The application of Ewende micro silica powder (silica fume) in railroad mainly includes the following aspects:
Railway tunnel engineering:
– Sprayed concrete: In the initial support of the tunnel, sprayed concrete is a common construction method. The addition of silica fume can significantly improve the strength, bonding and impermeability of shotcrete, reduce the amount of concrete rebound, and reduce construction costs. Silica fume can fill the pores in the concrete, make the concrete structure more dense, enhance its ability to support the tunnel surrounding rock, to protect the safety and stability of tunnel construction. For example, Norway, Sweden and other Nordic countries in the construction of railroad tunnels, a large number of the use of spray concrete mixed with silica fume.
– Lining concrete: The secondary lining of the tunnel is an important structure to ensure the long-term stability and safety of the tunnel. Silica fume can improve the performance of lining concrete, increase its compressive strength, crack resistance and durability, and extend the service life of the tunnel. The application of micro silica powder is especially important in some railroad tunnel projects with complex geological conditions and high requirements on tunnel structure.
Railway bridge project:
– High-performance concrete: Railway bridges have high requirements on the strength, durability and fatigue resistance of concrete. Silica fume is mixed into the concrete, which can formulate high-performance concrete to meet the needs of the construction of railroad bridges. Micro silica powder can react with the hydration products of cement to generate high-strength calcium silicate gel, which improves the strength and durability of concrete. At the same time, micro silica powder can also reduce the permeability of concrete, reduce the intrusion of moisture and harmful substances, and extend the service life of the bridge.
– Prestressed concrete: In prestressed concrete bridges, micro silica powder can improve the early strength and modulus of elasticity of concrete, so that the prestressing steel reinforcement can work better, and improve the load-bearing capacity and deformation resistance of the bridge. In addition, micro silica powder can also reduce the shrinkage and creep of prestressed concrete, reduce the loss of prestressing force, and ensure the construction quality of the bridge.
Railway track engineering:
– Ballastless track: Ballastless track is a new type of railroad track structure, which has the advantages of good stability, high smoothness and small maintenance workload. Micro silica powder can be used in the concrete bed of ballastless track to improve the strength and durability of the bed and reduce the cracks and deformation of the bed. At the same time, micro-silica powder can also improve the workability of the concrete bed, which is convenient for construction and pouring.
– Turnout: Turnout is an important part of the railroad track, its structure is complex, the performance requirements of the material is high. Micro silica powder can be used in the concrete foundation and mat of turnout to improve its strength and durability and ensure the normal use of turnout.
Railway roadbed engineering:
– Improved roadbed filler: Under some special geological conditions, such as soft ground and loess areas, the stability and bearing capacity of railroad roadbed may be affected. After mixing micro silica powder with other materials (such as cement, lime, etc.), it can be used to improve the filler of roadbed, improve the strength and stability of roadbed, and reduce the settlement and deformation of roadbed.
– Roadbed slope protection: micro silica powder can be used in shotcrete protection of roadbed slopes to improve the stability and anti-scouring ability of slopes, and prevent geological disasters such as slope collapse and landslide.
