A LIGHT REFRACTORY CONCRETE FOR THERMAL INSULATION
I. D. Kashcheev,
S. N. Sychev,
M. N. Dunaeva,
L. A. Karpets,
P. A. Emel’yanov,
and O. S. Ryakhova
Translated from Novye Ogneupory, No. 4, pp. 29 – 32, April, 2008.
Original article submitted November 29, 2007.
Compositions have been developed for nonshrinking vibrocast thermally insulating light refractory concretes
with densities of 1.0, 1.3, 1.5, and 1.8 g/cm
for temperatures of use up to 1400°C. The structure and
properties have been examined for the concrete of density 1.3 g/cm
Advances in metallurgy and other branches of industry
impose new requirements on the properties of light-weight
refractories, and one needs better refractories with a combi-
nation of properties providing the reduction of energy,
materials, labor, and time during production.
Although there has been a general reduction in the
production and use of refractory materials, there has been an
increase in the proportion of production for unmolded
refractories having many advantages over the usual ones.
Out of all forms of unmolded refractories, the commonest
have been refractory concretes, both traditional ones with
high contents of cement and low-cement new-generation
When heat-insulating refractories are used in industrial
ovens, there is 20 – 70% reduction in the consumption of
fuel, and it is possible to accelerate substantially the firing in
batch ovens while also reducing the wall thicknesses in
ovens and domes. If the thermal insulation is provided by
high porosity, then the mass of the lining is also reduced.
It is important to develop light concretes with low
density and thermal conductivity, which can be transported
in the form of dry mixtures and from which one can produce
the lining by vibrocasting directly at the user=s plant.
This study was performed to develop compositions for
light refractory concretes with various densities on the basis
of available and cheap raw materials. The basic concept was
to use a light spherical aluminosilicate filler with closed
porosity, which would allow one to use the minimum amount
of water to obtain the vibrational flow state. Eliminating
water from the structure of the concrete leads to the structure
becoming more open and weaker, so the task is to minimize
the amount of treatment water, including by the use of
deflocculants and the addition of ultrafine powders.
Rod specimens were shaped by vibration in demountable
metal molds. The molds containing the specimens were kept
for 24 h in a moist medium at room temperature. Then the
Refractories and Industrial Ceramics Vol. 49, No. 2, 2008
1083-4877/08/4902-0131 © 2008 Springer Science+Business Media, Inc.
GOUVPO of Urals State Technical University and Urals Poly
technical Institute, and Dinur Corporation, Russia.
TABLE 1. Characteristics of Light Concretes*
VGBTS-1.8 VGBTS-1.3 VGBTS-1.0
Mass fraction, %:
, not less than 73 60 56
, not more than 18 33 37
CaO, not more than 3.0 3.2 3.5
, not more than 1.0 1.1 1.0
O, not more than 1.0 0.6 0.7
Apparent density, g/cm
not more than
1.8 1.3 1.0
Compressive strength in Mpa
at temperature in °C:
120 40.1 15.6 6.4
400 49.4 11.5 5.7
1000 54.2 19.9 8.0
1400 85.1 34.9 22.5
Linear shrinkage after firing at
1400°C with hold for5hin%
0.36 0.35 0.3
Additional linear changes at
1400°C and hold for2hin%
+0.5 +0.2 –0.5
Thermal conductivity after
firing at 1400°C with hold 5 h
at an average temperature of
0.92 0.60 0.40
Water consumption, liter/100 kg
10 – 10.5 18 – 19 25 – 27
Temperature of use up to 1400°C.