Concrete is a building material composed of cement, fine aggregates (sand) and coarse aggregates mixed with water that hardens over time. Portland cement is the type of cement commonly used for the production of concrete. Concrete technology deals with the study of concrete properties and its practical applications in the construction industry. It addresses the concrete properties needed in construction applications, including strength and durability, and provides guidance on all aspects of concrete, from mix design to batching, mixing, transportation, placement, consolidation, finishing, and curing. Concrete is most often used as a basis for most structures in the construction industry.
It is also used in the construction of superstructures through the use of structural concrete, construction of slabs, construction of stairs and architectural features. Using advances in concrete technology to improve mixing solutions can include reinforcement for structures that support concrete, anchor points for structural steel, embedded fittings such as reinforcement couplings or embedded plates for steel, reinforcement for masonry construction or support for masonry facade construction. It is essential to ensure that the fibers are completely dispersed in the concrete, and it is common for steel fiber concrete to also include a high-ranking water-reducing mixture to improve the consistency of the concrete and facilitate thorough mixing. Concrete is the most widely used building material in the world and plays a very important role in the construction of modern infrastructures that stand the test of time. More recently, the focus on environmental issues and the concept of sustainability have led to changes in the way raw materials are manufactured and used for concrete production. Developments in mixing technology and a better understanding of SCC's rheological characteristics have allowed producers to reliably produce materials that can be placed without vibration, leading to the benefits of increased on-site efficiency, reduced environmental impact and improved surface area finish. Examples of famous and large concrete structures are the Hoover Dam, the Panama Canal and the Roman Pantheon.
The use of recycled aggregates is often seen as a logical way to reduce the environmental impact of concrete. The quality of concrete begins at the conception of the project, while specifying the appropriate strengths required to support the structure, designing concrete mix ingredients, desired finishes and specifying work that is buildable. The use of recycled water and disposal of washing waste are now benchmarks in the industry. Larger production units will have recovery facilities to recover materials from any returned concrete. The use of these mixtures is particularly beneficial in the construction of concrete floors, where they allow a much wider joint separation. There are different types of binder material that is used in addition to cement such as lime for lime concrete and bitumen for asphalt concrete which is used for road construction.
There has been an increase in the use of recycled and alternative materials that together can reduce environmental impact of concrete with further developments expected in this area. Despite barriers to application there have been notable successes in application of advanced technologies in ready-mixed concrete industry with developments such as high-strength concrete, fiber-reinforced concrete, use of self-compacting concrete and widespread use of high strength performance additives and additions to modify concrete properties. The PFA can be interground with cement clinker to produce a factory-mixed cement or can be added in the concrete mixer to produce an equivalent cement blend. Although basic concept remains unchanged today's concretes look little like those first produced at beginning of 20th century. The poured concrete is allowed to set in formworks for specific time depending on type of structural member in order to obtain sufficient strength.