EFFECT OF CARBON FIBER ON MEDIUM-CEMENT
HEAT-RESISTANT CONCRETE PROPERTIES
and R. Stonis
Translated from Novye Ogneupory, No. 8, pp. 45 – 48, August 2014.
Original article submitted April 17, 2014.
Heat-resistant medium-cement concrete with calcium aluminate filler is studied. It is established that addition
of carbon fiber facilitates an increase in concrete strength in compression and thermal stability. Explosive
breakage only does not occur for specimens with polypropylene fiber on heating a concrete specimen at a rate
of 40°C/min to 1000°C.
Keywords: heat-resistant concrete, carbon fiber, ultimate strength in compression, thermal stability, explosive
Metal and organic fibers, fulfilling specific functions, are
mainly used in heat-resistant concretes. Steel fibers improve
concrete mechanical properties and increase its thermal
shock resistance, retarding crack propagation [1, 2]. The lim-
iting temperature for use of steel fibers is about 1200°C. Or-
ganic fibers (polypropylene, from polyaramides, etc.) in
dense and deflocculated concretes, are required in order to
provide removal of water vapor during drying and the first
firing [3, 4], since these concreates are inclined towards ex
plosive breakage on rapid heating [5, 6]. Fibers provide
shrinkage and melt at 150°C, and water vapor is removed
from concrete through microchannels created within its
Attempts have been made to use in heat-resistant con
crete ceramic fibers, used in manufacture of refractory heat
insulation objects , and aluminosilicate fibers, prepared by
a plasma method . However, no significant effect was
achieved. As a rule, these fibers react at high temperature
with other concrete components and become an integral part
of a material.
Carbon fibers are used quite extensively for dispersed re-
inforcement of concrete normally used in civil construction
in order to improve its physicomechanical properties and
prevent formation of deformation cracks. There is some in-
terest in the results of research obtained using mechanically
activated carbon fiber in autoclave concrete [8, p.
362 – 371]. It was shown in the work that fine particles of
carbon fibre, formed with mechanical treatment, exhibit an
activated surface that serves as crystallization centers during
binder material hardening. As a result of this there is an in
crease the crystallinity of new formations, and autoclave
concrete mechanical properties are improved.
Consideration was given in  to micromechanics of
short glass and carbon fibers in a concrete matrix. The dy
namics of pull-out and stress field were studied around a sin
gle fiber, pulled from a matrix. The main stages of the pro
cess were established.
Carbon fibers oxidize in air at elevated temperature. The
temperature of its prolonged operation is 300 – 400°C, and
under conditions of short-term heating in inert or reducing
atmospheres a fiber withstands a temperature of
1500 – 2000°C . There is interest in using these fibers in
heat-resistant concrete for reinforcement in the drying stage
and the first firing in order to prevent crack formation and re
duce the danger of explosive breakage.
In this work the effect of carbon fibers on properties of
medium cement heat-resistant concrete were studied, con
centrating attention on concrete mechanical properties and
crack formation with thermal shocks and rapid heating.
Refractories and Industrial Ceramics Vol. 55, No. 4, November, 2014
1083-4877/14/05504-0352 © 2014 Springer Science+Business Media New York
Proceedings of International Conference of Refractory Workers
and Metallurgists (3 – 4 April, 2014, Moscow).
Gediminas Vilnius Technical University, Vilnius, Lithuania.
Physicotechnical Institute of the Belarus National Academy of
Sciences, Minsk, Belarus Republic.
Riga technical University, Riga, Latvia.