ELI5: Explain Like I'm 5

Portlandite

Portlandite is a powdery substance that comes from cement. Cement is used to make things like sidewalks, buildings, and roads. Portlandite is a special part of cement that is made from a material called calcium oxide. Calcium oxide is made from heating up limestone really hot, until it turns into a powdery material.

Portlandite is created when the calcium oxide in cement reacts with water and turns into a different kind of material called calcium hydroxide. It might sound complicated, but it's like magic happening right in front of our eyes! Portlandite is important because it helps hold the cement together and makes it strong.

So, when you're walking on a sidewalk, or looking at a building made of cement, you can remember that there's a special ingredient called Portlandite in there that helps keep it all together. Just like how glue sticks things together, Portlandite helps hold cement together. Pretty cool, right?