Influence of drying rate on carbonation of concrete with supplementary cementitious materials

Gopinath, Rakesh

Abstract

The relative humidity (RH) in concrete pores has a major influence on the rate of carbonation of concrete.
Since carbonation is a reaction-diffusion process, the favourable moisture condition for carbonation is in
the range of 50-70% RH. At higher RH, the diffusion of atmospheric carbon dioxide (CO2) into concrete
pores reduces and at lower RH conditions there is insufficient moisture for the carbonation reaction to take
place. The addition of supplementary cementitious material alters the concrete microstructure depending
on the curing regime adopted, which in turn governs the drying rate of concrete (internal RH) and as a
result, also influences the rate of carbonation. The paper addresses these issues based on an experimental
investigation. Six concrete mixes with two water:binder ratio (w/b), and two supplementary cementitious
materials - fly ash (FA) and ground granulated blast furnace slag (GGBS) - were used for the experimental
investigation. All the concrete specimens were subjected to two different curing regimes and tested for
permeability, rate of drying and carbonation. The test results show that the incorporation of supplementary
cementitious materials alters the concrete microstructure depending on the curing conditions, which results
in different drying rates of the concrete, in turn resulting in variation in the rates of carbonation.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: Concrete under Severe Conditions – Environment & Loading (CONSEC24)
• Start Date: Sep 25, 2024
• End Date: Sep 27, 2024
• Acceptance Date: May 24, 2024
• Online Publication Date: Oct 15, 2024
• Publication Date: Oct 15, 2024
• Deposit Date: Jan 16, 2025
• Publicly Available Date: Jan 22, 2025
• Peer Reviewed: Peer Reviewed
• Pages: 926-930
• Book Title: Proceedings of 10th International Conference (CONSEC24) Chennai, India
• Keywords: Carbonation, Drying, Relative humidity, Supplementary cementitious materials
• Public URL: https://uwe-repository.worktribe.com/output/13619722
• Publisher URL: https://consec24.com/assets/images/CONSEC24-Proceedings-Final.pdf