🔍 Key Concepts

• Difference between plastic and castable refractory materials • What a hydraulic-setting binder is and how it behaves (similar to concrete) • Which refractory types need to be rammed or plastic worked versus mixed with water and poured/cast

💭 Think About

• Which option sounds like it is mixed with water and then hardens on its own, similar to concrete, without first needing firing? • Which materials called "plastic" are usually supplied damp and molded or rammed into place, then gain strength mainly after being fired? • How is mortar normally used compared to a material that can form an entire monolithic lining?

✅ Before You Answer

• Identify which choice typically contains a cement-like (hydraulic) binder that sets with water. • Eliminate any options that must be fired first to gain significant strength. • Ask yourself which option is usually poured or troweled as a mix, not rammed in a plastic state.