Silica Fumese Essay

When reading of the concrete that the ancient Romans used, and learning of their unique mixture of volcanic ash and slaked lime (“pozzolana”) I find it most interesting that this concrete still proves to be standing in some places today! It is said to be less sturdy than what we use here in America (Andrews, 2012) but no doubt it gave modern civilization the ingenuity to create what we use today.

Concrete can be looked at as a material made from sand, gravel and cement. According to Lambert (2002), “the first major concrete users were the Egyptians in around 2,500 BC and the Romans from around 300 BC”. Roman concrete like modern concrete was an artificial building material made up of aggregate, binding agent and water. Aggregate could be gravel, chunks of stone, chunks of rubble, broken bricks, etc. Binding agent could be mud , lime or gypsum, mixed with rubbles stone. The Roman added pozzolona, a special volcanic dust found in central Italy (Archserve, n.d). The addition of pozzolona made the bond with the aggregate far stronger than what was traditionally being used. This development drastically changed and shaped construction work in the life of Rome.

Nevertheless, this was a standard concrete technique in history, the Romans decided to strengthen their concrete mixture with another substance.

Concrete is the ultimate building block of society; there are a plethora of ways that it has been used. Romans were some of the first, in recorded history, to use it; they used it to build their aqueducts and even the Colosseum. If anything, the Romans were some of the first to make huge developments in concrete, and they were some of the first to actually use concrete on a large scale. America has also used concrete on a large scale, using concrete to build the Hoover Dam and the Grand Coulee Dam. Those examples show how concrete is an incredibly strong and durable building material that has remained standing after all these years and will continue to be the primary

In this quotation from the author Vitruvius, he explains the process and creation of concrete, emphasizes on its durability and how it can withhold the forces of nature. This new formula had a higher silica content then before, which essentially allowed to concrete to set under water and made it stronger then before.10 Overall, the use of concrete was crucial to construction in ancient Rome because it was extremely durable compared to other materials such as brick, stone, or wood.11 Having a successful and powerful empire was very important to the Roman’s as they believed that without a strong foundation, a strong empire would not be possible.12

In order to discuss concrete; one must first mention cement. Cement is a water-based binder used to bind other building materials together. It is used in the production of mortar and concrete during the construction process. Concrete is a material used in construction, made by mixing aggregate, cement, small stones and water. Cement is important because it hold structures together. Many sources states concrete was invented 1756 by a British Engineer named John Smeaton. He did so by mixing pebbles as a coarse aggregate into a powdered brick into the cement. Years layer in 1824, a English inventor named Mr Joseph Aspdin created the first true artificial cement by burning ground limestone and clay together. He is also noted for creating today’s popular concrete; Portland cement. Many buildings use concrete because of its strong element. It solidifies then hardens after mixing with water and placement due to the chemical process known as hydration. Water reacts with the cement, which bonds the other components together, eventually creating a stone-like material. Concrete is used to make pavements, pipe, various structures, foundations, roads, bridges, brick walls and so on. It is either produced site-cast or pre-cast. Site-cast Concrete is standard concrete that is poured into site-specific forms and cured on site; the concrete is created on the actually construction site. Precast concrete is a construction

The definition of high strength changes over the years as concrete strength used in the field increases. Any construction activity requires several materials such as concrete, steel, brick, stone, glass, clay, mud, wood, and so on. However, the cement concrete remains the main construction material used in construction industries. For its suitability and adaptability with respect to the changing environment, the concrete must be such that it can conserve resources, protect the environment, economize and lead to proper utilization of energy. To achieve this, major emphasis must be laid on the use of wastes and byproducts in cement and concrete used for new constructions. The utilization of recycled aggregate

manufacturers as a source of fuel to fire their energy-intensive cement kilns. Alternatively, the company

Concrete is one of the oldest and durable composite materials in building and construction engineering. Its importance cannot be overestimated. However, some of its traditional aggregates release a lot of carbon dioxide to the environment during production. In broadening the use of concrete as internal household design like countertops, exploiting the potentials of crushed waste glass as a substitute for the carbon dioxide emitting aggregate is reasonable step towards a greener and healthy environment.

The production of Portland cement is high-energy consumption and produce large amount emission of CO2. Previous research indicates that 0.98kg of CO2 will be created by production of 1kg of Portland cement, including 0.53g from decarbonisation, 0.33g from burning process plus 0.12g from generation of electricity power required. Therefore, for every ton of cement produced, an approximately equal amount of carbon dioxide is relapsed in to atmosphere [2阿三]. The world cement industry contributes 7% of total CO2 emission [3]. This leads to the research of seeking more environmental friendly cements. One of these alternative materials is alkali-activated slag (AAS) cement. Comparing with Ordinary Portland cement (OPC), the AAS has is own advantages. Firstly, it uses ground granulated blast-furnace slag (GGBS) as the binder material of concrete, which is a by-product from industry production. Secondly, AAS cement has low energy cost and low GHGs emissions. Finally, AAS concrete has excellent engineering

Portland cement, the basic ingredient of concrete, is a closely controlled chemical combination of calcium,

4) Banthia. N and Sheng.J (1991): Durability of carbon fibre Reinforced cements in Acidic environments, AC1-SP 126, pp 836-850.

Watertight concrete is different from the ordinary one and is developed from the conventional one. Specifically, normal concrete

Nowadays, we talk much about high performance concrete. It has higher strength, better durability and elasticity. Although high strength concrete is often considered as relatively new material, its development has been gradually taking place over many years.

The concept of using Pervious Concrete Pavement have been developed many years ago, but it has come to light recently, because of the increase of storm due to climate change. Pervious Concrete pavement is a different type of concrete with high porosity, which allows the water to infiltrate and reach the groundwater; thereby it reduces the water runoff and filtrates it. This kind of permeable pavement, consist of large aggregates and less or no fine aggregates. The pervious concrete pavement is one of the important and sustainable construction for reducing the environmental impacts and it is a good choice for earning LEED credits.