Concrete is a ubiquitous building material used in infrastructure, buildings and artwork. As such, most people have at least a basic understanding of what the material is and how it’s formed.
However, there is a common misunderstanding that concrete eventually dries, which isn’t technically true. Here’s a quick overview of the composition of concrete and what is actually meant when we discuss concrete “drying” times.
Concrete and how it’s made
Concrete features a combination of cement, water and aggregates like gravel and sand. This slurry has a thick consistency and can be poured into molds to create just about any shape after enough concrete setting time has passed.
The most common type of concrete uses Portland cement as one of its primary ingredients. This material features a mix of compounds made from burning clay and limestone together.
When you add water to the aggregate-cement mixture, it results in chemical reactions that bind the materials together. These chemical reactions cause the concrete to harden and cure, but not necessarily dry out.
As the water is added to the mixture, each of the compounds in that mixture becomes hydrated. Calcium silicates influence the strength of the concrete, with some contributing earlier to the strength and others contributing later. These chemical reactions form calcium silicate hydrate, which morphs into some crystalline fibers that bind to each other and make sure the mixture stays tight and cemented.
The concrete never technically dries out because the water never actually leaves the concrete. It instead reacts with the concrete and remains a part of the form itself. While a certain amount of concrete setting time is required before the surface can be walked or driven upon, the curing process actually continues for months and years after initial installation, which results in enhanced strength over time. Think of it as an extremely long-lasting and progressing chemical reaction.
This is why it’s so important that concrete, unlike other building materials, does not reabsorb water after it’s cured. This could result in a sogginess that would cause its shape to morph and mess with the chemical reactions that have occurred and are ongoing.
So ultimately, when you think about concrete being “dry,” what you really are considering is how concrete feels after it has reached a certain stage of its curing process. It may feel dry to the touch, but the water remains within the material and continues to play an important role in how concrete maintains its strength and durability.
Want to learn more about the unique properties of concrete and what makes it such a beneficial building material for a wide range of applications? We encourage you to contact us at Mason & Associates. Our civil engineers are greatly experienced in working with concrete in a wide range of projects and settings, and are intimately familiar with all of the ins and outs of using concrete for masonry work, infrastructure, building construction and much more.
We look forward to answering any questions you have about concrete drying time and to helping you gain a better understanding of the material.