Thing to consider when pouring a concrete slab

Sidewalks, driveways, houses, skyscrapers, concrete floors, and ceiling often all have something in common. Each of the aforementioned structures can be, and often is, created using concrete slabs. A concrete slab is the name for a block of concrete, generally reinforced concrete, with reinforcement bars embedded in the concrete. Concrete slabs can be thick or thin, and can be utilized in a number of different ways, a few of which will be described in this article.

                The first thing to consider when discussing a concrete slab is whether it has been made in some factory, and transported to the construction site to be placed. The alternative to premade concrete slabs is creating the slabs on the job site, a method which possesses a number of advantages. Creating slabs on site ensures that the slab will be of accurate dimensions, because the slab is created exactly where it will need to go, using forms. Forms are pieces of wood, or other barriers, that are laid out in such a way as to allow the concrete to settle in between them, giving the concrete slab the exact shape desired. Sometimes creating concrete slabs on site is not plausible, and it is in these cases where concrete slabs would be shipped in from a factory.

                Once the concrete slab has been created, and is at the job site, there are a few ways it can be put in place. In the case of a foundation for a building, the concrete slab is often placed directly on the subsoil underneath where the structure will be developed. In the case of driveways or sidewalks, the concrete slab is generally poured into a form exactly where it is needed, on top of the ground, and there is no movement necessary. In the case of skyscrapers, or other large buildings which employ the use of a concrete slab; the slabs are lifted using a crane, and placed between the steel frames which make up the building. In skyscrapers, a concrete slab is often used to create both ceilings and floors.

                When concrete slabs are suspended between steel frames for use in constructing a skyscraper, there are a few methods which can be used to ensure the slab will be strong enough to support its load. The most common of these methods all involve changing the bottom of the slab in such a way as to support more load in either one, or two directions. For example: a corrugated slab is a concrete slab in which the bottom has been corrugated, in an effort to prevent the slab from caving in due to the pressure of its own weight; a ribbed slab is a concrete slab in which the bottom is ribbed, giving the concrete more strength in only one direction (i.e. either north-south, east-west, etc…). Depending on the needs of the building, the methods used to support the concrete slab will vary. However, all concrete slabs generally employ reinforcement bars (rebar), embedded within the slab itself to provide more strength, reinforcing the structure of the concrete.