The word concrete probably brings to mind different images for different people. One thing is for certain; concrete is an efficient, financially feasible and convenient way to construct a wide variety of useful things; in our buildings, sidewalks, driveways, garden frames, and many other things that we probably pass by regularly without even noticing. Concrete can be poured into moulds which allows for a wide variety of concrete shapes to be made, and it provides a fireproof and fairly waterproof material. It’s strong and will withstand massive amounts of weight without suffering any harm, which makes it the perfect option for foundations and walls.
Concrete is made with a mixture of aggregates (both coarse and fine) which may include gravel, stone, rock, glass (usually recycled) and sand. It can also include recycled concrete. This first set of ingredients typically comprises anywhere from 60 to 75% of the finished product. The second ingredient is cement, which usually comprises anywhere from 10 – 15% of the finished product, and the last ingredient is water, which, if you haven’t been calculating, would comprise the remaining 15 – 20%.
Although this seems like a pretty simple recipe, contractors are able to alter the mixture somewhat if they need a substance to be more liquid, or to dry faster. They are also able to alter the finished appearance by adding materials that change the finished colour of the concrete.
Although concrete is, of course heavy to lift in any quantity, it’s actually not as dense as some other materials like lead or steel. It actually is very close to the same density as glass.
Depending on the job, concrete can be mixed on site or precast into specific shapes and sizes. These shapes can be used to build walls, foundations, bridges, posts, sidewalk blocks, and many other useful items. A factory can easily use moulds to create identical shapes or slabs of concrete to be used in industrial or building applications.
One of the biggest drawbacks of concrete is that, although it can withstand plenty of weight, it does not do well under tension or if it is bent or stretched. When this type of pressure is applied, concrete tends to crack and break; not a desirable result. To combat this, a relatively simple process is required to ensure that concrete can withstand all of the forces that get thrown at it on a day to day basis.
We’ve already discussed how concrete is made, and why it’s such a useful material. Reinforced concrete is that same material poured over a skeletal structure of rebar to keep it from breaking under tension (like stretching or bending). In this process, the concrete becomes far more durable and able to withstand pressure besides simple weight applications. If you’ve ever seen a concrete driveway being poured, or been witness to the making of a garage floor, you’ve probably noticed that the initial step is to lay a framework of rebar within the form where the concrete is to be poured.