Study On Fatigue Property And Equation Of High Performance Concrete With High Propertion Ground Blast Furnace Slag

The bending fatigue performance of high performance concrete with high proportion ground blast furnace slag has been investigated, and the two type proportions of ground slag are 50% and 80%. The effect of different proportion of ground blast furnace slag on the fatigue performance of concrete is studied by using the forecasted results of GM computer application program that crated by the author. Among the experimental results of there mixes of concrete, the fatigue properties of concrete with 80 percentage ground slag is prominent, and that of concrete with 50 percentage ground slag is also better than concrete without ground slag. The fatigue equation and the stress coefficient kf of concrete with high proportion ground slag are been established on three P-S-N curves. Furthermore, the effect of ground slag on concrete fatigue performance is well, which are validated by the fractal theory from six aspects on follows: the fractal dimensions of exterior cracks D1-d, the fractal dimensions of fractured sections D2-d, the proportions of aggregates debongding area to the projected broken surface area, two kinds of fracture energy equations modified by fractal dimension, the brittleness variable R, and the hydration mechanism of ground slag. It is evident that the brittleness of concrete is weaken by mixing the ground slag, therefore, the capability to dissipate the fracture energy and the fatigue life of ground slag concrete is improved. In addition, the size-effect law of fatigue performance of high proportion ground slag concrete is investigated here.It is clear that this study can be referenced by engineering person to compute several parameters and modify the relative criterion, and the broad application of ground blast furnace slag to the engineering concrete can be guided by it.