At this research, effects of different main factors on durability of concrete shell structures, such as mosque domes are investigated experimentally. Rebar’s corrosion within concrete maybe the most important factor that leads to a poor concrete especially in terms of its appearance. The most effective factors on cracking of concrete cover, such as cover thickness, size and position of rebar, water on cement ratio (W/C), Porosity and permeability of concrete were evaluated at this paper. Concrete mixes in different three W/C ratios with three maximum sizes of aggregates and also with three different thicknesses of concrete covers were tested. The results show that required corrosion that results in cracks in concrete cover is increased by increase in W/C ratio. It has been found that corrosion value is mainly related to the porosity of concrete and is not so sensitive to the concrete’s strength class. In addition to the quality and performance of concrete, special attentions should be considered about the quality of placing concrete cover on rebar to increase the durability of concrete cover against corrosion.
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