Installation Guild for Engineering Fiber
Structure Design
Despite of the more improved properties of the fiber concrete, the fiber generally still serves as the minor reinforced bar to prevent the concrete from cracking and shrinking and prolong its life span rather than major reinforced bar to bear the load of the structure. A number of experiences have proved that the great increasing number of the fiber monofilament with the scattered polypropylene fiber-mesh has no evident effect on the design parameters like the intensity and elastic modulus, because 0.9kg/m3-1.8kg fiber is only converted into 0.1%-0.2% of the volume in per cubic meter of concrete. It is suggested that the ratio of the main reinforced bars remains the same as the original design.
Length
Generally, the proper length of the fiber added into the concrete is 20mm, and in the spray concrete is 10mm.
Ratio Design
Usually the proper amount of fiber to concrete is 0.9kg/m3, and the water-proof layer of the bridge requires 1.35-1.8kg/m3, and the spray concrete in the tunnel is also the same and other materials remain the same. The ratio of fiber and concrete can be determined by tests for special purposes. The fiber has better effects on the concrete with active compound materials, such as silicon ash, coal powder, ground slag and zeolite powder.
Mixer Adoption
Double-axle horizontal compelling mixer is better and self-dropping cylinder mixer can be used, too.
Mixing Process
Crushed stones, fibers and sands are put into the mixer in succession. After stirring for two minutes, fiber will fully spread and then add cement and water and stir normally. The addition of materials also can be put into as usual, but the stirring time should be properly prolonged to make fiber completely mixed.
Stirring Time
The purpose of the stirring is to make fiber fully spread into monofilament or the net fully spread, so generally the stirring time is 2-3 minutes after the addition of polypropylene fiber-mesh.
Shaping Process
There is no special requirement, but full solidification of the concrete should be guaranteed.
Maintenance Process
There is no special requirement. The maintenance of the fiber concrete can be done normally, and its early maintenance is needed.
Endurance
Any organic materials will get aging and lose their superior property under the integrative influence of heat, light and oxygen, but Fiber-mesh hasn't these influence because it is completely protected inside the concrete.