Let’s start with a basic fact; it is highly likely that you are only a few feet away from some kind of concrete. How do we know this? Quite simply because concrete is the world’s most widely used building material – and for good reason.
The first civilisation to embrace the widespread use of concrete was the Roman Empire. The Coliseum in Rome was built largely with concrete and the dome of the Pantheon is the world's largest unreinforced concrete dome. The Romans' use of concrete freed construction projects of the time from the restrictions of stone and brick material and allowed for revolutionary new designs in terms of both structural complexity and dimension. After the Roman Empire had collapsed, the use of concrete became rare until the technology was re-pioneered in the mid-18th century with France and the United Kingdom at the forefront of reintroducing the material.
Concrete is by far the world’s most versatile and popular construction material with a staggering 10 km3 (or 4.2 billion tonnes) used every year. There are many reasons for this popularity; it can be engineered to satisfy a wide range of performance specifications, it is reliable, relatively low cost and it is strong. Furthermore, it is fire resistant, sound insulating and resistant to water and environmental extremes. Plastic and malleable when newly mixed, strong and durable when hardened - concrete will play a major role in creating buildings, infrastructure and the society of the future.
Concrete is a heterogeneous composite material consisting of aggregates (sand, crushed rock or gravel), a binding medium made of Portland cement, and water. These constituents are available locally and in virtually unlimited quantities. Primary materials can be replaced by aggregates made from recycled concrete and by-products from other industries. For example: fly ash and slag, can be used to replace Portland cement.
Special types of concrete can be defined as those with extraordinary properties, or as those produced by unusual techniques. There are dozens of special concrete types, including architectural concrete, fibre concrete, self-compacting concrete, high-strength concrete and many more. The areas and industries where concrete is used are diverse; from the construction of buildings and infrastructure, to agriculture, architecture, energy production and much more. Concrete is a versatile building material and is of highest importance to modern society.
Working with concrete is relatively safe, however, like all construction materials, it should be treated with care and respect. When handling concrete, ensure the correct equipment for the task is being used, and that approved safety clothing is worn. In its early life, the fresh concrete must be protected from the detrimental effects of drying due to hot sun, dry air and drying winds. It also needs to be protected from frost and precipitation. In order to achieve the required durability and strength of any concrete, care must be given to curing. Always remember - concrete is a specialised product and handling it safely and correctly requires experience.