الفهرس 
Chapter 1 : IntroductionOnly 14 pages are availabe for public view
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Abstract
High-density(heavy weight) concrete has a density more than 3500 kg/m3. Heavy weight concrete is employed for radiation shielding but is also used for counter weights and other applications where high density is very important. Heavy weight concrete protects against the harmful effects of x-rays. Gama rays, and neutron radiation. Choice of constituents of concrete for radiation shielding is based on space requirements, the type and intensity of radiation. Type and intensity of radiation usually determine the requirements for density and water content of shielding concrete. Effectiveness of a concrete shield against gamma rays is approximately proportion to the density of the concrete; the heavier the concrete; the more effective the shield. On the other hand, an effective shield against neutron radiation requires both heavy and high light elements. The hydrogen in water provides an effective light element in concrete shields. Some aggregates contain crystallized water called fixed water, as a part of their structure. For this reason. Heavy weight aggregates with high fixed-water contents often are used if both gamma rays and neutron radiation are to be attenuated. The research reported in this thesis has the main objectives:- To investigate experimentally ferrocement box beams reinforced with welded metal mesh expanded metal mesh, welded steel mesh and polypropylene fibers for durability reason. The box beams were filled with different types of core materials such as by product materials produced from iron industry at El- Tebbin, Helwan, Cairo. Heavy weight concrete employing basalt and air cold slag aggregates. The flexural behaviors of twelve reinforced beams having the dimensions of 100mmx200mmx1700mm, span 1600mm and were subjected to four line loadings until failure and cracking patterns were determined extensively. An analytical model based on the ultimate strength theory suitable for mathematical calculations was developed to determine the ultimate strength and mode of failure of the developed beams. There was a good agreement between the results obtained from these theoretical models and their respective experimental results. This agreement verifies the validity of the model for determining ultimate strength of the proposed heavy weight concrete beams.