An Experimental Study On Unbonded Prestressed Composite Beams With Reaction Powder Concrete

Reaction powder concrete has a lot of excellent mechanics properties.In this thesis,it was applied in three unbonded prestressed composite beams.The performance of these beams are studied. The prime works are as follows:Strain and stress distribution of section was analyzed. The effect of prestress degree . on cracking moment was explored.The relation of the unbonded prestress increment to effective reinforcement index and corresponding bonded prestress increment were studied.The formulae had been established.The connection of effective reinforcement index and cracking moment upon the stiffness and deflection had been obtained.The calculating results agree well with the experimental datum.Two types of the equivalent mode of concrete compression zone were discussed and the corresponding formulae to calculate normal section strength of unbonded prestressed composite beams with reaction powder concrete were given.The calculating results tend to be conservative.Additional research work on the behavior of shear characteristics had been carried out. Though the tested beams had no stirrups,they possess fine mechanical properties and high shear capacity.A 21 meter span unbonded prestressed composite beam fabricated from reactive powder concrete (RFC) was designed .Then the performance and economy of this kind of beams were compared with conventional prestressed beams and steel-concrete composited beams.The results indicated that RFC beams have superior performance.The research in this paper indicated that reaction powder concrete will have a wide applied prospect.