Fire Testing of Shotcrete Samples in a Small Furnace

by Johan Mangs, Technical Research Cent of Finland, Espoo, Finland,
Olavi Keski-Rahkonen, Technical Research Cent of Finland, Espoo, Finland,

Document Type: Proceeding Paper

Part of: Shotcrete for Underground Support V


The fire resistance behaviour of 8 shotcrete samples were investigated in a laboratory furnace applying ISO 834 standard test. Shotcrete was applied on 20 to 30 cm thick granite slabs on an area of about 1 m2. Temperatures near the granite-shotcrete boundary and in the shotcrete layer were measured with thermocouples. Changes of the shotcrete and the granite substrate were observed visually. The results of the experiments show that the granite-shotcrete bond breaks 10 to 20 min after the beginning of the fire. Anchored shotcrete layers protected granite effectively despite bond breakage. Spalling occurred only mildly in wet-mix shotcrete without fibre reinforcement. It did not appear in fibre reinforced samples. Conclusions of the tests summarize as follows: 1. anchoring or other means to keep the shotcrete layer in place is necessary. 2. There is a slight positive indication that fibre reinforcement improves spalling resistance of shotcrete.

Subject Headings: Shotcrete | Fire resistance | Temperature measurement | Material tests | Load and resistance factor design | Fiber reinforced composites | Material mechanics

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