What Is The Role Of Micro Silica (Silica Fume) In UHPC?

Ewende Silica fume plays the following important roles in UHPC (Ultra High Performance Concrete):

I. Strengthening

1. Strength improvement: Micro silica fume has very high activity, which can react with calcium hydroxide produced by hydration of cement to generate calcium silicate gel, which fills in the pores of concrete and makes concrete more compact, thus significantly improving the strength of concrete, especially the early strength.

2. Improvement of durability: Due to its filling effect, it reduces the pores and micro-cracks in the concrete, lowers the infiltration channels of harmful substances, and improves the durability indexes of UHPC such as impermeability, freezing resistance, and chemical erosion resistance.

II. Optimize working performance

1. Improve the fluidity: micro-silica powder can improve the rheological properties of UHPC, so that it has better fluidity and filling in the process of mixing and pouring, which is convenient for construction operation.

2. Reduce water secretion: Reduce the water secretion rate of concrete, make the surface of concrete smoother and flatter, and improve the appearance quality of concrete.

III. Synergistic effect with other materials

1. synergistic with fiber: in UHPC will usually join the steel fiber and other reinforcing materials, silica fume can be better combined with the fiber to improve the bond between the fiber and the concrete matrix, thus giving full play to the reinforcing effect of the fiber. 2. synergistic with additives: to improve the bond between the fiber and the concrete matrix, thus giving full play to the fiber.

2. Synergy with additives: synergy with water reducing agents and other additives to improve the efficiency of the additives to further optimize the performance of UHPC.