eli5 how does cement and concrete become hard if it’s only rocks and water
In: 12
Concrete is comprised of at least 4 ingredients: water, fine aggregate (e.g. sand), coarse aggregate (e.g. gravel), and cementitious material (e.g. Portland cement and/or fly ash). It may also include other ingredients which alter key properties like slump, cure time, color, strength, flexibility, etc.
Cement is a chemically reactive material. When mixed with water, it undergoes a reaction called hydration. There are several types of compound (5 major ones) in cement include calcium and/or silica. When those are exposed to water, the extra stuff leaves those molecules and what’s left behind is a molecule made of calcium (like your bones) and silica (like glass). That stuff is very strong.
tl;dr: – Water pulls strong compounds out of cementing leaving behind something that is strong like a mixture of bone and glass.
Latest Answers