What are no cement castables?
Refractory concretes need a binder. You could think of the binder as the glue that holds the rocks together. In most cases the binder in castables, gunning mixes and shotcrete mixes is a calcium aluminate (CA) cement, a binder similar to calcium silicate cement (Portland cement) but designed to handle higher temperatures without breaking down. The CA cement is kind of like the Portland cement in that water is not only needed to start the binder reaction, and actually becomes part of the bond matrix. No Cement castables do not utilize a cement binder, rather the bond matrix is made up of a set of chemicals that form a bond matrix without the use of a cement. In most cases, the chemical reactions that create no cement binders are activated by water, but do not incorporate water as part of the bond. In some applications, no cement castables offer advantages over cement bonded products, especially in acidic environments or processes that operate at exceptionally high temperatures.
