* INTRODUCTIONDURABILITY TESTS ON HSC MIX DESIGN-DOE METHOD FIBRE REINFORCED CONCRETE PLANNING OF THE PROJECT

Topics Discussed

*MATERIALS USED IN HIGH STRENGTH CONCRETE

MaterialPrimary Contribution/Desired PropertyPortland cementCementing material / Durabilityblend cementCementing material / Durability / High strengthFly ash / Slag / Silica fumeCalcined clay/ MetakaolinCalcined shaleSuperplasticizersFlowabilityHigh-range water reducersReduce water-cement ratioHydration control admix.Control setting

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Egyptians used straw to reinforce mud bricks,but there is evidence that asbestos fiber was used to reinforce clay posts about 5000 years agoRomualdi and Batson (1963) after conducting impact test on fibre reinforced concrete specimens, they concluded that first crack strength improved by addition of closely spaced continuous steel fibres in it.Sridhara, (1971) carried out experimental investigations to study the blast resistance of concrete,and concluded the increase in impact strength using fibresRajagopalan (1973) developed equations to predict the first crack and ultimate moment of resistance of the beams with steel fibres.*

Data required for concrete mix design Grade of Cement : 53 Grade. Slump required : 50 100mm(medium workability). Type of Exposure : Moderate. Coarse aggregates : m.s.a= 20mm. Fine aggregates : zone-2 ,fines (35-59%).

Final proportions per cubic meter cement :590.91Kg/m3. F.A :597.21Kg/m3. C.A :1016.88Kg/m3. water :195Kg/m3. So final ratio becomesCement : F.A : C.A :water 1 : 1.01 : 1.72 :0.33*

Acid resistance : Hydro chloric acid(HCL) Sulphuric acid(H2SO4*

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*REFERENCESConcrete technology, Shetty.M.S Limit state design of reinforced concrete,VargheseIS 456 (2000)P.K. Mehta and P.J.M. Monteiro, Concrete: Microstructure, Properties, and MaterialsInternational Journal of Modern Engineering Research (IJMER) Vol. 3, Issue. 6, Nov - Dec. 2006Mix Design of Fiber Reinforced Concrete (FRC) Using Slag & Steel FiberInternational journal of scientific and technological research vol.1,issue 4 ,may 2012

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- Improves toughness by allowing the cement to bond to the fibers causing more resistance to damaging loads and more resistant to impact- Plain concrete fails because it is a very brittle and has a low tolerance for deflections. With added fibers the concrete has a greater ability to withstand deflections b/c fibers resist the tensile forces. In result the concrete does not break immediately after the appearance of first crack.- Do to the resistance between fibers and concrete tensile strength is increased. Depends also on the types of fibers used to reinforce. Plastic/glass fibers will not improve that much while certain steel fibers can have a relatively decent improvement on tensile strength. May reduce slab thickness and eliminate use of conventional reinforcement*