TA43 :
Thesis > Central Library of Shahrood University > Civil & Architectural Engineering > MSc > 2009
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Abstarct: Reinforced self-Compacting Concrete (RCC) has been used in the construction of conveying water conversion tunnels due to low permeability and durability of RCC in recent decades. The self-compacting concrete is a new type of concrete which has been considered as a great revolution in construction of complicated reinforced concrete structures. This concrete with unique advantages of no need for compacting, ability to flow easily through reinforced net, ability of generating concrete segments with complicated shapes has found special place in building industry.
In the order hand by using different types of fibers such as steel and propylene fibers, the mechanical properties of RCC such as tensile strength, control of cracking, abrasion resistance against impact and no segregation of concrete components have been improved largely.
There are only a few reports for experimental research performed in Iran using self compacting concrete with fibers meanwhile international works mainly limited to the usages of fibers especially steel fibers in normal concrete. Some of new works is the evaluation of the crack width of fiber concrete used in lining of tunnels which carried out by Bernadino et al (2009) in Turin University in Italy and the design of lining tunnels by using fiber concrete by Sorely et al (2005) in Bersha University in Italy.
In this study, a comprehensive set of experiments were designed to investigate the properties of RCC, the effects of using fibers in RCC and to compare the load capacity of FRCC with normal reinforced concrete. The results showed that the relation between compressive strength of 7 and 28 days for self-compacting concrete can be represented as fcu28 =1.6 fcu7. This means that RCC in 7 days obtains 62% of strength of 28 days which can be the effect of super plastezier (10pn) while in normal concrete after 7 days it obtains 70 to 80 percent of strength of 28 days. Other findings were the relation between and the compressive strength of 28 days of standard concrete as follows:
showing an increase of 117% and 6% and 60% in ultimate strength, elasticity modulus and tensile strength of FRCC in compare with those of normal concrete. The improvement in the properties of FRCC attributed to the presence of fibers and reduction in parentage of air in RCC. The results also showed that in the case 10 mm reinforcing bars, adding fibers with 0.1% of cement weight provides the maximum flextural strength and minimum number of cracks.
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