%0 Journal Article
%T Fire Resistant K-Based Metakaolin Geopolymer for Passive Fire Protection of Concrete Tunnel Linings
%A Konstantinos Sakkas
%A Stergiani Kapelari
%A Dimitrios Panias
%A Pavlos Nomikos
%A Alexandros Sofianos
%J Open Access Library Journal
%V 1
%N 6
%P 1-9
%@ 2333-9721
%D 2014
%I Open Access Library
%R 10.4236/oalib.1100806
%X A fire resistant metakaolin geopolymer is developed
and its performance under thermal loading is examined in this paper. The
geopolymer was prepared by mixing metakaolin, doped with solid SiO<sub>2</sub>,
with a highly alkaline potassium hydroxide aqueous phase in order to create a
paste that was subsequently cured at 70¡æ for a certain period
of time. The addition of solid SiO<sub>2</sub> was important in order the
geopolymer developed to be fire resistant for temperatures up to 1350¡æ. The mechanical,
physical and thermal properties of the metakaolin geopolymer were measured and
compared with available commercial fire resistant materials. The behavior of the metakaolin geopolymer upon exposure on fire
was studied following the EFNARC guidelines for testing of passive fire protection
for concrete tunnels linings. The geopolymer was subjected to the most
severe fire scenario, the Rijks Water Staat (RWS) temperature-time
curve.
During the test, the temperature in the geopolymer/concrete interface remained
under 220¡æ, which is 160¡æ lower than the RWS
test requirement, proving the ability of material to work successfully as an
efficient thermal barrier. After the test the surface of the geopolymer had
exfoliated and cracked, without losing its structural integrity. Thus, the
concrete slab protected by the geopolymer did not appear any form of spalling or
degradation of its compressive strength.
%K Metakaolin
%K Geopolymer
%K Tunnel Linings
%K Passive Fire Protection
%U http://www.oalib.com/paper/3101566