Low cement castable (LCC) refractory linings, over recent years, have superseded refractory bricks in many high temperature applications. There are concerns however, pertaining to their dry-out. In particular the catastrophic destruction of LCC shapes or linings as a result of phenomenate rmede xplosives palling. This thesis describes the study of both the on-site treatments of LCCs and the physicochemical changes that occur during heating. Two types of explosive spalling event are classified,b asedo n on-siteo bservationsa ndp ost-mortems tudy. A model is presented that describes the physicochemical changes in a LCC system as it is heated from ambient to 450°C. From this model a zone of high vulnerability to explosion has been identified between 230-280°C. The dehydration of the hydrated alumina phase gibbsite (AH3), within this zone, is identified as a possible cause of explosive spalling. An investigation of polypropylene fibres, which are added to LCCs as anti-explosion additives, found that the fibres block porosity between1 60-240°CI.t is suggested that this additive system is not optimised and that polymer fibre blends may be more advantageous. The diffusion characteristics of a LCC system cured at 5 and 20°C is presented. It was found that at the lower curing temperature the diffusion rate was lower. This supports the recommendation for the use of high curing temperature to facilitate the drying of LCCs and reduce the risk of explosive spalling. A list of guidelines that could be used to establish benchmark standards for the development of best practice in industry has been compiled from the results of these studies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:327700 |
| Date | January 2000 |
| Creators | Clayton, Daniel James |
| Publisher | Keele University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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