Study On The Mechanical Properties Of Fiber Reinforced Granulated Blast Furnace Slag Concrete In High Temperature

With the acceleration of urbanization, more and more the factors cause building fire. The problem of building structure fire is becoming increasingly conspicuous. High temperature performance of the structure materials is receiving more and more attention. With the development of application technology of concrete, high strength concrete (HSC) is more and more widely used in engineering structures. However, higher brittleness and lower fire resistance have been the main obstacles of further development of HSC.As a kind of high performance concrete (HPC), granulated blast furnace slag concrete has favorable workability, mechanical properties and durability. The addition of fibers is a good way to use the modifying mechanism of fiber to improve the high temperature performance of concrete. Through the addition of the hybrid fibers (steel fiber and polypropylene fiber) to the granulated blast furnace slag concrete, a new fiber reinforced high performance concrete named fiber reinforced granulated blast furnace slag concrete is produced in this study. Through the mechanical properties tests of fiber reinforced granulated blast furnace slag concrete in high temperature, the influences of temperature, replacement rate of cement by slag powder, steel fiber content, PP fiber content, base strength grade on the mechanical properties of concrete are analyzed, the calculation formulas of strength are established.(1) The research of the high temperature performance of concrete especially HPC in recent years are reviewed. The deterioration mechanics of the performance of concrete in high temperature is explained.(2) The influences of steel fiber and PP fiber on the burst of fiber reinforced granulated blast furnace slag concrete in high temperature are analyzed. The results show that burst of granulated blast furnace slag concrete will happen in high temperature. The addition of PP fiber can effectively prevent granulated blast furnace slag concrete from burst. The addition of steel fiber can not prevent burst, but it improves the temperature when the burst happening.(3) Though measuring the compressive strength, splitting tensile strength, bending strength in high temperature, the influences of temperature, replacement rate of cement by slag powder, steel fiber content, PP fiber content, base strength grade on the strength are analyzed. It is found that the higher the temperature is, the more serious the deterioration of the strength of concrete. The addition of steel fiber can increase the strength of fiber reinforced granulated blast furnace slag concrete in high temperature.(4) Though measuring the compressive deformation of prisms, splitting tensile deformation of cubic, it gets the compressive loading—deformation curve and splitting loading—deformation curve. It is found that the higher the temperature is, the loading—deformation curve is more lichen and the peak point resulted in right shift. The addition of steel fiber can increase the deformability of fiber reinforced granulated blast furnace slag concrete in high temperature, the more the steel fiber content is, the better the deformability and the ability of energy absorption of concrete 1s.(5) Though comparing the differences between normal and high temperature performance of fiber reinforced granulated blast furnace slag concrete, the deterioration mechanics of the properties of fiber reinforced granulated blast furnace slag concrete in high temperature is further analyzed.(6) Based on the experimental data and the statistical analysis, the calculation formulas of the compressive strength, splitting tensile strength and bending strength of fiber reinforced granulated blast furnace slag concrete which concerns with the effect of temperature and mixing amount of steel fiber are put forward.