Evaluation of test methods for self-healing concrete with macrocapsules by inter-laboratory testing
Abstract: Self-healing of concrete is a promising way to increase the service life of structures. Innovative research is being performed, yet it is difficult to compare results due to a lack of standardised test methods. In the framework of the COST action SARCOS (CA15202) [1] six different inter- laboratory tests are being executed, in which different test methods are being evaluated for six self-healing approaches. Here, the results of the inter-laboratory test concerning mortar and concrete with macrocapsules filled with a polyurethane healing agent will be discussed. The specimens were manufactured in one laboratory and then shipped to the other five participating laboratories. All six laboratories evaluated two test methods: a water permeability test and a capillary water absorption test. For the water permeability test, mortar specimens were cracked and afterwards their crack width was controlled using an active control technique. Due to the active crack control, the crack width of 90% of the samples deviated by less than 10 μm from the target of 300 μm. This made it more straightforward to compare the permeability test results, which indicated a similar sealing efficiency for several of the laboratories. For the capillary water absorption test, concrete specimens were cracked in a crack-width-controlled three-point bending test setup without active control after unloading. Compared to the water permeability specimens, there was a lot more variation on the crack width of the capillary water absorption specimens. The variability on the crack width and differences in quality of waterproofing resulted in diverging findings in the capillary water absorption test.
Reference of this article: Tim Van Mullem, Giovanni Anglani, Hanne Vanoutrive, Girts Bumanis, Chrysoula Litina, Marta Dudek, Arkadiusz Kwiecien, Abir Al-Tabbaa, Diana Bajare, Teresa Stryszewska, Robby Caspeele, Kim Van Tittelboom, Jean Marc Tulliani, Elke Gruyaert, Paola Antonaci and Nele De Belie (2021), Evaluation of test methods for self-healing concrete with macrocapsules by inter-laboratory testing, Proceedings Resilient Materials 4 Life 2020 (RM4L2020), Maddalena R, Wright-Syed M, (RM4L Eds), pp. 180-185, Cardiff, UK, 20-22 Sep 2021, ISBN 978-1-3999-0832-0
Affiliations:
Tim Van Mullem, Robby Caspeele, Kim Van Tittelboom and Nele De Belie: Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Ghent University, Belgium
Giovanni Anglani, Jean Marc Tulliani and Paola Antonaci: Politecnico di Torino, Italy
Hanne Vanoutrive and Elke Gruyaert: KU Leuven - Ghent Technology Campus, Belgium
Girts Bumanis and Diana Bajare: Riga Technical University, Latvia
Chrysoula Litina and Abir Al-Tabbaa: University of Cambridge, United Kingdom
Marta Dudek, Arkadiusz Kwiecien and Teresa Stryszewska: Cracow University of Technology, Poland
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