The Loss on Ignition (LOI) of cement refers to the percentage of weight loss that occurs when a cement sample is subjected to high temperatures. It is a measure of the volatile components present in the cement, including chemically bound water, carbon dioxide, and organic compounds.
The LOI test is conducted to determine the amount of volatile materials in the cement, as these can impact the cement's properties and performance. The volatile components can contribute to the development of strength, affect setting time, and influence the cement's behavior during hydration and curing.