Characterising cement carbonation curing using non-contact electrical resistivity measurement

Abstract

Carbonation curing of cement paste and concrete promotes early strength gain, improves durability and recycles carbon dioxide in a beneficial manner. To examine the carbonation curing mechanism, fresh cement pastes and concretes subject to carbonation are characterised using a non-contact electrical resistivity measurement method.Resistivity measurements reveal that characteristic features of the hydration accelerated by carbonation are different from conventional hydration. The typical induction period is absent in the carbonation curing owing to the rapid precipitation of calcium carbonate. The resistivity measurement method produces a superimposed result of early hardening and multiple instances of progressive hardening by carbonation curing. The electrical resistivity is 3-6 times higher in the carbonated cement paste and about 8-16 times higher in the carbonated concretes in comparison with the hydration references. The carbonated lightweight concrete shows lower bulk resistivity than the carbonated normal-weight concrete, possibly owing to the release of internal water from the lightweight aggregates during carbonation. This is evidence of internal curing by lightweight aggregates.

Evaluation of Concrete Carbonation Based on a Fiber Bragg Grating Sensor

“…Nevertheless, these methods are currently confined to laboratory settings and are inherently destructive, rendering them unsuitable for large-scale structures and critical components in engineering projects. Recently, non-destructive testing methods have been applied to the study of concrete carbonation, such as non-linear ultrasonic techniques [ 21 ], resistivity measurement [ 22 , 23 ], and electrochemical impedance spectroscopy [ 24 ], etc. Kim used a non-contact air-coupled transducer to detect Rayleigh wave signals and obtained the nonlinear parameters of the material.…”

Editorial

“…Morshed et al (2015) used a NC-ERM to investigate the hydration process of fresh mixes of cement pastes and concretes, and characterise the intake of CO 2 into hydration by the precipitation reaction. The authors observed the final resistivity of carbonation-cured samples was three to six times higher (pastes) and eight to 16 times higher (concretes) than the normally cured samples.…”