Research Of The Flexural Performance Of Reinforced Reinforced Concrete Beam Partly With S-P Hybrid Fibers

With the building becoming high,long span,heavy load and lightweight ,cement concrete which is widly used material has developed to high toughness ,high,high Volume stability and high durability, and how to improve the toughness and the cracking- resistance is key technology.According to the problems of fiber reinforced concrete application in steel reinforced beams,this work , sustaind by the project subsidized by JiangXi Province Natural Science Foundation.( NO.0650013)-"The research of part high density hybrid fibers self-stress reinforced high performance concrete, recearched the effect of the ratio and enhanced pattern of hybrid fibers on the flexural performance of reinforced concrete beam, including the cracking load, limit load and stiffness. The mainly work and results is as followed:(1) A concept"part high density"has been put forward, the design manage of hybrid fibers part reinforced reinforced concrete beam has also been established and some technology will be applied for the application of fiber reinforced concrete in reinforced beams.(2) The effect of S-P hybrid fibers on the working performance , compression strength and tensile strength was studied.(3)The effect of the ratio and enhanced pattern of hybrid fibers on the flexural performance of reinforced concrete beam, including the cracking load, limit load and stiffness.(4) Based on the plane section assumption,selceted right limit load formula and cracking load formula for S-P hybrid fibers reinforced concrete beam, and compared the results with the experimental results, the theory shows a good agreement except the limit load.Based on the beam test of 15 reinforced concrete beams, it is showed that the cracking load and bending rigidity of beam can be improved obvioursly in the low rate of reinforcement by steel and polyacrylonitril hybrid fibers, and limit load can also be improved on a certain degree ,especially the improvement of S-P hybrid fibers with high steel ratio is the most obvious. Although S-P hybrid fibers partly enhanced pattern can't improve the limit load obviously ,it can improve the cracking load obviously and appears to be more cost-effective.