The Behaviors Of Doubly Reinforced High Strength Concrete Beams And Slabs In Bending

Because of its high strength, high workability, high volume stability and high anti-permeability, HSC (high strength concrete) has been widely used throughout the world as a new generation structure material. But due to its low ductility, seldom has it been used in the protective engineering.Here the HSC of SOMPa is achieved through adding super-effective water reducer, fined slag and silicon fume, and decreasing the water/cement ratio. By varying the area (spacing) of tension bars, compressive bars, vertical links and distribution steel and embedding steel fiber and polypropylene fiber we try to improve the behaviors of reinforced high performance concrete one-way spanning slabs in bending, so that its ductility be greater than 5. With the same arrangement of steel the width of bending member is varied to observe the effect of the width/depth ratio on the ultimate compressive strain of concrete. The bending property of HSC structure under blast load is also observed. Throughout all these tests the development of cracks is recorded.The research shows that: 1) the ductility of the HSC bending members constructed is much greater than 5; 2) increasing the vertical links and distribution steel can increase the deflection under ultimate moment; 3) with appropriate compressive bars, vertical links and distribution steel the increase of moment after yield and the decrease of moment under ultimate moment can be ignored, so the ductility of the HSC bending member is much larger; 3) the width/depth ratio of HSC bending member has no obvious effect on the ultimate compressive strain of concrete; 4) the method used here to calculate the deflection is applicable; 5) the location of crack coincides with the location of vertical links and distribution steel; 6)the bending property of the HSC structure under the blast load can meet the demand of protective engineering.