The advantages of monolithic refractories have driven extensive research, and significant progress has been made. Flowable refractory castables (concretes) that self-compact or compact with vibration have become a widely used construction material. Flowable concrete offers a wide range of engineering properties and the potential for product innovation. Scientific research continues on controlling the rheological properties of a concrete with various deflocculants. In this study, we compare the effect on the properties of LCC castables incorporating a new calcined alumina from Alteo with other commercially available, reactive aluminas. The new alumina, FLO-2, is a very fine, milled alumina with a median particle size ~2 μm and medium soda content (0.25%). It has good flowability and may be an economical alternative to some reactive aluminas.

The development of low- and ultra-low-cement content castables (LCC and ULCCs) started in the late 1970s. Monolithics offer advantages over conventional refractory brick in terms of application rate as well as cost and flexibility, making them attractive to industrial users.^1-5 Because monolithics provide rapid setting times and harden quickly at room temperature, they are used for building structures as well as for patching and coating brick.