The use of PP fibers in tunnel construction to avoid explosive concrete spalling in case of fire. New test results for the clarification of the mode of action
Title: The use of PP fibers in tunnel construction to avoid explosive concrete spalling in case of fire. New test results for the clarification of the mode of action
Author(s): Ingo Knack
Paper category : conference
Book title: 2nd International RILEM Workshop on Concrete Spalling due to Fire Exposure
Editor(s): E.A.B. Koenders and F. Dehn
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 297 - 307
Total Pages: 11
Nb references: 19
Abstract: In tunnel construction PP fibers are being increasingly mixed into the concrete to prevent explosive concrete spalling in case of fire, being caused by evaporation of the moisture contained in the concrete. In general opinion the increased fire resistance is based on the fact that by the melting fibers in case of fire capillaries are formed in the concrete through which the steam can escape. The exact mode of action of the PP fibers is not yet clear in detail and there are different model conceptions in discussion. In a previous work we have already demonstrated that in this connection the diffusion of the polymer melt into the concrete is the determining process.
In this work now test results with new PP and PE fibers are presented which were developed particularly for the further clarification of the mode of action. The test results clearly prove that the diffusion process of the melting PP fibers is the only mechanism which in case of fire leads to a permeable capillary system to reduce the harmful pore pressure in the concrete.
There was no indicaton for any other processes.
Online publication: 2012-01-17
Publication type : full_text
Public price (Euros): 0.00