<abstract xmlns="http://www.w3.org/1999/xhtml"><p>During the construction of a rock tunnel in Stockholm, several sections with leaching shotcrete (sprayed concrete) were found one year after the spraying was completed. An investigation was therefore conducted, and its results are presented in this paper. The amount of leaching after such a short time indicated that a one-sided water pressure existed in combination with a permeable shotcrete. The reason for the water pressure was likely a partly unsuccessful grouting that created sections with leaking water. The permeable shotcrete could be a combined result of insufficient curing and the use of accelerators, and the effect of in-situ curing was therefore investigated. A total of six slabs were sprayed and cured under different conditions in the tunnel. Test results according to standards indicated that curing has no significant effect on the development of mechanical strength or water penetration through the shotcrete. However, this is believed to be a result of the test method rather than the non-existing effect of curing. Lastly, some modifications to the test standard were proposed for future studies of in-situ curing.</p></abstract>

During the construction of a rock tunnel in Stockholm, several sections with leaching shotcrete (sprayed concrete) were found one year after the spraying was completed. An investigation was therefore conducted, and its results are presented in this paper. The amount of leaching after such a short time indicated that a one-sided water pressure existed in combination with a permeable shotcrete. The reason for the water pressure was likely a partly unsuccessful grouting that created sections with leaking water. The permeable shotcrete could be a combined result of insufficient curing and the use of accelerators, and the effect of in-situ curing was therefore investigated. A total of six slabs were sprayed and cured under different conditions in the tunnel. Test results according to standards indicated that curing has no significant effect on the development of mechanical strength or water penetration through the shotcrete. However, this is believed to be a result of the test method rather than the non-existing effect of curing. Lastly, some modifications to the test standard were proposed for future studies of in-situ curing.

In-Situ and Laboratory Investigation on Leaching and Effects of Early Curing of Shotcrete

KTH Royal Institute of Technology Division of Concrete Structures

Nordic Concrete Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

During the construction of a rock tunnel in Stockholm, several sections with leaching shotcrete (sprayed concrete) were found one year after the spraying was...

In-Situ and Laboratory Investigation on Leaching and Effects of Early Curing of Shotcrete

Published Online: Dec 31, 2019

Page range: 23 - 37

Received: Mar 14, 2019

Accepted: Sep 30, 2019

DOI: https://doi.org/10.2478/ncr-2019-0014

Keywords
shotcrete, curing, experiments, investigation, testing

© 2019 Andreas Sjölander et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

In-Situ and Laboratory Investigation on Leaching and Effects of Early Curing of Shotcrete

Published Online: Dec 31, 2019

Page range: 23 - 37

Received: Mar 14, 2019

Accepted: Sep 30, 2019

DOI: https://doi.org/10.2478/ncr-2019-0014

Keywordsshotcrete, curing, experiments, investigation, testing

© 2019 Andreas Sjölander et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
shotcrete, curing, experiments, investigation, testing