In recent years, scientific studies are carried out to find new refractory
material. Having good mechanical properties under very high temperatures,
refractories are widely used in industries like iron, steel, glass, cement and pottery.
Researches are focused on monolithic refractory making because of their superior
properties comparing to conventional firebrick refractories. Providing a mono-block
body, having no joints makes the monolithic refractories more durable at elevated
temperatures. Easier production and installation are two main points that people are
choosing monolithic refractories, thus an economy is made.
In this study, for monolithic refractory production, high alumina cement was
used as binding material. It is known that the increase in alumina (Al2O3) content
increases the high temperature resistance, so that crushed firebrick, having 85%
Al2O3 was used as aggregate. Pozzolanic materials, which are silica fume, fly ash,
ground granulated firebrick and ground granulated blast furnace slag, were added to
improve physical and mechanical properties of mortar. With the addition of steel
fibres, change in compressive strength and flexural strength was observed.Superplasticizer was used to understand its behaviour under high temperatures.
Portland cement containing mortars were also prepared to make comparison with
high alumina cement containing specimens.
Specimens were prepared in 5x5x5 cm and 4x4x16 cm prisms. They were
cured for one day at curing room, then heated to 105° / C and then heated to 1100° / C.
Weight, size and ultrasound velocity change, compressive strength and flexural
strength tests were done to determine physical and mechanical properties of the
monolithic refractories, before and after heating. Heated and non-heated specimens
were pulverized for microstructural investigation with X-Ray diffraction (XRD)
method.
Using high alumina cement with 50 &ndash / 60 % granulated blast furnace slag or
granulated firebrick, by the weight of cement, and crushed firebrick as aggregate, a
satisfactory monolithic refractory material was made. It was observed that,
mechanical properties were decreased at the Portland cement used mortars after
several times of heating and cooling cycles. Also, it was determined that the
microstructure of the high alumina cement containing mortars did not deteriorate
much at 1100° / C, as long as there was no change observed from the results.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12606700/index.pdf |
| Date | 01 November 2005 |
| Creators | Morel, Bayram Murat |
| Contributors | Turanli, Lutfullah |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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