Load-bearing capabilities
In construction, microfibres are used to control plastic shrinkage and improve early-age durability, while macrofibres provide structural reinforcement, enhance post-crack toughness, and can replace rebar in certain applications.
The primary difference is size, which dictates function: microfibres are for early, non-structural crack control, whereas macrofibres are for load-bearing applications and long-term structural integrity.
Microfibres:
- Purpose: Primarily to control plastic shrinkage cracks during the early stages of concrete curing.
- Function: They act as a secondary reinforcement to prevent the formation of early-age micro-cracks, leading to improved durability and aesthetics.
- Benefits: Reduce early cracking, improve durability, and enhance surface finish.
- Limitations: Does not provide significant load-bearing capabilities, so they cannot replace traditional structural reinforcement.
Macrofibres:
- Purpose: To provide structural reinforcement and carry load, working as a secondary reinforcement to minimize early and late-stage cracking.
- Function: They enhance concrete’s post-crack residual strength, toughness, durability, and resistance to impacts and fatigue. They can also serve as a replacement for certain sizes of traditional rebar.
- Benefits: Improve structural capacity, provide protection against post-cracking, offer durability, and can be easier to use than steel reinforcement.
- Applications: Used in infrastructure projects like bridges and foundations, in shotcrete and for residential and commercial slabs on ground.
Combining Both:
In some cases, macro- and microfibres are blended to provide comprehensive concrete reinforcement, controlling both early and later-stage cracking while also offering structural benefits.