When did cement begin to exist in ancient times?

The word cement means adhesive. Therefore, bone glue and marrow glue can also be said to be substances like cement. But the cement we are talking about today only refers to portland cement. Portland cement was invented in19th century, but as early as 1700 years ago in ancient times, when building brick houses, the Romans enthusiastically studied how to make bricks stick to each other.

The Romans first used lime as a binder for making bricks. Ordinary lime is called quicklime. When water is added, it becomes sticky hydrated lime, and when sand is mixed, it becomes mortar. Mortar absorbs carbon dioxide in the air and becomes calcium carbonate, which gradually solidifies. Therefore, mortar can be used as a binder for bricks.

However, the Romans further baked lime, gypsum and volcanic ash and invented better adhesives. This is very similar in nature to the cement used today, and the Romans also used this adhesive as reinforcement cement. In Roman architecture, stones and bricks are often used to build walls in two layers, and this kind of "cement" is added in the middle to solidify them.

Because the Romans invented this excellent "cement", Europe has been using this Romanesque "cement" since then.