高分子ファイバー含有キャスタブル耐火物の乾燥挙動

摘要

Polypropylen (PP) fibers have been widely used in concretes and in refractory castables since their development in the early 70s. In addition to benefiting the mechanical strength of green castables, the use of fibers has been reported as an alternative method to minimize the risks of spelling and structural damage during drying and first heat-up. The purpose of this technique is to generate greater permeability and allow for the easy release of pressurized water vapor. The mechanism that increases permeability is temperature-activated and involves physicochemical changes in the polymeric material (such as melting and burnout), which heave permeable channels in the castables structure. However, it is not entirely clear how fibers affect the drying behavior of refractory castables, rendering it difficult to make a reliable choice of the most suitable fiber for each castable formulation and drying process. This lack of further research also hinders the development of new types of more efficient fibers. The objective of this work was to elucidate the mechanism whereby polymeric fibers affect the permeability and the drying behavior of refractory castables, using permeability evaluation techniques and thermal characterization of PP fibers.