Lashmipriya.s

5090

RAILWAY APPLICATIONS - CASE STUDY 
ABSTRCT: The development and success of railways in Bangladesh demands the variety of materials with diverse nature for day to day operations. In the research study, the materials being used by Bangladesh Railway and the assessment of the material quality of existing rail track with the newly constructed rail track have been portrayed elaborately. Moreover, the study illustrates the comparison between railway materials being used around the world and the materials being used in Bangladesh. All size, weight, property and specification are according to the American Standard. This study on material may be limited but it indicates remarkable development, modification and modernization of Bangladesh Railway projects.  
High alumina cement:          High alumina cement is composed of calcium aluminates, unlike Portland cement which is composed of calcium silicates. It is manufactured from limestone or chalk and bauxite. Uses: It is used widely in precasting. Corrosion protection of reinforcement in modified high-alumina.    

Alkali aggregate reaction:             AAR is a chemical reaction of alkali in concrete and certain alkaline reactive minerals in aggregate producing a hygroscopic gel which, when moisture present, absorbs water and expand. Gel expansion causes cracking in the concrete. 

Water cement ratio:            Water is added in concrete for mainly two purposes: Hydration of cement -0.38 to 0.4% Workability of concrete– 0.4 to 0.6% The water cement ratio is the ratio of the weight of water to the weight of cement used in a concrete mix. A lower ratio leads to higher strength and durability, but may make the mix difficult to work with and form. Workability can be resolved with the use of plasticizers or super plasticizers.