Compacting Concrete Waste Rubber Tires for Coarse Aggregate - Literature review Example

? Compacting Concrete Waste Rubber Tyres as Partial Replacement for Aggregate Literature Review Huge amounts of rubber are produced as waste annually. This is mostly common in countries that are already developed. Such countries include Australia where in 2006 twenty million tires were produced as waste. This is according to the Market Failure article of 2006 (Ana M, 2006 78). Some of these were reused while others were discarded. The effects of these waste tires are adverse. The discarded tires pile up into huge heaps of waste that are harmful to the environment. They occupy space and are a bad sight. This is besides the fact that they offer perfect breeding grounds for pests (Appleby, 2004, Pg.200). Mosquitoes, rats, mice are just but a few. Some of these such as mosquitoes spread diseases such as malaria. Rice and mice is a nuisance. The accumulated heaps of tires are prone to fires. This is because rubber is a substance that can easily catch fire. Once the fire starts, the destruction is always very devastating. They are difficult to put off and leave behind a trail of destruction. The smoke from the fires pollutes the environment. It reduces visibility and releases harmful substances into the atmosphere. All these negative effects of waste rubber lead to the need for a lasting solution (Barragan, 2005, Pg.45). Self-compacting concrete is one of such solutions. It refers to a form of concrete that does not require compression machines to be compressed into the building blocks. It flows freely under its own weight and keeps a uniform mixture composition. It has three major characteristics. It fills the building space easily, passes through the building space easily, and maintains its homogenous nature throughout the whole process. Self-compacting concrete can change shape in order to attain the shape of the destination place. It has a deformability aspect. Besides these three, it has other characteristics. It retains its characteristics even when the matter of other component material changes. Self-compacting concrete retains all its properties and is always very stable. All these properties of self-compacting concrete is very incompatible (Bui, 1999, Pg. 356). The filling ability of self-compacting concrete is of an interesting nature. Self-compacting concrete flows into the designated region without segregation. The friction between particles in the self-compacting concrete is minimized. This is done by use of superplasticiser. Anyone can argue that addition of water would produce the same effect. However, water reduces viscosity and weakens the mixture. In addition, the self-compacting concrete loses its durability. Hence, it is not advisable to add water (Felekoglu, 2008, Pg.54). The size of the particles also influences the filling ability of self-compacting concrete. The finer the particles are the less the friction between them and hence a greater filling ability (Bennenk, 1999, Pg.544). The self-compacting concrete must have the ability to penetrate all the available spaces of the building blocks. The particle composition of the self-compacting concrete plays a vital role in determining this property. The concrete is mainly composed of mortar and coarse aggregate. On approaching an opening, the different speeds of these compositions result in a collection of aggregate at the opening (Jin, 2002, Pg.192). This will block the passage of other particles. The blocking is determined by the size of the coarse aggregate, its shape and content. This means that the smaller the size the more effective the self-compacting concrete will be. A paste can also be used to prevent blocking of the coarse aggregate content. It must have a certain level of viscosity in order to achieve this (Bui, 1999, Pg.45). Segregation mainly involves the detachment of the solid particles from the self-compacting concrete. It usually takes place during spacing (Bostrom, 2003, Pg.34). The coarse aggregate separates from the water. This water is referred to as bleeding water. It is usually trapped in the spaces between the building blocks. This resulted in a reduction in the strength of the self-compacting concrete and its durability (Geiker, 2003, Pg.43). Robustness refers to the ability of self-compacting concrete to retain its characteristics even with variations in the component structure of the concrete or the environment. The above three characteristics of self-compacting concrete are known as fresh properties (McCarthy, 2002, Pg.56). They are not compatible with each other. Self-compacting concrete consists of a mixture of coarse aggregates and powder components. Its tolerance is thus reduced. In order to improve robustness the powder of self-compacting concrete and VMA has to be considered. The VMA improves the robustness of the self-compacting concrete (Billberg, 2002, Pg.454). The level of robustness can be tested by the use of water variations in the self-compacting concrete and variations of superplasticiser content (Billberg, 1999, Pg.333). There are three basic categories of self-compacting concrete. Powder self-compacting concrete, VMA and combined type. Powder self-compacting concrete is majorly made of powder in order to restrain water content and increase the resistance (Bui, 1994, Pg.96). It is also very strong and has low permeability. VMA self-compacting concrete is a type of self-compacting concrete with a lot of viscosity modifying agent dose. It has a higher viscosity than powder self-compacting concrete. The powder content of VMA is less than that of powder type. Combined self-compacting concrete consists of both powder self-compacting concrete and VMA (Bui, 1994, Pg.56). The powder self-compacting concrete has a higher percentage in composition than the VMA. VMA provides its viscosity while the powder self-compacting concrete provides the powder characteristics (Bui, 1999, Pg.543). However, self-compacting concrete has a number of advantages and disadvantages. This form of concrete is not only very strong but also durable. It is usually in the form of a thick substance that easily flows into the spaces between building blocks (Vanwalleghem, 2003, Pg.765). Thus, it eliminates the need for building machinery such as skyscrapers that make a lot of noise. In addition, fewer workers are required to accomplish the task. This reduces the overall cost and energy required in the building process. The spaces between the solid particles are filled up entirely. This results in a uniform colour and tone of the concrete. Besides all these advantages, the self-compacting concrete is expensive. The cost of the materials needed is high. This outweighs the benefit brought about in the reduction of the number of workers required. Self-compacting concrete needs a reduction in its coarse aggregate components. This leads to the need for more cement, increasing costs in the process. In a bid to provide, another alternative to the recycling of the waste rubber, rubberized concrete has been adopted in the building industry. It consists of melted rubber that is mixed with concrete. This results in a mixture that is used mainly in the road construction industry. This is because rubberized rubber offers a number of benefits. It is observed to have considerable strength as compared to normal concrete. The strength increases with the amount of rubber in the mixture. Rubberized rubber can thus be used to reduce cost of construction of pavements. The material required is half the normal concrete (Cauberg, 2005, Pg.453). This reduces the cost of construction and maintenance. Water absorption is greatly reduced. The rubberized concrete lasts 50 per cent longer than the normal concrete (Christensen BJ, 2005 234). Ultrasonic velocity increases with an increase in density of the rubberized concrete. This is brought about by an increase in the content of the amount of rubber in the rubberized mixture (Domone, 1997, Pg.433). The rubberized concrete is thus environment friendly. It reduces the amount of waste rubber that pollutes the environment. A good example is in California where 40 million waste rubber tires are produced yearly, and of which three quarters are used to manufacture rubberized concrete. . In the recent years, Self-compacting concrete has incorporated rubber as part of its components. This has been caused by the need to strengthen the self-compacting concrete. The major attributes of the self-compacting concrete are its fluidity nature and cohesive nature (Embrorg, 1999, Pg.34). Certain materials are used to make sure the compacting concrete has the needed qualities. Fly ash is one of such materials. The discovery of incorporating self-compacting concrete with rubber has resulted in the development of highly workable materials. The rubber added increases the strength of the compacting concrete. This is besides making the compacting concrete elastic. Elasticity aids in the building process. The rubber adds toughness of the concrete. The resulting mixture has a high level of tolerance to any form of strain. Fly ash aids to retain the density of the concrete, lessening any blocking risk and reducing the quantity of other constituent materials that may be required to get similar properties (Felekoglu, 2008, Pg.76). In conclusion, self-compacting concrete offers a perfect solution to the menace of rubber waste reuse. Self-compacting concrete has three major characteristics known as fresh properties. Self-compacting concrete has a filling ability. Self-compacting concrete flows into the designated region without segregation. The friction between particles in the self-compacting concrete is minimized. This is done by use of superplasticiser. Self-compacting concrete is passing ability. This is the ability to penetrate all the available spaces of the building blocks. The particle composition of the self-compacting concrete plays a vital role in determining this property. The concrete is mainly composed of mortar and coarse aggregate. On approaching an opening, the different speeds of these compositions result in a collection of aggregate at the opening. This will block the passage of other particles. The blocking is determined by the size of the coarse aggregate, its shape and content. Self-compacting concrete has segregation resistance. Segregation mainly involves the detachment of the solid particles from the self-compacting concrete. It usually takes place during spacing. The coarse aggregate separates water and is often referred to as bleeding water. It is usually trapped in the spaces between the building blocks. This results in a reduction in the strength of the self-compacting concrete and its durability. In addition, it has aspects that are important such as robustness and consistence retention Self-compacting concrete is a technology that is growing. It incorporates fresh properties together with hardened properties. It has three basic categories. Powder self-compacting concrete, VMA and combined type. Powder self-compacting concrete is majorly made of powder in order to restrain water content and increase the resistance. It is also very strong and has low permeability. VMA self-compacting concrete is a type of self-compacting concrete with a lot of viscosity modifying agent dose. It has a higher viscosity than powder self-compacting concrete. The powder content of VMA is less than that of powder type. Combined self-compacting concrete consists of both powder self-compacting concrete and VMA. Self-compacting concrete has a number of advantages and disadvantages. This form of concrete is not only very strong but also durable. It is usually in the form of a thick substance that easily flows into the spaces between the building blocks. Thus, it eliminates the need for building machinery such as skyscrapers that make a lot of noise. In addition, fewer workers are required to accomplish the task. This reduces the overall cost and energy required in the building process. The spaces between the solid particles are filled up entirely. This results in a uniform colour and tone of the concrete. Besides all these advantages, the self-compacting concrete is expensive. The cost of the materials needed is high. This outweighs the benefit brought about in the reduction of the number of workers required. Self-compacting concrete needs a reduction in its coarse aggregate components. This leads to the need for more cement, increasing costs in the process. Bibliography Ana M, F.-J. A. A. P. 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