Abstract
In the recent decades, the use of unshaped monolithic refractories has been increasing greatly because of their significant advantages over other shaped refractory bricks of the same class. A low cement high alumina castable was synthetised and sintered at 1300?C in order to investigate thermal and mechanical properties, as well as thermal shock behavior. The water quench test was applied as an experimental method for thermal stability testing. Modification of the water quench test was performed by additional monitoring of the samples behavior during the water quench test such as implementation of image analysis and ultrasonic measurements. The image analysis program was applied on samples in order to measure the level of surface damage before and during the water quench test. Ultrasonic measurements were performed with the aim to measure the Young modulus of elasticity during the testing. Strength deterioration of the samples was calculated by the model based on ultrasonic velocity changes during the water quench test. The influence of monitoring the damage level before and during the quench experiment and its influence on thermal shock behavior will be discussed.
Highlights
Among unshaped refractories, castables are used especially in critical high temperature applications for complex constructions, easy applications to thin sections and regions that are difficult to reach [1,2]
The results of image analysis are given in Fig. 2. as a function of the number of cycles of the water quench test
Results for the velocity change in samples suggest that materials were very stable during testing, as decrease of the velocity was not too significant from the velocity through the sample before water quench test. These results indicate that number of nucleated cracks and crack propagation did not resolute in rapid degradation of strength and Young modulus of elasticity, and samples exhibited excellent thermal shock behavior
Summary
Castables are used especially in critical high temperature applications for complex constructions, easy applications to thin sections and regions that are difficult to reach [1,2]. Conventional castables beside aggregates contained a relatively high cement content and high mixing water forming high strength bonding, high open porosity (up to 20%) and low raw density. Different fine and ultra fillers (in the form of calcined alumina, reactive alumina, microsilica) were added to the conventional castable composition with the aim to fill the open pore space between the coarse aggregates [3,4]. Their cement content and amount of mixing water can be reduced.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
