Experimental and statistical study on the irregularity of carbonation depth of cement mortar under supercritical condition

Bao, Hao and Yu, Min and Liu, Yu and Ye, Jianqiao (2018) Experimental and statistical study on the irregularity of carbonation depth of cement mortar under supercritical condition. Construction and Building Materials, 174. pp. 47-59. ISSN 0950-0618

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Abstract

The heterogeneity of a cement-based material results in a random spatial distribution of carbonation depth. Currently, there is a lack of both experimental and numerical investigations aiming at a statistical understanding of this important phenomenon. This paper presents both experimental and numerical supercritical carbonation test results of cement mortar blocks. The carbonation depths are measured along the carbonation boundary by the proposed rapid image processing technique, which are then statistically studied by calculating, e.g., their probability density and power spectral density (PSD). The results indicate that the distribution of the carbonation depth can be approximately represented by a lognormal distribution function and the PSD has quantitative correlation with some of the statistic parameters used in the simulations. In particular, the effects of the autocorrelation lengths and the coefficient of variation of porosity, which are used to define the random porosity field, on the irregularity of carbonation depth are analyzed numerically in details and validated by experimental results. The study has shown that using a random field of porosity with due consideration of spatial correlation and variance, the irregularity of carbonation depth can be realistically captured by the numerical model. The numerical results confirm that lognormal distributions represent the random nature of carbonation depth well and the average and variance of the irregular carbonation depth increase with the increase of carbonation time, autocorrelation length and coefficient of variation of porosity. The study also offers a potential method to numerically calibrate some of the statistic parameters required by a numerical carbonation model through comparing the PSD with that from experimental tests. Overall the methodology adopted in the paper can provide a foundation for future investigations on probability analysis of carbonation depth and other similar work based on multi-scale and -physics modelling.

Item Type:
Journal Article
Journal or Publication Title:
Construction and Building Materials
Additional Information:
This is the author’s version of a work that was accepted for publication in Construction and Building Materials. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Construction and Building Materials, 174, 2018 DOI: 10.1016/j.conbuildmat.2018.04.100
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2200/2215
Subjects:
ID Code:
124944
Deposited By:
Deposited On:
30 Apr 2018 09:10
Refereed?:
Yes
Published?:
Published
Last Modified:
05 Apr 2020 04:59