The alkali-silica reaction in concrete at the mesoscale: characterization by X-ray tomography
The alkali-silica reaction (ASR) is one of the most frequent and deleterious durability issues in concrete structures. In Switzerland, several types of structures, including bridges and dams, are affected by ASR.
The ASR is an endogenous chemical reaction. It occurs between the alkaline pore solution in concrete and silicates-rich aggregates. The ASR products can lead to a significant amount of cracking.
Significant research efforts have been dedicated to the understanding and to the prediction of ASR-related damage. However, reliable damage assessment and prediction are not yet feasible. That is because the mechanisms of the reaction and corresponding damage develop are still poorly understood.
This is the PhD project of Mahdieh Shakoorioskooie. It is one module of the Swiss National Science Foundation (SNF) Sinergia project Nr. 171018.
This module aims at advancing the understanding of the ASR chemo-mechanics (and respective damage) at the mesoscale by time-lapse, fully non-destructive and quantitative characterization of the cracking. X-ray tomography, performed at Empa's Center for X-ray Analytics, and 3D image analysis are the key methodologies used.
The results from this project will also act as essential input data for another module of the Sinergia project (PhD project of Emil Gallyamov at EPFL), dedicated to finite element method computational modeling of the mechanics of ASR damage progression.
June 2017 - August 2021
A. Leemann, I. Borchers, M. Shakoorioskooie, M. Griffa, C. Müller, P. Lura. "Microstructural analysis of ASR in concrete-accelerated testing versus natural exposure." In Proc. Int. Conf. Sustain. Mater. Syst. Struct.(SMSS2019). Durability, Monit. Repair Struct, Rilem Publications, Paris, pp. 222-229. 2019
Shakoorioskooie, M., Griffa, M., Leemann, A., Zboray, R., & Lura, P. (2021). Evolution of alkali-silica reaction cracks and products in concrete at the meso-scale studied by X-ray micro-tomography. In A. Lopes Batista, A. Santos Silva, I. Fernandes, L. Oliveira Santos, J. Custódio, & C. Serra (Eds.), Vol. 1. Proceedings of the 16th international conference on alkali-aggregate reaction in concrete (ICAAR) (pp. 1151-1162). Laboratório Nacional de Engenharia Civil.
Shakoorioskooie, M., Griffa, M., Leemann, A., Zboray, R., Lura, P. (2021). Alkali-silica reaction products and cracks: X-ray micro-tomography-based analysis of their spatial-temporal evolution at a mesoscale. Cem. Concr. Res. 150, 106593/1-16. DOI: 10.1016/j.cemconres.2021.106593. arXiv pre-print: https://arxiv.org/abs/2105.15092.