Journal Published Online: 26 October 2018
Volume 7, Issue 1

Monitoring the Carbonation-Induced Microcracking in Alkali-Activated Slag (AAS) by Nonlinear Resonant Acoustic Spectroscopy (NRAS)

CODEN: ACEMF9

Abstract

This article presents the potential of nonlinear resonant acoustic spectroscopy (NRAS) for noninvasive monitoring of the carbonation progress in alkali-activated slag (AAS) mortars. In the search for sustainable concrete, AAS has emerged as a potential substitute for ordinary portland cement binder. However, carbonation is reported to be an important durability concern for AAS due to the absence of portlandite. In this study, the correspondence between the physical properties and microstructural evolution of sodium silicate-activated slag (SS-AS) and sodium hydroxide-activated slag (SH-AS) mortars were studied over the full course of accelerated carbonation. The measured properties include the following: compressive strength, carbonation depth, porosity, pore size distribution, and phase assemblage. In addition, NRAS was used to track the changes in materials stiffness (linear resonance frequency) and hysteretic nonlinearity (amplitude dependency of resonance frequency). Scanning electron microscopy (SEM) images and porosimetry results showed the formation of microcracks and increased micrometer porosity in a carbonated AAS binder caused by calcium aluminum silicate hydrate decalcification; the cracking was more severe in the SS-AS than in the SH-AS. The NRAS results revealed a close correspondence between the observed microscopic changes in the samples and measured macroscopic test parameters, indicating the potential of acoustic techniques for monitoring the advancement of carbonation fronts in AAS mortars.

Author Information

Ghahramani, Sara
Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, USA
Guan, Yingjun
School of Information Sciences, University of Illinois at Urbana-Champaign, Champaign, IL, USA
Radlińska, Aleksandra
Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, USA
Shokouhi, Parisa
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
Pages: 23
Price: $25.00
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Stock #: ACEM20170133
ISSN: 2379-1357
DOI: 10.1520/ACEM20170133