1. Application of Fibers in Refractory Composites
Marcel JOGL, Pavel REITERMAN, Ondřej Holčapek, Petr KONVALINKA
Experimental Centre, Faculty of Civil Engineering, CTU in Prague,

2. Content Introduction Experimental investigation Results of measurement
The components and mixtures
Production and treatment of test specimens
Thermal loading
The examined properties
Results of measurement
Conclusion

3. Introduction
Development of materials with higher strength and durability
Low fire resistance of elements
The instability of the silica aggregates and Portland cement-based composites (over 500 °C)
Decrease in strength of constructure steel (over 400 °C)
Creation of composite material for high temperature applications
Required resistence
Excellent workability
Homogenous behavior

4. Experimental program The components and mixtures
Production of refractory composites by mixing selected components
Within the experiment were designed 6 mixtures
Chamotte filler was compared with the crushed brick aggregate
Program was also focused on the assessment of various doses of fibers
Components [kg/m3]
Basalt fibres
Aluminous Cement
Fireclay
Plast.
Water
6.35 mm
12.7 mm
0/1 mm
1/2 mm
2/4 mm
Ref-0
900
520
140
320
16.20
200
Ref-0.5
1.45
13.05
Ref-2.0
5.8
52.2
Recycled aggregate
0/4 mm
RA-0
1016
RA-0.5
RA-2.0

5. Experimental program Production and treatment of test samples
9 specimens made of each mixture
with the dimensions of 40x40x160 mm
Stored in a humid environment for 28 days
Drying at 105 °C for 24 hours
Divided into three groups of three samples:
1. group of samples dried at 105 °C
2. group of samples fired at 600 °C
3. group of samples fired at 1000 °C

6. Experimental program Thermal loading
Thermal loading was preformed in an automatic electric furnace
The temperature increase of 10 °C/min
Samples were left to cool down spontaneously

7. Experimental program The examined properties Flexural strenght [MPa]
Compressive strenght [MPa]
(fragments after bending test)
Bulk density [kg/m3]
Mechanical testing was carried with the use of the loading device EU 40 for all applied thermal levels

8. Evaluation of the experiment
The average values of the examined properties
Relative values of bulk density
Significant decline of the bulk density due to thermal loading
Effect of the increasing application of basalt fibers
Lower bulk density of applied recycled ceramic aggregate

9. Evaluation of the experiment
The average values of the examined properties
Relative values of residual flexural strenght
Influence of fibers application is visible only on the non-loaded composites

10. Evaluation of the experiment
The average values of the examined properties
Relative values of residual compressive strenght
Negative effect of high doses of basalt fibers
Measurement well correspond with the results of the bulk density

11. Conclusions
In term of mechanical properties, the most suitable values are achieved when the 0.5 % of fibers by volume was applied
However, the reference mixtures with no fibers exhibited higher or similar values of mechanical properties
Decreased quality of recycled aggregate led to the reduction of studied parameters
The program has confirmed the potential of ceramic grit for aluminous cement based composites production
Further application of various waste materials can help to reduce environmental impacts and total costs

12. Thank you for your attention
This work was carried out with financial support of the grant GAČR P104/12/0791