Recycled Rubber Tyres as Aggregate in Concrete - Essay Example

?2.0 Literature Review 2 Introduction The ability to change the levels of consumption in the UK is one which is essential to the needs to create asustainable world and to alter the pollutants which are coming from different resources. A technology which is being created is with the use of recycled rubber tyres. There is the option of allowing this to work as an aggregate in concrete, specifically to begin changing the consumption in the UK and to begin lowering the number of toxins with the tyre production that occurs every year. While there is a large amount of consumption and changes with the tyres, there is also a question of whether the aggregate in the concrete is able to create the same substance and material responses as other forms of technology for concrete. This is able to alter and change the way in which the aggregate can be used while determining if the tyres can be recycled into a different substance for other needs. The literature review will look at the past applications with the tyres and how effective the recycled materials are. The review will therefore reveal insights into the major findings in this area and discover potential areas for conducting further research. 2.2 Overview to Recycled Rubber Particles The first question which is associated with the recycled rubber particles is based on the understanding of cement paste and how it responds and reacts to the rubber tyre particles being added as a part of it. In a recent study (Segre, Joekes, 2000: 1421), there was a modification to the cement by adding in rubber tyre powder to the aggregate. The study looked at the cement paste and the way that the surface began to change after a period of 20 minutes. The substance was examined in terms of absorption, density, flexural strength, compressive strength, abrasion resistance, elasticity and fracture energy measurements. The measurement then looked at the level of Sodium Hydroxide (NaOH) with the rubber. It was found that the rubber not only assisted with the mix of the materials in the cement but also increased the level of flexibility, durability, toughness and compressive strength. The conclusion was not only with the improvement of quality with the cement. It was noted that by using the rubber tyres as a part of the cement, different formats for roads and other road construction areas could be used. The substance which was created from the recycled rubber tyres is one which is not as course, meaning that the use on road construction can help with more durability and sustainability with the recycled rubber (Segre, Joekes, 2000: 1421). The overall changes which were made with the concrete also refer to the rubber tyres changing the properties of the cement to create different levels of substance to be used in different areas. The association with tyres is one which is able to automatically change and assist with the overall needs and properties for strength, specifically with roads and areas which have continuous use and fluctuation. The changes with the cement also show that the use of magnesium oxychloride, a natural property found in rubber, is able to provide more functioning for the cement. This particular substance is able to work to bind the concrete mixtures in a way that improves the strength and durability of the substance. The rubberized concrete not only has the ability to directly impact and improves the concrete which is used. The magnesium oxychloride as a binding substance can help in changing the way in which concrete is used and allows the mixture to provide even more solutions to the substance. The substance differs with the types of tyres which are used, amount that is mixed with the concrete and is dependent on factors such as unit weight, air content and slump. Incorporating these into the mixture is then noted as essential for creating the correct mixture and alternatives with the rubber tyres and concrete mix that is used (Siddique, Naik, 2004: 563). 2.2 Compressive Strength The additional alternatives which are a part of the rubber tyres used in aggregate concrete include individual properties which begin to change with the mixtures which are used. The first is the compressive strength that is within the concrete and the way in which this assists or deters from the structure that is being made. In a recent study (Bignozzi, Sandrolini, 2006: 735), different levels of tyre waste were structured into self – compacting concrete. The mechanical and micro structural behaviour was then analyzed in regards to the formulation and the return which occurred. After analyzing the mechanical and microstructural behaviours, it was found that the formula allowed for the compressive strength to become stronger than the concrete. This was dependent on the binding rubber phases that were used with the concrete. As the concrete would bind to the rubber, self – compacting technology would take place with the concrete. The binding which naturally occurred between the rubber and concrete was then able to develop a different behaviour which helps to establish stronger compressive strength than regular concrete. This was combined with behaviours of the hardened concrete and the fresh concrete. During the fresh concrete phase, there was binding which continued to naturally take place. When this was hardened, it allowed for the compressive strength to be hardened and to offer more strength than the regular concrete (Bignozzi, Sandrolini, 2006: 735). The compressive strength noted with the self – compacting technology and the structural behaviours indicate that the natural chemicals in tyres and cement work together to create a stronger compressive strength. In another recent study (Turatsinze, Bonnet, Granju, 2005: 221), there was an observation of the mechanics which are associated with the rubber tyres. The study looked at the cement based materials that are prone to cracking, specifically from shrinkage cracking that occurs. It was noted that the fibre reinforcement of the cement is the main problem that is associated with the shrinking and the other problems. The experiment was based on finding substances which were able to change the level of deformation before the macrocracks began to appear and cause problems with the cement solutions. It was found that low – deformation aggregates work more effectively in stopping the amount of cracks in the cement, specifically with the use of rubber tyres. It was noted that the rubber tyres changed the size of the particles from 4 mm from sand aggregates that are commonly used with cement. The results with the rubber tyres indicate that there may be complexities with the compressive and tensile strength. This is seen in chart 1, as the level of grinding with the aggregate changed the binding capabilities. Chart 1: Binding Capabilities in Aggregate However, the experiment also indicated that the elasticity and strain capacity increased. The experiment also indicated that the ability to combine both fibre structures with rubber would assist with the lower compressive strength, such as shredding the tyres as opposed to using other methods. The experiment noted that the way in which the aggregates are added and worked with dramatically changes the solution with cement that is used.(Turatsinze, Bonnet, Granju, 2005: 221). 2.3 Tensile Strength The second component which affects the cement is the tensile strength that changes with the cement. The tensile strength mixed with the concrete is one which is able to alter and change according to the mixture and the way in which the rubber tyres react to the concrete. A recent research study (Ganjian, Khorami, Maghsoudi, 2009: 1828), looked at the use of tyres with tensile strength and how this altered. The research incorporated different levels of mixtures with the concrete, including 5%, 7.5% and 10% of rubber tyres as aggregate into the concrete mixture. The mixtures were then evaluated according to the weight from the rubber and aggregates as well as the permeability and water absorption. The conclusion indicated that the use of rubber tyres up to 5% did not have a direct effect on the tensile strength and changes in the concrete. However, when this continued with more than 5%, there were significant changes in the amount of tensile strength which occurred. It was also noted that the rubber concrete had different levels of strength depending on how the tyres were used with the aggregate, specifically with shreds and crumbs both used as substances. The result was one which either caused the strength to disintegrate or to become upgraded with the use of the rubber tyre substance. The study indicates that the amount of tensile strength is dependent on the amount of rubber used as an aggregate as well as how this is prepared. This changes the way in which one is able to work with the substance as well as how the cement will react to the mixture which is used (Ganjian, Khorami, Maghsoudi, 2009: 1828). The indications of changing the amount of rubber aggregate with cement as well as looking at the way in which the rubber is prepared leads to other questions of how the aggregate can be used with the tensile strength and what the results are in terms of changing the way in which the frequency is able to improve the strength of cement. In another current study (Batanyeh, Asi, 2007: 1870), there was an evaluation of a variety of materials in concrete. This included rubber, glass and plastic which could be used as an aggregate with complete substitution of the sand which would be used. In this study, the tensile strength, or the ability to stop splitting in the concrete was performed in conjunction with other aspects needed for the concrete. It was found that the rubber, as well as glass and plastic, could all be used with the substitution for the other materials. However, the study also indicated that the amount of the substance used was essential as this altered the use of the concrete mixtures. The sand or course aggregate needed to be a part of the concrete mixture. Combining this with the rubber or other substances could help in maintaining the current tensile strength and in stopping the splitting of the concrete.(Batanyeh, Asi, 2007: 1870). The indications with tensile strength have led into further investigations into the use of tyres for concrete and how it can be added for the sustainable construction required. The cement which is used requires an elimination of cracks and splitting over time, specifically through the use of rubber. The main approach is to create a sense of sustainable construction that is able to alter the way in which the concrete and the rubber tyres are used. In a current study (Snelson, Kinuthia, Chang, 2009: 360), there was an examination of how the physical, mechanical and chemical characteristics altered the tensile strength and sustainability of the construction. The tests in this study compared concrete blends with partial replacement with shredded was tyres. Strength tests were then performed based on the amount of rubber tyres which were added into the mixture and the reactions which occurred. It was noted that after 180days, there was improvement in the tensile strength of the aggregate replacement, specifically with the binders that are a part of the rubber tyre substance. This particular influence is noted in chart 1. Chart 1: Change in Aggregate after 180 days The indication was that the binders do not initially have a strong reaction to the cement. However, through time the aggregate improves in strength, specifically if it is cured for a longer period of time. The suggestions from the study indicate that the use of shredded rubber tyres combined with medium strength applications with concrete and roads are the best approaches. The ability to create the sustainable construction with tensile strength is one which then indicates positive results, dependent on the approach which is taken with the substances (Snelson, Kinuthia, Change, 2009: 360). 2.4 Shear The third form of strength which comes from concrete and is essential to the mixture is the shear, which is the internal force that allows the aggregate and cement to create the surface of the mixture. The complexity that is noted with the development of shear comes from the mixture of rubber and cement that indicates a loss in strength of concrete over time. The main reason that this has been assumed is through the lack of adhesion that takes place from other particles outside of the cement that is used with the rubber. The immersion of NaOH with production of the concrete is the main area in which this begins to change, causing the particles to begin to alter once the NaOH of the concrete is produced. However, the shear that is created may change according to the type of rubber used, specifically with differences between the fibre and crumb types of rubber cement that is created. The complexity which is noted between the different tests with rubber and the shear strength is based on the types of rubber added, amount added in and the purpose for the cement that is being made. In some instances, the amount of fatigue created when applying the concrete led to a lack of feasibility and rigid pavements which were created. However, different amounts of rubber aggregate and changes in the crumb and fibre material as well as self – compacting material with the rubber altered the way in which the particles and substances came together. The binding rubber particles with self – compacting materials were able to create and develop a different approach. With this, the freeze to thaw compatibility, sustainability of the concrete and the durability began to change and become strengthened. The indication is that the rubber concrete increases and strengthens the durability and shear effects. However, this is dependent on the styles of rubber mixtures which are placed with the concrete (Gesoglu, Gunyeisi, 2007: 953). Another way in which the rubber tyres mixed with concrete have been looked into with the shear substances is through the mixtures that take place in phases. According to another research study (Topcu, Bilir, 2009: 1251), a variety of developments could take place to alter the way in which the concrete was able to materialize and change. The use of rubber as an aggregate also indicates that there needs to be an alteration in how the mixtures take place and how this will develop in terms of the needs for the concrete and the tyre mixture. In this particular experiment, different phases were developed with adding in the rubber aggregate and the substances which were combined with the concrete. Aggregates and cement paste were able to change the amount of compressive strength and tensile strength which resulted. The phases which were developed also changed the flexibility that was a part of the concrete. The process used with the phases was based on how much rubber was used, when the materials began to change and how the binding changed between each of the phases. It was found that when the mixtures went through three different phases of mixtures that the particles were able to begin to transform more. The results also implied that a transition zone needed to occur in the third zone. At this point, the rubber aggregate could transition into being able to bind and transform with the particles of the cement. It was during this phase that the correct process could be completed, allowing the shear to also transition and be completed (Topcu, Bilir, 2009: 1251). 2.5 Bending The bending that is associated with concrete is one of the most important aspects that begin to change with the correct mixture. The concept of bending is one which implies that the time frame which the concrete is used will lead to binding that begins to deteriorate. The particles which are used with the concrete become essential in building and developing the correct structure so the bending of frameworks for the concrete do not cause the cracks or other difficulties with the bending. This is combined with the fatigue which occurs with the concrete over time, specifically when used by the reinforcements which occur and the ability to hold a large amount of substances over the concrete. These different sections and shapes of reinforcements are the first aspect which is considered with bending. However, the substance and mixture also changes the amount of dexterity and bending which occurs. The result is one that begins to transform over time and according to the fatigue which is a part of the concrete. While the cement substance and the amount of traffic continuously add into this with the concrete, there is also an understanding that compensation can begin with the right mixtures and substances with the concrete (Hsu, Mo, 2009: 79). The bending which occurs and the way in which this material works combines with the way in which frameworks combine with the substance to eliminate the fatigue which occurs with the concrete. In a recent study (Olivares, Barluenga, Landa, Witoszek, 2007: 1918), there was an association with the bending and fatigue which occurs with concrete and how this can be eliminated. The approach taken was to examine the fatigue that took place through a series of bending tests. The samples were based on the use of rubber recycled tyres that were filled with the concrete. The tests were divided by the amount of rubber mixed into the substance, with 0%, 3.5% and 5% being added into the mixture. The sampling was then examined over a longer period of time by looking at the long term exposition to weathering that took place in Madrid, Spain. The experiment was examined over one year while analyzing the change from fatigue between each of the mixtures. The experiment found that there was a need to have rigid pavements and a minimum thickness of the rubber tyre aggregate to create the right reactions. This needed to be based on the durability of the rigid pavements with the consideration of how many cycles and tons went across the roads on a continuous basis. The design of the road, amount of rubber and the mixtures for the roads were then noted to make a difference. When looking at Chart 3, it is noted that there is a direct difference with the type of pavement and the aggregate thickness which combines with this. Chart 3: Grades of Road and Aggregate Thickness More important than the mixture for bending, is the understanding that the design and the approach to different roads need to be considered to stop the amount of fatigue that is associated with each of the regions (Olivares, Barluenga, Landa, Witoszek, 2007: 1918). The properties and the indications with the design then are known to create a different approach to how the rubber tyres are used with the concrete and what is associated with the mixture. In another recent study (Qingyu, 2007: 9),there was an examination of pavement patterns and designs which could be used to improve the durability and flexibility with the concrete. It was found that crumb rubber concrete had more capacities to hold back cracks, specifically because it had better amounts of resistance and the ability to bind at a faster rate than the fibre based rubber. The new pavement material that was used also changed the amount of strength and ability to create a sense of durability with the pavements that were associated with this. The rubber began to change the amount of flexibility and durability with the new concrete and through time, specifically with the binding that was used and the holding of the materials that occurred with the bending process that was used. It was noted that there is a direct correlation between the bending strength and the compressive strength that was approached between the two. These each created a different understanding of how to approach the amount of strength needed for the rubber tyres and how these altered the durability with the road substances (Qingyu, 2007). Another approach used is based on the way in which the stress and fatigue is approached through both design and the approach of the other materials in how they relate to the concrete mixed with rubber. The flexible behaviours and the ability to have a larger amount of strength from the bending are other considerations made with the rubber. Through a recent study (Zhang, 2007), it was found that the amounts of strain occur through a stress – strain curve. This states that there are different levels of dynamics that occur with the concrete over time that changes the level of stress and strain that builds the bending of the concrete. The amount of compressive strength, tensile strains and the flexibility of the concrete changes the stress – strain curve by either lowering or heightening the amount of stress that occurs. It is from this that the bending occurs and begins to alter what is a part of the behaviours and the stress and fatigue. The study showed that the long term approaches to the bending required the use of crumb rubber mixed at higher frequencies. It also stated that the compressive strength was the main way to stop the bending and add in the needed levels of resistance to fatigue and stress. The stress – strain curve could then alter with the concrete used and the approaches created with the mixture. The behaviour of the cement could then alter according to the amount of stress and strain as well as how the mixture was able to change this. More important than the rubber mixture was the behaviours that continued to change through time as the stress indicators affected the strength of the rubber. (Zhang, 2007;). 2.6 Insulation The concept of insulation with the rubber – cement mixture is another factor which is associated with the rubber and what occurs with the concrete. The physio – mechanical properties that are associated with the concrete change the levels of insulation and the alterations which occur with the cement mixture over time. A recent study (Benazzouk, et al, 2006: 650), indicated that the physio – mechanical properties of the cement alter the way in which the insulation takes place over time. The properties are inclusive of aerated cement that combines with the rubber waste particles. There is the need to create a cellular concrete application with the materials while changing the volume of cement that is a part of the mixture. The use of aeration combined with the aggregate of tyres and cement resulted in a variety of positive benefits. This included more workability and flexibility with the cement. It was also indicative of air – entrained stability and air – bubbles in the matrix of the cement. The compressive strength, flexural strength was able to balance with the air voids and rubber particles which were used, specifically by creating an interaction system between all particles. The result was a higher amount of stability and insulation that was approached with the rubber – cement mixture and the components which were associated with this (Benazzouk et al, 2006: 650). The positive benefits of insulation that come from the cement and tyres is one which continues with a variety of concrete panels and the substances which add into the insulation. The crumb rubber is known to directly improve the insulation in terms of thermal and sound properties, specifically because of the binding and strength capacity which is used. In another study (Sukontasukkul, 2009: 1084), there was an investigation on the insulation with the cement and tyres in different conditions. A concrete panel was investigated with different levels of rubber that was added into the concrete. The aggregate was combined with ratios of 10%, 20% and 30%. The properties which were investigated included thermal conductivity, thermal resistivity, heat transfer, conductance value, sound absorption and the frequency of noise reduction. The indications from these showed positive results in all areas of insulation. This was inclusive of lighter substances and higher sound absorption that was used. The heat transfer properties were also lower than the traditional concrete substances which were used. There was not a difference between the ratios of aggregate combined, showing that the properties of the rubber, when combined with cement, have better insulation properties than other types of concrete used (Sukontasukkul, 2009: 1084). 2.7 Summary There are a variety of indications that are associated with the properties of rubber tyres as aggregate in concrete. The concept of using the recycled tyres as a part of changing the amount of waste that is used is only one of the variety of benefits that come from using the rubber with the tyre. There are also a variety of positive benefits that are associated with using the rubber and the way in which this is associated with the concrete. The positive benefits range from the changes in strength and durability to the flexibility and insulation of the rubber and concrete. The past research studies have indicated that there are a large amount of benefits and changes with the concrete that can be used to enhance the different properties of the rubber – cement. The solution which this offers is then able to provide more opportunities with the properties of rubber – concrete solutions while moving forward with the different alternatives with the concrete that is mixed with the rubber. While there are several indications of the benefits of rubber –concrete in the literature review, there is also a question on the mixtures that are associated with this. Each of the mixtures combined fibre or crumb rubber as well as different levels of aggregate which were used either in combination with sand and other aggregate or outside of other aggregates. The texture of the rubber and the amounts added into the mixture had different levels of responsiveness with what was used. This is important to note, as it changes the effectiveness of the concrete and whether it can be used in different respects. This is combined with the understanding of the rubber – concrete mixture and how this alters in terms of the different conditions. For instance, the compressive rubber did not have the best results with the crumb rubber and instead used the fibre rubber for binding. However, other aspects of the cement worked more effectively with the crumb rubber because of the density, binding and ability to result in long term benefits with reactions from the chemicals. The question of the rubber – cement having effective results is then not the question. Instead, there is a question of the amount of aggregate to use, the type of texture to add in and the other particles associated with this. There are also indications with the type of process to use for the mixture, such as the three step process or the ability to allow the particles to shape with their own binding connections. These all provide questions for further research while showing that the benefits of rubber – cement have not been thoroughly investigated to determine proper results of how the rubber can work to improve conditions with cement while assisting with environmental concerns. References 1. Batayneh, Malek, Ibrahim Asi. 2007. “Use of Selected Waste Materials in Concrete Mixes.” Waste Management 27 (12), available at http://www.eis.hu.edu.jo/deanshipfiles/pub10130207.pdf (accessed on January 19, 2012) 2. Benazzouk, A, O Douzane, K Merzerb, M Quenudec. 2006. “Physico – Mechanical Properties of Aerated Cement Composites Containing Shredded Rubber Waste.” Cement and Concrete Composites 28 (7), available at http://www.sciencedirect.com/science/article/pii/S0958946506000965 (accessed on January 19, 2012) 3. Bignozzi, MC, F Sandrolini. 2006. “Tyre Rubber Waste Recycling in Self – Compacting Concrete.” Cement and Concrete Research 36 (4), available at http://www.mendeley.com/research/tyre-rubber-waste-recycling-in-selfcompacting-concrete/(accessed on January 19, 2012) 4. El-Gammal, A., Abdel-Gawad, A, El-Sherbini, Y, Shalaby, A. (2010), Compressive Strength of Concrete Utilizing Waste Tyre Rubber, Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS)1 (1): 96-99, available at: http://jeteas.scholarlinkresearch.org/articles/Compressive%20Strength%20of%20Concrete%20Utilizing%20Waste%20Tire%20Rubber.pdf (accessed on February 7, 2012) 5. Ganjian, Eshmaiel, MortezaKhorami, Ali Maghsoudi. 2009. “Scrap – Tyre – Rubber Replacement for Aggregate and Filler in Concrete.” Construction and Building Materials 23 (5) 6. Gesoglu, Mehmet, ErhanGuneyisi. 2007. “Strength Development and Chloride Penetration in Rubber Concretes With and Without Silica Fume.” Materials and Structures 40 (9), available at http://www.mendeley.com/research/strength-development-chloride-penetration-rubberized-concretes-without-silica-fume/(accessed on January 19, 2012) 7. Hsu, Thomas, Yi – Ling Mo. (2009). Unified Theory of Concrete Structures. New York: John Wiley and Sons. 8. Mavroulidou, M., Figueiredo, J. (2010), Discarded Tyre Rubber as Concrete Aggregate: A Possible Outlet for Used Tyres, Global Nest Journal, Vol X, No. X, pp XX-XX, available at: https://docs.google.com/viewer?a=v&q=cache:xgqjSXakmV8J:www.gnest.org/journal/Articles_in_press/617_MAVROULIDOU_proof.pdf+Discarded+Tyre+Rubber+as+Concrete+Aggregate:+A+Possible+Outlet+for+Used+Tyres&hl=en&gl=in&pid=bl&srcid=ADGEESgUJMeTthp_SSquxvUfqVH8yEQlOd3Fb0bOfQKff9SKdVss1SgRcWQBe1AQS9Cqc96aiYovgyI-jCvLCopm9Xyk9OtgpYXltTuPo1nqvxeSVljG1CDvyFvk1TIA26KUxkD30KqS&sig=AHIEtbR-_r7DLEwt6PuFkOJvC_X0k7sXSw&pli=1 (accessed on February 7, 2012) 9. Olivares, F, G Barluenga, B Parga – Landa, B Witoszek. 2007. “Fatigue Behaviour of Recycled Tyre Rubber – Filled Concrete and Its Implications in the Design of Rigid Pavements.” Construction and Building Materials 21 (10). 10. Qingyu, Yang. 2007. “Experimental Study on Bending Strength of Crumb Rubber Concrete for Pavement.” Industrial Construction (9), available at http://en.cnki.com.cn/Article_en/CJFDTOTAL-GYJZ200709021.htm(accessed on January 19, 2012) 11. Sang Son, K., Hajirasouliha,I, Pilakoutas, K (2011),“Strength and deformability of waste tyre rubber filled reinforced concrete columns”Elsevier Journal 12. Segre, N, I Joekes. 2000. “Use of Tire Rubber Particles as Addition to Cement Paste.” Cement and Concrete Research 30 (9), available at http://www.sciencedirect.com/science/article/pii/S0008884600003732(accessed on January 19, 2012) 13. Siddique, Rafat, TarunNaik. 2004. “Properties of Concrete Containing Scrap Tire Rubber – An Overview.” Waste Management 24 (6). 14. Snelson, DG, JM Kinuthia, PA Davies, SR Chang. 2009. “Sustainable Construction: Composite Use of Tyres and Ash in Concrete.” Waste Management 29 (1), available at http://www.mendeley.com/research/sustainable-construction-composite-use-of-tyres-and-ash-in-concrete/(accessed on January 19, 2012) 15. Sukontasukkul, Piti. 2009. “Use of Crumb Rubber to Improve Thermal and Sound Properties of Pre – Cast Concrete Panel.” Construction and Building Materials 23 (2), available at http://www.mendeley.com/research/crumb-rubber-improve-thermal-sound-properties-precast-concrete-panel-1/(accessed on January 19, 2012) 16. Topcu, Ilker, TurhanBilir. 2009. “Analysis of Rubberized Concrete as a Three Phase Composite Material.” Journal of Composite Materials 43 (11), available at http://jcm.sagepub.com/content/43/11/1251.abstract(accessed on January 19, 2012) 17. Turatsinze, A, S Bonnet, JL Granju. 2005. “Mechanical Characterization of Cement Based Mortar Incorporating Rubber Aggregates From Recycled Worn Tyres.” Building and Environment 40 (2). 18. Toutanji, H.A (1996), “The Use of Rubber Tyre Particles in Concrete to Replace Mineral Aggregates” Cement and Concrete Composites, Vol 18, No. 2, 135-139, available at: http://www.sciencedirect.com/science/article/pii/0958946595000100 (accessed on February 7, 2012) 19. Zhang, Yong Ming. 2007. “Effect of Crumb Rubber Proportion on Compressive and Flexural Behavior of Concrete.” Journal of Tianjin University (7), available at http://en.cnki.com.cn/Article_en/CJFDTOTAL-TJDX200707003.htm(accessed on January 19, 2012) Read More