Recommendation of RILEM TC 281-CCC: RILEM CPC-18R1—guideline for measuring the carbonation depth of hardened concrete using a pH indicator solution

S. A. Bernal; Ueli M.  Angst; John L.  Provis; Charlotte Thiel; Gregor J.G. Gluth; Yury Villagran Zaccardi; Nele De Belie

doi:10.1617/s11527-026-02966-0

Recommendation of RILEM TC 281-CCC: RILEM CPC-18R1—guideline for measuring the carbonation depth of hardened concrete using a pH indicator solution

S. A. Bernal, Ueli M. Angst, John L. Provis, Charlotte Thiel, Gregor J.G. Gluth, Yury Villagran Zaccardi, Nele De Belie

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

Abstract

This recommendation provides a procedure for determining the carbonation depth on the surface of concrete by applying a pH indicator. This includes definitions of carbonation, carbonation depth and carbonation front, as well as descriptions of the different pH indicator solutions that can be used. Recommendations for testing laboratory-prepared specimens and those obtained from concrete structures are also given. This involves guidelines for sample preparation and/or extraction, CO2 exposure duration, carbonation depth determination and reporting of results. A section on data interpretation is also provided, as carbonation results are used for determining durability of concrete, as well as a criterion for materials selection or for carbon uptake calculations. The new Recommendation CPC-18R1 is intended to supersede the former RILEM recommendation CPC-18, particularly when prescribed as the preferred method for evaluating and reporting carbonation depths.

Original language	English
Article number	137
Number of pages	11
Journal	Materials and Structures
Volume	59
Issue number	3
Early online date	4 Mar 2026
DOIs	https://doi.org/10.1617/s11527-026-02966-0
Publication status	E-pub ahead of print - 4 Mar 2026

Acknowledgements

The authors would like to thank all members of RILEM TC 281-CCC, for the valuable discussions regarding carbonation of concrete with SCMs, and their insight and valuable discussions leading to the preparation of this recommendation.

Funding

Participation of S.A. Bernal was sponsored by the UK Engineering and Physical Sciences Research Council (EPSRC) the ECF EP/R001642/1 and EP/T008407/1.

Funders	Funder number
Engineering and Physical Sciences Research Council
ECF	EP/R001642/1, EP/T008407/1

Keywords

Carbonation
Carbonation depth
Carbonation front
pH indicator
RILEM CPC-18
Test method

ASJC Scopus subject areas

Civil and Structural Engineering
Building and Construction
General Materials Science
Mechanics of Materials

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Cite this

Bernal, S. A., Angst, U. M., Provis, J. L., Thiel, C., Gluth, G. J. G., Villagran Zaccardi, Y., & De Belie, N. (2026). Recommendation of RILEM TC 281-CCC: RILEM CPC-18R1—guideline for measuring the carbonation depth of hardened concrete using a pH indicator solution. Materials and Structures, 59(3), Article 137. Advance online publication. https://doi.org/10.1617/s11527-026-02966-0

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abstract = "This recommendation provides a procedure for determining the carbonation depth on the surface of concrete by applying a pH indicator. This includes definitions of carbonation, carbonation depth and carbonation front, as well as descriptions of the different pH indicator solutions that can be used. Recommendations for testing laboratory-prepared specimens and those obtained from concrete structures are also given. This involves guidelines for sample preparation and/or extraction, CO2 exposure duration, carbonation depth determination and reporting of results. A section on data interpretation is also provided, as carbonation results are used for determining durability of concrete, as well as a criterion for materials selection or for carbon uptake calculations. The new Recommendation CPC-18R1 is intended to supersede the former RILEM recommendation CPC-18, particularly when prescribed as the preferred method for evaluating and reporting carbonation depths.",

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Recommendation of RILEM TC 281-CCC: RILEM CPC-18R1—guideline for measuring the carbonation depth of hardened concrete using a pH indicator solution

Abstract

Acknowledgements

Funding

Keywords

ASJC Scopus subject areas

Access to Document

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