The meta-kaolinite content of the calcined clay source impacts the mechanical and durability performance of blended Portland concrete

Yuvaraj Dhandapani; Kirthika Kala Subramanian; Fragkoulis Kanavaris; Leon Black; Susan A. Bernal

doi:10.1016/j.cemconres.2025.107922

The meta-kaolinite content of the calcined clay source impacts the mechanical and durability performance of blended Portland concrete

Yuvaraj Dhandapani, Kirthika Kala Subramanian, Fragkoulis Kanavaris, Leon Black, Susan A. Bernal

Research output: Contribution to journal › Article › peer-review

1 Citation (SciVal)

Abstract

This study evaluated the mechanical and durability performance of CEM I and CEM I plus limestone blended concrete produced with calcined clays (CC) with a varying meta-kaolinite content (70, 50 or 20 wt%). Results revealed that concrete with >45 MPa can be produced with a CC with only 20 wt% meta-kaolinite. Increased compressive and flexural strengths were obtained using higher meta-kaolinite content CC. Limestone addition did not significantly change the concretes' transport or durability properties when compared to binary mixes, despite the reduced clinker factor. CC-containing concretes exhibited excellent chloride resistance, but reduced carbonation performance compared with CEM I. Using a CC with higher meta-kaolinite content enhanced the concrete's carbonation resistance, when evaluated for 650 days of natural exposure. This suggests that generalising the impact of CC addition on concrete performance can be misleading, as bespoke concrete, compliant with specific exposure class requirements, can be produced by appropriate clay selection.

Original language	English
Article number	107922
Journal	Cement and Concrete Research
Volume	196
Early online date	10 May 2025
DOIs	https://doi.org/10.1016/j.cemconres.2025.107922
Publication status	E-pub ahead of print - 10 May 2025

Data Availability Statement

The data associated with this paper are openly available from the University of Leeds Data Repository at https://doi.org/10.5518/1675.

Acknowledgements

The calcined excavated London clay was donated by Arup and SCS JV through the REAL Project. The donation of the superplasticiser by Sika UK Ltd., and CEM I 52.5R and limestone by Heidelberg Materials is greatly acknowledged. The authors are also grateful to Mr. Ehsaanul Laskar for his support during some of the experimentation in the laboratory.

Funding

This study was conducted as part of project ‘CMMI-EPSRC RENACEM: Response to CO2 exposure of concrete with natural supplementary cementitious materials’ sponsored by the National Science Foundation (NSF) through award #1903457 and the UK Engineering and Physical Sciences Research Council (EPSRC) through award EP/T008407/1. Y. Dhandapani, L. Black and S.A. Bernal participation in this study was partially supported by EPSRC grant EP/W021811/1.

Funders	Funder number
Engineering and Physical Sciences Research Council	EP/T008407/1 , EP/W021811/1

Keywords

Calcined clay
Carbonation
Chlorides
Concrete
Durability
Kaolinite
Limestone
Mechanical strength

ASJC Scopus subject areas

Building and Construction
General Materials Science

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10.1016/j.cemconres.2025.107922Licence: CC BY

Cite this

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title = "The meta-kaolinite content of the calcined clay source impacts the mechanical and durability performance of blended Portland concrete",

abstract = "This study evaluated the mechanical and durability performance of CEM I and CEM I plus limestone blended concrete produced with calcined clays (CC) with a varying meta-kaolinite content (70, 50 or 20 wt%). Results revealed that concrete with >45 MPa can be produced with a CC with only 20 wt% meta-kaolinite. Increased compressive and flexural strengths were obtained using higher meta-kaolinite content CC. Limestone addition did not significantly change the concretes' transport or durability properties when compared to binary mixes, despite the reduced clinker factor. CC-containing concretes exhibited excellent chloride resistance, but reduced carbonation performance compared with CEM I. Using a CC with higher meta-kaolinite content enhanced the concrete's carbonation resistance, when evaluated for 650 days of natural exposure. This suggests that generalising the impact of CC addition on concrete performance can be misleading, as bespoke concrete, compliant with specific exposure class requirements, can be produced by appropriate clay selection.",

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AU - Black, Leon

AU - Bernal, Susan A.

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N2 - This study evaluated the mechanical and durability performance of CEM I and CEM I plus limestone blended concrete produced with calcined clays (CC) with a varying meta-kaolinite content (70, 50 or 20 wt%). Results revealed that concrete with >45 MPa can be produced with a CC with only 20 wt% meta-kaolinite. Increased compressive and flexural strengths were obtained using higher meta-kaolinite content CC. Limestone addition did not significantly change the concretes' transport or durability properties when compared to binary mixes, despite the reduced clinker factor. CC-containing concretes exhibited excellent chloride resistance, but reduced carbonation performance compared with CEM I. Using a CC with higher meta-kaolinite content enhanced the concrete's carbonation resistance, when evaluated for 650 days of natural exposure. This suggests that generalising the impact of CC addition on concrete performance can be misleading, as bespoke concrete, compliant with specific exposure class requirements, can be produced by appropriate clay selection.

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KW - Calcined clay

KW - Carbonation

KW - Chlorides

KW - Concrete

KW - Durability

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KW - Limestone

KW - Mechanical strength

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The meta-kaolinite content of the calcined clay source impacts the mechanical and durability performance of blended Portland concrete

Abstract

Data Availability Statement

Acknowledgements

Funding

Keywords

ASJC Scopus subject areas

Access to Document

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