Evolution of Concrete
Evolution of Concrete
Concrete is a mixture of cement, which is in turn a combination of several minerals that bind with sand and gravel to form a hard solid block when mixed with water through a process called hydration. Today concrete is one of the basic materials in construction of buildings, dams, roads and bridges although very few know its history on how it evolved. The invention of concrete is not certain especially in relation to when it was first discovered, since it has evolved over time through inventions and modifications to bring about we know today as Portland cement, the binding material for concrete. The first form of concrete was used by Syrians in making fireplaces for cooking and heating, which accidentally led to discovery of using lime in making rubble-wall houses and floors made of concrete in about 6500 B.C. Egyptians made their pyramids around 3000 BC using lime and gypsum as the binding agent. Around 300 BC, the Romans used the elements Pozzuoli and fine volcanic ash and mixed them with lime to make a stronger material used to build such buildings as the Pantheon. The next major development in concrete occurred in 1824, when Joseph Aspdin, by burning limestone and clay together, changed their chemical form to create a stronger binding material that he called Portland Cement, which is still in use today (Brown, 2001). Circumstances leading to its invention were the need to have water and heat resistant material for building shelter.
Invention of concrete went ahead to affect the art at that time especially in Rome when major development before the fall of Rome saw increased use of concrete. The invention of concrete made it possible to build stronger structures. It made it possible to make bridges in the Roman Empire and caused massive civilization in Europe (Cleaver, n.d.). Concrete influenced the construction of ports, aqueducts and bridges as well as walls around the city. More so, due to the increasing population, Rome demanded more concrete for its construction work where even small houses were made using concrete. Concrete changed the arts and architecture when it replaced wood on many occasions such as building of dams and walls including the Great Wall of China. It also enabled the Romans to make more architectural designs that were better than the previously made buildings. However, after the fall of Rome, it was forgotten and scholars learned about it through written works of Vitruvius and Pliny who left clear descriptions of its elements (Cleaver, n.d.).
Concrete was later developed in the 19th Century when Portland cement was invented by Aspdin and still used today. It was used in construction of functional buildings and industries, though it was not accepted to replace stone and bricks in domestic construction. The concrete made from Portland cement was stronger, and hardened even further if submerged in water after it dried. Later, there came the reinforced concrete that was made around metal rails for more strength by some of the 19th century builders such as Wilkinson of England. For even more strength, in 1884 twisted steel bars were introduced to make the bonding of the concrete and steel stronger, which are the current in use (Brown, 2001). The reinforced concrete is able to handle more weight and the steel rods prevent it from cracking, hence making it more durable. Today, reinforced concrete is used everywhere in constructions. More still, reinforced concrete can be curved in the desired shapes since the steel holds it together, making more elaborate architectural designs is easy.
The reinforced concrete further changed the art of building, where it was now possible to build high-rise buildings or skyscrapers with some of the high ones having up to 100 floors. This could not have been achieved without reinforced concrete that is stronger as the steel holds the concrete together preventing it from cracking. More still, reinforced concrete is today used in construction of infrastructures such as highway roads, and railway lines that run underground. In addition, dams are also built using reinforced concrete to make them stronger to withstand great weight of a large mass of water, and bridges can run quite far even over deep waters and last for centuries considering concrete is hardened by water. Recently, other metals are used to reinforce the concrete such as glass fibers, organic materials and asbestos (Lamond, 2006).
Moreover, the concrete has undergone further developments and engineers calculate the concrete in terms of the strength they need and the amount of reinforcement through use of different kinds of admixtures. For light concrete, admixtures such as “polystyrene beads, perlite and vermiculite are considered low density and can produce concrete weights as low as 50 pounds per cubic foot (800 kg/m3),” (Ali, 2001). Medium weight concrete uses admixtures such as pumice, scoria and herculite that have strength of 1,000 to 2,500 psi (6.9 to 17.2 MPa) (Ali, 2001). The lightweight concrete is used in multistory buildings in making frames, roof shells, curtain walls, and pipes among others. On the other hand, there is the high strength concrete that is made of silica that is condensed and a by-product of furnace production from silicon and ferro-silicon alloys.
It also contains admixtures of Portland cement, water and crushed gravel, as well as fine sand and super plasticizers with a strength of 5000 psi (34.5 MPa) up to 20,000 psi (138 MPa) (Ali, 2001). It finds its use in skyscrapers and considering its strength per cubic feet, it helps in saving space since smaller columns of it are strong enough to hold a high-rise building. The other type of concrete developed in the early 20th century is the high performance concrete that takes about 24 hours to cure and reach its maximum strength unlike the other types that take about a week.
According to Ali (2001), “It is a mixture whose properties include increased strength and better performances in the areas of durability, ductility, density, mixture stability and chemical resistance, to name only a few.” However, this is dependent on the admixtures in the cement gravel and sand as well as water that will affect the last result. The advantage of this type of concrete is its ability to save time while concurrently saving costs that are associated with long waits of concrete to reach its full strength and still does not sacrifice the strength required. Its strength ranges from 3,500 psi (24.1 MPa) to 6000 (41.4 MPa) (Ali, 2001). This concrete ensures quick completion of projects since it does not require waiting for days and another placing of concreting can be done after 24 hours of the previous. It is applicable for tall buildings and tunnels.
More still, mixing of concrete today has changed, as it is not like in the 19th century. In the 19th century during the construction of the first multistory building mixing was done on site by machines that were power driven. Later, mixing was done using open trucks when transportation had improved and other than having to take all materials to the site, the trucks could just transport it ready to the site. Today, concrete for such buildings is mixed by hydraulic mixer trucks that were introduced in the 1947. Even after this innovation, there was the problem of delivering the concrete to the high height of the buildings, which was solved later in 1960, where pumps mounted on the hydraulic mixers are used to deliver the concrete in up to the high levels of the building, which requires large amount of energy to pump. However, innovations continue to evolve, making it easier each time to use concrete for construction such as the formation of concrete into the desired form or shape where materials such as ply woods, steel, plastics and even fiber glasses unlike the earlier years when only wood was used. The formwork is organized in a reusable way where after the concrete reaches full strength the formwork is removed and moved to the next level of the building for another placing of concrete (Ali, 2001).
With this evolution, concrete continues to influence the kind of buildings and style that can be made in buildings. Today, architectures are able to design tall buildings that are quite strong to withstand tremors and resistant to high and low temperatures and can last for many centuries more than the roman buildings that were build before its fall but still stand today. People’s preferences are changing all the time, requiring more comfort and space as well as buildings designed to fit their needs that has been influenced by the ability of concrete in fitting into any desired form even making curve. Much of concrete’s effect on today is its ability to save space that continues to become limited. Skyscrapers accommodate many people and put many floors on top of each other, which other wise could have been built on other lands. This has clearly saved land that could have been used for building many low-rise building that cannot hold many people and offices together. More still, with high-rise buildings, several interdependent firms could be held in the same building and enhance faster operations that save time used when buildings are scattered.
Humanities are the studies of how human beings live meant to give intellectual knowledge other than professional skills to study conditions of humans in an analytical and qualitative way. Some subjects included are history, archeology, visual arts and music. Evolution of concrete is connected to advancement in humanities through its study of how people have lived in the past, how the concrete has impacted on their life as well as it continues to impact on current living conditions. It also illustrate the development of human beings and how their knowledge has evolved, creating much concern in humanity scholars. More so, the evolution of concrete is considered an art that is part of humanities explaining how people live.
Concrete has been around the world for quite a long time in different forms, starting with the Syrians who used concrete in making fire places and went ahead to use the for plastering floors and wall. The other evidence is shown by the pyramids of Egypt that continue to exist today and the roman buildings. It is worth noting that most of the earlier forms of concrete used lime as the binding agent for the bricks and gravel. This continued to develop until innovation of Portland cement, and today other admixtures are used together with reinforcement from steel to come up with different types of concrete depending on their required strength and weight. Concrete has continued to affect the whole world today, as it is the primary construction materials for majority of structures and has enabled development of high-rise buildings with architectural designs. Today, its evolution continues and it can be colored to ones desired color, and can be polished for decoration.
Ali, M.M. (2001). Evolution of Concrete Skyscrapers: from Ingalls to Jin Mao. Electronic Journal of Structural Engineering, 1 (1): 2-14.
Brown, D. J. (200i). Bridges: Three thousand years of defying nature. Richmond Hill, Ont: Firefly Books.
Clever, J. n.d. Surface and Textured Finishes for Concrete and their Impact upon the Environment. Steel Reinforcement Institute of Australia, NSW, Australia. National Architect
Lamond, J.F. (2006). Significance of tests and properties of concrete and concrete-making material. Warrendale, PA: ASTM International