Development of Shotcreting Castable

Particle packing is one of important parameters, which dictates physical and thermo-mechanical properties of refractories. Fillers play a substantial role in the packing behaviour of low cement castable. Fine filler particles fill the voids of the castable aggregate leading to a high packing density of the castable and thereby decrease the cement as well as water requirement of the castable. Micro-silica and calcined alumina are normally used as filler materials in the development of low cement castable. It has been established that these fine fillers particles are responsible to provide ceramic bond and the intermediate temperature and provides high strength at high temperature due to formation of secondary mullite. In the present work an attempt has been made to develop low cement castable with suitable filler addition. Effect of particle size and particle size distribution of calcined alumina filler has been studied in order to achieve high flow behaviour in low cement 70% alumina based vibratable castable formulation. This alumina filler particle has further been used to optimize and develop a suitable self-flow castable, wherein the amount of micro-silica and calcined alumina amount has been optimized. Physical and thermo-mechanical properties of the castables thus developed have also been studied in detail. Attempt has also been made to study the effect of setting accelerator amount on the properties of self-flow castable thus developed with an aim for shotcreating application