Concrete mixers: a guide to reinforced concrete

 

Whether you are at the helm of a construction company or simply an individual looking to build or mend something substantial, purchasing concrete mixers to help you on your way is a wise decision. It is widely known that the strongest and most universal form of concrete is reinforced concrete, which is why using it for larger scale constructions or projects is always a good idea. There is much to learn about this type of concrete and what it takes to create it, so in just a few minutes of reading, check out our guide to reinforced concrete and how concrete mixers will help you get a head start.

 

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What is reinforced concrete?

 

As one of the most renowned and omnipresent building materials on the planet, reinforced concrete is the heart of many large structures and projects. On its own, concrete is in fact much more brittle than one may imagine. It is usually best for basic repairs and small-scale projects. However, once you take concrete mixers and add steel to the equation, you are creating reinforced concrete.

 

This means that the concrete can then be used for frames, columns, foundations, slabs as well as beams that are highly durable and not likely to fall down any time soon – should you do the job properly, of course. It must be noted that while concrete on its own is strong against the forces of compression, it has low ductility and tensile strength. Ductility refers to the extent to which a structure, in this case concrete, can withstand large deformations without failing. Tensile strength is measured by a material’s capacity to resist breaking or cracking when under tension.

 

This is why in many cases, it is necessary to apply reinforcement materials to help the building material withstand both tensile and shear forces. This is where steel comes in. It is widely utilised since it not only bonds well with the concrete, but it is also known to contract and expand at similar rates due to changes in temperature. Taking a closer look at the intricacies of how both concrete and steel behave individually, one can easily see that their properties complement one another in various ways.

 

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Does all concrete need to be reinforced with steel?

 

If you ask most people what the strongest material is, many are likely to reply with the word “concrete”. It is true that in many senses, concrete is extremely strong. However, this is usually only the case when pressure or force is applied in a specific direction. In a situation where the same kind of force is applied in another direction, which is usually what happens in most concrete structures and building applications, it has been noted that concrete is rather brittle.

 

There are 3 basic types of pressure or stresses with which concrete structures are faced:

 

  1. Tension (which refers to the action of pulling apart)
  2. Compression (which refers to the action of pushing together)
  3. Shear (which refers to the action of sliding along a line, examples being wind and earthquakes)

 

Concrete is strong when it comes to withstanding compression, but weaker against shear forces and tension. Fortunately, steel is strong against all 3 of these stresses, which is what makes it such a valuable asset in the world of building.

 

The different types of structural failure

 

If and when a non-reinforced concrete structure fails, it happens very abruptly. When forces become greater than the levels the concrete can endure, it breaks apart or crumbles into pieces. This is referred to as “brittle mode” failure. This type of failure is hair-raising to think about, as there are no visual warning signs beforehand to let you know it is starting to fail.

 

On the other hand, concrete that has been reinforced experiences a type of failure called “ductile mode” failure. In this case, visual cracks begin to form in before the structure shatters altogether. This is because even though the concrete is failing to stand up against the stresses, the steel rebars are still holding it together to a degree.

 

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Why use steel as a reinforcement material?

 

As previously mentioned, steel is the most popular choice of reinforcement when it comes to concrete structures. This is the cumulative result of steel’s many properties that make it more suitable than other materials. One of these properties is its high ductility.

 

It is easy to see how ductile steel is. One need only bend a bar and notice how it stays bent afterwards. The ductility comes in handy during the pouring process, especially, since it can be bent into a plethora of different shapes that will be the most suitable to support whatever form that will be poured. This also makes it easy to create grids of steel rebars when it comes to the design of the building.

 

Another property that makes steel an appealing choice for reinforcement is the similarity between steel and concrete’s thermal expansion capabilities. In order to understand this, it is important to know that when solids are heated, the molecules with which they are made move faster. The faster these active molecules move, the more the material expands. The opposite is true when solids are cooled.

 

Usually, this process happens at different rates in individual materials. It happens to be a very fortunate convenience that both concrete and steel have highly similar factors when it comes to thermal expansions and contractions. This means that when exposed to the cold or heat, they shrink or expand respectively at around the same rate. If this were not the case, steel would not be such a great choice of reinforcement for concrete, as it would result in a weak and unreliable structure.

 

Some other reasons why steel is such a great material for reinforcement include the facts that:

 

It is affordable and readily available

 

It is a happy coincidence that steel is both advantageous in reinforcing concrete and cheap at the same time. Further, it is available almost anywhere.

 

It is easy to weld

 

Due to the fact that reinforced concrete is used in so many distinct situations, builders must often construct relatively elaborate inner frame rebar before the concrete is poured and moulded around it. Steel is a frequently welded metal, since it not only melts easily, but also heats up in the welding location without making changes elsewhere on the bar.

 

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Steel is an easily recyclable material

 

Another aspect of steel that makes it so popular is the fact that it makes reinforced concrete last for so many years while maintaining its structural integrity. When the time for deconstruction does come around, however, the steel used in the concrete can be easily recycled. This can be done through pulverizing the reinforced concrete with the correct tools in order to separate and extract the steel rebar from inside.

 

The steel can then be melted down once more and reformed again as a new steel rebar to be used in the next project. Interestingly, concrete can also be recycled. This is done through crushing up the old concrete structure and using it as part of the coarse and fine aggregate that comprises around 60% t0 75% of cement that is used in concrete mixers.

 

Reinforced concrete, both in the past and now

 

A great guide could never be complete without a brief history of the subject matter, in this case, reinforced concrete. It was the ancient Romans who instituted the early forms of concrete as we know and use it today. This occurred through the discovery of a alumina and silica bearing material on the slopes of Mount Vesuvius while quarrying limestone to be used for mortar.

 

They discovered that when mixed with limestone and subjected to high temperatures, a type of cement was the result. This, they found, could be mixed with sand and water to create a mortar which was stronger, more adhesive and harder than the lime mortar they had been using in the past for their structures and building efforts. Like the concrete we know and love today, their mixture hardened both under water as well as in air.

 

Despite these exciting discoveries and the resulting Colosseum and Pantheon that succeeded them, there was no evidence of concrete being used from about 400 CE to 1750 CE. In 1867 CE, a Frenchman by the name of Joseph Monier invented reinforced concrete. Comically, he only used it to create cement flowerpots. It was only in the 1880s that reinforced concrete became a widely used building material.

 

Today, the world is full with unbelievable reinforced concrete structures, all made possible through the efforts of ingenious minds and concrete mixers galore. For example, The Burj Khalifa, which is the tallest concrete structure in the world. It stands at a startling 829.8 metres, and comprises 330,00 metric cubes of reinforced concrete. It took 6 years to complete and cost approximately 1.5 billion US dollars.

 

The heaviest concrete structure to date, on the other hand, is the Three Gorges Dam, located in the Hubei province of China. It is the largest concrete dam in the world, and weighs a shocking 144, 309, 356, 753.51 pounds.

 

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Another awe-striking reinforced concrete structure resides in Eastern China, known the be the longest concrete bridge in the world, The Danyang-Kushan Grand Bridge. It stretches a whopping 165 kilometres and is located on the rail line between Nanjing and Shanghai. Its construction was made possible by 10,000 workers who took 4 years to complete it. Today, it stands testament to the power of reinforced concrete.

 

Create your own reinforced concrete with concrete mixers from BS Power

 

It goes without saying that the above-mentioned structures would never have been a possibility were it not for the presence of various concrete mixers. Imagine hand-mixing every bit of concrete needed to create the reinforced concrete of which the structures are comprised. The idea is simply ludicrous.

 

For smaller-scale projects, there is no need to purchase outrageously large concrete mixers that are hard to operate and even harder to transport. We at BS Power stock a range of concrete mixers that are efficient, durable, aesthetically-pleasing and easily transportable. They are best suited to construction companies and individuals who wish to make use of concrete in any capacity.

 

Our concrete mixers bear the respected Baumax title, and are celebrated for their sizable volume capacities, safety measures as well as smooth wheels that make transport a dream come true. Should you be interested in pursuing a career to do with construction work, purchasing your very own concrete mixers is a great place to start. Be sure to check out the rest of our blog and find out how to safely operate your mixer as well as how to start-up your very own construction company using concrete mixers.

 

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