Wednesday, September 25, 2019

Experimental work on the mechanical properties of concrete using Dissertation

Experimental work on the mechanical properties of concrete using recycled aggregates - Dissertation Example This paper illustrates that the main environmental problem in the world today is the disposal of waste material. In order to protect the environment, the consumption of natural energy is reduced while the consumption of waste energy is increased. This minimizes the amount of natural resources that is used which in turn helps in the conservation of natural resources. Every construction activity needs a lot of materials. Some of these materials include; sand, bricks, timber and mud. However amongst these materials, concrete remains the most important of them all. With respect to the environment and adaptability, the concrete that is used in any construction must satisfy all the environmental and economical needs of any given area. When we use recycled aggregate for construction then we are able to construct the environment while at the same time minimize the cost used in the construction process. The waste and by products of cement contain almost 75% of natural aggregates and so it is of greater importance as natural aggregates. When we talk about recycled aggregates here we mean; slag, waste from power plants, used concrete, quarrying and mining wastes, waste glass and many more. There are lots of demolished concrete that is left without use in demolished sites as well as construction sites. These concrete wastes provide are the main source of recycled waste that we will look at their strength. Cement (Portland cement) History Portland cement is the main type of cement that is used in making concrete in construction site. Its fine powder is produced by grinding clinker and some limited amount of calcium sulfate. It was developed in the early 19th century in Britain from natural cement. The name is derived from Portland stone, a building stone that was used during the same time. The origin of Portland cement is believed to be from Aspdin Joseph. He was a brick layer from Britain Leeds. One of his employees Johnson developed a production technique which resulted i n hard and fast drying cement. The cement also had high compressive strength as compared to other concrete. As days passed, people started to prefer the Portland cement to the roman cement which had been in use for many years. In 1843 Aspin’s son William made a version of this cement which was improved. He named it patent Portland cement though it did not have patent in it. He later moved to Germany to improve cement making and came up with Portland cement. In 1878 the German government gave a standard for Portland cement. Hydration When Portland is mixed with water and it reacts with it, a process called hydration, this mixed with sand and some gravel produces a synthetic rock, which we call concrete. This concrete is very essential in today’s world as electricity and water. During the hydration process, four main types of minerals are always present. They include belite, alite, aluminate, and ferrite. The addition of water causes an exothermic reaction to occur, afte r this reaction, (C3A) reacts with water forming aluminum gel. This gel in turn reacts with any sulphates in the mixture to form ettringite. The

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