What Is The Difference Between Concrete And Reinforced Concrete?

Plain concrete, as in a sidewalk, is merely concrete poured into a shape and trowled on the surface, or otherwise finished. It’s very robust, but is susceptible to fracturing as the subsoil moves, or when the roots of the frost or tree press up from below. Basement floors in a private home are typically constructed of plain concrete, so the loading of the floor is likely to be minimal, the subsoil is unlikely to move, and frost or roots probably won’t be a concern.

Reinforced concrete is concrete within which contains a mesh wire or steel bar frame. The wet concrete is poured over the steel, and it hardens, thereby enclosing the steel permanently. Reinforced concrete is much stronger, so cracks are much less likely. It’s used in commercial houses, highways, etc.

Reinforced concrete an unreinforced concrete is, generally, the same material. There are a multitude of different concrete mix types, however, a certain strength, aggregate material, and Portland cement mixture can harden and cure for most purposes whether reinforcement bars, mesh, or fibers are used or not. An example is concrete formulations that are specifically designed for use without reinforcement, flexible, or flexural pavement.

A third type is called concrete which is pre-stressed. Here solid steel forms are used to surround whatever the final form is to be. For such types, steel bars are inserted into matching openings, and special nuts are inserted at the threaded ends of those bars. The bars are put in a high voltage state by tightening the nuts.

Concrete is then poured into the shapes, and allowed to harden. The nuts are gone, and the shapes replaced. The bars are placed tightly within the mortar. However, they try to shrink back to their original dimension as they were originally stretched (placed into tension). This is not likely since they are firmly bound into the concrete across their existence.

The net result is that the pre-stressed steel bars seek to compress the entire piece of concrete indefinitely. So the concrete is in a constant compression state.

Concrete now has enormous compressive strength but only low-stress strength. When you put a simple concrete slab across an opening and only support it at the two opposite ends, then any weight placed in the center of the concrete would strain the slab. Rupture of the slab doesn’t take much weight. But if that slab has prestressed bars embedded in it, the slab would be much stronger and can support much more weight, until the concrete is hardened.

For this purpose, prestressed concrete is used, for example, to create beams that hold up a parking garage. And why prestressed concrete is mostly used in tall buildings to render floors.