. Therefore, 400 °C could be regarded as the critical temperature for change in the properties of HPC. Quantitative analysis of the SEM images of Interfacial Transition Zone (ITZ) indicated that pore area fraction increased with the increase in temperature. This resulted in the degradation of microstructure and affected the strength and durability of concrete. In general, at temperatures (400 °C and above) FA20 showed better performance while MK mixes (MK10 and MK20) showed higher degradation in terms of durability. This gives an indication that MK mixes should be used with care especially in structures which may be subjected to temperature of 400 °C and above.",
keywords = "Compressive strength, Elevated temperature, Fly ash, Interfacial transition zone, Metakaolin, Thermal shock",
author = "Abid Nadeem and Memon, {Shazim Ali} and Lo, {Tommy Yiu}",
year = "2014",
month = "7",
day = "15",
doi = "10.1016/j.conbuildmat.2014.02.073",
language = "English",
volume = "62",
pages = "67--76",
journal = "Construction and Building Materials",
issn = "0950-0618",
publisher = "Elsevier",

}

TY - JOUR

T1 - The performance of Fly ash and Metakaolin concrete at elevated temperatures

AU - Nadeem, Abid

AU - Memon, Shazim Ali

AU - Lo, Tommy Yiu

PY - 2014/7/15

Y1 - 2014/7/15

N2 - Ordinary concrete is generally considered to have satisfactory fire resistance but when it comes to high strength concrete it shows extensive damage or even catastrophic failure at elevated temperatures. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with Fly ash (FA) and Metakaolin (MK) at elevated temperatures. Variables of the test program include partial replacement of cement with MK from 5% to 20%, FA from 20% to 60%, temperatures from 27 °C to 800 °C and two types of cooling methods (in air and water). The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability and water sorptivity tests. Mass loss at elevated temperatures was also determined. Moreover, quantitative analysis of the SEM images on selected concrete specimens was performed using Image Pro-plus software. Test results showed degradation in the mechanical and durability properties of HPC at elevated temperatures. Quick cooling produced greater loss in compressive strength than slow cooling. This is because of the effect of thermal shock which was more pronounced at 400 °C. From the standpoint of durability, all mixes showed major increase in charge pass and sorptivity values in between 400 °C and 600 °C. Therefore, 400 °C could be regarded as the critical temperature for change in the properties of HPC. Quantitative analysis of the SEM images of Interfacial Transition Zone (ITZ) indicated that pore area fraction increased with the increase in temperature. This resulted in the degradation of microstructure and affected the strength and durability of concrete. In general, at temperatures (400 °C and above) FA20 showed better performance while MK mixes (MK10 and MK20) showed higher degradation in terms of durability. This gives an indication that MK mixes should be used with care especially in structures which may be subjected to temperature of 400 °C and above.

AB - Ordinary concrete is generally considered to have satisfactory fire resistance but when it comes to high strength concrete it shows extensive damage or even catastrophic failure at elevated temperatures. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with Fly ash (FA) and Metakaolin (MK) at elevated temperatures. Variables of the test program include partial replacement of cement with MK from 5% to 20%, FA from 20% to 60%, temperatures from 27 °C to 800 °C and two types of cooling methods (in air and water). The mechanical performance was assessed from compressive strength while the durability was assessed from chloride permeability and water sorptivity tests. Mass loss at elevated temperatures was also determined. Moreover, quantitative analysis of the SEM images on selected concrete specimens was performed using Image Pro-plus software. Test results showed degradation in the mechanical and durability properties of HPC at elevated temperatures. Quick cooling produced greater loss in compressive strength than slow cooling. This is because of the effect of thermal shock which was more pronounced at 400 °C. From the standpoint of durability, all mixes showed major increase in charge pass and sorptivity values in between 400 °C and 600 °C. Therefore, 400 °C could be regarded as the critical temperature for change in the properties of HPC. Quantitative analysis of the SEM images of Interfacial Transition Zone (ITZ) indicated that pore area fraction increased with the increase in temperature. This resulted in the degradation of microstructure and affected the strength and durability of concrete. In general, at temperatures (400 °C and above) FA20 showed better performance while MK mixes (MK10 and MK20) showed higher degradation in terms of durability. This gives an indication that MK mixes should be used with care especially in structures which may be subjected to temperature of 400 °C and above.

KW - Compressive strength

KW - Elevated temperature

KW - Fly ash

KW - Interfacial transition zone

KW - Metakaolin

KW - Thermal shock

UR - http://www.scopus.com/inward/record.url?scp=84905056331&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84905056331&partnerID=8YFLogxK

U2 - 10.1016/j.conbuildmat.2014.02.073

DO - 10.1016/j.conbuildmat.2014.02.073

M3 - Article

VL - 62

SP - 67

EP - 76

JO - Construction and Building Materials

JF - Construction and Building Materials

SN - 0950-0618

ER -