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Material properties related to fire spalling of concrete

Jansson, Robert LU (2008)
Abstract
Despite almost 100 years of research, the fundamentals of fire spalling of concrete are not

yet fully understood. Many different theories exist, each trying to describe the coupling

between different phenomenon leading to fire spalling. Some of these phenomenon have

been investigated and are presented in this thesis.

The thermal properties at high temperature have been investigated using the Transient

Plane Source (TPS) technique. Measurements of temperature in the cross-section of selfcompacting

concrete with the addition of polypropylene fibres (PP-fibres) during fire

exposure are presented. A verification calculation, based on the measured values of

temperature in... (More)
Despite almost 100 years of research, the fundamentals of fire spalling of concrete are not

yet fully understood. Many different theories exist, each trying to describe the coupling

between different phenomenon leading to fire spalling. Some of these phenomenon have

been investigated and are presented in this thesis.

The thermal properties at high temperature have been investigated using the Transient

Plane Source (TPS) technique. Measurements of temperature in the cross-section of selfcompacting

concrete with the addition of polypropylene fibres (PP-fibres) during fire

exposure are presented. A verification calculation, based on the measured values of

temperature in the cross-section of the fire exposed concrete, was compared with results

from a full-scale fire test with the same concrete. Good correlation was obtained.

Using a measurement system consisting of oil filled steel pipes, the pressure inside the

concrete during fire exposure, was measured. Results from pressure measurement tests on

self compacting concrete show relatively low internal pressure before spalling. In fact, the

pressure was highest in a specimen that did not spall during fire exposure. Conclusions

from the tests were that pore pressure only played a secondary role in the spalling process

of the concrete investigated. Thermal stresses were believed to be the primary reason for

spalling.

With a small addition of polypropylene fibres (PP) in concrete the fire spalling can be

limited or totally avoided. Comparative studies of concrete with and without PP- fibres

were performed, and the function of PP-fibres was illustrated in small and large scale fire

tests. When determining the free thermal expansion as a function of temperature a strain

plateau was found in specimens containing PP-fibres. The plateau corresponds fairly well

with the temperature where accelerated drying behaviour was shown. This is an

indication that an accelerated drying creep phenomenon might be present. Further

experimental work is needed to verify this postulate. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Concrete, thermal properties, fire spalling, polypropylene fibres
pages
62 pages
publisher
Division of Building Materials, LTH, Lund University
external identifiers
  • other:TVBM-3143
language
English
LU publication?
yes
id
a925a6a9-878a-42bb-bba4-06972e15e566 (old id 1273307)
date added to LUP
2008-12-07 18:34:04
date last changed
2016-09-19 08:44:48
@misc{a925a6a9-878a-42bb-bba4-06972e15e566,
  abstract     = {Despite almost 100 years of research, the fundamentals of fire spalling of concrete are not<br/><br>
yet fully understood. Many different theories exist, each trying to describe the coupling<br/><br>
between different phenomenon leading to fire spalling. Some of these phenomenon have<br/><br>
been investigated and are presented in this thesis.<br/><br>
The thermal properties at high temperature have been investigated using the Transient<br/><br>
Plane Source (TPS) technique. Measurements of temperature in the cross-section of selfcompacting<br/><br>
concrete with the addition of polypropylene fibres (PP-fibres) during fire<br/><br>
exposure are presented. A verification calculation, based on the measured values of<br/><br>
temperature in the cross-section of the fire exposed concrete, was compared with results<br/><br>
from a full-scale fire test with the same concrete. Good correlation was obtained.<br/><br>
Using a measurement system consisting of oil filled steel pipes, the pressure inside the<br/><br>
concrete during fire exposure, was measured. Results from pressure measurement tests on<br/><br>
self compacting concrete show relatively low internal pressure before spalling. In fact, the<br/><br>
pressure was highest in a specimen that did not spall during fire exposure. Conclusions<br/><br>
from the tests were that pore pressure only played a secondary role in the spalling process<br/><br>
of the concrete investigated. Thermal stresses were believed to be the primary reason for<br/><br>
spalling.<br/><br>
With a small addition of polypropylene fibres (PP) in concrete the fire spalling can be<br/><br>
limited or totally avoided. Comparative studies of concrete with and without PP- fibres<br/><br>
were performed, and the function of PP-fibres was illustrated in small and large scale fire<br/><br>
tests. When determining the free thermal expansion as a function of temperature a strain<br/><br>
plateau was found in specimens containing PP-fibres. The plateau corresponds fairly well<br/><br>
with the temperature where accelerated drying behaviour was shown. This is an<br/><br>
indication that an accelerated drying creep phenomenon might be present. Further<br/><br>
experimental work is needed to verify this postulate.},
  author       = {Jansson, Robert},
  keyword      = {Concrete,thermal properties,fire spalling,polypropylene fibres},
  language     = {eng},
  note         = {Licentiate Thesis},
  pages        = {62},
  publisher    = {Division of Building Materials, LTH, Lund University},
  title        = {Material properties related to fire spalling of concrete},
  year         = {2008},
}